diff options
Diffstat (limited to 'third_party/sqlite/src/random.c')
-rw-r--r-- | third_party/sqlite/src/random.c | 75 |
1 files changed, 50 insertions, 25 deletions
diff --git a/third_party/sqlite/src/random.c b/third_party/sqlite/src/random.c index f328232..f90a34e 100644 --- a/third_party/sqlite/src/random.c +++ b/third_party/sqlite/src/random.c @@ -15,7 +15,7 @@ ** Random numbers are used by some of the database backends in order ** to generate random integer keys for tables or random filenames. ** -** $Id: random.c,v 1.25 2008/06/19 01:03:18 drh Exp $ +** $Id: random.c,v 1.29 2008/12/10 19:26:24 drh Exp $ */ #include "sqliteInt.h" @@ -23,7 +23,7 @@ /* All threads share a single random number generator. ** This structure is the current state of the generator. */ -static struct sqlite3PrngType { +static SQLITE_WSD struct sqlite3PrngType { unsigned char isInit; /* True if initialized */ unsigned char i, j; /* State variables */ unsigned char s[256]; /* State variables */ @@ -45,10 +45,24 @@ static struct sqlite3PrngType { ** (Later): Actually, OP_NewRowid does not depend on a good source of ** randomness any more. But we will leave this code in all the same. */ -static int randomByte(void){ +static u8 randomByte(void){ unsigned char t; + /* The "wsdPrng" macro will resolve to the pseudo-random number generator + ** state vector. If writable static data is unsupported on the target, + ** we have to locate the state vector at run-time. In the more common + ** case where writable static data is supported, wsdPrng can refer directly + ** to the "sqlite3Prng" state vector declared above. + */ +#ifdef SQLITE_OMIT_WSD + struct sqlite3PrngType *p = &GLOBAL(struct sqlite3PrngType, sqlite3Prng); +# define wsdPrng p[0] +#else +# define wsdPrng sqlite3Prng +#endif + + /* Initialize the state of the random number generator once, ** the first time this routine is called. The seed value does ** not need to contain a lot of randomness since we are not @@ -58,33 +72,33 @@ static int randomByte(void){ ** encryption. The RC4 algorithm is being used as a PRNG (pseudo-random ** number generator) not as an encryption device. */ - if( !sqlite3Prng.isInit ){ + if( !wsdPrng.isInit ){ int i; char k[256]; - sqlite3Prng.j = 0; - sqlite3Prng.i = 0; + wsdPrng.j = 0; + wsdPrng.i = 0; sqlite3OsRandomness(sqlite3_vfs_find(0), 256, k); for(i=0; i<256; i++){ - sqlite3Prng.s[i] = i; + wsdPrng.s[i] = (u8)i; } for(i=0; i<256; i++){ - sqlite3Prng.j += sqlite3Prng.s[i] + k[i]; - t = sqlite3Prng.s[sqlite3Prng.j]; - sqlite3Prng.s[sqlite3Prng.j] = sqlite3Prng.s[i]; - sqlite3Prng.s[i] = t; + wsdPrng.j += wsdPrng.s[i] + k[i]; + t = wsdPrng.s[wsdPrng.j]; + wsdPrng.s[wsdPrng.j] = wsdPrng.s[i]; + wsdPrng.s[i] = t; } - sqlite3Prng.isInit = 1; + wsdPrng.isInit = 1; } /* Generate and return single random byte */ - sqlite3Prng.i++; - t = sqlite3Prng.s[sqlite3Prng.i]; - sqlite3Prng.j += t; - sqlite3Prng.s[sqlite3Prng.i] = sqlite3Prng.s[sqlite3Prng.j]; - sqlite3Prng.s[sqlite3Prng.j] = t; - t += sqlite3Prng.s[sqlite3Prng.i]; - return sqlite3Prng.s[t]; + wsdPrng.i++; + t = wsdPrng.s[wsdPrng.i]; + wsdPrng.j += t; + wsdPrng.s[wsdPrng.i] = wsdPrng.s[wsdPrng.j]; + wsdPrng.s[wsdPrng.j] = t; + t += wsdPrng.s[wsdPrng.i]; + return wsdPrng.s[t]; } /* @@ -92,7 +106,7 @@ static int randomByte(void){ */ void sqlite3_randomness(int N, void *pBuf){ unsigned char *zBuf = pBuf; -#ifndef SQLITE_MUTEX_NOOP +#if SQLITE_THREADSAFE sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_PRNG); #endif sqlite3_mutex_enter(mutex); @@ -105,18 +119,29 @@ void sqlite3_randomness(int N, void *pBuf){ #ifndef SQLITE_OMIT_BUILTIN_TEST /* ** For testing purposes, we sometimes want to preserve the state of -** PRNG and restore the PRNG to its saved state at a later time. +** PRNG and restore the PRNG to its saved state at a later time, or +** to reset the PRNG to its initial state. These routines accomplish +** those tasks. +** ** The sqlite3_test_control() interface calls these routines to ** control the PRNG. */ -static struct sqlite3PrngType sqlite3SavedPrng; +static SQLITE_WSD struct sqlite3PrngType sqlite3SavedPrng; void sqlite3PrngSaveState(void){ - memcpy(&sqlite3SavedPrng, &sqlite3Prng, sizeof(sqlite3Prng)); + memcpy( + &GLOBAL(struct sqlite3PrngType, sqlite3SavedPrng), + &GLOBAL(struct sqlite3PrngType, sqlite3Prng), + sizeof(sqlite3Prng) + ); } void sqlite3PrngRestoreState(void){ - memcpy(&sqlite3Prng, &sqlite3SavedPrng, sizeof(sqlite3Prng)); + memcpy( + &GLOBAL(struct sqlite3PrngType, sqlite3Prng), + &GLOBAL(struct sqlite3PrngType, sqlite3SavedPrng), + sizeof(sqlite3Prng) + ); } void sqlite3PrngResetState(void){ - sqlite3Prng.isInit = 0; + GLOBAL(struct sqlite3PrngType, sqlite3Prng).isInit = 0; } #endif /* SQLITE_OMIT_BUILTIN_TEST */ |