/*
* Copyright (C) 2012, 2013
* 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 <stdarg.h>
#include <errno.h>
#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;
mem_at++;
mem_ab += info->byte;
return data;
}
void util_memory_d(void *ptrn) {
struct memblock_t *info = NULL;
if (!ptrn) return;
info = ((struct memblock_t*)ptrn - 1);
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);
return NULL;
}
oldinfo = ((struct memblock_t*)ptrn - 1);
newinfo = ((struct memblock_t*)malloc(sizeof(struct memblock_t) + byte));
/* new data */
if (!newinfo) {
util_memory_d(oldinfo+1);
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_OPTION_BOOL(OPTION_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_OPTION_BOOL(OPTION_DEBUG))
return;
if (!strcmp(area, "MEM") && !OPTS_OPTION_BOOL(OPTION_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);
}
/*
* A basic implementation of a hash-set. Unlike a hashtable, a hash
* set doesn't maintain key-value pairs. It simply maintains a key
* that can be set, removed, and checked for.
*
* See EXPOSED interface comment below
*/
#define GMQCC_HASHSET_PRIME0 0x0049
#define GMQCC_HASHSET_PRIME1 0x1391
static int util_hsput(hash_set_t *set, void *item) {
size_t hash = (size_t)item; /* shouldn't drop the bits */
size_t iter;
/* a == 0 || a == 1 */
if (hash >> 1)
return -1;
iter = set->mask & (GMQCC_HASHSET_PRIME0 * hash);
/* while (set->items[iter] != 0 && set->items[iter] != 1) */
while (!(set->items[iter] >> 1)) {
if (set->items[iter] == hash)
return 0;
iter = set->mask & (iter + GMQCC_HASHSET_PRIME1);
}
set->total ++;
set->items[iter] = hash;
return 1;
}
static void util_hsupdate(hash_set_t *set) {
size_t *old;
size_t end;
size_t itr;
/* time to rehash? */
if ((float)set->total >= (size_t)((double)set->capacity * 0.85)) {
old = set->items;
end = set->capacity;
set->bits ++;
set->capacity = (size_t)(1 << set->bits);
set->mask = set->capacity - 1;
set->items = mem_a(set->capacity * sizeof(size_t));
set->total = 0;
/*assert(set->items);*/
/*
* this shouldn't be slow? if so unroll it a little perhaps
* (shouldn't be though)
*/
for (itr = 0; itr < end; itr++)
util_hsput(set, (void*)old[itr]);
mem_d(old);
}
}
/*
* EXPOSED interface: all of these functions are exposed to the outside
* for use. The stuff above is static because it's the "internal" mechanics
* for syncronizing the set for updating, and putting data into the set.
*/
int util_hsadd(hash_set_t *set, void *item) {
int run = util_hsput(set, item); /* inlined */
util_hsupdate(set);
return run;
}
/* remove item in set */
int util_hsrem(hash_set_t *set, void *item) {
size_t hash = (size_t)item;
size_t iter = set->mask & (GMQCC_HASHSET_PRIME0 * hash);
while (set->items[iter]) {
if (set->items[iter] == hash) {
set->items[iter] = 1;
set->total --;
return 1;
}
iter = set->mask & (iter + GMQCC_HASHSET_PRIME1);
}
return 0;
}
/* check if item is set */
int util_hshas(hash_set_t *set, void *item) {
size_t hash = (size_t)item;
size_t iter = set->mask & (GMQCC_HASHSET_PRIME0 * hash);
while (set->items[iter]) {
if (set->items[iter] == hash)
return 1;
iter = set->mask & (iter + GMQCC_HASHSET_PRIME1);
}
return 0;
}
hash_set_t *util_hsnew(void) {
hash_set_t *set;
if (!(set = mem_a(sizeof(hash_set_t))))
return NULL;
set->bits = 3;
set->total = 0;
set->capacity = (size_t)(1 << set->bits);
set->mask = set->capacity - 1;
set->items = mem_a(set->capacity * sizeof(size_t));
if (!set->items) {
util_hsdel(set);
return NULL;
}
return set;
}
void util_hsdel(hash_set_t *set) {
if (!set) return;
if (set->items)
mem_d(set->items);
mem_d(set);
}
#undef GMQCC_HASHSET_PRIME0
#undef GMQCC_HASHSET_PRIME1
/*
* Portable implementation of vasprintf/asprintf. Assumes vsnprintf
* exists, otherwise compiler error.
*
* TODO: fix for MSVC ....
*/
int util_vasprintf(char **dat, const char *fmt, va_list args) {
int ret;
int len;
char *tmp = NULL;
/*
* For visuals tido _vsnprintf doesn't tell you the length of a
* formatted string if it overflows. However there is a MSVC
* intrinsic (which is documented wrong) called _vcsprintf which
* will return the required amount to allocate.
*/
#ifdef _MSC_VER
char *str;
if ((len = _vscprintf(fmt, args)) < 0) {
*dat = NULL;
return -1;
}
tmp = mem_a(len + 1);
if ((ret = _vsnprintf(tmp, len+1, fmt, args)) != len) {
mem_d(tmp);
*dat = NULL;
return -1;
}
*dat = tmp;
return len;
#else
/*
* For everything else we have a decent conformint vsnprintf that
* returns the number of bytes needed. We give it a try though on
* a short buffer, since efficently speaking, it could be nice to
* above a second vsnprintf call.
*/
char buf[128];
va_list cpy;
va_copy(cpy, args);
len = vsnprintf(buf, sizeof(buf), fmt, cpy);
va_end (cpy);
if (len < (int)sizeof(buf)) {
*dat = util_strdup(buf);
return len;
}
/* not large enough ... */
tmp = mem_a(len + 1);
if ((ret = vsnprintf(tmp, len + 1, fmt, args)) != len) {
mem_d(tmp);
*dat = NULL;
return -1;
}
*dat = tmp;
return len;
#endif
}
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;
}