Refactor the interface to the randomness generator. (CVS 1224)

FossilOrigin-Name: f2bdccf4bb2f796aafb64c33e55f62a1794d750c

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;
 }