This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
running mktables on VMS
[perl5.git] / pp_pack.c
index b653362..427269f 100644 (file)
--- a/pp_pack.c
+++ b/pp_pack.c
@@ -1,6 +1,7 @@
 /*    pp_pack.c
  *
- *    Copyright (c) 1991-2002, Larry Wall
+ *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+ *    2000, 2001, 2002, 2003, 2004, by Larry Wall and others
  *
  *    You may distribute under the terms of either the GNU General Public
  *    License or the Artistic License, as specified in the README file.
  * some salt.
  */
 
+/* This file contains pp ("push/pop") functions that
+ * execute the opcodes that make up a perl program. A typical pp function
+ * expects to find its arguments on the stack, and usually pushes its
+ * results onto the stack, hence the 'pp' terminology. Each OP structure
+ * contains a pointer to the relevant pp_foo() function.
+ *
+ * This particular file just contains pp_pack() and pp_unpack(). See the
+ * other pp*.c files for the rest of the pp_ functions.
+ */
+
+
 #include "EXTERN.h"
 #define PERL_IN_PP_PACK_C
 #include "perl.h"
 
 /*
- * The compiler on Concurrent CX/UX systems has a subtle bug which only
- * seems to show up when compiling pp.c - it generates the wrong double
- * precision constant value for (double)UV_MAX when used inline in the body
- * of the code below, so this makes a static variable up front (which the
- * compiler seems to get correct) and uses it in place of UV_MAX below.
- */
-#ifdef CXUX_BROKEN_CONSTANT_CONVERT
-static double UV_MAX_cxux = ((double)UV_MAX);
-#endif
-
-/*
  * Offset for integer pack/unpack.
  *
  * On architectures where I16 and I32 aren't really 16 and 32 bits,
@@ -54,16 +55,12 @@ static double UV_MAX_cxux = ((double)UV_MAX);
 /* CROSSCOMPILE and MULTIARCH are going to affect pp_pack() and pp_unpack().
    --jhi Feb 1999 */
 
-#if SHORTSIZE != SIZE16 || LONGSIZE != SIZE32
-#   define PERL_NATINT_PACK
-#endif
-
-#if LONGSIZE > 4 && defined(_CRAY)
-#  if BYTEORDER == 0x12345678
+#if U16SIZE > SIZE16 || U32SIZE > SIZE32
+#  if BYTEORDER == 0x1234 || BYTEORDER == 0x12345678    /* little-endian */
 #    define OFF16(p)   (char*)(p)
 #    define OFF32(p)   (char*)(p)
 #  else
-#    if BYTEORDER == 0x87654321
+#    if BYTEORDER == 0x4321 || BYTEORDER == 0x87654321  /* big-endian */
 #      define OFF16(p) ((char*)(p) + (sizeof(U16) - SIZE16))
 #      define OFF32(p) ((char*)(p) + (sizeof(U32) - SIZE32))
 #    else
@@ -83,6 +80,16 @@ static double UV_MAX_cxux = ((double)UV_MAX);
 #  define CAT32(sv,p)  sv_catpvn(sv, (char*)(p), SIZE32)
 #endif
 
+/* Avoid stack overflow due to pathological templates. 100 should be plenty. */
+#define MAX_SUB_TEMPLATE_LEVEL 100
+
+/* flags (note that type modifiers can also be used as flags!) */
+#define FLAG_UNPACK_ONLY_ONE  0x10
+#define FLAG_UNPACK_DO_UTF8   0x08
+#define FLAG_SLASH            0x04
+#define FLAG_COMMA            0x02
+#define FLAG_PACK             0x01
+
 STATIC SV *
 S_mul128(pTHX_ SV *sv, U8 m)
 {
@@ -104,8 +111,8 @@ S_mul128(pTHX_ SV *sv, U8 m)
     t--;
   while (t > s) {
     i = ((*t - '0') << 7) + m;
-    *(t--) = '0' + (i % 10);
-    m = i / 10;
+    *(t--) = '0' + (char)(i % 10);
+    m = (char)(i / 10);
   }
   return (sv);
 }
@@ -123,114 +130,166 @@ S_mul128(pTHX_ SV *sv, U8 m)
 #define ISUUCHAR(ch)    (memchr(PL_uuemap, (ch), sizeof(PL_uuemap)-1) || (ch) == ' ')
 #endif
 
-#define UNPACK_ONLY_ONE        0x1
-#define UNPACK_DO_UTF8 0x2
-
-STATIC char *
-S_group_end(pTHX_ register char *pat, register char *patend, char ender)
-{
-    while (pat < patend) {
-       char c = *pat++;
-
-       if (isSPACE(c))
-           continue;
-       else if (c == ender)
-           return --pat;
-       else if (c == '#') {
-           while (pat < patend && *pat != '\n')
-               pat++;
-           continue;
-       } else if (c == '(')
-           pat = group_end(pat, patend, ')') + 1;
-       else if (c == '[')
-           pat = group_end(pat, patend, ']') + 1;
-    }
-    Perl_croak(aTHX_ "No group ending character `%c' found", ender);
-    return 0;
-}
-
+/* type modifiers */
 #define TYPE_IS_SHRIEKING      0x100
+#define TYPE_IS_BIG_ENDIAN     0x200
+#define TYPE_IS_LITTLE_ENDIAN  0x400
+#define TYPE_ENDIANNESS_MASK   (TYPE_IS_BIG_ENDIAN|TYPE_IS_LITTLE_ENDIAN)
+#define TYPE_ENDIANNESS(t)     ((t) & TYPE_ENDIANNESS_MASK)
+#define TYPE_NO_ENDIANNESS(t)  ((t) & ~TYPE_ENDIANNESS_MASK)
+#define TYPE_MODIFIERS(t)      ((t) & ~0xFF)
+#define TYPE_NO_MODIFIERS(t)   ((t) & 0xFF)
+
+#define ENDIANNESS_ALLOWED_TYPES   "sSiIlLqQjJfFdDpP("
+
+#define DO_BO_UNPACK(var, type)                                               \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+            case TYPE_IS_BIG_ENDIAN:    var = my_betoh ## type (var); break;  \
+            case TYPE_IS_LITTLE_ENDIAN: var = my_letoh ## type (var); break;  \
+            default: break;                                                   \
+          }                                                                   \
+        } STMT_END
+
+#define DO_BO_PACK(var, type)                                                 \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+            case TYPE_IS_BIG_ENDIAN:    var = my_htobe ## type (var); break;  \
+            case TYPE_IS_LITTLE_ENDIAN: var = my_htole ## type (var); break;  \
+            default: break;                                                   \
+          }                                                                   \
+        } STMT_END
+
+#define DO_BO_UNPACK_PTR(var, type, pre_cast)                                 \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+            case TYPE_IS_BIG_ENDIAN:                                          \
+              var = (void *) my_betoh ## type ((pre_cast) var);               \
+              break;                                                          \
+            case TYPE_IS_LITTLE_ENDIAN:                                       \
+              var = (void *) my_letoh ## type ((pre_cast) var);               \
+              break;                                                          \
+            default:                                                          \
+              break;                                                          \
+          }                                                                   \
+        } STMT_END
+
+#define DO_BO_PACK_PTR(var, type, pre_cast)                                   \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+            case TYPE_IS_BIG_ENDIAN:                                          \
+              var = (void *) my_htobe ## type ((pre_cast) var);               \
+              break;                                                          \
+            case TYPE_IS_LITTLE_ENDIAN:                                       \
+              var = (void *) my_htole ## type ((pre_cast) var);               \
+              break;                                                          \
+            default:                                                          \
+              break;                                                          \
+          }                                                                   \
+        } STMT_END
+
+#define BO_CANT_DOIT(action, type)                                            \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+             case TYPE_IS_BIG_ENDIAN:                                         \
+               Perl_croak(aTHX_ "Can't %s big-endian %ss on this "            \
+                                "platform", #action, #type);                  \
+               break;                                                         \
+             case TYPE_IS_LITTLE_ENDIAN:                                      \
+               Perl_croak(aTHX_ "Can't %s little-endian %ss on this "         \
+                                "platform", #action, #type);                  \
+               break;                                                         \
+             default:                                                         \
+               break;                                                         \
+           }                                                                  \
+         } STMT_END
+
+#if PTRSIZE == INTSIZE
+# define DO_BO_UNPACK_P(var)   DO_BO_UNPACK_PTR(var, i, int)
+# define DO_BO_PACK_P(var)     DO_BO_PACK_PTR(var, i, int)
+#elif PTRSIZE == LONGSIZE
+# define DO_BO_UNPACK_P(var)   DO_BO_UNPACK_PTR(var, l, long)
+# define DO_BO_PACK_P(var)     DO_BO_PACK_PTR(var, l, long)
+#else
+# define DO_BO_UNPACK_P(var)   BO_CANT_DOIT(unpack, pointer)
+# define DO_BO_PACK_P(var)     BO_CANT_DOIT(pack, pointer)
+#endif
+
+#if defined(my_htolen) && defined(my_letohn) && \
+    defined(my_htoben) && defined(my_betohn)
+# define DO_BO_UNPACK_N(var, type)                                            \
+         STMT_START {                                                         \
+           switch (TYPE_ENDIANNESS(datumtype)) {                              \
+             case TYPE_IS_BIG_ENDIAN:    my_betohn(&var, sizeof(type)); break;\
+             case TYPE_IS_LITTLE_ENDIAN: my_letohn(&var, sizeof(type)); break;\
+             default: break;                                                  \
+           }                                                                  \
+         } STMT_END
+
+# define DO_BO_PACK_N(var, type)                                              \
+         STMT_START {                                                         \
+           switch (TYPE_ENDIANNESS(datumtype)) {                              \
+             case TYPE_IS_BIG_ENDIAN:    my_htoben(&var, sizeof(type)); break;\
+             case TYPE_IS_LITTLE_ENDIAN: my_htolen(&var, sizeof(type)); break;\
+             default: break;                                                  \
+           }                                                                  \
+         } STMT_END
+#else
+# define DO_BO_UNPACK_N(var, type)     BO_CANT_DOIT(unpack, type)
+# define DO_BO_PACK_N(var, type)       BO_CANT_DOIT(pack, type)
+#endif
 
 /* Returns the sizeof() struct described by pat */
 STATIC I32
-S_measure_struct(pTHX_ char *pat, register char *patend)
+S_measure_struct(pTHX_ register tempsym_t* symptr)
 {
-    I32 datumtype;
-    register I32 len;
+    register I32 len = 0;
     register I32 total = 0;
-    int commas = 0;
-    int star;          /* 1 if count is *, -1 if no count given, -2 for / */
-#ifdef PERL_NATINT_PACK
-    int natint;                /* native integer */
-    int unatint;       /* unsigned native integer */
-#endif
-    char buf[2];
+    int star;
+
     register int size;
 
-    while ((pat = next_symbol(pat, patend)) < patend) {
-       datumtype = *pat++ & 0xFF;
-#ifdef PERL_NATINT_PACK
-       natint = 0;
-#endif
-       if (*pat == '!') {
-           static const char *natstr = "sSiIlLxX";
+    while (next_symbol(symptr)) {
 
-           if (strchr(natstr, datumtype)) {
-               if (datumtype == 'x' || datumtype == 'X') {
-                   datumtype |= TYPE_IS_SHRIEKING;
-               } else {                /* XXXX Should be redone similarly! */
-#ifdef PERL_NATINT_PACK
-                   natint = 1;
-#endif
-               }
-               pat++;
-           }
-           else
-               Perl_croak(aTHX_ "'!' allowed only after types %s", natstr);
-       }
-       len = find_count(&pat, patend, &star);
-       if (star > 0)                   /*  */
-               Perl_croak(aTHX_ "%s not allowed in length fields", "count *");
-       else if (star < 0)              /* No explicit len */
-               len = datumtype != '@';
+        switch( symptr->howlen ){
+        case e_no_len:
+       case e_number:
+           len = symptr->length;
+           break;
+        case e_star:
+           Perl_croak(aTHX_ "Within []-length '*' not allowed in %s",
+                       symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+            break;
+        }
 
