Index: third_party/sqlite/sqlite-src-3080704/src/random.c |
diff --git a/third_party/sqlite/sqlite-src-3080704/src/random.c b/third_party/sqlite/sqlite-src-3080704/src/random.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..b82566524c40c6bb87154a259d7c24077d54e394 |
--- /dev/null |
+++ b/third_party/sqlite/sqlite-src-3080704/src/random.c |
@@ -0,0 +1,126 @@ |
+/* |
+** 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 = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_PRNG); |
+ sqlite3_mutex_enter(mutex); |
+#endif |
+ |
+ if( N<=0 ){ |
+ wsdPrng.isInit = 0; |
+ sqlite3_mutex_leave(mutex); |
+ return; |
+ } |
+ |
+ /* 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 |
+ ** trying to do secure encryption or anything like that... |
+ ** |
+ ** Nothing in this file or anywhere else in SQLite does any kind of |
+ ** encryption. The RC4 algorithm is being used as a PRNG (pseudo-random |
+ ** number generator) not as an encryption device. |
+ */ |
+ if( !wsdPrng.isInit ){ |
+ int i; |
+ char k[256]; |
+ wsdPrng.j = 0; |
+ wsdPrng.i = 0; |
+ sqlite3OsRandomness(sqlite3_vfs_find(0), 256, k); |
+ for(i=0; i<256; i++){ |
+ wsdPrng.s[i] = (u8)i; |
+ } |
+ for(i=0; i<256; i++){ |
+ wsdPrng.j += wsdPrng.s[i] + k[i]; |
+ t = wsdPrng.s[wsdPrng.j]; |
+ wsdPrng.s[wsdPrng.j] = wsdPrng.s[i]; |
+ wsdPrng.s[i] = t; |
+ } |
+ wsdPrng.isInit = 1; |
+ } |
+ |
+ assert( N>0 ); |
+ do{ |
+ 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]; |
+ *(zBuf++) = wsdPrng.s[t]; |
+ }while( --N ); |
+ sqlite3_mutex_leave(mutex); |
+} |
+ |
+#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, 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 SQLITE_WSD struct sqlite3PrngType sqlite3SavedPrng; |
+void sqlite3PrngSaveState(void){ |
+ memcpy( |
+ &GLOBAL(struct sqlite3PrngType, sqlite3SavedPrng), |
+ &GLOBAL(struct sqlite3PrngType, sqlite3Prng), |
+ sizeof(sqlite3Prng) |
+ ); |
+} |
+void sqlite3PrngRestoreState(void){ |
+ memcpy( |
+ &GLOBAL(struct sqlite3PrngType, sqlite3Prng), |
+ &GLOBAL(struct sqlite3PrngType, sqlite3SavedPrng), |
+ sizeof(sqlite3Prng) |
+ ); |
+} |
+#endif /* SQLITE_OMIT_BUILTIN_TEST */ |