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random: Clean Up the Mt19937 state struct #13577

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Merged
merged 3 commits into from
Mar 4, 2024
Merged

random: Clean Up the Mt19937 state struct #13577

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f58f1b3
random: Make Mt19937's `mode` field an enum
TimWolla Mar 2, 2024
190d4b5
random: Reorder the `php_random_status_state_mt19937` struct
TimWolla Nov 12, 2023
8cffeb5
random: Remove the `MT_N` constant
TimWolla Mar 2, 2024
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22 changes: 13 additions & 9 deletions ext/random/engine_mt19937.c
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Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,11 @@
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#define N MT_N /* length of state vector */
#define N 624 /* length of state vector */
ZEND_STATIC_ASSERT(
N == sizeof(((php_random_status_state_mt19937*)0)->state) / sizeof(((php_random_status_state_mt19937*)0)->state[0]),
"Assumed length of Mt19937 state vector does not match actual size."
);
#define M (397) /* a period parameter */
#define hiBit(u) ((u) & 0x80000000U) /* mask all but highest bit of u */
#define loBit(u) ((u) & 0x00000001U) /* mask all but lowest bit of u */
Expand Down Expand Up @@ -130,7 +134,7 @@ PHPAPI inline void php_random_mt19937_seed32(php_random_status_state_mt19937 *st
In previous versions, most significant bits (MSBs) of the seed affect
only MSBs of the state array. Modified 9 Jan 2002 by Makoto Matsumoto. */
state->state[0] = seed;
for (i = 1; i < MT_N; i++) {
for (i = 1; i < N; i++) {
prev_state = state->state[i - 1];
state->state[i] = (1812433253U * (prev_state ^ (prev_state >> 30)) + i) & 0xffffffffU;
}
Expand All @@ -144,7 +148,7 @@ static php_random_result generate(void *state)
php_random_status_state_mt19937 *s = state;
uint32_t s1;

if (s->count >= MT_N) {
if (s->count >= N) {
mt19937_reload(s);
}

Expand Down Expand Up @@ -172,7 +176,7 @@ static bool serialize(void *state, HashTable *data)
php_random_status_state_mt19937 *s = state;
zval t;

for (uint32_t i = 0; i < MT_N; i++) {
for (uint32_t i = 0; i < N; i++) {
ZVAL_STR(&t, php_random_bin2hex_le(&s->state[i], sizeof(uint32_t)));
zend_hash_next_index_insert(data, &t);
}
Expand All @@ -190,11 +194,11 @@ static bool unserialize(void *state, HashTable *data)
zval *t;

/* Verify the expected number of elements, this implicitly ensures that no additional elements are present. */
if (zend_hash_num_elements(data) != (MT_N + 2)) {
if (zend_hash_num_elements(data) != (N + 2)) {
return false;
}

for (uint32_t i = 0; i < MT_N; i++) {
for (uint32_t i = 0; i < N; i++) {
t = zend_hash_index_find(data, i);
if (!t || Z_TYPE_P(t) != IS_STRING || Z_STRLEN_P(t) != (2 * sizeof(uint32_t))) {
return false;
Expand All @@ -203,16 +207,16 @@ static bool unserialize(void *state, HashTable *data)
return false;
}
}
t = zend_hash_index_find(data, MT_N);
t = zend_hash_index_find(data, N);
if (!t || Z_TYPE_P(t) != IS_LONG) {
return false;
}
s->count = Z_LVAL_P(t);
if (s->count > MT_N) {
if (s->count > N) {
return false;
}

t = zend_hash_index_find(data, MT_N + 1);
t = zend_hash_index_find(data, N + 1);
if (!t || Z_TYPE_P(t) != IS_LONG) {
return false;
}
Expand Down
12 changes: 6 additions & 6 deletions ext/random/php_random.h
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Original file line number Diff line number Diff line change
Expand Up @@ -45,10 +45,10 @@ PHPAPI double php_combined_lcg(void);

# define PHP_MT_RAND_MAX ((zend_long) (0x7FFFFFFF)) /* (1<<31) - 1 */

# define MT_RAND_MT19937 0
# define MT_RAND_PHP 1

# define MT_N (624)
enum php_random_mt19937_mode {
MT_RAND_MT19937 = 0,
MT_RAND_PHP = 1,
};

#define PHP_RANDOM_RANGE_ATTEMPTS (50)

Expand All @@ -71,9 +71,9 @@ typedef struct _php_random_status_state_combinedlcg {
} php_random_status_state_combinedlcg;

typedef struct _php_random_status_state_mt19937 {
uint32_t state[MT_N];
uint32_t count;
uint8_t mode;
enum php_random_mt19937_mode mode;
uint32_t state[624];
} php_random_status_state_mt19937;

typedef struct _php_random_status_state_pcgoneseq128xslrr64 {
Expand Down