X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/9607fc9c489d4095e3baa795d7ead7acba96137d..4b1aa53e75357addb0d99a877dc385e70b2f795b:/hv.h diff --git a/hv.h b/hv.h index 20af4ea..81044c9 100644 --- a/hv.h +++ b/hv.h @@ -1,33 +1,43 @@ /* hv.h * - * Copyright (c) 1991-1997, Larry Wall + * Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999, + * 2000, 2001, 2002, 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. * */ +/* typedefs to eliminate some typing */ typedef struct he HE; typedef struct hek HEK; +/* entry in hash value chain */ struct he { - HE *hent_next; - HEK *hent_hek; - SV *hent_val; + HE *hent_next; /* next entry in chain */ + HEK *hent_hek; /* hash key */ + SV *hent_val; /* scalar value that was hashed */ }; +/* hash key -- defined separately for use as shared pointer */ struct hek { - U32 hek_hash; - I32 hek_len; - char hek_key[1]; + U32 hek_hash; /* hash of key */ + I32 hek_len; /* length of hash key */ + char hek_key[1]; /* variable-length hash key */ + /* the hash-key is \0-terminated */ + /* after the \0 there is a byte for flags, such as whether the key + is UTF-8 */ }; +/* hash structure: */ +/* This structure must match the beginning of struct xpvmg in sv.h. */ struct xpvhv { char * xhv_array; /* pointer to malloced string */ STRLEN xhv_fill; /* how full xhv_array currently is */ STRLEN xhv_max; /* subscript of last element of xhv_array */ - I32 xhv_keys; /* how many elements in the array */ - double xnv_nv; /* numeric value, if any */ + IV xhv_keys; /* how many elements in the array */ + NV xnv_nv; /* numeric value, if any */ +#define xhv_placeholders xnv_nv MAGIC* xmg_magic; /* magic for scalar array */ HV* xmg_stash; /* class package */ @@ -37,40 +47,185 @@ struct xpvhv { char *xhv_name; /* name, if a symbol table */ }; +/* hash a key */ +/* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins + * from requirements by Colin Plumb. + * (http://burtleburtle.net/bob/hash/doobs.html) */ +/* The use of a temporary pointer and the casting games + * is needed to serve the dual purposes of + * (a) the hashed data being interpreted as "unsigned char" (new since 5.8, + * a "char" can be either signed or signed, depending on the compiler) + * (b) catering for old code that uses a "char" + * + * The "hash seed" feature was added in Perl 5.8.1 to perturb the results + * to avoid "algorithmic complexity attacks". + * + * If USE_HASH_SEED is defined, hash randomisation is done by default + * If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done + * only if the environment variable PERL_HASH_SEED is set. + * For maximal control, one can define PERL_HASH_SEED. + * (see also erl.c:perl_parse()). + */ +#ifndef PERL_HASH_SEED +# if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT) +# define PERL_HASH_SEED PL_hash_seed +# else +# define PERL_HASH_SEED 0 +# endif +#endif #define PERL_HASH(hash,str,len) \ STMT_START { \ - register char *s_PeRlHaSh = str; \ + register const char *s_PeRlHaSh_tmp = str; \ + register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \ + register I32 i_PeRlHaSh = len; \ + register U32 hash_PeRlHaSh = PERL_HASH_SEED; \ + while (i_PeRlHaSh--) { \ + hash_PeRlHaSh += *s_PeRlHaSh++; \ + hash_PeRlHaSh += (hash_PeRlHaSh << 10); \ + hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \ + } \ + hash_PeRlHaSh += (hash_PeRlHaSh << 3); \ + hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \ + (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \ + } STMT_END + +/* Only hv.c and mod_perl should be doing this. */ +#ifdef PERL_HASH_INTERNAL_ACCESS +#define PERL_HASH_INTERNAL(hash,str,len) \ + STMT_START { \ + register const char *s_PeRlHaSh_tmp = str; \ + register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \ register I32 i_PeRlHaSh = len; \ - register U32 hash_PeRlHaSh = 0; \ - while (i_PeRlHaSh--) \ - hash_PeRlHaSh = hash_PeRlHaSh * 33 + *s_PeRlHaSh++; \ - (hash) = hash_PeRlHaSh; \ + register U32 hash_PeRlHaSh = PL_rehash_seed; \ + while (i_PeRlHaSh--) { \ + hash_PeRlHaSh += *s_PeRlHaSh++; \ + hash_PeRlHaSh += (hash_PeRlHaSh << 10); \ + hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \ + } \ + hash_PeRlHaSh += (hash_PeRlHaSh << 3); \ + hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \ + (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \ } STMT_END +#endif + +/* +=head1 Hash Manipulation Functions + +=for apidoc AmU||HEf_SVKEY +This flag, used in the length slot of hash entries and magic structures, +specifies the structure contains an C pointer where a C pointer +is to be expected. (For information only--not to be used). + +=head1 Handy Values + +=for apidoc AmU||Nullhv +Null HV pointer. + +=head1 Hash Manipulation Functions + +=for apidoc Am|char*|HvNAME|HV* stash +Returns the package name of a stash. See C, C. + +=for apidoc Am|void*|HeKEY|HE* he +Returns the actual pointer stored in the key slot of the hash entry. The +pointer may be either C or C, depending on the value of +C. Can be assigned to. The C or C macros are +usually preferable for finding the value of a key. + +=for apidoc Am|STRLEN|HeKLEN|HE* he +If this is negative, and amounts to C, it indicates the entry +holds an C key. Otherwise, holds the actual length of the key. Can +be assigned to. The C macro is usually preferable for finding key +lengths. + +=for apidoc Am|SV*|HeVAL|HE* he +Returns the value slot (type C) stored in the hash entry. + +=for apidoc Am|U32|HeHASH|HE* he +Returns the computed hash stored in the hash entry. + +=for apidoc Am|char*|HePV|HE* he|STRLEN len +Returns the key slot of the hash entry as a C value, doing any +necessary dereferencing of possibly C keys. The length of the string +is placed in C (this is a macro, so do I use C<&len>). If you do +not care about what the length of the key is, you may use the global +variable C, though this is rather less efficient than using a local +variable. Remember though, that hash keys in perl are free to contain +embedded nulls, so using C or similar is not a good way to find +the length of hash keys. This is very similar to the C macro +described elsewhere in this document. + +=for apidoc Am|SV*|HeSVKEY|HE* he +Returns the key as an C, or C if the hash entry does not +contain an C key. +=for apidoc Am|SV*|HeSVKEY_force|HE* he +Returns the key as an C. Will create and return a temporary mortal +C if the hash entry contains only a C key. + +=for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv +Sets the key to a given C, taking care to set the appropriate flags to +indicate the presence of an C key, and returns the same +C. + +=cut +*/ /* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */ -#define HEf_SVKEY -2 /* hent_key is a SV* */ +#define HEf_SVKEY -2 /* hent_key is an SV* */ #define Nullhv Null(HV*) -#define HvARRAY(hv) ((HE**)((XPVHV*) SvANY(hv))->xhv_array) +#define HvARRAY(hv) (*(HE***)&((XPVHV*) SvANY(hv))->xhv_array) #define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill #define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max -#define HvKEYS(hv) ((XPVHV*) SvANY(hv))->xhv_keys #define HvRITER(hv) ((XPVHV*) SvANY(hv))->xhv_riter #define HvEITER(hv) ((XPVHV*) SvANY(hv))->xhv_eiter #define HvPMROOT(hv) ((XPVHV*) SvANY(hv))->xhv_pmroot #define HvNAME(hv) ((XPVHV*) SvANY(hv))->xhv_name +/* the number of keys (including any placeholers) */ +#define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys) + +/* The number of placeholders in the enumerated-keys hash */ +#define XHvPLACEHOLDERS(xhv) ((xhv)->xhv_placeholders) + +/* the number of keys that exist() (i.e. excluding placeholders) */ +#define XHvUSEDKEYS(xhv) (XHvTOTALKEYS(xhv) - (IV)XHvPLACEHOLDERS(xhv)) + +/* + * HvKEYS gets the number of keys that actually exist(), and is provided + * for backwards compatibility with old XS code. The core uses HvUSEDKEYS + * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders) + */ +#define HvKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv)) +#define HvUSEDKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv)) +#define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv)) +#define HvPLACEHOLDERS(hv) XHvPLACEHOLDERS((XPVHV*) SvANY(hv)) + #define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS) #define HvSHAREKEYS_on(hv) (SvFLAGS(hv) |= SVphv_SHAREKEYS) #define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS) +/* This is an optimisation flag. It won't be set if all hash keys have a 0 + * flag. Currently the only flags relate to utf8. + * Hence it won't be set if all keys are 8 bit only. It will be set if any key + * is utf8 (including 