-       switch(datumtype) {
+        /* endianness doesn't influence the size of a type */
+       switch(TYPE_NO_ENDIANNESS(symptr->code)) {
        default:
-           Perl_croak(aTHX_ "Invalid type in unpack: '%c'", (int)datumtype);
+            Perl_croak(aTHX_ "Invalid type '%c' in %s",
+                       (int)TYPE_NO_MODIFIERS(symptr->code),
+                       symptr->flags & FLAG_PACK ? "pack" : "unpack" );
        case '@':
        case '/':
        case 'U':                       /* XXXX Is it correct? */
        case 'w':
        case 'u':
-           buf[0] = datumtype;
-           buf[1] = 0;
-           Perl_croak(aTHX_ "%s not allowed in length fields", buf);
-       case ',': /* grandfather in commas but with a warning */
-           if (commas++ == 0 && ckWARN(WARN_UNPACK))
-               Perl_warner(aTHX_ packWARN(WARN_UNPACK),
-                           "Invalid type in unpack: '%c'", (int)datumtype);
-           /* FALL THROUGH */
+           Perl_croak(aTHX_ "Within []-length '%c' not allowed in %s",
+                       (int)symptr->code,
+                       symptr->flags & FLAG_PACK ? "pack" : "unpack" );
        case '%':
            size = 0;
            break;
        case '(':
        {
-           char *beg = pat, *end;
-
-           if (star >= 0)
-               Perl_croak(aTHX_ "()-group starts with a count");
-           end = group_end(beg, patend, ')');
-           pat = end + 1;
-           len = find_count(&pat, patend, &star);
-           if (star < 0)               /* No count */
-               len = 1;
-           else if (star > 0)  /* Star */
-               Perl_croak(aTHX_ "%s not allowed in length fields", "count *");
+            tempsym_t savsym = *symptr;
+           symptr->patptr = savsym.grpbeg;
+            symptr->patend = savsym.grpend;
            /* XXXX Theoretically, we need to measure many times at different
               positions, since the subexpression may contain
               alignment commands, but be not of aligned length.
               Need to detect this and croak().  */
-           size = measure_struct(beg, end);
+           size = measure_struct(symptr);
+            *symptr = savsym;
            break;
        }
        case 'X' | TYPE_IS_SHRIEKING:
@@ -242,7 +301,8 @@ S_measure_struct(pTHX_ char *pat, register char *patend)
        case 'X':
            size = -1;
            if (total < len)
-               Perl_croak(aTHX_ "X outside of string");
+               Perl_croak(aTHX_ "'X' outside of string in %s",
+                          symptr->flags & FLAG_PACK ? "pack" : "unpack" );
            break;
        case 'x' | TYPE_IS_SHRIEKING:
            if (!len)                   /* Avoid division by 0 */
@@ -271,26 +331,35 @@ S_measure_struct(pTHX_ char *pat, register char *patend)
            len = (len + 1)/2;
            size = 1;
            break;
+       case 's' | TYPE_IS_SHRIEKING:
+#if SHORTSIZE != SIZE16
+           size = sizeof(short);
+           break;
+#else
+            /* FALL THROUGH */
+#endif
        case 's':
-#if SHORTSIZE == SIZE16
            size = SIZE16;
+           break;
+       case 'S' | TYPE_IS_SHRIEKING:
+#if SHORTSIZE != SIZE16
+           size = sizeof(unsigned short);
+           break;
 #else
-           size = (natint ? sizeof(short) : SIZE16);
+            /* FALL THROUGH */
 #endif
-           break;
+       case 'v' | TYPE_IS_SHRIEKING:
+       case 'n' | TYPE_IS_SHRIEKING:
        case 'v':
        case 'n':
        case 'S':
-#if SHORTSIZE == SIZE16
            size = SIZE16;
-#else
-           unatint = natint && datumtype == 'S';
-           size = (unatint ? sizeof(unsigned short) : SIZE16);
-#endif
            break;
+       case 'i' | TYPE_IS_SHRIEKING:
        case 'i':
            size = sizeof(int);
            break;
+       case 'I' | TYPE_IS_SHRIEKING:
        case 'I':
            size = sizeof(unsigned int);
            break;
@@ -300,22 +369,29 @@ S_measure_struct(pTHX_ char *pat, register char *patend)
        case 'J':
            size = UVSIZE;
            break;
+       case 'l' | TYPE_IS_SHRIEKING:
+#if LONGSIZE != SIZE32
+           size = sizeof(long);
+            break;
+#else
+            /* FALL THROUGH */
+#endif
        case 'l':
-#if LONGSIZE == SIZE32
            size = SIZE32;
+           break;
+       case 'L' | TYPE_IS_SHRIEKING:
+#if LONGSIZE != SIZE32
+           size = sizeof(unsigned long);
+           break;
 #else
-           size = (natint ? sizeof(long) : SIZE32);
+            /* FALL THROUGH */
 #endif
-           break;
+       case 'V' | TYPE_IS_SHRIEKING:
+       case 'N' | TYPE_IS_SHRIEKING:
        case 'V':
        case 'N':
        case 'L':
-#if LONGSIZE == SIZE32
            size = SIZE32;
-#else
-           unatint = natint && datumtype == 'L';
-           size = (unatint ? sizeof(unsigned long) : SIZE32);
-#endif
            break;
        case 'P':
            len = 1;
@@ -351,160 +427,343 @@ S_measure_struct(pTHX_ char *pat, register char *patend)
     return total;
 }
 
-/* Returns -1 on no count or on star */
-STATIC I32
-S_find_count(pTHX_ char **ppat, register char *patend, int *star)
+
+/* locate matching closing parenthesis or bracket
+ * returns char pointer to char after match, or NULL
+ */
+STATIC char *
+S_group_end(pTHX_ register char *patptr, register char *patend, char ender)
 {
-    char *pat = *ppat;
-    I32 len;
-
-    *star = 0;
-    if (pat >= patend)
-       len = 1;
-    else if (*pat == '*') {
-       pat++;
-       *star = 1;
-       len = -1;
-    }
-    else if (isDIGIT(*pat)) {
-       len = *pat++ - '0';
-       while (isDIGIT(*pat)) {
-           len = (len * 10) + (*pat++ - '0');
-           if (len < 0)                /* 50% chance of catching... */
-               Perl_croak(aTHX_ "Repeat count in pack/unpack overflows");
-       }
-    }
-    else if (*pat == '[') {
-       char *end = group_end(++pat, patend, ']');
-
-       len = 0;
-       *ppat = end + 1;
-       if (isDIGIT(*pat))
-           return find_count(&pat, end, star);
-       return measure_struct(pat, end);
+    while (patptr < patend) {
+       char c = *patptr++;
+
+       if (isSPACE(c))
+           continue;
+       else if (c == ender)
+           return patptr-1;
+       else if (c == '#') {
+           while (patptr < patend && *patptr != '\n')
+               patptr++;
+           continue;
+       } else if (c == '(')
+           patptr = group_end(patptr, patend, ')') + 1;
+       else if (c == '[')
+           patptr = group_end(patptr, patend, ']') + 1;
     }
-    else
-       len = *star = -1;
-    *ppat = pat;
-    return len;
+    Perl_croak(aTHX_ "No group ending character '%c' found in template",
+               ender);
+    return 0;
 }
 
+
+/* Convert unsigned decimal number to binary.
+ * Expects a pointer to the first digit and address of length variable
+ * Advances char pointer to 1st non-digit char and returns number
+ */ 
 STATIC char *
-S_next_symbol(pTHX_ register char *pat, register char *patend)
+S_get_num(pTHX_ register char *patptr, I32 *lenptr )
+{
+  I32 len = *patptr++ - '0';
+  while (isDIGIT(*patptr)) {
+    if (len >= 0x7FFFFFFF/10)
+      Perl_croak(aTHX_ "pack/unpack repeat count overflow");
+    len = (len * 10) + (*patptr++ - '0');
+  }
+  *lenptr = len;
+  return patptr;
+}
+
+/* The marvellous template parsing routine: Using state stored in *symptr,
+ * locates next template code and count
+ */
+STATIC bool
+S_next_symbol(pTHX_ register tempsym_t* symptr )
 {
-    while (pat < patend) {
-       if (isSPACE(*pat))
-           pat++;
-       else if (*pat == '#') {
-           pat++;
-           while (pat < patend && *pat != '\n')
-               pat++;
-           if (pat < patend)
-               pat++;
+  register char* patptr = symptr->patptr; 
+  register char* patend = symptr->patend; 
+
+  symptr->flags &= ~FLAG_SLASH;
+
+  while (patptr < patend) {
+    if (isSPACE(*patptr))
+      patptr++;
+    else if (*patptr == '#') {
+      patptr++;
+      while (patptr < patend && *patptr != '\n')
+       patptr++;
+      if (patptr < patend)
+       patptr++;
+    } else {
+      /* We should have found a template code */ 
+      I32 code = *patptr++ & 0xFF;
+      U32 inherited_modifiers = 0;
+
+      if (code == ','){ /* grandfather in commas but with a warning */
+       if (((symptr->flags & FLAG_COMMA) == 0) && ckWARN(WARN_UNPACK)){
+          symptr->flags |= FLAG_COMMA;
+         Perl_warner(aTHX_ packWARN(WARN_UNPACK),
+                     "Invalid type ',' in %s",
+                      symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+        }
+       continue;
+      }
+      
+      /* for '(', skip to ')' */
+      if (code == '(') {  
+        if( isDIGIT(*patptr) || *patptr == '*' || *patptr == '[' )
+          Perl_croak(aTHX_ "()-group starts with a count in %s",
+                     symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+        symptr->grpbeg = patptr;
+        patptr = 1 + ( symptr->grpend = group_end(patptr, patend, ')') );
+        if( symptr->level >= MAX_SUB_TEMPLATE_LEVEL )
+         Perl_croak(aTHX_ "Too deeply nested ()-groups in %s",
+                     symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+      }
+
+      /* look for group modifiers to inherit */
+      if (TYPE_ENDIANNESS(symptr->flags)) {
+        if (strchr(ENDIANNESS_ALLOWED_TYPES, TYPE_NO_MODIFIERS(code)))
+          inherited_modifiers |= TYPE_ENDIANNESS(symptr->flags);
+      }
+
+      /* look for modifiers */
+      while (patptr < patend) {
+        const char *allowed;
+        I32 modifier = 0;
+        switch (*patptr) {
+          case '!':
+            modifier = TYPE_IS_SHRIEKING;
+            allowed = "sSiIlLxXnNvV";
+            break;
+          case '>':
+            modifier = TYPE_IS_BIG_ENDIAN;
+            allowed = ENDIANNESS_ALLOWED_TYPES;
+            break;
+          case '<':
+            modifier = TYPE_IS_LITTLE_ENDIAN;
+            allowed = ENDIANNESS_ALLOWED_TYPES;
+            break;
+          default:
+            break;
+        }
+
+        if (modifier == 0)
+          break;
+
+        if (!strchr(allowed, TYPE_NO_MODIFIERS(code)))
+          Perl_croak(aTHX_ "'%c' allowed only after types %s in %s", *patptr,
+                     allowed, symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+
+        if (TYPE_ENDIANNESS(code | modifier) == TYPE_ENDIANNESS_MASK)
+          Perl_croak(aTHX_ "Can't use both '<' and '>' after type '%c' in %s",
+                     (int) TYPE_NO_MODIFIERS(code),
+                     symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+        else if (TYPE_ENDIANNESS(code | modifier | inherited_modifiers) ==
+                 TYPE_ENDIANNESS_MASK)
+          Perl_croak(aTHX_ "Can't use '%c' in a group with different byte-order in %s",
+                     *patptr, symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+
+        if (ckWARN(WARN_UNPACK)) {
+          if (code & modifier)
+           Perl_warner(aTHX_ packWARN(WARN_UNPACK),
+                        "Duplicate modifier '%c' after '%c' in %s",
+                        *patptr, (int) TYPE_NO_MODIFIERS(code),
+                        symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+        }
+
+        code |= modifier;
+        patptr++;
+      }
+
+      /* inherit modifiers */
+      code |= inherited_modifiers;
+
+      /* look for count and/or / */ 
+      if (patptr < patend) {
+       if (isDIGIT(*patptr)) {
+         patptr = get_num( patptr, &symptr->length );
+          symptr->howlen = e_number;
+
+        } else if (*patptr == '*') {
+          patptr++;
+          symptr->howlen = e_star;
+
+        } else if (*patptr == '[') {
+          char* lenptr = ++patptr;            
+          symptr->howlen = e_number;
+          patptr = group_end( patptr, patend, ']' ) + 1;
+          /* what kind of [] is it? */
+          if (isDIGIT(*lenptr)) {
+            lenptr = get_num( lenptr, &symptr->length );
+            if( *lenptr != ']' )
+              Perl_croak(aTHX_ "Malformed integer in [] in %s",
+                         symptr->flags & FLAG_PACK ? "pack" : "unpack");
+          } else {
+            tempsym_t savsym = *symptr;
+            symptr->patend = patptr-1;
+            symptr->patptr = lenptr;
+            savsym.length = measure_struct(symptr);
+            *symptr = savsym;
+          }
+        } else {
+          symptr->howlen = e_no_len;
+          symptr->length = 1;
+        }
+
+        /* try to find / */
+        while (patptr < patend) {
+          if (isSPACE(*patptr))
+            patptr++;
+          else if (*patptr == '#') {
+            patptr++;
+            while (patptr < patend && *patptr != '\n')
+             patptr++;
+            if (patptr < patend)
+             patptr++;
+          } else {
+            if (*patptr == '/') {
+              symptr->flags |= FLAG_SLASH;
+              patptr++;
+              if (patptr < patend &&
+                  (isDIGIT(*patptr) || *patptr == '*' || *patptr == '['))
+                Perl_croak(aTHX_ "'/' does not take a repeat count in %s",
+                           symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+            }
+            break;
+         }
        }
-       else
-           return pat;
+      } else {
+        /* at end - no count, no / */
+        symptr->howlen = e_no_len;
+        symptr->length = 1;
+      }
+
+      symptr->code = code;
+      symptr->patptr = patptr; 
+      return TRUE;
     }
-    return pat;
+  }
+  symptr->patptr = patptr; 
+  return FALSE;
 }
 
