doco improvement for attributes.pm

[perl5.git] / utf8.c

diff --git a/utf8.c b/utf8.c
index bfcc40c..2b1e99b 100644 (file)
--- a/utf8.c
+++ b/utf8.c
@@ -257,9 +257,9 @@ Perl_uvuni_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags)
 
 /*
 
-Tests if some arbitrary number of bytes begins in a valid UTF-8
+Tests if the first C<len> bytes of string C<s> form a valid UTF-8
 character.  Note that an INVARIANT (i.e. ASCII) character is a valid
-UTF-8 character.  The actual number of bytes in the UTF-8 character
+UTF-8 character.  The number of bytes in the UTF-8 character
 will be returned if it is valid, otherwise 0.
 
 This is the "slow" version as opposed to the "fast" version which is
@@ -283,7 +283,7 @@ S_is_utf8_char_slow(const U8 *s, const STRLEN len)
     PERL_ARGS_ASSERT_IS_UTF8_CHAR_SLOW;
 
     if (UTF8_IS_INVARIANT(u))
-       return 1;
+       return len == 1;
 
     if (!UTF8_IS_START(u))
        return 0;
@@ -316,28 +316,65 @@ S_is_utf8_char_slow(const U8 *s, const STRLEN len)
 }
 
 /*
+=for apidoc is_utf8_char_buf
+
+Returns the number of bytes that comprise the first UTF-8 encoded character in
+buffer C<buf>.  C<buf_end> should point to one position beyond the end of the
+buffer.  0 is returned if C<buf> does not point to a complete, valid UTF-8
+encoded character.
+
+Note that an INVARIANT character (i.e. ASCII on non-EBCDIC
+machines) is a valid UTF-8 character.
+
+=cut */
+
+STRLEN
+Perl_is_utf8_char_buf(const U8 *buf, const U8* buf_end)
+{
+
+    STRLEN len;
+
+    PERL_ARGS_ASSERT_IS_UTF8_CHAR_BUF;
+
+    if (buf_end <= buf) {
+       return 0;
+    }
+
+    len = buf_end - buf;
+    if (len > UTF8SKIP(buf)) {
+       len = UTF8SKIP(buf);
+    }
+
+#ifdef IS_UTF8_CHAR
+    if (IS_UTF8_CHAR_FAST(len))
+        return IS_UTF8_CHAR(buf, len) ? len : 0;
+#endif /* #ifdef IS_UTF8_CHAR */
+    return is_utf8_char_slow(buf, len);
+}
+
+/*
 =for apidoc is_utf8_char
 
+DEPRECATED!
+
 Tests if some arbitrary number of bytes begins in a valid UTF-8
 character.  Note that an INVARIANT (i.e. ASCII on non-EBCDIC machines)
 character is a valid UTF-8 character.  The actual number of bytes in the UTF-8
 character will be returned if it is valid, otherwise 0.
 
-WARNING: use only if you *know* that C<s> has at least either UTF8_MAXBYTES or
-UTF8SKIP(s) bytes.
+This function is deprecated due to the possibility that malformed input could
+cause reading beyond the end of the input buffer.  Use C<is_utf8_char_buf>
+instead.
 
 =cut */
+
 STRLEN
 Perl_is_utf8_char(const U8 *s)
 {
-    const STRLEN len = UTF8SKIP(s);
-
     PERL_ARGS_ASSERT_IS_UTF8_CHAR;
-#ifdef IS_UTF8_CHAR
-    if (IS_UTF8_CHAR_FAST(len))
-        return IS_UTF8_CHAR(s, len) ? len : 0;
-#endif /* #ifdef IS_UTF8_CHAR */
-    return is_utf8_char_slow(s, len);
+
+    /* Assumes we have enough space, which is why this is deprecated */
+    return is_utf8_char_buf(s, s + UTF8SKIP(s));
 }
 
 
@@ -1645,7 +1682,12 @@ S_is_utf8_common(pTHX_ const U8 *const p, SV **swash,
 
     PERL_ARGS_ASSERT_IS_UTF8_COMMON;
 
-    if (!is_utf8_char(p))
+    /* The API should have included a length for the UTF-8 character in <p>,
+     * but it doesn't.  We therefor assume that p has been validated at least
+     * as far as there being enough bytes available in it to accommodate the
+     * character without reading beyond the end, and pass that number on to the
+     * validating routine */
+    if (!is_utf8_char_buf(p, p + UTF8SKIP(p)))
        return FALSE;
     if (!*swash)
        *swash = swash_init("utf8", swashname, &PL_sv_undef, 1, 0);
@@ -1987,6 +2029,18 @@ Perl_is_utf8_X_LV_LVT_V(pTHX_ const U8 *p)
     return is_utf8_common(p, &PL_utf8_X_LV_LVT_V, "_X_LV_LVT_V");
 }
 
+bool
+Perl__is_utf8_quotemeta(pTHX_ const U8 *p)
+{
+    /* For exclusive use of pp_quotemeta() */
+
+    dVAR;
+
+    PERL_ARGS_ASSERT__IS_UTF8_QUOTEMETA;
+
+    return is_utf8_common(p, &PL_utf8_quotemeta, "_Perl_Quotemeta");
+}
+
 /*
 =for apidoc to_utf8_case