/* * Copyright (C) 2012 * Dale Weiler * Wolfgang Bumiller * * Permission is hereby granted, free of charge, to any person obtaining a copy of * this software and associated documentation files (the "Software"), to deal in * the Software without restriction, including without limitation the rights to * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies * of the Software, and to permit persons to whom the Software is furnished to do * so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ #include #include #include "gmqcc.h" /* TODO: remove globals ... */ uint64_t mem_ab = 0; uint64_t mem_db = 0; uint64_t mem_at = 0; uint64_t mem_dt = 0; struct memblock_t { const char *file; unsigned int line; size_t byte; struct memblock_t *next; struct memblock_t *prev; }; static struct memblock_t *mem_start = NULL; void *util_memory_a(size_t byte, unsigned int line, const char *file) { struct memblock_t *info = (struct memblock_t*)malloc(sizeof(struct memblock_t) + byte); void *data = (void*)(info+1); if (!info) return NULL; info->line = line; info->byte = byte; info->file = file; info->prev = NULL; info->next = mem_start; if (mem_start) mem_start->prev = info; mem_start = info; util_debug("MEM", "allocation: % 8u (bytes) address 0x%08X @ %s:%u\n", byte, data, file, line); mem_at++; mem_ab += info->byte; return data; } void util_memory_d(void *ptrn, unsigned int line, const char *file) { struct memblock_t *info = NULL; if (!ptrn) return; info = ((struct memblock_t*)ptrn - 1); util_debug("MEM", "released: % 8u (bytes) address 0x%08X @ %s:%u\n", info->byte, ptrn, file, line); mem_db += info->byte; mem_dt++; if (info->prev) info->prev->next = info->next; if (info->next) info->next->prev = info->prev; if (info == mem_start) mem_start = info->next; free(info); } void *util_memory_r(void *ptrn, size_t byte, unsigned int line, const char *file) { struct memblock_t *oldinfo = NULL; struct memblock_t *newinfo; if (!ptrn) return util_memory_a(byte, line, file); if (!byte) { util_memory_d(ptrn, line, file); return NULL; } oldinfo = ((struct memblock_t*)ptrn - 1); newinfo = ((struct memblock_t*)malloc(sizeof(struct memblock_t) + byte)); util_debug("MEM", "reallocation: % 8u -> %u (bytes) address 0x%08X -> 0x%08X @ %s:%u\n", oldinfo->byte, byte, ptrn, (void*)(newinfo+1), file, line); /* new data */ if (!newinfo) { util_memory_d(oldinfo+1, line, file); return NULL; } /* copy old */ memcpy(newinfo+1, oldinfo+1, oldinfo->byte); /* free old */ if (oldinfo->prev) oldinfo->prev->next = oldinfo->next; if (oldinfo->next) oldinfo->next->prev = oldinfo->prev; if (oldinfo == mem_start) mem_start = oldinfo->next; /* fill info */ newinfo->line = line; newinfo->byte = byte; newinfo->file = file; newinfo->prev = NULL; newinfo->next = mem_start; if (mem_start) mem_start->prev = newinfo; mem_start = newinfo; mem_ab -= oldinfo->byte; mem_ab += newinfo->byte; free(oldinfo); return newinfo+1; } void util_meminfo() { struct memblock_t *info; if (!opts.memchk) return; for (info = mem_start; info; info = info->next) { util_debug("MEM", "lost: % 8u (bytes) at %s:%u\n", info->byte, info->file, info->line); } util_debug("MEM", "Memory information:\n\ Total allocations: %llu\n\ Total deallocations: %llu\n\ Total allocated: %llu (bytes)\n\ Total deallocated: %llu (bytes)\n\ Leaks found: lost %llu (bytes) in %d allocations\n", mem_at, mem_dt, mem_ab, mem_db, (mem_ab - mem_db), (mem_at - mem_dt) ); } /* * Some string utility functions, because strdup uses malloc, and we want * to track all memory (without replacing malloc). */ char *util_strdup(const char *s) { size_t len = 0; char *ptr = NULL; if (!s) return NULL; if ((len = strlen(s)) && (ptr = (char*)mem_a(len+1))) { memcpy(ptr, s, len); ptr[len] = '\0'; } return ptr; } void util_debug(const char *area, const char *ms, ...) { va_list va; if (!opts.debug) return; if (!strcmp(area, "MEM") && !opts.memchk) return; va_start(va, ms); con_out ("[%s] ", area); con_vout(ms, va); va_end (va); } /* * only required if big endian .. otherwise no need to swap * data. */ #if PLATFORM_BYTE_ORDER == GMQCC_BYTE_ORDER_BIG static GMQCC_INLINE void util_swap16(uint16_t *d, size_t l) { while (l--) { d[l] = (d[l] << 8) | (d[l] >> 8); } } static GMQCC_INLINE void util_swap32(uint32_t *d, size_t l) { while (l--) { uint32_t v; v = ((d[l] << 8) & 0xFF00FF00) | ((d[l] >> 8) & 0x00FF00FF); d[l] = (v << 16) | (v >> 16); } } /* Some strange system doesn't like constants that big, AND doesn't recognize an ULL suffix * so let's go the safe way */ static GMQCC_INLINE void util_swap64(uint32_t *d, size_t l) { /* while (l--) { uint64_t v; v = ((d[l] << 8) & 0xFF00FF00FF00FF00) | ((d[l] >> 8) & 0x00FF00FF00FF00FF); v = ((v << 16) & 0xFFFF0000FFFF0000) | ((v >> 16) & 0x0000FFFF0000FFFF); d[l] = (v << 32) | (v >> 32); } */ size_t i; for (i = 0; i < l; i += 2) { uint32_t v1 = d[i]; d[i] = d[i+1]; d[i+1] = v1; util_swap32(d+i, 2); } } #endif void util_endianswap(void *_data, size_t length, unsigned int typesize) { # if PLATFORM_BYTE_ORDER == -1 /* runtime check */ if (*((char*)&typesize)) return; #else /* prevent unused warnings */ (void) _data; (void) length; (void) typesize; # if PLATFORM_BYTE_ORDER == GMQCC_BYTE_ORDER_LITTLE return; # else switch (typesize) { case 1: return; case 2: util_swap16((uint16_t*)_data, length>>1); return; case 4: util_swap32((uint32_t*)_data, length>>2); return; case 8: util_swap64((uint32_t*)_data, length>>3); return; default: abort(); /* please blow the fuck up! */ } # endif #endif } /* * CRC algorithms vary in the width of the polynomial, the value of said polynomial, * the initial value used for the register, weather the bits of each byte are reflected * before being processed, weather the algorithm itself feeds input bytes through the * register or XORs them with a byte from one end and then straight into the table, as * well as (but not limited to the idea of reflected versions) where the final register * value becomes reversed, and finally weather the value itself is used to XOR the final * register value. AS such you can already imagine how painfully annoying CRCs are, * of course we stand to target Quake, which expects it's certian set of rules for proper * calculation of a CRC. * * In most traditional CRC algorithms on uses a reflected table driven method where a value * or register is reflected if it's bits are swapped around it's center. For example: * take the bits 0101 is the 4-bit reflection of 1010, and respectfully 0011 would be the * reflection of 1100. Quake however expects a NON-Reflected CRC on the output, but still * requires a final XOR on the values (0xFFFF and 0x0000) this is a standard CCITT CRC-16 * which I respectfully as a programmer don't agree with. * * So now you know what we target, and why we target it, despite how unsettling it may seem * but those are what Quake seems to request. */ static const uint16_t util_crc16_table[] = { 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485, 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D, 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4, 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823, 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12, 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A, 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41, 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49, 