 /*
 =for apidoc unpack_str
 
-The engine implementing unpack() Perl function.
+The engine implementing unpack() Perl function. Note: parameters strbeg, new_s
+and ocnt are not used. This call should not be used, use unpackstring instead.
 
 =cut */
 
 I32
 Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *strbeg, char *strend, char **new_s, I32 ocnt, U32 flags)
 {
+    tempsym_t sym = { 0 };
+    sym.patptr = pat;
+    sym.patend = patend;
+    sym.flags  = flags;
+
+    return unpack_rec(&sym, s, s, strend, NULL );
+}
+
+/*
+=for apidoc unpackstring
+
+The engine implementing unpack() Perl function. C<unpackstring> puts the
+extracted list items on the stack and returns the number of elements.
+Issue C<PUTBACK> before and C<SPAGAIN> after the call to this function.
+
+=cut */
+
+I32
+Perl_unpackstring(pTHX_ char *pat, register char *patend, register char *s, char *strend, U32 flags)
+{
+    tempsym_t sym = { 0 };
+    sym.patptr = pat;
+    sym.patend = patend;
+    sym.flags  = flags;
+
+    return unpack_rec(&sym, s, s, strend, NULL );
+}
+
+STATIC
+I32
+S_unpack_rec(pTHX_ register tempsym_t* symptr, register char *s, char *strbeg, char *strend, char **new_s )
+{
     dSP;
     I32 datumtype;
-    register I32 len;
+    register I32 len = 0;
     register I32 bits = 0;
     register char *str;
     SV *sv;
     I32 start_sp_offset = SP - PL_stack_base;
+    howlen_t howlen;
 
     /* These must not be in registers: */
-    short ashort;
-    int aint;
-    long along;
+    I16 ai16;
+    U16 au16;
+    I32 ai32;
+    U32 au32;
 #ifdef HAS_QUAD
     Quad_t aquad;
+    Uquad_t auquad;
 #endif
-    U16 aushort;
+#if SHORTSIZE != SIZE16
+    short ashort;
+    unsigned short aushort;
+#endif
+    int aint;
     unsigned int auint;
-    U32 aulong;
-#ifdef HAS_QUAD
-    Uquad_t auquad;
+    long along;
+#if LONGSIZE != SIZE32
+    unsigned long aulong;
 #endif
     char *aptr;
     float afloat;
     double adouble;
-    I32 checksum = 0;
-    UV cuv = 0;
-    NV cdouble = 0.0;
-    const int bits_in_uv = 8 * sizeof(cuv);
-    int commas = 0;
-    int star;          /* 1 if count is *, -1 if no count given, -2 for / */
-#ifdef PERL_NATINT_PACK
-    int natint;                /* native integer */
-    int unatint;       /* unsigned native integer */
+#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
+    long double aldouble;
 #endif
     IV aiv;
     UV auv;
     NV anv;
-#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
-    long double aldouble;
-#endif
-    bool do_utf8 = flags & UNPACK_DO_UTF8;
 
-    while ((pat = next_symbol(pat, patend)) < patend) {
-       datumtype = *pat++ & 0xFF;
-#ifdef PERL_NATINT_PACK
-       natint = 0;
-#endif
+    I32 checksum = 0;
+    UV cuv = 0;
+    NV cdouble = 0.0;
+    const int bits_in_uv = 8 * sizeof(cuv);
+    char* strrelbeg = s;
+    bool beyond = FALSE;
+    bool unpack_only_one = (symptr->flags & FLAG_UNPACK_ONLY_ONE) != 0;
+
+    while (next_symbol(symptr)) {
+        datumtype = symptr->code;
        /* do first one only unless in list context
           / is implemented by unpacking the count, then poping it from the
           stack, so must check that we're not in the middle of a /  */
-        if ( (flags & UNPACK_ONLY_ONE)
+        if ( unpack_only_one
             && (SP - PL_stack_base == start_sp_offset + 1)
-            && (datumtype != '/') )
+            && (datumtype != '/') )   /* XXX can this be omitted */
             break;
-       if (*pat == '!') {
-           static const char natstr[] = "sSiIlLxX";
 
-           if (strchr(natstr, datumtype)) {
-               if (datumtype == 'x' || datumtype == 'X') {
-                   datumtype |= TYPE_IS_SHRIEKING;
-               } else {                /* XXXX Should be redone similarly! */
-#ifdef PERL_NATINT_PACK
-                   natint = 1;
-#endif
-               }
-               pat++;
-           }
-           else
-               Perl_croak(aTHX_ "'!' allowed only after types %s", natstr);
-       }
-       len = find_count(&pat, patend, &star);
-       if (star > 0)
-               len = strend - strbeg;  /* long enough */
-       else if (star < 0)              /* No explicit len */
-               len = datumtype != '@';
+        switch( howlen = symptr->howlen ){
+        case e_no_len:
+       case e_number:
+           len = symptr->length;
+           break;
+        case e_star:
+           len = strend - strbeg;      /* long enough */          
+           break;
+        }
 
