| /* |
| ** 2007 August 14 |
| ** |
| ** 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 low-level memory allocation drivers for when |
| ** SQLite will use the standard C-library malloc/realloc/free interface |
| ** to obtain the memory it needs. |
| ** |
| ** This file contains implementations of the low-level memory allocation |
| ** routines specified in the sqlite3_mem_methods object. |
| */ |
| #include "sqliteInt.h" |
| |
| /* |
| ** This version of the memory allocator is the default. It is |
| ** used when no other memory allocator is specified using compile-time |
| ** macros. |
| */ |
| #ifdef SQLITE_SYSTEM_MALLOC |
| |
| /* |
| ** Like malloc(), but remember the size of the allocation |
| ** so that we can find it later using sqlite3MemSize(). |
| ** |
| ** For this low-level routine, we are guaranteed that nByte>0 because |
| ** cases of nByte<=0 will be intercepted and dealt with by higher level |
| ** routines. |
| */ |
| static void *sqlite3MemMalloc(int nByte){ |
| sqlite3_int64 *p; |
| assert( nByte>0 ); |
| nByte = ROUND8(nByte); |
| p = malloc( nByte+8 ); |
| if( p ){ |
| p[0] = nByte; |
| p++; |
| }else{ |
| testcase( sqlite3GlobalConfig.xLog!=0 ); |
| sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte); |
| } |
| return (void *)p; |
| } |
| |
| /* |
| ** Like free() but works for allocations obtained from sqlite3MemMalloc() |
| ** or sqlite3MemRealloc(). |
| ** |
| ** For this low-level routine, we already know that pPrior!=0 since |
| ** cases where pPrior==0 will have been intecepted and dealt with |
| ** by higher-level routines. |
| */ |
| static void sqlite3MemFree(void *pPrior){ |
| sqlite3_int64 *p = (sqlite3_int64*)pPrior; |
| assert( pPrior!=0 ); |
| p--; |
| free(p); |
| } |
| |
| /* |
| ** Report the allocated size of a prior return from xMalloc() |
| ** or xRealloc(). |
| */ |
| static int sqlite3MemSize(void *pPrior){ |
| sqlite3_int64 *p; |
| if( pPrior==0 ) return 0; |
| p = (sqlite3_int64*)pPrior; |
| p--; |
| return (int)p[0]; |
| } |
| |
| /* |
| ** Like realloc(). Resize an allocation previously obtained from |
| ** sqlite3MemMalloc(). |
| ** |
| ** For this low-level interface, we know that pPrior!=0. Cases where |
| ** pPrior==0 while have been intercepted by higher-level routine and |
| ** redirected to xMalloc. Similarly, we know that nByte>0 becauses |
| ** cases where nByte<=0 will have been intercepted by higher-level |
| ** routines and redirected to xFree. |
| */ |
| static void *sqlite3MemRealloc(void *pPrior, int nByte){ |
| sqlite3_int64 *p = (sqlite3_int64*)pPrior; |
| assert( pPrior!=0 && nByte>0 ); |
| assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */ |
| p--; |
| p = realloc(p, nByte+8 ); |
| if( p ){ |
| p[0] = nByte; |
| p++; |
| }else{ |
| testcase( sqlite3GlobalConfig.xLog!=0 ); |
| sqlite3_log(SQLITE_NOMEM, |
| "failed memory resize %u to %u bytes", |
| sqlite3MemSize(pPrior), nByte); |
| } |
| return (void*)p; |
| } |
| |
| /* |
| ** Round up a request size to the next valid allocation size. |
| */ |
| static int sqlite3MemRoundup(int n){ |
| return ROUND8(n); |
| } |
| |
| /* |
| ** Initialize this module. |
| */ |
| static int sqlite3MemInit(void *NotUsed){ |
| UNUSED_PARAMETER(NotUsed); |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** Deinitialize this module. |
| */ |
| static void sqlite3MemShutdown(void *NotUsed){ |
| UNUSED_PARAMETER(NotUsed); |
| return; |
| } |
| |
| /* |
| ** This routine is the only routine in this file with external linkage. |
| ** |
| ** Populate the low-level memory allocation function pointers in |
| ** sqlite3GlobalConfig.m with pointers to the routines in this file. |
| */ |
| void sqlite3MemSetDefault(void){ |
| static const sqlite3_mem_methods defaultMethods = { |
| sqlite3MemMalloc, |
| sqlite3MemFree, |
| sqlite3MemRealloc, |
| sqlite3MemSize, |
| sqlite3MemRoundup, |
| sqlite3MemInit, |
| sqlite3MemShutdown, |
| 0 |
| }; |
| sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods); |
| } |
| |
| #endif /* SQLITE_SYSTEM_MALLOC */ |