1.1 --- a/extensions/sqlite/sqlite-source/mem1.c Fri Jul 11 06:51:21 2008 +0000
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,229 +0,0 @@
1.4 -/*
1.5 -** 2007 August 14
1.6 -**
1.7 -** The author disclaims copyright to this source code. In place of
1.8 -** a legal notice, here is a blessing:
1.9 -**
1.10 -** May you do good and not evil.
1.11 -** May you find forgiveness for yourself and forgive others.
1.12 -** May you share freely, never taking more than you give.
1.13 -**
1.14 -*************************************************************************
1.15 -** This file contains the C functions that implement a memory
1.16 -** allocation subsystem for use by SQLite.
1.17 -**
1.18 -** $Id$
1.19 -*/
1.20 -
1.21 -/*
1.22 -** This version of the memory allocator is the default. It is
1.23 -** used when no other memory allocator is specified using compile-time
1.24 -** macros.
1.25 -*/
1.26 -#if !defined(SQLITE_MEMDEBUG) && !defined(SQLITE_OMIT_MEMORY_ALLOCATION)
1.27 -
1.28 -/*
1.29 -** We will eventually construct multiple memory allocation subsystems
1.30 -** suitable for use in various contexts:
1.31 -**
1.32 -** * Normal multi-threaded builds
1.33 -** * Normal single-threaded builds
1.34 -** * Debugging builds
1.35 -**
1.36 -** This initial version is suitable for use in normal multi-threaded
1.37 -** builds. We envision that alternative versions will be stored in
1.38 -** separate source files. #ifdefs will be used to select the code from
1.39 -** one of the various memN.c source files for use in any given build.
1.40 -*/
1.41 -#include "sqliteInt.h"
1.42 -
1.43 -/*
1.44 -** All of the static variables used by this module are collected
1.45 -** into a single structure named "mem". This is to keep the
1.46 -** static variables organized and to reduce namespace pollution
1.47 -** when this module is combined with other in the amalgamation.
1.48 -*/
1.49 -static struct {
1.50 - /*
1.51 - ** The alarm callback and its arguments. The mem.mutex lock will
1.52 - ** be held while the callback is running. Recursive calls into
1.53 - ** the memory subsystem are allowed, but no new callbacks will be
1.54 - ** issued. The alarmBusy variable is set to prevent recursive
1.55 - ** callbacks.
1.56 - */
1.57 - sqlite3_int64 alarmThreshold;
1.58 - void (*alarmCallback)(void*, sqlite3_int64,int);
1.59 - void *alarmArg;
1.60 - int alarmBusy;
1.61 -
1.62 - /*
1.63 - ** Mutex to control access to the memory allocation subsystem.
1.64 - */
1.65 - sqlite3_mutex *mutex;
1.66 -
1.67 - /*
1.68 - ** Current allocation and high-water mark.
1.69 - */
1.70 - sqlite3_int64 nowUsed;
1.71 - sqlite3_int64 mxUsed;
1.72 -
1.73 -
1.74 -} mem;
1.75 -
1.76 -/*
1.77 -** Enter the mutex mem.mutex. Allocate it if it is not already allocated.
1.78 -*/
1.79 -static void enterMem(void){
1.80 - if( mem.mutex==0 ){
1.81 - mem.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM);
1.82 - }
1.83 - sqlite3_mutex_enter(mem.mutex);
1.84 -}
1.85 -
1.86 -/*
1.87 -** Return the amount of memory currently checked out.
1.88 -*/
1.89 -sqlite3_int64 sqlite3_memory_used(void){
1.90 - sqlite3_int64 n;
1.91 - enterMem();
1.92 - n = mem.nowUsed;
1.93 - sqlite3_mutex_leave(mem.mutex);
1.94 - return n;
1.95 -}
1.96 -
1.97 -/*
1.98 -** Return the maximum amount of memory that has ever been
1.99 -** checked out since either the beginning of this process
1.100 -** or since the most recent reset.