       redo_switch:
-       switch(datumtype) {
+        beyond = s >= strend;
+       switch(TYPE_NO_ENDIANNESS(datumtype)) {
        default:
-           Perl_croak(aTHX_ "Invalid type in unpack: '%c'", (int)datumtype);
-       case ',': /* grandfather in commas but with a warning */
-           if (commas++ == 0 && ckWARN(WARN_UNPACK))
-               Perl_warner(aTHX_ packWARN(WARN_UNPACK),
-                           "Invalid type in unpack: '%c'", (int)datumtype);
-           break;
+           Perl_croak(aTHX_ "Invalid type '%c' in unpack", (int)TYPE_NO_MODIFIERS(datumtype) );
+
        case '%':
-           if (len == 1 && pat[-1] != '1' && pat[-1] != ']')
+           if (howlen == e_no_len)
                len = 16;               /* len is not specified */
            checksum = len;
            cuv = 0;
@@ -513,35 +772,30 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            break;
        case '(':
        {
-           char *beg = pat;
            char *ss = s;               /* Move from register */
-
-           if (star >= 0)
-               Perl_croak(aTHX_ "()-group starts with a count");
-           aptr = group_end(beg, patend, ')');
-           pat = aptr + 1;
-           if (star != -2) {
-               len = find_count(&pat, patend, &star);
-               if (star < 0)           /* No count */
-                   len = 1;
-               else if (star > 0)      /* Star */
-                   len = strend - strbeg; /* long enough? */
-           }
+            tempsym_t savsym = *symptr;
+           U32 group_modifiers = TYPE_MODIFIERS(datumtype & ~symptr->flags);
+           symptr->flags |= group_modifiers;
+            symptr->patend = savsym.grpend;
+            symptr->level++;
            PUTBACK;
            while (len--) {
-               unpack_str(beg, aptr, ss, strbeg, strend, &ss,
-                          ocnt + SP - PL_stack_base - start_sp_offset, flags);
-               if (star > 0 && ss == strend)
-                   break;              /* No way to continue */
+               symptr->patptr = savsym.grpbeg;
+               unpack_rec(symptr, ss, strbeg, strend, &ss );
+                if (ss == strend && savsym.howlen == e_star)
+                   break; /* No way to continue */
            }
            SPAGAIN;
            s = ss;
+           symptr->flags &= ~group_modifiers;
+            savsym.flags = symptr->flags;
+            *symptr = savsym;
            break;
        }
        case '@':
-           if (len > strend - strbeg)
-               Perl_croak(aTHX_ "@ outside of string");
-           s = strbeg + len;
+           if (len > strend - strrelbeg)
+               Perl_croak(aTHX_ "'@' outside of string in unpack");
+           s = strrelbeg + len;
            break;
        case 'X' | TYPE_IS_SHRIEKING:
            if (!len)                   /* Avoid division by 0 */
@@ -550,7 +804,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            /* FALL THROUGH */
        case 'X':
            if (len > s - strbeg)
-               Perl_croak(aTHX_ "X outside of string");
+               Perl_croak(aTHX_ "'X' outside of string in unpack" );
            s -= len;
            break;
        case 'x' | TYPE_IS_SHRIEKING:
@@ -564,20 +818,12 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            /* FALL THROUGH */
        case 'x':
            if (len > strend - s)
-               Perl_croak(aTHX_ "x outside of string");
+               Perl_croak(aTHX_ "'x' outside of string in unpack");
            s += len;
            break;
        case '/':
-           if (ocnt + SP - PL_stack_base - start_sp_offset <= 0)
-               Perl_croak(aTHX_ "/ must follow a numeric type");
-           datumtype = *pat++;
-           if (*pat == '*')
-               pat++;          /* ignore '*' for compatibility with pack */
-           if (isDIGIT(*pat))
-               Perl_croak(aTHX_ "/ cannot take a count" );
-           len = POPi;
-           star = -2;
-           goto redo_switch;
+           Perl_croak(aTHX_ "'/' must follow a numeric type in unpack");
+            break;
        case 'A':
        case 'Z':
        case 'a':
@@ -587,13 +833,13 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                goto uchar_checksum;
            sv = NEWSV(35, len);
            sv_setpvn(sv, s, len);
-           if (datumtype == 'A' || datumtype == 'Z') {
+           if (len > 0 && (datumtype == 'A' || datumtype == 'Z')) {
                aptr = s;       /* borrow register */
                if (datumtype == 'Z') { /* 'Z' strips stuff after first null */
                    s = SvPVX(sv);
                    while (*s)
                        s++;
-                   if (star > 0) /* exact for 'Z*' */
+                   if (howlen == e_star) /* exact for 'Z*' */
                        len = s - SvPVX(sv) + 1;
                }
                else {          /* 'A' strips both nulls and spaces */
@@ -610,7 +856,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            break;
        case 'B':
        case 'b':
-           if (star > 0 || len > (strend - s) * 8)
+           if (howlen == e_star || len > (strend - s) * 8)
                len = (strend - s) * 8;
            if (checksum) {
                if (!PL_bitcount) {
@@ -676,7 +922,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            break;
        case 'H':
        case 'h':
-           if (star > 0 || len > (strend - s) * 2)
+           if (howlen == e_star || len > (strend - s) * 2)
                len = (strend - s) * 2;
            sv = NEWSV(35, len + 1);
            SvCUR_set(sv, len);
@@ -720,6 +966,8 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
@@ -735,7 +983,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
        case 'C':
        unpack_C: /* unpack U will jump here if not UTF-8 */
             if (len == 0) {
-               do_utf8 = FALSE;
+                symptr->flags &= ~FLAG_UNPACK_DO_UTF8;
                break;
            }
            if (len > strend - s)
@@ -748,6 +996,8 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
@@ -760,17 +1010,17 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            break;
        case 'U':
            if (len == 0) {
-               do_utf8 = TRUE;
+                symptr->flags |= FLAG_UNPACK_DO_UTF8;
                break;
            }
-           if (!do_utf8)
+           if ((symptr->flags & FLAG_UNPACK_DO_UTF8) == 0)
                 goto unpack_C;
            if (len > strend - s)
                len = strend - s;
            if (checksum) {
                while (len-- > 0 && s < strend) {
                    STRLEN alen;
-                   auint = NATIVE_TO_UNI(utf8n_to_uvchr((U8*)s, strend - s, &alen, 0));
+                   auint = NATIVE_TO_UNI(utf8n_to_uvchr((U8*)s, strend - s, &alen, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANYUV));
                    along = alen;
                    s += along;
                    if (checksum > bits_in_uv)
@@ -780,11 +1030,13 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0 && s < strend) {
                    STRLEN alen;
-                   auint = NATIVE_TO_UNI(utf8n_to_uvchr((U8*)s, strend - s, &alen, 0));
+                   auint = NATIVE_TO_UNI(utf8n_to_uvchr((U8*)s, strend - s, &alen, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANYUV));
                    along = alen;
                    s += along;
                    sv = NEWSV(37, 0);
@@ -793,163 +1045,215 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
            break;
-       case 's':
-#if SHORTSIZE == SIZE16
-           along = (strend - s) / SIZE16;
-#else
-           along = (strend - s) / (natint ? sizeof(short) : SIZE16);
-#endif
+       case 's' | TYPE_IS_SHRIEKING:
+#if SHORTSIZE != SIZE16
+           along = (strend - s) / sizeof(short);
            if (len > along)
                len = along;
            if (checksum) {
-#if SHORTSIZE != SIZE16
-               if (natint) {
-                   short ashort;
-                   while (len-- > 0) {
-                       COPYNN(s, &ashort, sizeof(short));
-                       s += sizeof(short);
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)ashort;
-                       else
-                           cuv += ashort;
-
-                   }
+               while (len-- > 0) {
+                   COPYNN(s, &ashort, sizeof(short));
+                   DO_BO_UNPACK(ashort, s);
+                   s += sizeof(short);
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)ashort;
+                   else
+                       cuv += ashort;
                }
-               else
-#endif
-                {
-                   while (len-- > 0) {
-                       COPY16(s, &ashort);
-#if SHORTSIZE > SIZE16
-                       if (ashort > 32767)
-                         ashort -= 65536;
+           }
+           else {
+                if (len && unpack_only_one)
+                    len = 1;
+               EXTEND(SP, len);
+               EXTEND_MORTAL(len);
+               while (len-- > 0) {
+                   COPYNN(s, &ashort, sizeof(short));
+                   DO_BO_UNPACK(ashort, s);
+                   s += sizeof(short);
+                   sv = NEWSV(38, 0);
+                   sv_setiv(sv, (IV)ashort);
+                   PUSHs(sv_2mortal(sv));
+               }
+           }
+           break;
+#else
+           /* Fallthrough! */
 #endif
-                       s += SIZE16;
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)ashort;
-                       else
-                           cuv += ashort;
-                   }
+       case 's':
+           along = (strend - s) / SIZE16;
+           if (len > along)
+               len = along;
+           if (checksum) {
+               while (len-- > 0) {
+                   COPY16(s, &ai16);
+                   DO_BO_UNPACK(ai16, 16);
+#if U16SIZE > SIZE16
+                   if (ai16 > 32767)
+                       ai16 -= 65536;
+#endif
+                   s += SIZE16;
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)ai16;
+                   else
+                       cuv += ai16;
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
+
+               while (len-- > 0) {
+                   COPY16(s, &ai16);
+                   DO_BO_UNPACK(ai16, 16);
+#if U16SIZE > SIZE16
+                   if (ai16 > 32767)
+                       ai16 -= 65536;
+#endif
+                   s += SIZE16;
+                   sv = NEWSV(38, 0);
+                   sv_setiv(sv, (IV)ai16);
+                   PUSHs(sv_2mortal(sv));
+               }
+           }
+           break;
+       case 'S' | TYPE_IS_SHRIEKING:
 #if SHORTSIZE != SIZE16
-               if (natint) {
-                   short ashort;
-                   while (len-- > 0) {
-                       COPYNN(s, &ashort, sizeof(short));
-                       s += sizeof(short);
-                       sv = NEWSV(38, 0);
-                       sv_setiv(sv, (IV)ashort);
-                       PUSHs(sv_2mortal(sv));
-                   }
+           along = (strend - s) / sizeof(unsigned short);
+           if (len > along)
+               len = along;
+           if (checksum) {
+               while (len-- > 0) {
+                   COPYNN(s, &aushort, sizeof(unsigned short));
+                   DO_BO_UNPACK(aushort, s);
+                   s += sizeof(unsigned short);
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)aushort;
+                   else
+                       cuv += aushort;
                }
-               else
-#endif
-                {
-                   while (len-- > 0) {
-                       COPY16(s, &ashort);
-#if SHORTSIZE > SIZE16
-                       if (ashort > 32767)
-                         ashort -= 65536;
-#endif
-                       s += SIZE16;
-                       sv = NEWSV(38, 0);
-                       sv_setiv(sv, (IV)ashort);
-                       PUSHs(sv_2mortal(sv));
-                   }
+           }
+           else {
+                if (len && unpack_only_one)
+                    len = 1;
+               EXTEND(SP, len);
+               EXTEND_MORTAL(len);
+               while (len-- > 0) {
+                   COPYNN(s, &aushort, sizeof(unsigned short));
+                   DO_BO_UNPACK(aushort, s);
+                   s += sizeof(unsigned short);
+                   sv = NEWSV(39, 0);
+                   sv_setiv(sv, (UV)aushort);
+                   PUSHs(sv_2mortal(sv));
                }
            }
            break;
+#else
+            /* Fallhrough! */
+#endif
        case 'v':
        case 'n':
        case 'S':
-#if SHORTSIZE == SIZE16
            along = (strend - s) / SIZE16;
-#else
-           unatint = natint && datumtype == 'S';
-           along = (strend - s) / (unatint ? sizeof(unsigned short) : SIZE16);
-#endif
            if (len > along)
                len = along;
            if (checksum) {
-#if SHORTSIZE != SIZE16
-               if (unatint) {
-                   unsigned short aushort;
-                   while (len-- > 0) {
-                       COPYNN(s, &aushort, sizeof(unsigned short));
-                       s += sizeof(unsigned short);
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)aushort;
-                       else
-                           cuv += aushort;
-                   }
-               }
-               else
-#endif
-                {
-                   while (len-- > 0) {
-                       COPY16(s, &aushort);
-                       s += SIZE16;
+               while (len-- > 0) {
+                   COPY16(s, &au16);
+                   DO_BO_UNPACK(au16, 16);
+                   s += SIZE16;
 #ifdef HAS_NTOHS
-                       if (datumtype == 'n')
-                           aushort = PerlSock_ntohs(aushort);
+                   if (datumtype == 'n')
+                       au16 = PerlSock_ntohs(au16);
 #endif
 #ifdef HAS_VTOHS
-                       if (datumtype == 'v')
-                           aushort = vtohs(aushort);
+                   if (datumtype == 'v')
+                       au16 = vtohs(au16);
 #endif
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)aushort;
-                       else
-                           cuv += aushort;
-                   }
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)au16;
+                   else
+                       cuv += au16;
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
-#if SHORTSIZE != SIZE16
-               if (unatint) {
-                   unsigned short aushort;
-                   while (len-- > 0) {
-                       COPYNN(s, &aushort, sizeof(unsigned short));
-                       s += sizeof(unsigned short);
-                       sv = NEWSV(39, 0);
-                       sv_setiv(sv, (UV)aushort);
-                       PUSHs(sv_2mortal(sv));
-                   }
+               while (len-- > 0) {
+                   COPY16(s, &au16);
+                   DO_BO_UNPACK(au16, 16);
+                   s += SIZE16;
+                   sv = NEWSV(39, 0);
+#ifdef HAS_NTOHS
+                   if (datumtype == 'n')
+                       au16 = PerlSock_ntohs(au16);
+#endif
+#ifdef HAS_VTOHS
+                   if (datumtype == 'v')
+                       au16 = vtohs(au16);
+#endif
+                   sv_setiv(sv, (UV)au16);
+                   PUSHs(sv_2mortal(sv));
                }
-               else
+           }
+           break;
+       case 'v' | TYPE_IS_SHRIEKING:
+       case 'n' | TYPE_IS_SHRIEKING:
+           along = (strend - s) / SIZE16;
+           if (len > along)
+               len = along;
+           if (checksum) {
+               while (len-- > 0) {
+                   COPY16(s, &ai16);
+                   s += SIZE16;
+#ifdef HAS_NTOHS
+                   if (datumtype == ('n' | TYPE_IS_SHRIEKING))
+                       ai16 = (I16)PerlSock_ntohs((U16)ai16);
 #endif
-                {
-                   while (len-- > 0) {
-                       COPY16(s, &aushort);
-                       s += SIZE16;
-                       sv = NEWSV(39, 0);
+#ifdef HAS_VTOHS
+                   if (datumtype == ('v' | TYPE_IS_SHRIEKING))
+                       ai16 = (I16)vtohs((U16)ai16);
+#endif
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)ai16;
+                   else
+                       cuv += ai16;
+               }
+           }
+           else {
+                if (len && unpack_only_one)
+                    len = 1;
+               EXTEND(SP, len);
+               EXTEND_MORTAL(len);
+               while (len-- > 0) {
+                   COPY16(s, &ai16);
+                   s += SIZE16;
 #ifdef HAS_NTOHS
-                       if (datumtype == 'n')
-                           aushort = PerlSock_ntohs(aushort);
+                   if (datumtype == ('n' | TYPE_IS_SHRIEKING))
+                       ai16 = (I16)PerlSock_ntohs((U16)ai16);
 #endif
 #ifdef HAS_VTOHS
-                       if (datumtype == 'v')
-                           aushort = vtohs(aushort);
+                   if (datumtype == ('v' | TYPE_IS_SHRIEKING))
+                       ai16 = (I16)vtohs((U16)ai16);
 #endif
-                       sv_setiv(sv, (UV)aushort);
-                       PUSHs(sv_2mortal(sv));
-                   }
+                   sv = NEWSV(39, 0);
+                   sv_setiv(sv, (IV)ai16);
+                   PUSHs(sv_2mortal(sv));
                }
            }
            break;
        case 'i':
+       case 'i' | TYPE_IS_SHRIEKING:
            along = (strend - s) / sizeof(int);
            if (len > along)
                len = along;
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &aint, 1, int);
+                   DO_BO_UNPACK(aint, i);
                    s += sizeof(int);
                    if (checksum > bits_in_uv)
                        cdouble += (NV)aint;
@@ -958,10 +1262,13 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
                    Copy(s, &aint, 1, int);
+                   DO_BO_UNPACK(aint, i);
                    s += sizeof(int);
                    sv = NEWSV(40, 0);
 #ifdef __osf__
@@ -995,12 +1302,14 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            }
            break;
        case 'I':
+       case 'I' | TYPE_IS_SHRIEKING:
            along = (strend - s) / sizeof(unsigned int);
            if (len > along)
                len = along;
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &auint, 1, unsigned int);
+                   DO_BO_UNPACK(auint, i);
                    s += sizeof(unsigned int);
                    if (checksum > bits_in_uv)
                        cdouble += (NV)auint;
@@ -1009,10 +1318,13 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
                    Copy(s, &auint, 1, unsigned int);
+                   DO_BO_UNPACK(auint, i);
                    s += sizeof(unsigned int);
                    sv = NEWSV(41, 0);
 #ifdef __osf__
@@ -1034,6 +1346,13 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &aiv, 1, IV);
+#if IVSIZE == INTSIZE
+                   DO_BO_UNPACK(aiv, i);
+#elif IVSIZE == LONGSIZE
+                   DO_BO_UNPACK(aiv, l);
+#elif defined(HAS_QUAD) && IVSIZE == U64SIZE
+                   DO_BO_UNPACK(aiv, 64);
+#endif
                    s += IVSIZE;
                    if (checksum > bits_in_uv)
                        cdouble += (NV)aiv;
@@ -1042,10 +1361,19 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
                    Copy(s, &aiv, 1, IV);
+#if IVSIZE == INTSIZE
+                   DO_BO_UNPACK(aiv, i);
+#elif IVSIZE == LONGSIZE
+                   DO_BO_UNPACK(aiv, l);
+#elif defined(HAS_QUAD) && IVSIZE == U64SIZE
+                   DO_BO_UNPACK(aiv, 64);
+#endif
                    s += IVSIZE;
                    sv = NEWSV(40, 0);
                    sv_setiv(sv, aiv);
@@ -1060,6 +1388,13 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &auv, 1, UV);
+#if UVSIZE == INTSIZE
+                   DO_BO_UNPACK(auv, i);
+#elif UVSIZE == LONGSIZE
+                   DO_BO_UNPACK(auv, l);
+#elif defined(HAS_QUAD) && UVSIZE == U64SIZE
+                   DO_BO_UNPACK(auv, 64);
+#endif
                    s += UVSIZE;
                    if (checksum > bits_in_uv)
                        cdouble += (NV)auv;
@@ -1068,10 +1403,19 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
                    Copy(s, &auv, 1, UV);
+#if UVSIZE == INTSIZE
+                   DO_BO_UNPACK(auv, i);
+#elif UVSIZE == LONGSIZE
+                   DO_BO_UNPACK(auv, l);
+#elif defined(HAS_QUAD) && UVSIZE == U64SIZE
+                   DO_BO_UNPACK(auv, 64);
+#endif
                    s += UVSIZE;
                    sv = NEWSV(41, 0);
                    sv_setuv(sv, auv);
@@ -1079,156 +1423,202 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
            break;
-       case 'l':
-#if LONGSIZE == SIZE32
-           along = (strend - s) / SIZE32;
-#else
-           along = (strend - s) / (natint ? sizeof(long) : SIZE32);
-#endif
+       case 'l' | TYPE_IS_SHRIEKING:
+#if LONGSIZE != SIZE32
+           along = (strend - s) / sizeof(long);
            if (len > along)
                len = along;
            if (checksum) {
-#if LONGSIZE != SIZE32
-               if (natint) {
-                   while (len-- > 0) {
-                       COPYNN(s, &along, sizeof(long));
-                       s += sizeof(long);
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)along;
-                       else
-                           cuv += along;
-                   }
+               while (len-- > 0) {
+                   COPYNN(s, &along, sizeof(long));
+                   DO_BO_UNPACK(along, l);
+                   s += sizeof(long);
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)along;
+                   else
+                       cuv += along;
                }
-               else
-#endif
-                {
-                   while (len-- > 0) {
-#if LONGSIZE > SIZE32 && INTSIZE == SIZE32
-                       I32 along;
+           }
+           else {
+                if (len && unpack_only_one)
+                    len = 1;
+               EXTEND(SP, len);
+               EXTEND_MORTAL(len);
+               while (len-- > 0) {
+                   COPYNN(s, &along, sizeof(long));
+                   DO_BO_UNPACK(along, l);
+                   s += sizeof(long);
+                   sv = NEWSV(42, 0);
+                   sv_setiv(sv, (IV)along);
+                   PUSHs(sv_2mortal(sv));
+               }
+           }
+           break;
+#else
+           /* Fallthrough! */
 #endif
-                       COPY32(s, &along);
-#if LONGSIZE > SIZE32
-                       if (along > 2147483647)
-                         along -= 4294967296;
+       case 'l':
+           along = (strend - s) / SIZE32;
+           if (len > along)
+               len = along;
+           if (checksum) {
+               while (len-- > 0) {
+                   COPY32(s, &ai32);
+                   DO_BO_UNPACK(ai32, 32);
+#if U32SIZE > SIZE32
+                   if (ai32 > 2147483647)
+                       ai32 -= 4294967296;
 #endif
-                       s += SIZE32;
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)along;
-                       else
-                           cuv += along;
-                   }
+                   s += SIZE32;
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)ai32;
+                   else
+                       cuv += ai32;
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
+               while (len-- > 0) {
+                   COPY32(s, &ai32);
+                   DO_BO_UNPACK(ai32, 32);
+#if U32SIZE > SIZE32
+                   if (ai32 > 2147483647)
+                       ai32 -= 4294967296;
+#endif
+                   s += SIZE32;
+                   sv = NEWSV(42, 0);
+                   sv_setiv(sv, (IV)ai32);
+                   PUSHs(sv_2mortal(sv));
+               }
+           }
+           break;
+       case 'L' | TYPE_IS_SHRIEKING:
 #if LONGSIZE != SIZE32
-               if (natint) {
-                   while (len-- > 0) {
-                       COPYNN(s, &along, sizeof(long));
-                       s += sizeof(long);
-                       sv = NEWSV(42, 0);
-                       sv_setiv(sv, (IV)along);
-                       PUSHs(sv_2mortal(sv));
-                   }
+           along = (strend - s) / sizeof(unsigned long);
+           if (len > along)
+               len = along;
+           if (checksum) {
+               while (len-- > 0) {
+                   COPYNN(s, &aulong, sizeof(unsigned long));
+                   DO_BO_UNPACK(aulong, l);
+                   s += sizeof(unsigned long);
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)aulong;
+                   else
+                       cuv += aulong;
                }
-               else
-#endif
-                {
-                   while (len-- > 0) {
-#if LONGSIZE > SIZE32 && INTSIZE == SIZE32
-                       I32 along;
-#endif
-                       COPY32(s, &along);
-#if LONGSIZE > SIZE32
-                       if (along > 2147483647)
-                         along -= 4294967296;
-#endif
-                       s += SIZE32;
-                       sv = NEWSV(42, 0);
-                       sv_setiv(sv, (IV)along);
-                       PUSHs(sv_2mortal(sv));
-                   }
+           }
+           else {
+                if (len && unpack_only_one)
+                    len = 1;
+               EXTEND(SP, len);
+               EXTEND_MORTAL(len);
+               while (len-- > 0) {
+                   COPYNN(s, &aulong, sizeof(unsigned long));
+                   DO_BO_UNPACK(aulong, l);
+                   s += sizeof(unsigned long);
+                   sv = NEWSV(43, 0);
+                   sv_setuv(sv, (UV)aulong);
+                   PUSHs(sv_2mortal(sv));
                }
            }
            break;
+#else
+            /* Fall through! */
+#endif
        case 'V':
        case 'N':
        case 'L':
-#if LONGSIZE == SIZE32
            along = (strend - s) / SIZE32;
-#else
-           unatint = natint && datumtype == 'L';
-           along = (strend - s) / (unatint ? sizeof(unsigned long) : SIZE32);
-#endif
            if (len > along)
                len = along;
            if (checksum) {
-#if LONGSIZE != SIZE32
-               if (unatint) {
-                   unsigned long aulong;
-                   while (len-- > 0) {
-                       COPYNN(s, &aulong, sizeof(unsigned long));
-                       s += sizeof(unsigned long);
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)aulong;
-                       else
-                           cuv += aulong;
-                   }
-               }
-               else
-#endif
-                {
-                   while (len-- > 0) {
-                       COPY32(s, &aulong);
-                       s += SIZE32;
+               while (len-- > 0) {
+                   COPY32(s, &au32);
+                   DO_BO_UNPACK(au32, 32);
+                   s += SIZE32;
 #ifdef HAS_NTOHL
-                       if (datumtype == 'N')
-                           aulong = PerlSock_ntohl(aulong);
+                   if (datumtype == 'N')
+                       au32 = PerlSock_ntohl(au32);
 #endif
 #ifdef HAS_VTOHL
-                       if (datumtype == 'V')
-                           aulong = vtohl(aulong);
+                   if (datumtype == 'V')
+                       au32 = vtohl(au32);
 #endif
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)aulong;
-                       else
-                           cuv += aulong;
-                   }
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)au32;
+                   else
+                       cuv += au32;
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
-#if LONGSIZE != SIZE32
-               if (unatint) {
-                   unsigned long aulong;
-                   while (len-- > 0) {
-                       COPYNN(s, &aulong, sizeof(unsigned long));
-                       s += sizeof(unsigned long);
-                       sv = NEWSV(43, 0);
-                       sv_setuv(sv, (UV)aulong);
-                       PUSHs(sv_2mortal(sv));
-                   }
+               while (len-- > 0) {
+                   COPY32(s, &au32);
+                   DO_BO_UNPACK(au32, 32);
+                   s += SIZE32;
+#ifdef HAS_NTOHL
+                   if (datumtype == 'N')
+                       au32 = PerlSock_ntohl(au32);
+#endif
+#ifdef HAS_VTOHL
+                   if (datumtype == 'V')
+                       au32 = vtohl(au32);
+#endif
+                   sv = NEWSV(43, 0);
+                   sv_setuv(sv, (UV)au32);
+                   PUSHs(sv_2mortal(sv));
                }
-               else
+           }
+           break;
+       case 'V' | TYPE_IS_SHRIEKING:
+       case 'N' | TYPE_IS_SHRIEKING:
+           along = (strend - s) / SIZE32;
+           if (len > along)
+               len = along;
+           if (checksum) {
+               while (len-- > 0) {
+                   COPY32(s, &ai32);
+                   s += SIZE32;
+#ifdef HAS_NTOHL
+                   if (datumtype == ('N' | TYPE_IS_SHRIEKING))
+                       ai32 = (I32)PerlSock_ntohl((U32)ai32);
 #endif
-                {
-                   while (len-- > 0) {
-                       COPY32(s, &aulong);
-                       s += SIZE32;
+#ifdef HAS_VTOHL
+                   if (datumtype == ('V' | TYPE_IS_SHRIEKING))
+                       ai32 = (I32)vtohl((U32)ai32);
+#endif
+                   if (checksum > bits_in_uv)
+                       cdouble += (NV)ai32;
+                   else
+                       cuv += ai32;
+               }
+           }
+           else {
+                if (len && unpack_only_one)
+                    len = 1;
+               EXTEND(SP, len);
+               EXTEND_MORTAL(len);
+               while (len-- > 0) {
+                   COPY32(s, &ai32);
+                   s += SIZE32;
 #ifdef HAS_NTOHL
-                       if (datumtype == 'N')
-                           aulong = PerlSock_ntohl(aulong);
+                   if (datumtype == ('N' | TYPE_IS_SHRIEKING))
+                       ai32 = (I32)PerlSock_ntohl((U32)ai32);
 #endif
 #ifdef HAS_VTOHL
-                       if (datumtype == 'V')
-                           aulong = vtohl(aulong);
+                   if (datumtype == ('V' | TYPE_IS_SHRIEKING))
+                       ai32 = (I32)vtohl((U32)ai32);
 #endif
-                       sv = NEWSV(43, 0);
-                       sv_setuv(sv, (UV)aulong);
-                       PUSHs(sv_2mortal(sv));
-                   }
+                   sv = NEWSV(43, 0);
+                   sv_setiv(sv, (IV)ai32);
+                   PUSHs(sv_2mortal(sv));
                }
            }
            break;
@@ -1243,6 +1633,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                    break;
                else {
                    Copy(s, &aptr, 1, char*);
+                   DO_BO_UNPACK_P(aptr);
                    s += sizeof(char*);
                }
                sv = NEWSV(44, 0);
@@ -1252,6 +1643,8 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            }
            break;
        case 'w':
+            if (len && unpack_only_one)
+                len = 1;
            EXTEND(SP, len);
            EXTEND_MORTAL(len);
            {
@@ -1275,7 +1668,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
 
                        sv = Perl_newSVpvf(aTHX_ "%.*"UVf, (int)TYPE_DIGITS(UV), auv);
                        while (s < strend) {
-                           sv = mul128(sv, *s & 0x7f);
+                           sv = mul128(sv, (U8)(*s & 0x7f));
                            if (!(*s++ & 0x80)) {
                                bytes = 0;
                                break;
@@ -1291,17 +1684,18 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                    }
                }
                if ((s >= strend) && bytes)
-                   Perl_croak(aTHX_ "Unterminated compressed integer");
+                   Perl_croak(aTHX_ "Unterminated compressed integer in unpack");
            }
            break;
        case 'P':
-           if (star > 0)
-               Perl_croak(aTHX_ "P must have an explicit size");
+           if (symptr->howlen == e_star)
+               Perl_croak(aTHX_ "'P' must have an explicit size in unpack");
            EXTEND(SP, 1);
            if (sizeof(char*) > strend - s)
                break;
            else {
                Copy(s, &aptr, 1, char*);
+               DO_BO_UNPACK_P(aptr);
                s += sizeof(char*);
            }
            sv = NEWSV(44, 0);
@@ -1317,6 +1711,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &aquad, 1, Quad_t);
+                   DO_BO_UNPACK(aquad, 64);
                    s += sizeof(Quad_t);
                    if (checksum > bits_in_uv)
                        cdouble += (NV)aquad;
@@ -1325,6 +1720,8 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
             else {
+                if (len && unpack_only_one)
+                    len = 1;
                 EXTEND(SP, len);
                 EXTEND_MORTAL(len);
                 while (len-- > 0) {
@@ -1332,6 +1729,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                         aquad = 0;
                     else {
                        Copy(s, &aquad, 1, Quad_t);
+                       DO_BO_UNPACK(aquad, 64);
                        s += sizeof(Quad_t);
                     }
                     sv = NEWSV(42, 0);
@@ -1350,6 +1748,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &auquad, 1, Uquad_t);
+                   DO_BO_UNPACK(auquad, 64);
                    s += sizeof(Uquad_t);
                    if (checksum > bits_in_uv)
                        cdouble += (NV)auquad;
@@ -1358,6 +1757,8 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                }
            }
             else {
+                if (len && unpack_only_one)
+                    len = 1;
                 EXTEND(SP, len);
                 EXTEND_MORTAL(len);
                 while (len-- > 0) {
@@ -1365,6 +1766,7 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                         auquad = 0;
                     else {
                         Copy(s, &auquad, 1, Uquad_t);
+                       DO_BO_UNPACK(auquad, 64);
                         s += sizeof(Uquad_t);
                     }
                     sv = NEWSV(43, 0);
@@ -1385,15 +1787,19 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &afloat, 1, float);
+                   DO_BO_UNPACK_N(afloat, float);
                    s += sizeof(float);
                    cdouble += afloat;
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
                    Copy(s, &afloat, 1, float);
+                   DO_BO_UNPACK_N(afloat, float);
                    s += sizeof(float);
                    sv = NEWSV(47, 0);
                    sv_setnv(sv, (NV)afloat);
@@ -1408,15 +1814,19 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &adouble, 1, double);
+                   DO_BO_UNPACK_N(adouble, double);
                    s += sizeof(double);
                    cdouble += adouble;
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
                    Copy(s, &adouble, 1, double);
+                   DO_BO_UNPACK_N(adouble, double);
                    s += sizeof(double);
                    sv = NEWSV(48, 0);
                    sv_setnv(sv, (NV)adouble);
@@ -1431,15 +1841,19 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &anv, 1, NV);
+                   DO_BO_UNPACK_N(anv, NV);
                    s += NVSIZE;
                    cdouble += anv;
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
                    Copy(s, &anv, 1, NV);
+                   DO_BO_UNPACK_N(anv, NV);
                    s += NVSIZE;
                    sv = NEWSV(48, 0);
                    sv_setnv(sv, anv);
@@ -1455,15 +1869,19 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            if (checksum) {
                while (len-- > 0) {
                    Copy(s, &aldouble, 1, long double);
+                   DO_BO_UNPACK_N(aldouble, long double);
                    s += LONG_DOUBLESIZE;
                    cdouble += aldouble;
                }
            }
            else {
+                if (len && unpack_only_one)
+                    len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
                while (len-- > 0) {
                    Copy(s, &aldouble, 1, long double);
+                   DO_BO_UNPACK_N(aldouble, long double);
                    s += LONG_DOUBLESIZE;
                    sv = NEWSV(48, 0);
                    sv_setnv(sv, (NV)aldouble);
@@ -1517,25 +1935,27 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                        d = PL_uudmap[*(U8*)s++] & 077;
                    else
                        d = 0;
-                   hunk[0] = (a << 2) | (b >> 4);
-                   hunk[1] = (b << 4) | (c >> 2);
-                   hunk[2] = (c << 6) | d;
+                   hunk[0] = (char)((a << 2) | (b >> 4));
+                   hunk[1] = (char)((b << 4) | (c >> 2));
+                   hunk[2] = (char)((c << 6) | d);
                    sv_catpvn(sv, hunk, (len > 3) ? 3 : len);
                    len -= 3;
                }
                if (*s == '\n')
                    s++;
-               else if (s[1] == '\n')          /* possible checksum byte */
-                   s += 2;
+               else    /* possible checksum byte */
+                   if (s + 1 < strend && s[1] == '\n')
+                       s += 2;
            }
            XPUSHs(sv_2mortal(sv));
            break;
        }
+
        if (checksum) {
            sv = NEWSV(42, 0);
-           if (strchr("fFdD", datumtype) ||
+           if (strchr("fFdD", TYPE_NO_MODIFIERS(datumtype)) ||
              (checksum > bits_in_uv &&
-              strchr("csSiIlLnNUvVqQjJ", datumtype)) ) {
+              strchr("csSiIlLnNUvVqQjJ", TYPE_NO_MODIFIERS(datumtype))) ) {
                NV trouble;
 