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70, 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78, 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F, 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067, 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E, 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256, 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D, 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C, 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634, 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB, 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3, 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A, 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92, 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1, 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 }; /* Non - Reflected */ uint16_t util_crc16(uint16_t current, const char *k, size_t len) { register uint16_t h = current; for (; len; --len, ++k) h = util_crc16_table[(h>>8)^((unsigned char)*k)]^(h<<8); return h; } /* Reflective Varation (for reference) */ #if 0 uint16_t util_crc16(const char *k, int len, const short clamp) { register uint16_t h= (uint16_t)0xFFFFFFFF; for (; len; --len, ++k) h = util_crc16_table[(h^((unsigned char)*k))&0xFF]^(h>>8); return (~h)%clamp; } #endif size_t util_strtocmd(const char *in, char *out, size_t outsz) { size_t sz = 1; for (; *in && sz < outsz; ++in, ++out, ++sz) *out = (*in == '-') ? '_' : (isalpha(*in) && !isupper(*in)) ? *in + 'A' - 'a': *in; *out = 0; return sz-1; } size_t util_strtononcmd(const char *in, char *out, size_t outsz) { size_t sz = 1; for (; *in && sz < outsz; ++in, ++out, ++sz) *out = (*in == '_') ? '-' : (isalpha(*in) && isupper(*in)) ? *in + 'a' - 'A' : *in; *out = 0; return sz-1; } /* TODO: rewrite ... when I redo the ve cleanup */ void _util_vec_grow(void **a, size_t i, size_t s) { vector_t *d = vec_meta(*a); size_t m = *a ? 2 * d->allocated +i : i+1; void *p = mem_r((*a ? d : NULL), s * m + sizeof(vector_t)); if (!*a) ((vector_t*)p)->used = 0; *a = (vector_t*)p + 1; vec_meta(*a)->allocated = m; } /* * Hash table for generic data, based on dynamic memory allocations * all around. This is the internal interface, please look for * EXPOSED INTERFACE comment below */ typedef struct hash_node_t { char *key; /* the key for this node in table */ void *value; /* pointer to the data as void* */ struct hash_node_t *next; /* next node (linked list) */ } hash_node_t; GMQCC_INLINE size_t util_hthash(hash_table_t *ht, const char *key) { const uint32_t mix = 0x5BD1E995; const uint32_t rot = 24; size_t size = strlen(key); uint32_t hash = 0x1EF0 /* LICRC TAB */ ^ size; uint32_t alias = 0; const unsigned char *data = (const unsigned char*)key; while (size >= 4) { alias = *(uint32_t*)data; alias *= mix; alias ^= alias >> rot; alias *= mix; hash *= mix; hash ^= alias; data += 4; size -= 4; } switch (size) { case 3: hash ^= data[2] << 16; case 2: hash ^= data[1] << 8; case 1: hash ^= data[0]; hash *= mix; } hash ^= hash >> 13; hash *= mix; hash ^= hash >> 15; return (size_t) (hash % ht->size); } hash_node_t *_util_htnewpair(const char *key, void *value) { hash_node_t *node; if (!(node = (hash_node_t*)mem_a(sizeof(hash_node_t)))) return NULL; if (!(node->key = util_strdup(key))) { mem_d(node); return NULL; } node->value = value; node->next = NULL; return node; } /* * EXPOSED INTERFACE for the hashtable implementation * util_htnew(size) -- to make a new hashtable * util_htset(table, key, value, sizeof(value)) -- to set something in the table * util_htget(table, key) -- to get something from the table * util_htdel(table) -- to delete the table */ hash_table_t *util_htnew(size_t size) { hash_table_t *hashtable = NULL; if (size < 1) return NULL; if (!