1.101 -*/
1.102 -sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
1.103 - sqlite3_int64 n;
1.104 - enterMem();
1.105 - n = mem.mxUsed;
1.106 - if( resetFlag ){
1.107 - mem.mxUsed = mem.nowUsed;
1.108 - }
1.109 - sqlite3_mutex_leave(mem.mutex);
1.110 - return n;
1.111 -}
1.112 -
1.113 -/*
1.114 -** Change the alarm callback
1.115 -*/
1.116 -int sqlite3_memory_alarm(
1.117 - void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
1.118 - void *pArg,
1.119 - sqlite3_int64 iThreshold
1.120 -){
1.121 - enterMem();
1.122 - mem.alarmCallback = xCallback;
1.123 - mem.alarmArg = pArg;
1.124 - mem.alarmThreshold = iThreshold;
1.125 - sqlite3_mutex_leave(mem.mutex);
1.126 - return SQLITE_OK;
1.127 -}
1.128 -
1.129 -/*
1.130 -** Trigger the alarm
1.131 -*/
1.132 -static void sqlite3MemsysAlarm(int nByte){
1.133 - void (*xCallback)(void*,sqlite3_int64,int);
1.134 - sqlite3_int64 nowUsed;
1.135 - void *pArg;
1.136 - if( mem.alarmCallback==0 || mem.alarmBusy ) return;
1.137 - mem.alarmBusy = 1;
1.138 - xCallback = mem.alarmCallback;
1.139 - nowUsed = mem.nowUsed;
1.140 - pArg = mem.alarmArg;
1.141 - sqlite3_mutex_leave(mem.mutex);
1.142 - xCallback(pArg, nowUsed, nByte);
1.143 - sqlite3_mutex_enter(mem.mutex);
1.144 - mem.alarmBusy = 0;
1.145 -}
1.146 -
1.147 -/*
1.148 -** Allocate nBytes of memory
1.149 -*/
1.150 -void *sqlite3_malloc(int nBytes){
1.151 - sqlite3_int64 *p = 0;
1.152 - if( nBytes>0 ){
1.153 - enterMem();
1.154 - if( mem.alarmCallback!=0 && mem.nowUsed+nBytes>=mem.alarmThreshold ){
1.155 - sqlite3MemsysAlarm(nBytes);
1.156 - }
1.157 - p = malloc(nBytes+8);
1.158 - if( p==0 ){
1.159 - sqlite3MemsysAlarm(nBytes);
1.160 - p = malloc(nBytes+8);
1.161 - }
1.162 - if( p ){
1.163 - p[0] = nBytes;
1.164 - p++;
1.165 - mem.nowUsed += nBytes;
1.166 - if( mem.nowUsed>mem.mxUsed ){
1.167 - mem.mxUsed = mem.nowUsed;
1.168 - }
1.169 - }
1.170 - sqlite3_mutex_leave(mem.mutex);
1.171 - }
1.172 - return (void*)p;
1.173 -}
1.174 -
1.175 -/*
1.176 -** Free memory.
1.177 -*/
1.178 -void sqlite3_free(void *pPrior){
1.179 - sqlite3_int64 *p;
1.180 - int nByte;
1.181 - if( pPrior==0 ){
1.182 - return;
1.183 - }
1.184 - assert( mem.mutex!=0 );
1.185 - p = pPrior;
1.186 - p--;
1.187 - nByte = (int)*p;
1.188 - sqlite3_mutex_enter(mem.mutex);
1.189 - mem.nowUsed -= nByte;
1.190 - free(p);
1.191 - sqlite3_mutex_leave(mem.mutex);
1.192 -}
1.193 -
1.194 -/*
1.195 -** Change the size of an existing memory allocation
1.196 -*/
1.197 -void *sqlite3_realloc(void *pPrior, int nBytes){
1.198 - int nOld;
1.199 - sqlite3_int64 *p;
1.200 - if( pPrior==0 ){
1.201 - return sqlite3_malloc(nBytes);
1.202 - }
1.203 - if( nBytes<=0 ){
1.204 - sqlite3_free(pPrior);
1.205 - return 0;
1.206 - }
1.207 - p = pPrior;
1.208 - p--;
1.209 - nOld = (int)p[0];
1.210 - assert( mem.mutex!=0 );
1.211 - sqlite3_mutex_enter(mem.mutex);
1.212 - if( mem.nowUsed+nBytes-nOld>=mem.alarmThreshold ){
1.213 - sqlite3MemsysAlarm(nBytes-nOld);
1.214 - }
1.215 - p = realloc(p, nBytes+8);
1.216 - if( p==0 ){
1.217 - sqlite3MemsysAlarm(nBytes);
1.218 - p = realloc(p, nBytes+8);
1.219 - }
1.220 - if( p ){
1.221 - p[0] = nBytes;
1.222 - p++;
1.223 - mem.nowUsed += nBytes-nOld;
1.224 - if( mem.nowUsed>mem.mxUsed ){
1.225 - mem.mxUsed = mem.nowUsed;
1.226 - }
1.227 - }
1.228 - sqlite3_mutex_leave(mem.mutex);
1.229 - return (void*)p;
1.230 -}
1.231 -
1.232 -#endif /* !SQLITE_MEMDEBUG && !SQLITE_OMIT_MEMORY_ALLOCATION */