                 adouble = (NV) (1 << (checksum & 15));
@@ -1551,7 +1971,6 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            else {
                if (checksum < bits_in_uv) {
                    UV mask = ((UV)1 << checksum) - 1;
-
                    cuv &= mask;
                }
                sv_setuv(sv, cuv);
@@ -1559,7 +1978,30 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            XPUSHs(sv_2mortal(sv));
            checksum = 0;
        }
+    
+        if (symptr->flags & FLAG_SLASH){
+            if (SP - PL_stack_base - start_sp_offset <= 0)
+                Perl_croak(aTHX_ "'/' must follow a numeric type in unpack");
+            if( next_symbol(symptr) ){
+              if( symptr->howlen == e_number )
+               Perl_croak(aTHX_ "Count after length/code in unpack" );
+              if( beyond ){
+               /* ...end of char buffer then no decent length available */
+               Perl_croak(aTHX_ "length/code after end of string in unpack" );
+              } else {
+               /* take top of stack (hope it's numeric) */
+                len = POPi;
+                if( len < 0 )
+                    Perl_croak(aTHX_ "Negative '/' count in unpack" );
+              }
+            } else {
+               Perl_croak(aTHX_ "Code missing after '/' in unpack" );
+            }
+            datumtype = symptr->code;
+           goto redo_switch;
+        }
     }
+
     if (new_s)
        *new_s = s;
     PUTBACK;
@@ -1587,9 +2029,10 @@ PP(pp_unpack)
     register I32 cnt;
 
     PUTBACK;
-    cnt = unpack_str(pat, patend, s, s, strend, NULL, 0,
-                    ((gimme == G_SCALAR) ? UNPACK_ONLY_ONE : 0)
-                    | (DO_UTF8(right) ? UNPACK_DO_UTF8 : 0));
+    cnt = unpackstring(pat, patend, s, strend,
+                    ((gimme == G_SCALAR) ? FLAG_UNPACK_ONLY_ONE : 0)
+                    | (DO_UTF8(right) ? FLAG_UNPACK_DO_UTF8 : 0));
+
     SPAGAIN;
     if ( !cnt && gimme == G_SCALAR )
        PUSHs(&PL_sv_undef);
@@ -1700,107 +2143,144 @@ S_div128(pTHX_ SV *pnum, bool *done)
   return (m);
 }
 
-#define PACK_CHILD     0x1
+
 
 /*
 =for apidoc pack_cat
 
-The engine implementing pack() Perl function.
+The engine implementing pack() Perl function. Note: parameters next_in_list and
+flags are not used. This call should not be used; use packlist instead.
 
 =cut */
 
+
 void
 Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beglist, SV **endlist, SV ***next_in_list, U32 flags)
 {
+    tempsym_t sym = { 0 };
+    sym.patptr = pat;
+    sym.patend = patend;
+    sym.flags  = FLAG_PACK;
+
+    (void)pack_rec( cat, &sym, beglist, endlist );
+}
+
+
+/*
+=for apidoc packlist
+
+The engine implementing pack() Perl function.
+
+=cut */
+
+
+void
+Perl_packlist(pTHX_ SV *cat, char *pat, register char *patend, register SV **beglist, SV **endlist )
+{
+    tempsym_t sym = { 0 };
+    sym.patptr = pat;
+    sym.patend = patend;
+    sym.flags  = FLAG_PACK;
+
+    (void)pack_rec( cat, &sym, beglist, endlist );
+}
+
+
+STATIC
+SV **
+S_pack_rec(pTHX_ SV *cat, register tempsym_t* symptr, register SV **beglist, SV **endlist )
+{
     register I32 items;
     STRLEN fromlen;
-    register I32 len;
-    I32 datumtype;
+    register I32 len = 0;
     SV *fromstr;
     /*SUPPRESS 442*/
     static char null10[] = {0,0,0,0,0,0,0,0,0,0};
     static char *space10 = "          ";
-    int star;
+    bool found;
 
     /* These must not be in registers: */
     char achar;
-    I16 ashort;
-    int aint;
-    unsigned int auint;
-    I32 along;
-    U32 aulong;
-    IV aiv;
-    UV auv;
-    NV anv;
-#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
-    long double aldouble;
-#endif
+    I16 ai16;
+    U16 au16;
+    I32 ai32;
+    U32 au32;
 #ifdef HAS_QUAD
     Quad_t aquad;
     Uquad_t auquad;
 #endif
+#if SHORTSIZE != SIZE16
+    short ashort;
+    unsigned short aushort;
+#endif
+    int aint;
+    unsigned int auint;
+#if LONGSIZE != SIZE32
+    long along;
+    unsigned long aulong;
+#endif
     char *aptr;
     float afloat;
     double adouble;
-    int commas = 0;
-#ifdef PERL_NATINT_PACK
-    int natint;                /* native integer */
+#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
+    long double aldouble;
 #endif
+    IV aiv;
+    UV auv;
+    NV anv;
+
+    int strrelbeg = SvCUR(cat);
+    tempsym_t lookahead;
 
     items = endlist - beglist;
+    found = next_symbol( symptr );
+
 #ifndef PACKED_IS_OCTETS
-    pat = next_symbol(pat, patend);
-    if (pat < patend && *pat == 'U' && !flags)
+    if (symptr->level == 0 && found && symptr->code == 'U' ){
        SvUTF8_on(cat);
+    }
 #endif
-    while ((pat = next_symbol(pat, patend)) < patend) {
+
+    while (found) {
        SV *lengthcode = Nullsv;
 #define NEXTFROM ( lengthcode ? lengthcode : items-- > 0 ? *beglist++ : &PL_sv_no)
-       datumtype = *pat++ & 0xFF;
-#ifdef PERL_NATINT_PACK
-       natint = 0;
-#endif
-        if (*pat == '!') {
-           static const char natstr[] = "sSiIlLxX";
 
