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Diffstat (limited to 'json-c/linkhash.c')
| -rw-r--r-- | json-c/linkhash.c | 602 |
1 files changed, 0 insertions, 602 deletions
diff --git a/json-c/linkhash.c b/json-c/linkhash.c deleted file mode 100644 index 712c387..0000000 --- a/json-c/linkhash.c +++ /dev/null @@ -1,602 +0,0 @@ -/* - * $Id: linkhash.c,v 1.4 2006/01/26 02:16:28 mclark Exp $ - * - * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd. - * Michael Clark <michael@metaparadigm.com> - * Copyright (c) 2009 Hewlett-Packard Development Company, L.P. - * - * This library is free software; you can redistribute it and/or modify - * it under the terms of the MIT license. See COPYING for details. - * - */ - -#include <stdio.h> -#include <string.h> -#include <stdlib.h> -#include <stdarg.h> -#include <stddef.h> -#include <limits.h> - -#ifdef HAVE_ENDIAN_H -# include <endian.h> /* attempt to define endianness */ -#endif - -#include "random_seed.h" -#include "linkhash.h" - -void lh_abort(const char *msg, ...) -{ - va_list ap; - va_start(ap, msg); - vprintf(msg, ap); - va_end(ap); - exit(1); -} - -unsigned long lh_ptr_hash(const void *k) -{ - /* CAW: refactored to be 64bit nice */ - return (unsigned long)((((ptrdiff_t)k * LH_PRIME) >> 4) & ULONG_MAX); -} - -int lh_ptr_equal(const void *k1, const void *k2) -{ - return (k1 == k2); -} - -/* - * hashlittle from lookup3.c, by Bob Jenkins, May 2006, Public Domain. - * http://burtleburtle.net/bob/c/lookup3.c - * minor modifications to make functions static so no symbols are exported - * minor mofifications to compile with -Werror - */ - -/* -------------------------------------------------------------------------------- -lookup3.c, by Bob Jenkins, May 2006, Public Domain. - -These are functions for producing 32-bit hashes for hash table lookup. -hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final() -are externally useful functions. Routines to test the hash are included -if SELF_TEST is defined. You can use this free for any purpose. It's in -the public domain. It has no warranty. - -You probably want to use hashlittle(). hashlittle() and hashbig() -hash byte arrays. hashlittle() is is faster than hashbig() on -little-endian machines. Intel and AMD are little-endian machines. -On second thought, you probably want hashlittle2(), which is identical to -hashlittle() except it returns two 32-bit hashes for the price of one. -You could implement hashbig2() if you wanted but I haven't bothered here. - -If you want to find a hash of, say, exactly 7 integers, do - a = i1; b = i2; c = i3; - mix(a,b,c); - a += i4; b += i5; c += i6; - mix(a,b,c); - a += i7; - final(a,b,c); -then use c as the hash value. If you have a variable length array of -4-byte integers to hash, use hashword(). If you have a byte array (like -a character string), use hashlittle(). If you have several byte arrays, or -a mix of things, see the comments above hashlittle(). - -Why is this so big? I read 12 bytes at a time into 3 4-byte integers, -then mix those integers. This is fast (you can do a lot more thorough -mixing with 12*3 instructions on 3 integers than you can with 3 instructions -on 1 byte), but shoehorning those bytes into integers efficiently is messy. -------------------------------------------------------------------------------- -*/ - -/* - * My best guess at if you are big-endian or little-endian. This may - * need adjustment. - */ -#if (defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && \ - __BYTE_ORDER == __LITTLE_ENDIAN) || \ - (defined(i386) || defined(__i386__) || defined(__i486__) || \ - defined(__i586__) || defined(__i686__) || defined(vax) || defined(MIPSEL)) -# define HASH_LITTLE_ENDIAN 1 -# define HASH_BIG_ENDIAN 0 -#elif (defined(__BYTE_ORDER) && defined(__BIG_ENDIAN) && \ - __BYTE_ORDER == __BIG_ENDIAN) || \ - (defined(sparc) || defined(POWERPC) || defined(mc68000) || defined(sel)) -# define HASH_LITTLE_ENDIAN 0 -# define HASH_BIG_ENDIAN 1 -#else -# define HASH_LITTLE_ENDIAN 0 -# define HASH_BIG_ENDIAN 0 -#endif - -#define hashsize(n) ((uint32_t)1<<(n)) -#define hashmask(n) (hashsize(n)-1) -#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k)))) - -/* -------------------------------------------------------------------------------- -mix -- mix 3 32-bit values reversibly. - -This is reversible, so any information in (a,b,c) before mix() is -still in (a,b,c) after mix(). - -If four pairs of (a,b,c) inputs are run through mix(), or through -mix() in reverse, there are at least 32 bits of the output that -are sometimes the same for one pair and different for another pair. -This was tested for: -* pairs that differed by one bit, by two bits, in any combination - of top bits of (a,b,c), or in any combination of bottom bits of - (a,b,c). -* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed - the output delta to a Gray code (a^(a>>1)) so a string of 1's (as - is commonly produced by subtraction) look like a single 1-bit - difference. -* the base values were pseudorandom, all zero but one bit set, or - all zero plus a counter that starts at zero. - -Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that -satisfy this are - 4 6 8 16 19 4 - 9 15 3 18 27 15 - 14 9 3 7 17 3 -Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing -for "differ" defined as + with a one-bit base and a two-bit delta. I -used http://burtleburtle.net/bob/hash/avalanche.html to choose -the operations, constants, and arrangements of the variables. - -This does not achieve avalanche. There are input bits of (a,b,c) -that fail to affect some output bits of (a,b,c), especially of a. The -most thoroughly mixed value is c, but it doesn't really even achieve -avalanche in c. - -This allows some parallelism. Read-after-writes are good at doubling -the number of bits affected, so the goal of mixing pulls in the opposite -direction as the goal of parallelism. I did what I could. Rotates -seem to cost as much as shifts on every machine I could lay my hands -on, and rotates are much kinder to the top and bottom bits, so I used -rotates. -------------------------------------------------------------------------------- -*/ -#define mix(a,b,c) \ -{ \ - a -= c; a ^= rot(c, 4); c += b; \ - b -= a; b ^= rot(a, 6); a += c; \ - c -= b; c ^= rot(b, 8); b += a; \ - a -= c; a ^= rot(c,16); c += b; \ - b -= a; b ^= rot(a,19); a += c; \ - c -= b; c ^= rot(b, 4); b += a; \ -} - -/* -------------------------------------------------------------------------------- -final -- final mixing of 3 32-bit values (a,b,c) into c - -Pairs of (a,b,c) values differing in only a few bits will usually -produce values of c that look totally different. This was tested for -* pairs that differed by one bit, by two bits, in any combination - of top bits of (a,b,c), or in any combination of bottom bits of - (a,b,c). -* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed - the output delta to a Gray code (a^(a>>1)) so a string of 1's (as - is commonly produced by subtraction) look like a single 1-bit - difference. -* the base values were pseudorandom, all zero but one bit set, or - all zero plus a counter that starts at zero. - -These constants passed: - 14 11 25 16 4 14 24 - 12 14 25 16 4 14 24 -and these came close: - 4 8 15 26 3 22 24 - 10 8 15 26 3 22 24 - 11 8 15 26 3 22 24 -------------------------------------------------------------------------------- -*/ -#define final(a,b,c) \ -{ \ - c ^= b; c -= rot(b,14); \ - a ^= c; a -= rot(c,11); \ - b ^= a; b -= rot(a,25); \ - c ^= b; c -= rot(b,16); \ - a ^= c; a -= rot(c,4); \ - b ^= a; b -= rot(a,14); \ - c ^= b; c -= rot(b,24); \ -} - - -/* -------------------------------------------------------------------------------- -hashlittle() -- hash a variable-length key into a 32-bit value - k : the key (the unaligned variable-length array of bytes) - length : the length of the key, counting by bytes - initval : can be any 4-byte value -Returns a 32-bit value. Every bit of the key affects every bit of -the return value. Two keys differing by one or two bits will have -totally different hash values. - -The best hash table sizes are powers of 2. There is no need to do -mod a prime (mod is sooo slow!). If you need less than 32 bits, -use a bitmask. For example, if you need only 10 bits, do - h = (h & hashmask(10)); -In which case, the hash table should have hashsize(10) elements. - -If you are hashing n strings (uint8_t **)k, do it like this: - for (i=0, h=0; i<n; ++i) h = hashlittle( k[i], len[i], h); - -By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this -code any way you wish, private, educational, or commercial. It's free. - -Use for hash table lookup, or anything where one collision in 2^^32 is -acceptable. Do NOT use for cryptographic purposes. -------------------------------------------------------------------------------- -*/ - -static uint32_t hashlittle( const void *key, size_t length, uint32_t initval) -{ - uint32_t a,b,c; /* internal state */ - union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */ - - /* Set up the internal state */ - a = b = c = 0xdeadbeef + ((uint32_t)length) + initval; - - u.ptr = key; - if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) { - const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */ - - /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */ - while (length > 12) - { - a += k[0]; - b += k[1]; - c += k[2]; - mix(a,b,c); - length -= 12; - k += 3; - } - - /*----------------------------- handle the last (probably partial) block */ - /* - * "k[2]&0xffffff" actually reads beyond the end of the string, but - * then masks off the part it's not allowed to read. Because the - * string is aligned, the masked-off tail is in the same word as the - * rest of the string. Every machine with memory protection I've seen - * does it on word boundaries, so is OK with this. But VALGRIND will - * still catch it and complain. The masking trick does make the hash - * noticably faster for short strings (like English words). - */ -#ifndef VALGRIND - - switch(length) - { - case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; - case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break; - case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break; - case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break; - case 8 : b+=k[1]; a+=k[0]; break; - case 7 : b+=k[1]&0xffffff; a+=k[0]; break; - case 6 : b+=k[1]&0xffff; a+=k[0]; break; - case 5 : b+=k[1]&0xff; a+=k[0]; break; - case 4 : a+=k[0]; break; - case 3 : a+=k[0]&0xffffff; break; - case 2 : a+=k[0]&0xffff; break; - case 1 : a+=k[0]&0xff; break; - case 0 : return c; /* zero length strings require no mixing */ - } - -#else /* make valgrind happy */ - - const uint8_t *k8 = (const uint8_t *)k; - switch(length) - { - case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; - case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ - case 10: c+=((uint32_t)k8[9])<<8; /* fall through */ - case 9 : c+=k8[8]; /* fall through */ - case 8 : b+=k[1]; a+=k[0]; break; - case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ - case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */ - case 5 : b+=k8[4]; /* fall through */ - case 4 : a+=k[0]; break; - case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ - case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */ - case 1 : a+=k8[0]; break; - case 0 : return c; - } - -#endif /* !valgrind */ - - } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) { - const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */ - const uint8_t *k8; - - /*--------------- all but last block: aligned reads and different mixing */ - while (length > 12) - { - a += k[0] + (((uint32_t)k[1])<<16); - b += k[2] + (((uint32_t)k[3])<<16); - c += k[4] + (((uint32_t)k[5])<<16); - mix(a,b,c); - length -= 12; - k += 6; - } - - /*----------------------------- handle the last (probably partial) block */ - k8 = (const uint8_t *)k; - switch(length) - { - case 12: c+=k[4]+(((uint32_t)k[5])<<16); - b+=k[2]+(((uint32_t)k[3])<<16); - a+=k[0]+(((uint32_t)k[1])<<16); - break; - case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ - case 10: c+=k[4]; - b+=k[2]+(((uint32_t)k[3])<<16); - a+=k[0]+(((uint32_t)k[1])<<16); - break; - case 9 : c+=k8[8]; /* fall through */ - case 8 : b+=k[2]+(((uint32_t)k[3])<<16); - a+=k[0]+(((uint32_t)k[1])<<16); - break; - case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ - case 6 : b+=k[2]; - a+=k[0]+(((uint32_t)k[1])<<16); - break; - case 5 : b+=k8[4]; /* fall through */ - case 4 : a+=k[0]+(((uint32_t)k[1])<<16); - break; - case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ - case 2 : a+=k[0]; - break; - case 1 : a+=k8[0]; - break; - case 0 : return c; /* zero length requires no mixing */ - } - - } else { /* need to read the key one byte at a time */ - const uint8_t *k = (const uint8_t *)key; - - /*--------------- all but the last block: affect some 32 bits of (a,b,c) */ - while (length > 12) - { - a += k[0]; - a += ((uint32_t)k[1])<<8; - a += ((uint32_t)k[2])<<16; - a += ((uint32_t)k[3])<<24; - b += k[4]; - b += ((uint32_t)k[5])<<8; - b += ((uint32_t)k[6])<<16; - b += ((uint32_t)k[7])<<24; - c += k[8]; - c += ((uint32_t)k[9])<<8; - c += ((uint32_t)k[10])<<16; - c += ((uint32_t)k[11])<<24; - mix(a,b,c); - length -= 12; - k += 12; - } - - /*-------------------------------- last block: affect all 32 bits of (c) */ - switch(length) /* all the case statements fall through */ - { - case 12: c+=((uint32_t)k[11])<<24; - case 11: c+=((uint32_t)k[10])<<16; - case 10: c+=((uint32_t)k[9])<<8; - case 9 : c+=k[8]; - case 8 : b+=((uint32_t)k[7])<<24; - case 7 : b+=((uint32_t)k[6])<<16; - case 6 : b+=((uint32_t)k[5])<<8; - case 5 : b+=k[4]; - case 4 : a+=((uint32_t)k[3])<<24; - case 3 : a+=((uint32_t)k[2])<<16; - case 2 : a+=((uint32_t)k[1])<<8; - case 1 : a+=k[0]; - break; - case 0 : return c; - } - } - - final(a,b,c); - return c; -} - -unsigned long lh_char_hash(const void *k) -{ - static volatile int random_seed = -1; - - if (random_seed == -1) { - int seed; - /* we can't use -1 as it is the unitialized sentinel */ - while ((seed = json_c_get_random_seed()) == -1); -#if defined __GNUC__ - __sync_val_compare_and_swap(&random_seed, -1, seed); -#elif defined _MSC_VER - InterlockedCompareExchange(&random_seed, seed, -1); -#else -#warning "racy random seed initializtion if used by multiple threads" - random_seed = seed; /* potentially racy */ -#endif - } - - return hashlittle((const char*)k, strlen((const char*)k), random_seed); -} - -int lh_char_equal(const void *k1, const void *k2) -{ - return (strcmp((const char*)k1, (const char*)k2) == 0); -} - -struct lh_table* lh_table_new(int size, const char *name, - lh_entry_free_fn *free_fn, - lh_hash_fn *hash_fn, - lh_equal_fn *equal_fn) -{ - int i; - struct lh_table *t; - - t = (struct lh_table*)calloc(1, sizeof(struct lh_table)); - if(!t) lh_abort("lh_table_new: calloc failed\n"); - t->count = 0; - t->size = size; - t->name = name; - t->table = (struct lh_entry*)calloc(size, sizeof(struct lh_entry)); - if(!t->table) lh_abort("lh_table_new: calloc failed\n"); - t->free_fn = free_fn; - t->hash_fn = hash_fn; - t->equal_fn = equal_fn; - for(i = 0; i < size; i++) t->table[i].k = LH_EMPTY; - return t; -} - -struct lh_table* lh_kchar_table_new(int size, const char *name, - lh_entry_free_fn *free_fn) -{ - return lh_table_new(size, name, free_fn, lh_char_hash, lh_char_equal); -} - -struct lh_table* lh_kptr_table_new(int size, const char *name, - lh_entry_free_fn *free_fn) -{ - return lh_table_new(size, name, free_fn, lh_ptr_hash, lh_ptr_equal); -} - -void lh_table_resize(struct lh_table *t, int new_size) -{ - struct lh_table *new_t; - struct lh_entry *ent; - - new_t = lh_table_new(new_size, t->name, NULL, t->hash_fn, t->equal_fn); - ent = t->head; - while(ent) { - lh_table_insert(new_t, ent->k, ent->v); - ent = ent->next; - } - free(t->table); - t->table = new_t->table; - t->size = new_size; - t->head = new_t->head; - t->tail = new_t->tail; - t->resizes++; - free(new_t); -} - -void lh_table_free(struct lh_table *t) -{ - struct lh_entry *c; - for(c = t->head; c != NULL; c = c->next) { - if(t->free_fn) { - t->free_fn(c); - } - } - free(t->table); - free(t); -} - - -int lh_table_insert(struct lh_table *t, void *k, const void *v) -{ - unsigned long h, n; - - t->inserts++; - if(t->count >= t->size * LH_LOAD_FACTOR) lh_table_resize(t, t->size * 2); - - h = t->hash_fn(k); - n = h % t->size; - - while( 1 ) { - if(t->table[n].k == LH_EMPTY || t->table[n].k == LH_FREED) break; - t->collisions++; - if ((int)++n == t->size) n = 0; - } - - t->table[n].k = k; - t->table[n].v = v; - t->count++; - - if(t->head == NULL) { - t->head = t->tail = &t->table[n]; - t->table[n].next = t->table[n].prev = NULL; - } else { - t->tail->next = &t->table[n]; - t->table[n].prev = t->tail; - t->table[n].next = NULL; - t->tail = &t->table[n]; - } - - return 0; -} - - -struct lh_entry* lh_table_lookup_entry(struct lh_table *t, const void *k) -{ - unsigned long h = t->hash_fn(k); - unsigned long n = h % t->size; - int count = 0; - - t->lookups++; - while( count < t->size ) { - if(t->table[n].k == LH_EMPTY) return NULL; - if(t->table[n].k != LH_FREED && - t->equal_fn(t->table[n].k, k)) return &t->table[n]; - if ((int)++n == t->size) n = 0; - count++; - } - return NULL; -} - - -const void* lh_table_lookup(struct lh_table *t, const void *k) -{ - void *result; - lh_table_lookup_ex(t, k, &result); - return result; -} - -json_bool lh_table_lookup_ex(struct lh_table* t, const void* k, void **v) -{ - struct lh_entry *e = lh_table_lookup_entry(t, k); - if (e != NULL) { - if (v != NULL) *v = (void *)e->v; - return TRUE; /* key found */ - } - if (v != NULL) *v = NULL; - return FALSE; /* key not found */ -} - -int lh_table_delete_entry(struct lh_table *t, struct lh_entry *e) -{ - ptrdiff_t n = (ptrdiff_t)(e - t->table); /* CAW: fixed to be 64bit nice, still need the crazy negative case... */ - - /* CAW: this is bad, really bad, maybe stack goes other direction on this machine... */ - if(n < 0) { return -2; } - - if(t->table[n].k == LH_EMPTY || t->table[n].k == LH_FREED) return -1; - t->count--; - if(t->free_fn) t->free_fn(e); - t->table[n].v = NULL; - t->table[n].k = LH_FREED; - if(t->tail == &t->table[n] && t->head == &t->table[n]) { - t->head = t->tail = NULL; - } else if (t->head == &t->table[n]) { - t->head->next->prev = NULL; - t->head = t->head->next; - } else if (t->tail == &t->table[n]) { - t->tail->prev->next = NULL; - t->tail = t->tail->prev; - } else { - t->table[n].prev->next = t->table[n].next; - t->table[n].next->prev = t->table[n].prev; - } - t->table[n].next = t->table[n].prev = NULL; - return 0; -} - - -int lh_table_delete(struct lh_table *t, const void *k) -{ - struct lh_entry *e = lh_table_lookup_entry(t, k); - if(!e) return -1; - return lh_table_delete_entry(t, e); -} - -int lh_table_length(struct lh_table *t) -{ - return t->count; -} |