(hashtable = (hash_table_t*)mem_a(sizeof(hash_table_t)))) return NULL; if (!(hashtable->table = (hash_node_t**)mem_a(sizeof(hash_node_t*) * size))) { mem_d(hashtable); return NULL; } hashtable->size = size; memset(hashtable->table, 0, sizeof(hash_node_t*) * size); return hashtable; } void util_htseth(hash_table_t *ht, const char *key, size_t bin, void *value) { hash_node_t *newnode = NULL; hash_node_t *next = NULL; hash_node_t *last = NULL; next = ht->table[bin]; while (next && next->key && strcmp(key, next->key) > 0) last = next, next = next->next; /* already in table, do a replace */ if (next && next->key && strcmp(key, next->key) == 0) { next->value = value; } else { /* not found, grow a pair man :P */ newnode = _util_htnewpair(key, value); if (next == ht->table[bin]) { newnode->next = next; ht->table[bin] = newnode; } else if (!next) { last->next = newnode; } else { newnode->next = next; last->next = newnode; } } } void util_htset(hash_table_t *ht, const char *key, void *value) { util_htseth(ht, key, util_hthash(ht, key), value); } void *util_htgeth(hash_table_t *ht, const char *key, size_t bin) { hash_node_t *pair = ht->table[bin]; while (pair && pair->key && strcmp(key, pair->key) > 0) pair = pair->next; if (!pair || !pair->key || strcmp(key, pair->key) != 0) return NULL; return pair->value; } void *util_htget(hash_table_t *ht, const char *key) { return util_htgeth(ht, key, util_hthash(ht, key)); } void *code_util_str_htgeth(hash_table_t *ht, const char *key, size_t bin) { hash_node_t *pair; size_t len, keylen; int cmp; keylen = strlen(key); pair = ht->table[bin]; while (pair && pair->key) { len = strlen(pair->key); if (len < keylen) { pair = pair->next; continue; } if (keylen == len) { cmp = strcmp(key, pair->key); if (cmp == 0) return pair->value; if (cmp < 0) return NULL; pair = pair->next; continue; } cmp = strcmp(key, pair->key + len - keylen); if (cmp == 0) { uintptr_t up = (uintptr_t)pair->value; up += len - keylen; return (void*)up; } pair = pair->next; } return NULL; } /* * Free all allocated data in a hashtable, this is quite the amount * of work. */ void util_htdel(hash_table_t *ht) { size_t i = 0; for (; i < ht->size; i++) { hash_node_t *n = ht->table[i]; hash_node_t *p; /* free in list */ while (n) { if (n->key) mem_d(n->key); p = n; n = n->next; mem_d(p); } } /* free table */ mem_d(ht->table); mem_d(ht); } /* * Portable implementation of vasprintf/asprintf. Assumes vsnprintf * exists, otherwise compiler error. */ int util_vasprintf(char **ret, const char *fmt, va_list args) { int read; va_list copy; va_copy(copy, args); *ret = 0; if ((read = vsnprintf(NULL, 0, fmt, args)) >= 0) { char *buffer; if ((buffer = (char*)mem_a(read + 1))) { if ((read = vsnprintf(buffer, read + 1, fmt, copy)) < 0) mem_d(buffer); else *ret = buffer; } } va_end(copy); return read; } int util_asprintf(char **ret, const char *fmt, ...) { va_list args; int read; va_start(args, fmt); read = util_vasprintf(ret, fmt, args); va_end (args); return read; } /* * Implementation of the Mersenne twister PRNG (pseudo random numer * generator). Implementation of MT19937. Has a period of 2^19937-1 * which is a Mersenne Prime (hence the name). * * Implemented from specification and original paper: * http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/ARTICLES/mt.pdf * * This code is placed in the public domain by me personally * (Dale Weiler, a.k.a graphitemaster). */ #define MT_SIZE 624 #define MT_PERIOD 397 #define MT_SPACE (MT_SIZE - MT_PERIOD) static uint32_t mt_state[MT_SIZE]; static size_t