8 bit keys that were entered as utf8, and need upgrading + * when retrieved during iteration. It may still be set when there are no longer + * any utf8 keys. + * See HVhek_ENABLEHVKFLAGS for the trigger. + */ +#define HvHASKFLAGS(hv) (SvFLAGS(hv) & SVphv_HASKFLAGS) +#define HvHASKFLAGS_on(hv) (SvFLAGS(hv) |= SVphv_HASKFLAGS) +#define HvHASKFLAGS_off(hv) (SvFLAGS(hv) &= ~SVphv_HASKFLAGS) + #define HvLAZYDEL(hv) (SvFLAGS(hv) & SVphv_LAZYDEL) #define HvLAZYDEL_on(hv) (SvFLAGS(hv) |= SVphv_LAZYDEL) #define HvLAZYDEL_off(hv) (SvFLAGS(hv) &= ~SVphv_LAZYDEL) -#ifdef OVERLOAD +#define HvREHASH(hv) (SvFLAGS(hv) & SVphv_REHASH) +#define HvREHASH_on(hv) (SvFLAGS(hv) |= SVphv_REHASH) +#define HvREHASH_off(hv) (SvFLAGS(hv) &= ~SVphv_REHASH) /* Maybe amagical: */ /* #define HV_AMAGICmb(hv) (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */ @@ -85,14 +240,17 @@ struct xpvhv { #define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM) */ -#endif /* OVERLOAD */ - #define Nullhe Null(HE*) #define HeNEXT(he) (he)->hent_next #define HeKEY_hek(he) (he)->hent_hek #define HeKEY(he) HEK_KEY(HeKEY_hek(he)) #define HeKEY_sv(he) (*(SV**)HeKEY(he)) #define HeKLEN(he) HEK_LEN(HeKEY_hek(he)) +#define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he)) +#define HeKWASUTF8(he) HEK_WASUTF8(HeKEY_hek(he)) +#define HeKREHASH(he) HEK_REHASH(HeKEY_hek(he)) +#define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he)) +#define HeKFLAGS(he) HEK_FLAGS(HeKEY_hek(he)) #define HeVAL(he) (he)->hent_val #define HeHASH(he) HEK_HASH(HeKEY_hek(he)) #define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \ @@ -107,9 +265,9 @@ struct xpvhv { #define HeSVKEY_force(he) (HeKEY(he) ? \ ((HeKLEN(he) == HEf_SVKEY) ? \ HeKEY_sv(he) : \ - sv_2mortal(newSVpv(HeKEY(he), \ + sv_2mortal(newSVpvn(HeKEY(he), \ HeKLEN(he)))) : \ - &sv_undef) + &PL_sv_undef) #define HeSVKEY_set(he,sv) ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv)) #define Nullhek Null(HEK*) @@ -117,3 +275,49 @@ struct xpvhv { #define HEK_HASH(hek) (hek)->hek_hash #define HEK_LEN(hek) (hek)->hek_len #define HEK_KEY(hek) (hek)->hek_key +#define HEK_FLAGS(hek) (*((unsigned char *)(HEK_KEY(hek))+HEK_LEN(hek)+1)) + +#define HVhek_UTF8 0x01 /* Key is utf8 encoded. */ +#define HVhek_WASUTF8 0x02 /* Key is bytes here, but was supplied as utf8. */ +#define HVhek_REHASH 0x04 /* This key is in an hv using a custom HASH . */ +#define HVhek_FREEKEY 0x100 /* Internal flag to say key is malloc()ed. */ +#define HVhek_PLACEHOLD 0x200 /* Internal flag to create placeholder. + * (may change, but Storable is a core module) */ +#define HVhek_MASK 0xFF + +/* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as + HVhek_REHASH is only needed because the rehash flag has to be duplicated + into all keys as hv_iternext has no access to the hash flags. At this + point Storable's tests get upset, because sometimes hashes are "keyed" + and sometimes not, depending on the order of data insertion, and whether + it triggered rehashing. So currently HVhek_REHAS is exempt. +*/ + +#define HVhek_ENABLEHVKFLAGS (HVhek_MASK - HVhek_REHASH) + +#define HEK_UTF8(hek) (HEK_FLAGS(hek) & HVhek_UTF8) +#define HEK_UTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_UTF8) +#define HEK_UTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_UTF8) +#define HEK_WASUTF8(hek) (HEK_FLAGS(hek) & HVhek_WASUTF8) +#define HEK_WASUTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_WASUTF8) +#define HEK_WASUTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_WASUTF8) +#define HEK_REHASH(hek) (HEK_FLAGS(hek) & HVhek_REHASH) +#define HEK_REHASH_on(hek) (HEK_FLAGS(hek) |= HVhek_REHASH) + +/* calculate HV array allocation */ +#if defined(STRANGE_MALLOC) || defined(MYMALLOC) +# define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*)) +#else +# define MALLOC_OVERHEAD 16 +# define PERL_HV_ARRAY_ALLOC_BYTES(size) \ + (((size) < 64) \ + ? (size) * sizeof(HE*) \ + : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD) +#endif + +/* Flags for hv_iternext_flags. */ +#define HV_ITERNEXT_WANTPLACEHOLDERS 0x01 /* Don't skip placeholders. */ + +/* available as a function in hv.c */ +#define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash)) +#define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash)