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Fix bogus assumption that MAXALIGN is at least sizeof(pointer).

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This commit is contained in:
Tom Lane
1999-05-12 04:38:24 +00:00
parent 5085132c6d
commit a36a7a16eb
1 changed files with 14 additions and 9 deletions
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23
src/interfaces/libpq/fe-exec.c
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@ -7,7 +7,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.78 1999/04/04 20:10:12 tgl Exp $ * $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.79 1999/05/12 04:38:24 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -92,11 +92,10 @@ static int getNotice(PGconn *conn);
* PGRESULT_SEP_ALLOC_THRESHOLD: objects bigger than this are given separate * PGRESULT_SEP_ALLOC_THRESHOLD: objects bigger than this are given separate
* blocks, instead of being crammed into a regular allocation block. * blocks, instead of being crammed into a regular allocation block.
* Requirements for correct function are: * Requirements for correct function are:
* PGRESULT_ALIGN_BOUNDARY >= sizeof(pointer)
* to ensure the initial pointer in a block is not overwritten.
* PGRESULT_ALIGN_BOUNDARY must be a multiple of the alignment requirements * PGRESULT_ALIGN_BOUNDARY must be a multiple of the alignment requirements
* of all machine data types. * of all machine data types. (Currently this is set from configure
* PGRESULT_SEP_ALLOC_THRESHOLD + PGRESULT_ALIGN_BOUNDARY <= * tests, so it should be OK automatically.)
* PGRESULT_SEP_ALLOC_THRESHOLD + PGRESULT_BLOCK_OVERHEAD <=
* PGRESULT_DATA_BLOCKSIZE * PGRESULT_DATA_BLOCKSIZE
* pqResultAlloc assumes an object smaller than the threshold will fit * pqResultAlloc assumes an object smaller than the threshold will fit
* in a new block. * in a new block.
@ -105,8 +104,14 @@ static int getNotice(PGconn *conn);
* ---------------- * ----------------
*/ */
#ifdef MAX
#undef MAX
#endif
#define MAX(a,b) ((a) > (b) ? (a) : (b))
#define PGRESULT_DATA_BLOCKSIZE 2048 #define PGRESULT_DATA_BLOCKSIZE 2048
#define PGRESULT_ALIGN_BOUNDARY MAXIMUM_ALIGNOF /* from configure */ #define PGRESULT_ALIGN_BOUNDARY MAXIMUM_ALIGNOF /* from configure */
#define PGRESULT_BLOCK_OVERHEAD MAX(sizeof(PGresult_data), PGRESULT_ALIGN_BOUNDARY)
#define PGRESULT_SEP_ALLOC_THRESHOLD (PGRESULT_DATA_BLOCKSIZE / 2) #define PGRESULT_SEP_ALLOC_THRESHOLD (PGRESULT_DATA_BLOCKSIZE / 2)
@ -213,10 +218,10 @@ pqResultAlloc(PGresult *res, int nBytes, int isBinary)
*/ */
if (nBytes >= PGRESULT_SEP_ALLOC_THRESHOLD) if (nBytes >= PGRESULT_SEP_ALLOC_THRESHOLD)
{ {
block = (PGresult_data *) malloc(nBytes + PGRESULT_ALIGN_BOUNDARY); block = (PGresult_data *) malloc(nBytes + PGRESULT_BLOCK_OVERHEAD);
if (! block) if (! block)
return NULL; return NULL;
space = block->space + PGRESULT_ALIGN_BOUNDARY; space = block->space + PGRESULT_BLOCK_OVERHEAD;
if (res->curBlock) if (res->curBlock)
{ {
/* Tuck special block below the active block, so that we don't /* Tuck special block below the active block, so that we don't
@ -244,8 +249,8 @@ pqResultAlloc(PGresult *res, int nBytes, int isBinary)
if (isBinary) if (isBinary)
{ {
/* object needs full alignment */ /* object needs full alignment */
res->curOffset = PGRESULT_ALIGN_BOUNDARY; res->curOffset = PGRESULT_BLOCK_OVERHEAD;
res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - PGRESULT_ALIGN_BOUNDARY; res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - PGRESULT_BLOCK_OVERHEAD;
} }
else else
{ {