/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code to implement a pseudo-random number
** generator (PRNG) for SQLite.
**
** Random numbers are used by some of the database backends in order
** to generate random integer keys for tables or random filenames.
*/
#include "sqliteInt.h"


/* All threads share a single random number generator.
** This structure is the current state of the generator.
*/
static SQLITE_WSD struct sqlite3PrngType {
  unsigned char isInit;          /* True if initialized */
  unsigned char i, j;            /* State variables */
  unsigned char s[256];          /* State variables */
} sqlite3Prng;

/*
** Return N random bytes.
*/
void sqlite3_randomness(int N, void *pBuf){
  unsigned char t;
  unsigned char *zBuf = pBuf;

  /* 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

#if SQLITE_THREADSAFE
  sqlite3_mutex *mutex;
#endif

#ifndef SQLITE_OMIT_AUTOINIT
  if( sqlite3_initialize() ) return;
#endif

#if SQLITE_THREADSAFE
  mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_PRNG);
#endif

  sqlite3_mutex_enter(mutex);
  if( N