1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/os/persistentdata/persistentstorage/sqlite3api/SQLite/vdbefifo.c	Fri Jun 15 03:10:57 2012 +0200
     1.3 @@ -0,0 +1,130 @@
     1.4 +/*
     1.5 +** 2005 June 16
     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 implements a FIFO queue of rowids used for processing
    1.16 +** UPDATE and DELETE statements.
    1.17 +**
    1.18 +** $Id: vdbefifo.c,v 1.8 2008/07/28 19:34:54 drh Exp $
    1.19 +*/
    1.20 +#include "sqliteInt.h"
    1.21 +#include "vdbeInt.h"
    1.22 +
    1.23 +/*
    1.24 +** Constants FIFOSIZE_FIRST and FIFOSIZE_MAX are the initial
    1.25 +** number of entries in a fifo page and the maximum number of
    1.26 +** entries in a fifo page.
    1.27 +*/
    1.28 +#define FIFOSIZE_FIRST (((128-sizeof(FifoPage))/8)+1)
    1.29 +#ifdef SQLITE_MALLOC_SOFT_LIMIT
    1.30 +# define FIFOSIZE_MAX   (((SQLITE_MALLOC_SOFT_LIMIT-sizeof(FifoPage))/8)+1)
    1.31 +#else
    1.32 +# define FIFOSIZE_MAX   (((262144-sizeof(FifoPage))/8)+1)
    1.33 +#endif
    1.34 +
    1.35 +/*
    1.36 +** Allocate a new FifoPage and return a pointer to it.  Return NULL if
    1.37 +** we run out of memory.  Leave space on the page for nEntry entries.
    1.38 +*/
    1.39 +static FifoPage *allocateFifoPage(sqlite3 *db, int nEntry){
    1.40 +  FifoPage *pPage;
    1.41 +  if( nEntry>FIFOSIZE_MAX ){
    1.42 +    nEntry = FIFOSIZE_MAX;
    1.43 +  }
    1.44 +  pPage = sqlite3DbMallocRaw(db, sizeof(FifoPage) + sizeof(i64)*(nEntry-1) );
    1.45 +  if( pPage ){
    1.46 +    pPage->nSlot = nEntry;
    1.47 +    pPage->iWrite = 0;
    1.48 +    pPage->iRead = 0;
    1.49 +    pPage->pNext = 0;
    1.50 +  }
    1.51 +  return pPage;
    1.52 +}
    1.53 +
    1.54 +/*
    1.55 +** Initialize a Fifo structure.
    1.56 +*/
    1.57 +void sqlite3VdbeFifoInit(Fifo *pFifo, sqlite3 *db){
    1.58 +  memset(pFifo, 0, sizeof(*pFifo));
    1.59 +  pFifo->db = db;
    1.60 +}
    1.61 +
    1.62 +/*
    1.63 +** Push a single 64-bit integer value into the Fifo.  Return SQLITE_OK
    1.64 +** normally.   SQLITE_NOMEM is returned if we are unable to allocate
    1.65 +** memory.
    1.66 +*/
    1.67 +int sqlite3VdbeFifoPush(Fifo *pFifo, i64 val){
    1.68 +  FifoPage *pPage;
    1.69 +  pPage = pFifo->pLast;
    1.70 +  if( pPage==0 ){
    1.71 +    pPage = pFifo->pLast = pFifo->pFirst =
    1.72 +         allocateFifoPage(pFifo->db, FIFOSIZE_FIRST);
    1.73 +    if( pPage==0 ){
    1.74 +      return SQLITE_NOMEM;
    1.75 +    }
    1.76 +  }else if( pPage->iWrite>=pPage->nSlot ){
    1.77 +    pPage->pNext = allocateFifoPage(pFifo->db, pFifo->nEntry);
    1.78 +    if( pPage->pNext==0 ){
    1.79 +      return SQLITE_NOMEM;
    1.80 +    }
    1.81 +    pPage = pFifo->pLast = pPage->pNext;
    1.82 +  }
    1.83 +  pPage->aSlot[pPage->iWrite++] = val;
    1.84 +  pFifo->nEntry++;
    1.85 +  return SQLITE_OK;
    1.86 +}
    1.87 +
    1.88 +/*
    1.89 +** Extract a single 64-bit integer value from the Fifo.  The integer
    1.90 +** extracted is the one least recently inserted.  If the Fifo is empty
    1.91 +** return SQLITE_DONE.
    1.92 +*/
    1.93 +int sqlite3VdbeFifoPop(Fifo *pFifo, i64 *pVal){
    1.94 +  FifoPage *pPage;
    1.95 +  if( pFifo->nEntry==0 ){
    1.96 +    return SQLITE_DONE;
    1.97 +  }
    1.98 +  assert( pFifo->nEntry>0 );
    1.99 +  pPage = pFifo->pFirst;
   1.100 +  assert( pPage!=0 );
   1.101 +  assert( pPage->iWrite>pPage->iRead );
   1.102 +  assert( pPage->iWrite<=pPage->nSlot );
   1.103 +  assert( pPage->iRead<pPage->nSlot );
   1.104 +  assert( pPage->iRead>=0 );
   1.105 +  *pVal = pPage->aSlot[pPage->iRead++];
   1.106 +  pFifo->nEntry--;
   1.107 +  if( pPage->iRead>=pPage->iWrite ){
   1.108 +    pFifo->pFirst = pPage->pNext;
   1.109 +    sqlite3DbFree(pFifo->db, pPage);
   1.110 +    if( pFifo->nEntry==0 ){
   1.111 +      assert( pFifo->pLast==pPage );
   1.112 +      pFifo->pLast = 0;
   1.113 +    }else{
   1.114 +      assert( pFifo->pFirst!=0 );
   1.115 +    }
   1.116 +  }else{
   1.117 +    assert( pFifo->nEntry>0 );
   1.118 +  }
   1.119 +  return SQLITE_OK;
   1.120 +}
   1.121 +
   1.122 +/*
   1.123 +** Delete all information from a Fifo object.   Free all memory held
   1.124 +** by the Fifo.
   1.125 +*/
   1.126 +void sqlite3VdbeFifoClear(Fifo *pFifo){
   1.127 +  FifoPage *pPage, *pNextPage;
   1.128 +  for(pPage=pFifo->pFirst; pPage; pPage=pNextPage){
   1.129 +    pNextPage = pPage->pNext;
   1.130 +    sqlite3DbFree(pFifo->db, pPage);
   1.131 +  }
   1.132 +  sqlite3VdbeFifoInit(pFifo, pFifo->db);
   1.133 +}