-           if (strchr(natstr, datumtype)) {
-               if (datumtype == 'x' || datumtype == 'X') {
-                   datumtype |= TYPE_IS_SHRIEKING;
-               } else {                /* XXXX Should be redone similarly! */
-#ifdef PERL_NATINT_PACK
-                   natint = 1;
-#endif
-               }
-               pat++;
-           }
-           else
-               Perl_croak(aTHX_ "'!' allowed only after types %s", natstr);
-       }
-       len = find_count(&pat, patend, &star);
-       if (star > 0)                   /* Count is '*' */
-           len = strchr("@Xxu", datumtype) ? 0 : items;
-       else if (star < 0)              /* Default len */
-           len = 1;
-       if (*pat == '/') {              /* doing lookahead how... */
-           ++pat;
-           if ((*pat != 'a' && *pat != 'A' && *pat != 'Z') || pat[1] != '*')
-               Perl_croak(aTHX_ "/ must be followed by a*, A* or Z*");
-           lengthcode = sv_2mortal(newSViv(sv_len(items > 0
+        I32 datumtype = symptr->code;
+        howlen_t howlen;
+
+        switch( howlen = symptr->howlen ){
+        case e_no_len:
+       case e_number:
+           len = symptr->length;
+           break;
+        case e_star:
+           len = strchr("@Xxu", TYPE_NO_MODIFIERS(datumtype)) ? 0 : items; 
+           break;
+        }
+
+        /* Look ahead for next symbol. Do we have code/code? */
+        lookahead = *symptr;
+        found = next_symbol(&lookahead);
+       if ( symptr->flags & FLAG_SLASH ) {
+           if (found){
+               if ( 0 == strchr( "aAZ", lookahead.code ) ||
+                     e_star != lookahead.howlen )
+                   Perl_croak(aTHX_ "'/' must be followed by 'a*', 'A*' or 'Z*' in pack");
+               lengthcode = sv_2mortal(newSViv(sv_len(items > 0
                                                   ? *beglist : &PL_sv_no)
-                                            + (*pat == 'Z' ? 1 : 0)));
+                                           + (lookahead.code == 'Z' ? 1 : 0)));
+           } else {
+               Perl_croak(aTHX_ "Code missing after '/' in pack");
+            }
        }
-       switch(datumtype) {
+
+       switch(TYPE_NO_ENDIANNESS(datumtype)) {
        default:
-           Perl_croak(aTHX_ "Invalid type in pack: '%c'", (int)datumtype);
-       case ',': /* grandfather in commas but with a warning */
-           if (commas++ == 0 && ckWARN(WARN_PACK))
-               Perl_warner(aTHX_ packWARN(WARN_PACK),
-                           "Invalid type in pack: '%c'", (int)datumtype);
-           break;
+           Perl_croak(aTHX_ "Invalid type '%c' in pack", (int)TYPE_NO_MODIFIERS(datumtype));
        case '%':
-           Perl_croak(aTHX_ "%% may only be used in unpack");
+           Perl_croak(aTHX_ "'%%' may not be used in pack");
        case '@':
-           len -= SvCUR(cat);
+           len += strrelbeg - SvCUR(cat);
            if (len > 0)
                goto grow;
            len = -len;
@@ -1809,27 +2289,20 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            break;
        case '(':
        {
-           char *beg = pat;
-           SV **savebeglist = beglist; /* beglist de-register-ed */
-
-           if (star >= 0)
-               Perl_croak(aTHX_ "()-group starts with a count");
-           aptr = group_end(beg, patend, ')');
-           pat = aptr + 1;
-           if (star != -2) {
-               len = find_count(&pat, patend, &star);
-               if (star < 0)           /* No count */
-                   len = 1;
-               else if (star > 0)      /* Star */
-                   len = items;        /* long enough? */
-           }
+            tempsym_t savsym = *symptr;
+           U32 group_modifiers = TYPE_MODIFIERS(datumtype & ~symptr->flags);
+           symptr->flags |= group_modifiers;
+            symptr->patend = savsym.grpend;
+            symptr->level++;
            while (len--) {
-               pack_cat(cat, beg, aptr, savebeglist, endlist,
-                        &savebeglist, PACK_CHILD);
-               if (star > 0 && savebeglist == endlist)
+               symptr->patptr = savsym.grpbeg;
+               beglist = pack_rec(cat, symptr, beglist, endlist );
+               if (savsym.howlen == e_star && beglist == endlist)
                    break;              /* No way to continue */
            }
-           beglist = savebeglist;
+           symptr->flags &= ~group_modifiers;
+            lookahead.flags = symptr->flags;
+            *symptr = savsym;
            break;
        }
        case 'X' | TYPE_IS_SHRIEKING:
@@ -1839,8 +2312,8 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            /* FALL THROUGH */
        case 'X':
          shrink:
-           if (SvCUR(cat) < len)
-               Perl_croak(aTHX_ "X outside of string");
+           if ((I32)SvCUR(cat) < len)
+               Perl_croak(aTHX_ "'X' outside of string in pack");
            SvCUR(cat) -= len;
            *SvEND(cat) = '\0';
            break;
@@ -1853,6 +2326,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            else
                len = 0;
            /* FALL THROUGH */
+
        case 'x':
          grow:
            while (len >= 10) {
@@ -1866,12 +2340,12 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
        case 'a':
            fromstr = NEXTFROM;
            aptr = SvPV(fromstr, fromlen);
-           if (star > 0) { /* -2 after '/' */  
+           if (howlen == e_star) {   
                len = fromlen;
                if (datumtype == 'Z')
                    ++len;
            }
-           if (fromlen >= len) {
+           if ((I32)fromlen >= len) {
                sv_catpvn(cat, aptr, len);
                if (datumtype == 'Z')
                    *(SvEND(cat)-1) = '\0';
@@ -1904,13 +2378,13 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                fromstr = NEXTFROM;
                saveitems = items;
                str = SvPV(fromstr, fromlen);
-               if (star > 0)
+               if (howlen == e_star)
                    len = fromlen;
                aint = SvCUR(cat);
                SvCUR(cat) += (len+7)/8;
                SvGROW(cat, SvCUR(cat) + 1);
                aptr = SvPVX(cat) + aint;
-               if (len > fromlen)
+               if (len > (I32)fromlen)
                    len = fromlen;
                aint = len;
                items = 0;
@@ -1960,13 +2434,13 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                fromstr = NEXTFROM;
                saveitems = items;
                str = SvPV(fromstr, fromlen);
-               if (star > 0)
+               if (howlen == e_star)
                    len = fromlen;
                aint = SvCUR(cat);
                SvCUR(cat) += (len+1)/2;
                SvGROW(cat, SvCUR(cat) + 1);
                aptr = SvPVX(cat) + aint;
-               if (len > fromlen)
+               if (len > (I32)fromlen)
                    len = fromlen;
                aint = len;
                items = 0;
@@ -2011,13 +2485,13 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
        case 'c':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               switch (datumtype) {
+               switch (TYPE_NO_MODIFIERS(datumtype)) {
                case 'C':
                    aint = SvIV(fromstr);
                    if ((aint < 0 || aint > 255) &&
                        ckWARN(WARN_PACK))
                        Perl_warner(aTHX_ packWARN(WARN_PACK),
-                                   "Character in \"C\" format wrapped");
+                                   "Character in 'C' format wrapped in pack");
                    achar = aint & 255;
                    sv_catpvn(cat, &achar, sizeof(char));
                    break;
@@ -2026,7 +2500,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                    if ((aint < -128 || aint > 127) &&
                        ckWARN(WARN_PACK))
                        Perl_warner(aTHX_ packWARN(WARN_PACK),
-                                   "Character in \"c\" format wrapped");
+                                   "Character in 'c' format wrapped in pack" );
                    achar = aint & 255;
                    sv_catpvn(cat, &achar, sizeof(char));
                    break;
@@ -2038,8 +2512,12 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                fromstr = NEXTFROM;
                auint = UNI_TO_NATIVE(SvUV(fromstr));
                SvGROW(cat, SvCUR(cat) + UTF8_MAXLEN + 1);
-               SvCUR_set(cat, (char*)uvchr_to_utf8((U8*)SvEND(cat),auint)
-                              - SvPVX(cat));
+               SvCUR_set(cat,
+                         (char*)uvchr_to_utf8_flags((U8*)SvEND(cat),
+                                                    auint,
+                                                    ckWARN(WARN_UTF8) ?
+                                                    0 : UNICODE_ALLOW_ANY)
+                         - SvPVX(cat));
            }
            *SvEND(cat) = '\0';
            break;
@@ -2047,102 +2525,165 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
        case 'f':
            while (len-- > 0) {
                fromstr = NEXTFROM;
+#ifdef __VOS__
+/* VOS does not automatically map a floating-point overflow
+   during conversion from double to float into infinity, so we
+   do it by hand.  This code should either be generalized for
+   any OS that needs it, or removed if and when VOS implements
+   posix-976 (suggestion to support mapping to infinity).
+   Paul.Green@stratus.com 02-04-02.  */
+               if (SvNV(fromstr) > FLT_MAX)
+                    afloat = _float_constants[0];   /* single prec. inf. */
+               else if (SvNV(fromstr) < -FLT_MAX)
+                    afloat = _float_constants[0];   /* single prec. inf. */
+               else afloat = (float)SvNV(fromstr);
+#else
+# if defined(VMS) && !defined(__IEEE_FP)
+/* IEEE fp overflow shenanigans are unavailable on VAX and optional
+ * on Alpha; fake it if we don't have them.
+ */
+               if (SvNV(fromstr) > FLT_MAX)
+                    afloat = FLT_MAX;
+               else if (SvNV(fromstr) < -FLT_MAX)
+                    afloat = -FLT_MAX;
+               else afloat = (float)SvNV(fromstr);
+# else
                afloat = (float)SvNV(fromstr);
+# endif
+#endif
+               DO_BO_PACK_N(afloat, float);
                sv_catpvn(cat, (char *)&afloat, sizeof (float));
            }
            break;
        case 'd':
            while (len-- > 0) {
                fromstr = NEXTFROM;
+#ifdef __VOS__
+/* VOS does not automatically map a floating-point overflow
+   during conversion from long double to double into infinity,
+   so we do it by hand.  This code should either be generalized
+   for any OS that needs it, or removed if and when VOS
+   implements posix-976 (suggestion to support mapping to
+   infinity).  Paul.Green@stratus.com 02-04-02.  */
+               if (SvNV(fromstr) > DBL_MAX)
+                    adouble = _double_constants[0];   /* double prec. inf. */
+               else if (SvNV(fromstr) < -DBL_MAX)
+                    adouble = _double_constants[0];   /* double prec. inf. */
+               else adouble = (double)SvNV(fromstr);
+#else
+# if defined(VMS) && !defined(__IEEE_FP)
+/* IEEE fp overflow shenanigans are unavailable on VAX and optional
+ * on Alpha; fake it if we don't have them.
+ */
+               if (SvNV(fromstr) > DBL_MAX)
+                    adouble = DBL_MAX;
+               else if (SvNV(fromstr) < -DBL_MAX)
+                    adouble = -DBL_MAX;
+               else adouble = (double)SvNV(fromstr);
+# else
                adouble = (double)SvNV(fromstr);
+# endif
+#endif
+               DO_BO_PACK_N(adouble, double);
                sv_catpvn(cat, (char *)&adouble, sizeof (double));
            }
            break;
        case 'F':
+           Zero(&anv, 1, NV); /* can be long double with unused bits */
            while (len-- > 0) {
                fromstr = NEXTFROM;
                anv = SvNV(fromstr);
+               DO_BO_PACK_N(anv, NV);
                sv_catpvn(cat, (char *)&anv, NVSIZE);
            }
            break;
 #if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
        case 'D':
+           /* long doubles can have unused bits, which may be nonzero */
+           Zero(&aldouble, 1, long double);
            while (len-- > 0) {
                fromstr = NEXTFROM;
                aldouble = (long double)SvNV(fromstr);
+               DO_BO_PACK_N(aldouble, long double);
                sv_catpvn(cat, (char *)&aldouble, LONG_DOUBLESIZE);
            }
            break;
 #endif
+       case 'n' | TYPE_IS_SHRIEKING:
        case 'n':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               ashort = (I16)SvIV(fromstr);
+               ai16 = (I16)SvIV(fromstr);
 #ifdef HAS_HTONS
-               ashort = PerlSock_htons(ashort);
+               ai16 = PerlSock_htons(ai16);
 #endif
-               CAT16(cat, &ashort);
+               CAT16(cat, &ai16);
            }
            break;
+       case 'v' | TYPE_IS_SHRIEKING:
        case 'v':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               ashort = (I16)SvIV(fromstr);
+               ai16 = (I16)SvIV(fromstr);
 #ifdef HAS_HTOVS
-               ashort = htovs(ashort);
+               ai16 = htovs(ai16);
 #endif
-               CAT16(cat, &ashort);
+               CAT16(cat, &ai16);
            }
            break;
-       case 'S':
+        case 'S' | TYPE_IS_SHRIEKING:
 #if SHORTSIZE != SIZE16
-           if (natint) {
-               unsigned short aushort;
-
+           {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
                    aushort = SvUV(fromstr);
+                   DO_BO_PACK(aushort, s);
                    sv_catpvn(cat, (char *)&aushort, sizeof(unsigned short));
                }
-           }
-           else
+            }
+            break;
+#else
+            /* Fall through! */
 #endif
+       case 'S':
             {
-               U16 aushort;
-
                while (len-- > 0) {
                    fromstr = NEXTFROM;
-                   aushort = (U16)SvUV(fromstr);
-                   CAT16(cat, &aushort);
+                   au16 = (U16)SvUV(fromstr);
+                   DO_BO_PACK(au16, 16);
+                   CAT16(cat, &au16);
                }
 
