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

diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index 7a7a9076fe0844bdbe3f16a1be3352c9c85efcc1..7c1540ae159cd06559a4bd0232a723ba2e52c9cf 100644 (file)
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -7,7 +7,7 @@
  *
  *
  * 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
  *   blocks, instead of being crammed into a regular allocation block.
  * 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
- *     of all machine data types.
- * PGRESULT_SEP_ALLOC_THRESHOLD + PGRESULT_ALIGN_BOUNDARY <=
+ *     of all machine data types.  (Currently this is set from configure
+ *     tests, so it should be OK automatically.)
+ * PGRESULT_SEP_ALLOC_THRESHOLD + PGRESULT_BLOCK_OVERHEAD <=
  *         PGRESULT_DATA_BLOCKSIZE
  *     pqResultAlloc assumes an object smaller than the threshold will fit
  *     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_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)
 
 
@@ -213,10 +218,10 @@ pqResultAlloc(PGresult *res, int nBytes, int isBinary)
     */
    if (nBytes >= PGRESULT_SEP_ALLOC_THRESHOLD)
    {
-       block = (PGresult_data *) malloc(nBytes + PGRESULT_ALIGN_BOUNDARY);
+       block = (PGresult_data *) malloc(nBytes + PGRESULT_BLOCK_OVERHEAD);
        if (! block)
            return NULL;
-       space = block->space + PGRESULT_ALIGN_BOUNDARY;
+       space = block->space + PGRESULT_BLOCK_OVERHEAD;
        if (res->curBlock)
        {
            /* 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)
    {
        /* object needs full alignment */
-       res->curOffset = PGRESULT_ALIGN_BOUNDARY;
-       res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - PGRESULT_ALIGN_BOUNDARY;
+       res->curOffset = PGRESULT_BLOCK_OVERHEAD;
+       res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - PGRESULT_BLOCK_OVERHEAD;
    }
    else
    {