mt_index = 0; static GMQCC_INLINE void mt_generate() { /* * The loop has been unrolled here: the original paper and implemenation * Called for the following code: * for (register unsigned i = 0; i < MT_SIZE; ++i) { * register uint32_t load; * load = (0x80000000 & mt_state[i]) // most significant 32nd bit * load |= (0x7FFFFFFF & mt_state[(i + 1) % MT_SIZE]) // least significant 31nd bit * * mt_state[i] = mt_state[(i + MT_PERIOD) % MT_SIZE] ^ (load >> 1); * * if (load & 1) mt_state[i] ^= 0x9908B0DF; * } * * This essentially is a waste: we have two modulus operations, and * a branch that is executed every iteration from [0, MT_SIZE). * * Please see: http://www.quadibloc.com/crypto/co4814.htm for more * information on how this clever trick works. */ static const uint32_t matrix[2] = { 0x00000000, 0x9908B0Df }; /* * This register gives up a little more speed by instructing the compiler * to force these into CPU registers (they're counters for indexing mt_state * which we can force the compiler to generate prefetch instructions for) */ register uint32_t y; register uint32_t i; /* * Said loop has been unrolled for MT_SPACE (226 iterations), opposed * to [0, MT_SIZE) (634 iterations). */ for (i = 0; i < MT_SPACE; ++i) { y = (0x80000000 & mt_state[i]) | (0x7FFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i + MT_PERIOD] ^ (y >> 1) ^ matrix[y & 1]; i ++; /* loop unroll */ y = (0x80000000 & mt_state[i]) | (0x7FFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i + MT_PERIOD] ^ (y >> 1) ^ matrix[y & 1]; } /* * collapsing the walls unrolled (evenly dividing 396 [632-227 = 396 * = 2*2*3*3*11]) */ i = MT_SPACE; while (i < MT_SIZE - 1) { /* * We expand this 11 times .. manually, no macros are required * here. This all fits in the CPU cache. */ y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; y = (0x80000000 & mt_state[i]) | (0x7FFFFFFF & mt_state[i + 1]); mt_state[i] = mt_state[i - MT_SPACE] ^ (y >> 1) ^ matrix[y & 1]; ++i; } /* i = mt_state[623] */ y = (0x80000000 & mt_state[MT_SIZE - 1]) | (0x7FFFFFFF & mt_state[MT_SIZE - 1]); mt_state[MT_SIZE - 1] = mt_state[MT_PERIOD - 1] ^ (y >> 1) ^ matrix[y & 1]; } void util_seed(uint32_t value) { /* * We seed the mt_state with a LCG (linear congruential generator) * We're operating exactly on exactly m=32, so there is no need to * use modulus. * * The multipler of choice is 0x6C07865, also knows as the Borosh- * Niederreiter multipler used for modulus 2^32. More can be read * about this in Knuth's TAOCP Volume 2, page 106. * * If you don't own TAOCP something is wrong with you :-) .. so I * also provided a link to the original paper by Borosh and * Niederreiter. It's called "Optional Multipliers for PRNG by The * Linear Congruential Method" (1983). * http://en.wikipedia.org/wiki/Linear_congruential_generator * * From said page, it says the following: * "A common Mersenne twister implementation, interestingly enough * used an LCG to generate seed data." * * Remarks: * The data we're operating on is 32-bits for the mt_state array, so * there is no masking required with 0xFFFFFFFF */ register size_t i; mt_state[0] = value; for (i = 1; i < MT_SIZE; ++i) mt_state[i] = 0x6C078965 * (mt_state[i - 1] ^ mt_state[i - 1] >> 30) + i; } uint32_t util_rand() { register uint32_t y; /* * This is inlined with any sane compiler (I checked) * for some reason though, SubC seems to be generating invalid * code when it inlines this. */ if (!mt_index) mt_generate(); y = mt_state[mt_index]; /* Standard tempering */ y ^= y >> 11; /* +7 */ y ^= y << 7 & 0x9D2C5680; /* +4 */ y ^= y << 15 & 0xEFC60000; /* -4 */ y ^= y >> 18; /* -7 */ if(++mt_index == MT_SIZE) mt_index = 0; return y; }