            }
            break;
-       case 's':
+       case 's' | TYPE_IS_SHRIEKING:
 #if SHORTSIZE != SIZE16
-           if (natint) {
-               short ashort;
-
+           {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
                    ashort = SvIV(fromstr);
+                   DO_BO_PACK(ashort, s);
                    sv_catpvn(cat, (char *)&ashort, sizeof(short));
                }
            }
-           else
+            break;
+#else
+            /* Fall through! */
 #endif
-            {
-               while (len-- > 0) {
-                   fromstr = NEXTFROM;
-                   ashort = (I16)SvIV(fromstr);
-                   CAT16(cat, &ashort);
-               }
+       case 's':
+           while (len-- > 0) {
+               fromstr = NEXTFROM;
+               ai16 = (I16)SvIV(fromstr);
+               DO_BO_PACK(ai16, 16);
+               CAT16(cat, &ai16);
            }
            break;
        case 'I':
+       case 'I' | TYPE_IS_SHRIEKING:
            while (len-- > 0) {
                fromstr = NEXTFROM;
                auint = SvUV(fromstr);
+               DO_BO_PACK(auint, i);
                sv_catpvn(cat, (char*)&auint, sizeof(unsigned int));
            }
            break;
@@ -2150,6 +2691,13 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (len-- > 0) {
                fromstr = NEXTFROM;
                aiv = SvIV(fromstr);
+#if IVSIZE == INTSIZE
+               DO_BO_PACK(aiv, i);
+#elif IVSIZE == LONGSIZE
+               DO_BO_PACK(aiv, l);
+#elif defined(HAS_QUAD) && IVSIZE == U64SIZE
+               DO_BO_PACK(aiv, 64);
+#endif
                sv_catpvn(cat, (char*)&aiv, IVSIZE);
            }
            break;
@@ -2157,30 +2705,37 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (len-- > 0) {
                fromstr = NEXTFROM;
                auv = SvUV(fromstr);
+#if UVSIZE == INTSIZE
+               DO_BO_PACK(auv, i);
+#elif UVSIZE == LONGSIZE
+               DO_BO_PACK(auv, l);
+#elif defined(HAS_QUAD) && UVSIZE == U64SIZE
+               DO_BO_PACK(auv, 64);
+#endif
                sv_catpvn(cat, (char*)&auv, UVSIZE);
            }
            break;
        case 'w':
             while (len-- > 0) {
                fromstr = NEXTFROM;
-               adouble = SvNV(fromstr);
+               anv = SvNV(fromstr);
 
-               if (adouble < 0)
-                   Perl_croak(aTHX_ "Cannot compress negative numbers");
+               if (anv < 0)
+                   Perl_croak(aTHX_ "Cannot compress negative numbers in pack");
 
                 /* 0xFFFFFFFFFFFFFFFF may cast to 18446744073709551616.0,
                    which is == UV_MAX_P1. IOK is fine (instead of UV_only), as
                    any negative IVs will have already been got by the croak()
                    above. IOK is untrue for fractions, so we test them
                    against UV_MAX_P1.  */
-               if (SvIOK(fromstr) || adouble < UV_MAX_P1)
+               if (SvIOK(fromstr) || anv < UV_MAX_P1)
                {
-                   char   buf[1 + sizeof(UV)];
+                   char   buf[(sizeof(UV)*8)/7+1];
                    char  *in = buf + sizeof(buf);
                    UV     auv = SvUV(fromstr);
 
                    do {
-                       *--in = (auv & 0x7f) | 0x80;
+                       *--in = (char)((auv & 0x7f) | 0x80);
                        auv >>= 7;
                    } while (auv);
                    buf[sizeof(buf) - 1] &= 0x7f; /* clear continue bit */
@@ -2195,7 +2750,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                    /* Copy string and check for compliance */
                    from = SvPV(fromstr, len);
                    if ((norm = is_an_int(from, len)) == NULL)
-                       Perl_croak(aTHX_ "can compress only unsigned integer");
+                       Perl_croak(aTHX_ "Can only compress unsigned integers in pack");
 
                    New('w', result, len, char);
                    in = result + len;
@@ -2208,17 +2763,33 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                    SvREFCNT_dec(norm); /* free norm */
                 }
                else if (SvNOKp(fromstr)) {
-                   char   buf[sizeof(double) * 2];     /* 8/7 <= 2 */
+                   /* 10**NV_MAX_10_EXP is the largest power of 10
+                      so 10**(NV_MAX_10_EXP+1) is definately unrepresentable
+                      given 10**(NV_MAX_10_EXP+1) == 128 ** x solve for x:
+                      x = (NV_MAX_10_EXP+1) * log (10) / log (128)
+                      And with that many bytes only Inf can overflow.
+                      Some C compilers are strict about integral constant
+                      expressions so we conservatively divide by a slightly
+                      smaller integer instead of multiplying by the exact
+                      floating-point value.
+                   */
+#ifdef NV_MAX_10_EXP
+/*                 char   buf[1 + (int)((NV_MAX_10_EXP + 1) * 0.47456)]; -- invalid C */
+                   char   buf[1 + (int)((NV_MAX_10_EXP + 1) / 2)]; /* valid C */
+#else
+/*                 char   buf[1 + (int)((308 + 1) * 0.47456)]; -- invalid C */
+                   char   buf[1 + (int)((308 + 1) / 2)]; /* valid C */
+#endif
                    char  *in = buf + sizeof(buf);
 
-                    adouble = Perl_floor(adouble);
+                    anv = Perl_floor(anv);
                    do {
-                       double next = floor(adouble / 128);
-                       *--in = (unsigned char)(adouble - (next * 128)) | 0x80;
+                       NV next = Perl_floor(anv / 128);
                        if (in <= buf)  /* this cannot happen ;-) */
-                           Perl_croak(aTHX_ "Cannot compress integer");
-                       adouble = next;
-                   } while (adouble > 0);
+                           Perl_croak(aTHX_ "Cannot compress integer in pack");
+                       *--in = (unsigned char)(anv - (next * 128)) | 0x80;
+                       anv = next;
+                   } while (anv > 0);
                    buf[sizeof(buf) - 1] &= 0x7f; /* clear continue bit */
                    sv_catpvn(cat, in, (buf + sizeof(buf)) - in);
                }
@@ -2231,7 +2802,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                    /* Copy string and check for compliance */
                    from = SvPV(fromstr, len);
                    if ((norm = is_an_int(from, len)) == NULL)
-                       Perl_croak(aTHX_ "can compress only unsigned integer");
+                       Perl_croak(aTHX_ "Can only compress unsigned integers in pack");
 
                    New('w', result, len, char);
                    in = result + len;
@@ -2246,72 +2817,80 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            }
             break;
        case 'i':
+       case 'i' | TYPE_IS_SHRIEKING:
            while (len-- > 0) {
                fromstr = NEXTFROM;
                aint = SvIV(fromstr);
+               DO_BO_PACK(aint, i);
                sv_catpvn(cat, (char*)&aint, sizeof(int));
            }
            break;
+       case 'N' | TYPE_IS_SHRIEKING:
        case 'N':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               aulong = SvUV(fromstr);
+               au32 = SvUV(fromstr);
 #ifdef HAS_HTONL
-               aulong = PerlSock_htonl(aulong);
+               au32 = PerlSock_htonl(au32);
 #endif
-               CAT32(cat, &aulong);
+               CAT32(cat, &au32);
            }
            break;
+       case 'V' | TYPE_IS_SHRIEKING:
        case 'V':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               aulong = SvUV(fromstr);
+               au32 = SvUV(fromstr);
 #ifdef HAS_HTOVL
-               aulong = htovl(aulong);
+               au32 = htovl(au32);
 #endif
-               CAT32(cat, &aulong);
+               CAT32(cat, &au32);
            }
            break;
-       case 'L':
+       case 'L' | TYPE_IS_SHRIEKING:
 #if LONGSIZE != SIZE32
-           if (natint) {
-               unsigned long aulong;
-
+           {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
                    aulong = SvUV(fromstr);
+                   DO_BO_PACK(aulong, l);
                    sv_catpvn(cat, (char *)&aulong, sizeof(unsigned long));
                }
            }
-           else
+           break;
+#else
+            /* Fall though! */
 #endif
+       case 'L':
             {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
-                   aulong = SvUV(fromstr);
-                   CAT32(cat, &aulong);
+                   au32 = SvUV(fromstr);
+                   DO_BO_PACK(au32, 32);
+                   CAT32(cat, &au32);
                }
            }
            break;
-       case 'l':
+       case 'l' | TYPE_IS_SHRIEKING:
 #if LONGSIZE != SIZE32
-           if (natint) {
-               long along;
-
+           {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
                    along = SvIV(fromstr);
+                   DO_BO_PACK(along, l);
                    sv_catpvn(cat, (char *)&along, sizeof(long));
                }
            }
-           else
+           break;
+#else
+            /* Fall though! */
 #endif
-            {
-               while (len-- > 0) {
-                   fromstr = NEXTFROM;
-                   along = SvIV(fromstr);
-                   CAT32(cat, &along);
-               }
+       case 'l':
+            while (len-- > 0) {
+               fromstr = NEXTFROM;
+               ai32 = SvIV(fromstr);
+               DO_BO_PACK(ai32, 32);
+               CAT32(cat, &ai32);
            }
            break;
 #ifdef HAS_QUAD
@@ -2319,6 +2898,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (len-- > 0) {
                fromstr = NEXTFROM;
                auquad = (Uquad_t)SvUV(fromstr);
+               DO_BO_PACK(auquad, 64);
                sv_catpvn(cat, (char*)&auquad, sizeof(Uquad_t));
            }
            break;
@@ -2326,13 +2906,14 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (len-- > 0) {
                fromstr = NEXTFROM;
                aquad = (Quad_t)SvIV(fromstr);
+               DO_BO_PACK(aquad, 64);
                sv_catpvn(cat, (char*)&aquad, sizeof(Quad_t));
            }
            break;
 #endif
        case 'P':
            len = 1;            /* assume SV is correct length */
-           /* FALL THROUGH */
+           /* Fall through! */
        case 'p':
            while (len-- > 0) {
                fromstr = NEXTFROM;
@@ -2357,6 +2938,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                    else
                        aptr = SvPV_force(fromstr,n_a);
                }
+               DO_BO_PACK_P(aptr);
                sv_catpvn(cat, (char*)&aptr, sizeof(char*));
            }
            break;
@@ -2371,7 +2953,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (fromlen > 0) {
                I32 todo;
 
-               if (fromlen > len)
+               if ((I32)fromlen > len)
                    todo = len;
                else
                    todo = fromlen;
@@ -2381,9 +2963,9 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            }
            break;
        }
+       *symptr = lookahead;
     }
-    if (next_in_list)
-       *next_in_list = beglist;
+    return beglist;
 }
 #undef NEXTFROM
 
@@ -2399,7 +2981,7 @@ PP(pp_pack)
     MARK++;
     sv_setpvn(cat, "", 0);
 
-    pack_cat(cat, pat, patend, MARK, SP + 1, NULL, 0);
+    packlist(cat, pat, patend, MARK, SP + 1);
 
     SvSETMAGIC(cat);
     SP = ORIGMARK;