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Fix for ticket #142: Make sure we get the correct sort order even when the

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columns being sorted contain NULLs. (CVS 730)

FossilOrigin-Name: 45847390d007718a4b7a4e9fa445136d013113f8
This commit is contained in:
drh
2002-08-26 19:55:07 +00:00
parent d2df27e41d
commit da30d3696b
5 changed files with 100 additions and 27 deletions
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31
src/util.c
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@@ -14,7 +14,7 @@
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.49 2002/08/25 18:29:12 drh Exp $
** $Id: util.c,v 1.50 2002/08/26 19:55:08 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
@@ -710,6 +710,10 @@ int sqliteCompare(const char *atext, const char *btext){
**
** Aone\000Dtwo\000Athree\000\000
**
** All elements begin with one of the characters "+-AD" and end with "\000"
** with zero or more text elements in between. Except, NULL elements
** consist of the special two-character sequence "N\000".
**
** Both arguments will have the same number of elements. This routine
** returns negative, zero, or positive if the first argument is less
** than, equal to, or greater than the first. (Result is a-b).
@@ -744,17 +748,26 @@ int sqliteSortCompare(const char *a, const char *b){
int len;
int res = 0;
int isNumA, isNumB;
int dir;
while( res==0 && *a && *b ){
assert( a[0]==b[0] );
if( a[1]==0 ){
res = -1;
break;
}else if( b[1]==0 ){
res = +1;
if( a[0]=='N' || b[0]=='N' ){
if( a[0]==b[0] ){
a += 2;
b += 2;
continue;
}
if( a[0]=='N' ){
dir = b[0];
res = -1;
}else{
dir = a[0];
res = +1;
}
break;
}
if( a[0]=='A' || a[0]=='D' ){
assert( a[0]==b[0] );
if( (dir=a[0])=='A' || a[0]=='D' ){
res = strcmp(&a[1],&b[1]);
if( res ) break;
}else{
@@ -788,7 +801,7 @@ int sqliteSortCompare(const char *a, const char *b){
a += len;
b += len;
}
if( *a=='-' || *a=='D' ) res = -res;
if( dir=='-' || dir=='D' ) res = -res;
return res;
}