Simplifications and additional comments on the sqlite3_get_table()

implementation.  Changes to facilitate full branch test coverage. (CVS 6482)

FossilOrigin-Name: 57e3e6b3cb54e6626bee41a084c927ee264b6d03

manifest

@@ -1,5 +1,5 @@
-C Changes\sto\sensure\sthat\swhen\srunning\sin\sshared-cache\smode\swith\sa\snon-threadsafe\sbuild,\sthe\scorrect\sbusy-handler\scallback\sis\salways\sinvoked.\s(CVS\s6481)
-D 2009-04-10T12:55:17
+C Simplifications\sand\sadditional\scomments\son\sthe\ssqlite3_get_table()\nimplementation.\s\sChanges\sto\sfacilitate\sfull\sbranch\stest\scoverage.\s(CVS\s6482)
+D 2009-04-10T14:28:00
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -162,7 +162,7 @@ F src/sqlite3ext.h 1db7d63ab5de4b3e6b83dd03d1a4e64fef6d2a17
 F src/sqliteInt.h fcdad0896da9c8b6372db974131e33b7a06606ce
 F src/sqliteLimit.h ffe93f5a0c4e7bd13e70cd7bf84cfb5c3465f45d
 F src/status.c 237b193efae0cf6ac3f0817a208de6c6c6ef6d76
-F src/table.c 332ab0ea691e63862e2a8bdfe2c0617ee61062a3
+F src/table.c cc86ad3d6ad54df7c63a3e807b5783c90411a08d
 F src/tclsqlite.c d3195e0738c101a155404ecdb1cd9532a2fd34f2
 F src/test1.c c4feac6518b0523e944e9cc6a4864854d81a2216
 F src/test2.c 71c22e2974f8094fe0fd1eba8f27872dde9b2a39
@@ -717,7 +717,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P ed6620ba589ddbb6ca86f42a7652e3b019195647
-R 59f76bf89532711f903241145d0b77ea
-U danielk1977
-Z ac75d7099ed4abde9c5f40681fcfbea3
+P 683e4bd74783e6e3f6cf75f9582008c7b7e02a01
+R 65240198d5802c3e7624e2bd2d3785c6
+U drh
+Z e03e042fa6bf5790b1eb4d8b0880d63a

manifest.uuid

@@ -1 +1 @@
-683e4bd74783e6e3f6cf75f9582008c7b7e02a01
+57e3e6b3cb54e6626bee41a084c927ee264b6d03

src/table.c

@@ -16,7 +16,7 @@
 ** These routines are in a separate files so that they will not be linked
 ** if they are not used.
 **
-** $Id: table.c,v 1.39 2009/01/19 20:49:10 drh Exp $
+** $Id: table.c,v 1.40 2009/04/10 14:28:00 drh Exp $
 */
 #include "sqliteInt.h"
 #include <stdlib.h>
@@ -29,14 +29,13 @@
 ** to the callback function is uses to build the result.
 */
 typedef struct TabResult {
-  char **azResult;
-  char *zErrMsg;
-  int nResult;
-  int nAlloc;
-  int nRow;
-  int nColumn;
-  int nData;
-  int rc;
+  char **azResult;   /* Accumulated output */
+  char *zErrMsg;     /* Error message text, if an error occurs */
+  int nAlloc;        /* Slots allocated for azResult[] */
+  int nRow;          /* Number of rows in the result */
+  int nColumn;       /* Number of columns in the result */
+  int nData;         /* Slots used in azResult[].  (nRow+1)*nColumn */
+  int rc;            /* Return code from sqlite3_exec() */
 } TabResult;
 
 /*
@@ -45,10 +44,10 @@ typedef struct TabResult {
 ** memory as necessary.
 */
 static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){
-  TabResult *p = (TabResult*)pArg;
-  int need;
-  int i;
-  char *z;
+  TabResult *p = (TabResult*)pArg;  /* Result accumulator */
+  int need;                         /* Slots needed in p->azResult[] */
+  int i;                            /* Loop counter */
+  char *z;                          /* A single column of result */
 
   /* Make sure there is enough space in p->azResult to hold everything
   ** we need to remember from this invocation of the callback.
@@ -58,9 +57,9 @@ static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){
   }else{
     need = nCol;
   }
-  if( p->nData + need >= p->nAlloc ){
+  if( p->nData + need > p->nAlloc ){
     char **azNew;
-    p->nAlloc = p->nAlloc*2 + need + 1;
+    p->nAlloc = p->nAlloc*2 + need;
     azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc );
     if( azNew==0 ) goto malloc_failed;
     p->azResult = azNew;
@@ -134,7 +133,6 @@ int sqlite3_get_table(
   if( pnRow ) *pnRow = 0;
   if( pzErrMsg ) *pzErrMsg = 0;
   res.zErrMsg = 0;
-  res.nResult = 0;
   res.nRow = 0;
   res.nColumn = 0;
   res.nData = 1;
@@ -168,13 +166,12 @@ int sqlite3_get_table(
   }
   if( res.nAlloc>res.nData ){
     char **azNew;
-    azNew = sqlite3_realloc( res.azResult, sizeof(char*)*(res.nData+1) );
+    azNew = sqlite3_realloc( res.azResult, sizeof(char*)*res.nData );
     if( azNew==0 ){
       sqlite3_free_table(&res.azResult[1]);
       db->errCode = SQLITE_NOMEM;
       return SQLITE_NOMEM;
     }
-    res.nAlloc = res.nData+1;
     res.azResult = azNew;
   }
   *pazResult = &res.azResult[1];