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Diffstat (limited to 'src/mem1.c')
-rw-r--r-- | src/mem1.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/src/mem1.c b/src/mem1.c new file mode 100644 index 0000000..61fbf4b --- /dev/null +++ b/src/mem1.c @@ -0,0 +1,150 @@ +/* +** 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 */ |