251cced1f8
Various minor things done to project files Updated sample extension project file and updated makefile to the new unified version (more changes likely on the way) Updated regex project file and makefile --HG-- extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%401971
115 lines
2.9 KiB
C
115 lines
2.9 KiB
C
/*
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** 2005 June 16
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** This file implements a FIFO queue of rowids used for processing
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** UPDATE and DELETE statements.
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*/
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#include "sqliteInt.h"
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#include "vdbeInt.h"
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/*
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** Allocate a new FifoPage and return a pointer to it. Return NULL if
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** we run out of memory. Leave space on the page for nEntry entries.
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*/
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static FifoPage *allocateFifoPage(int nEntry){
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FifoPage *pPage;
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if( nEntry>32767 ){
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nEntry = 32767;
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}
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pPage = sqlite3_malloc( sizeof(FifoPage) + sizeof(i64)*(nEntry-1) );
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if( pPage ){
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pPage->nSlot = nEntry;
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pPage->iWrite = 0;
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pPage->iRead = 0;
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pPage->pNext = 0;
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}
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return pPage;
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}
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/*
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** Initialize a Fifo structure.
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*/
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void sqlite3VdbeFifoInit(Fifo *pFifo){
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memset(pFifo, 0, sizeof(*pFifo));
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}
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/*
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** Push a single 64-bit integer value into the Fifo. Return SQLITE_OK
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** normally. SQLITE_NOMEM is returned if we are unable to allocate
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** memory.
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*/
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int sqlite3VdbeFifoPush(Fifo *pFifo, i64 val){
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FifoPage *pPage;
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pPage = pFifo->pLast;
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if( pPage==0 ){
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pPage = pFifo->pLast = pFifo->pFirst = allocateFifoPage(20);
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if( pPage==0 ){
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return SQLITE_NOMEM;
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}
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}else if( pPage->iWrite>=pPage->nSlot ){
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pPage->pNext = allocateFifoPage(pFifo->nEntry);
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if( pPage->pNext==0 ){
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return SQLITE_NOMEM;
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}
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pPage = pFifo->pLast = pPage->pNext;
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}
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pPage->aSlot[pPage->iWrite++] = val;
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pFifo->nEntry++;
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return SQLITE_OK;
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}
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/*
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** Extract a single 64-bit integer value from the Fifo. The integer
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** extracted is the one least recently inserted. If the Fifo is empty
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** return SQLITE_DONE.
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*/
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int sqlite3VdbeFifoPop(Fifo *pFifo, i64 *pVal){
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FifoPage *pPage;
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if( pFifo->nEntry==0 ){
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return SQLITE_DONE;
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}
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assert( pFifo->nEntry>0 );
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pPage = pFifo->pFirst;
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assert( pPage!=0 );
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assert( pPage->iWrite>pPage->iRead );
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assert( pPage->iWrite<=pPage->nSlot );
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assert( pPage->iRead<pPage->nSlot );
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assert( pPage->iRead>=0 );
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*pVal = pPage->aSlot[pPage->iRead++];
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pFifo->nEntry--;
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if( pPage->iRead>=pPage->iWrite ){
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pFifo->pFirst = pPage->pNext;
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sqlite3_free(pPage);
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if( pFifo->nEntry==0 ){
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assert( pFifo->pLast==pPage );
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pFifo->pLast = 0;
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}else{
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assert( pFifo->pFirst!=0 );
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}
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}else{
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assert( pFifo->nEntry>0 );
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}
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return SQLITE_OK;
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}
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/*
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** Delete all information from a Fifo object. Free all memory held
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** by the Fifo.
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*/
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void sqlite3VdbeFifoClear(Fifo *pFifo){
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FifoPage *pPage, *pNextPage;
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for(pPage=pFifo->pFirst; pPage; pPage=pNextPage){
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pNextPage = pPage->pNext;
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sqlite3_free(pPage);
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}
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sqlite3VdbeFifoInit(pFifo);
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}
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