diff options
Diffstat (limited to 'src/random.c')
-rw-r--r-- | src/random.c | 46 |
1 files changed, 15 insertions, 31 deletions
diff --git a/src/random.c b/src/random.c index 39148b490..bf4b6d0a9 100644 --- a/src/random.c +++ b/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 1.10 2002/02/19 13:39:23 drh Exp $ +** $Id: random.c,v 1.11 2004/02/11 09:46:33 drh Exp $ */ #include "sqliteInt.h" #include "os.h" @@ -35,15 +35,15 @@ ** on RC4, which we know works very well. */ static int randomByte(){ - int t; + unsigned char t; /* All threads share a single random number generator. ** This structure is the current state of the generator. */ static struct { - int isInit; /* True if initialized */ - int i, j; /* State variables */ - int s[256]; /* State variables */ + unsigned char isInit; /* True if initialized */ + unsigned char i, j; /* State variables */ + unsigned char s[256]; /* State variables */ } prng; /* Initialize the state of the random number generator once, @@ -65,8 +65,7 @@ static int randomByte(){ prng.s[i] = i; } for(i=0; i<256; i++){ - int t; - prng.j = (prng.j + prng.s[i] + k[i]) & 0xff; + prng.j += prng.s[i] + k[i]; t = prng.s[prng.j]; prng.s[prng.j] = prng.s[i]; prng.s[i] = t; @@ -76,38 +75,23 @@ static int randomByte(){ /* Generate and return single random byte */ - prng.i = (prng.i + 1) & 0xff; - prng.j = (prng.j + prng.s[prng.i]) & 0xff; + prng.i++; t = prng.s[prng.i]; + prng.j += t; prng.s[prng.i] = prng.s[prng.j]; prng.s[prng.j] = t; - t = prng.s[prng.i] + prng.s[prng.j]; - return prng.s[t & 0xff]; + t += prng.s[prng.i]; + return prng.s[t]; } /* -** Return an random 8-bit integer. +** Return N random bytes. */ -int sqliteRandomByte(){ - int r; +void sqliteRandomness(int N, void *pBuf){ + unsigned char *zBuf = pBuf; sqliteOsEnterMutex(); - r = randomByte(); - sqliteOsLeaveMutex(); - return r; -} - -/* -** Return a random 32-bit integer. The integer is generated by making -** 4 calls to sqliteRandomByte(). -*/ -int sqliteRandomInteger(){ - int r; - int i; - sqliteOsEnterMutex(); - r = randomByte(); - for(i=1; i<4; i++){ - r = (r<<8) + randomByte(); + while( N-- ){ + *(zBuf++) = randomByte(); } sqliteOsLeaveMutex(); - return r; } |