Change functions to handle NULLs correctly. Added the NULLIF() function. (CVS 590)

FossilOrigin-Name: 46ce1a9ab6e527958ebc757fa2175c488299cd84

diff --git a/manifest b/manifest
index c8b0abd05b362d1f722cc468db90483fa98cb3db..ad6cf7c78683bbe07c5c576fd9e97305ac42fee3 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C NULL\svalues\sare\sdistinct.\s\sA\scomparison\sinvolving\sa\sNULL\sis\salways\sfalse.\nOperations\son\sa\sNULL\svalue\syield\sa\sNULL\sresult.\s\sThis\schange\smakes\sSQLite\noperate\smore\slike\sthe\sSQL\sspec,\sbut\sit\smay\sbreak\sexisting\sapplications\sthat\nassumed\sthe\sold\sbehavior.\s\sAll\sthe\sold\stests\spass\sbut\swe\sstill\sneed\sto\sadd\nnew\stests\sto\sbetter\sverify\sthe\snew\sbehavior.\s\sFix\sfor\sticket\s#44.\s(CVS\s589)
-D 2002-05-26T20:54:33
+C Change\sfunctions\sto\shandle\sNULLs\scorrectly.\s\sAdded\sthe\sNULLIF()\sfunction.\s(CVS\s590)
+D 2002-05-26T21:34:58
 F Makefile.in 6291a33b87d2a395aafd7646ee1ed562c6f2c28c
 F Makefile.template 4e11752e0b5c7a043ca50af4296ec562857ba495
 F README a4c0ba11354ef6ba0776b400d057c59da47a4cc0
@@ -24,7 +24,7 @@ F src/build.c 36e42718a7a94f554ea39508993378482f5335c7
 F src/delete.c a2b098cbbf518e6b641847e26de85827793bc523
 F src/encode.c 346b12b46148506c32038524b95c4631ab46d760
 F src/expr.c 1a7a2f5f2b7dd37659783cdb6efaac74a092ba71
-F src/func.c a31dcba85bc2ecb9b752980289cf7e6cd0cafbce
+F src/func.c 16e994eea8cceb0cd451938e63d337f7d9d089bf
 F src/hash.c 6a6236b89c8c060c65dabd300a1c8ce7c10edb72
 F src/hash.h dca065dda89d4575f3176e75e9a3dc0f4b4fb8b9
 F src/insert.c 24b4e146319bada6f82a1d5eae6b38b3065d132f
@@ -51,7 +51,7 @@ F src/threadtest.c 81f0598e0f031c1bd506af337fdc1b7e8dff263f
 F src/tokenize.c facec7dc0b4a13e17ad67702f548dac2f7c6a732
 F src/trigger.c f9adb404ea355a8be2c9cd9740794a898cf1096c
 F src/update.c f68375173bf5338cae3e97012708e10f206aedd9
-F src/util.c 707c30f8c13cddace7c08556ac450c0b786660b3
+F src/util.c a9f6e6f03e8b7137204ac15b35a58f321e38037e
 F src/vdbe.c caa269517b2392986c8f55401f272e76b9de82d9
 F src/vdbe.h b8706429131c14b307a07aab7e47f95a9da53610
 F src/where.c b054f2f23127bd57eb5f973bcd38764b875d73fe
@@ -135,7 +135,7 @@ F www/speed.tcl da8afcc1d3ccc5696cfb388a68982bc3d9f7f00f
 F www/sqlite.tcl 8b5884354cb615049aed83039f8dfe1552a44279
 F www/tclsqlite.tcl 1db15abeb446aad0caf0b95b8b9579720e4ea331
 F www/vdbe.tcl 2013852c27a02a091d39a766bc87cff329f21218
-P d8d04c14f18d1feba89ccea0be70530a18248c51
-R 2ee233b2a9ebb3e4a8fe3e93b3747a0c
+P 9051173742f1b0e15a809d12a0c9c98fd2c4614d
+R 0620e522ec88d7386c2177fd29ebfac3
 U drh
-Z f507bf5d6b83b961339e312ca54783e8
+Z 0624defcbccb679d773bc9ffe5a1ecda

diff --git a/manifest.uuid b/manifest.uuid
index f0e8ac5b721a4d7d6e16313b292985037041a089..424c86b5e6a29997734e41afcc6f99020e35b734 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-9051173742f1b0e15a809d12a0c9c98fd2c4614d
\ No newline at end of file
+46ce1a9ab6e527958ebc757fa2175c488299cd84
\ No newline at end of file

diff --git a/src/func.c b/src/func.c
index ac4c05f44886b5d1d9f644b269c13bfb8337c7a1..cf523e3b8df2663c8e8cf78a00f1d3c0266a56f9 100644 (file)
--- a/src/func.c
+++ b/src/func.c
@@ -16,7 +16,7 @@
 ** sqliteRegisterBuildinFunctions() found at the bottom of the file.
 ** All other code has file scope.
 **
-** $Id: func.c,v 1.16 2002/04/20 14:24:42 drh Exp $
+** $Id: func.c,v 1.17 2002/05/26 21:34:58 drh Exp $
 */
 #include <ctype.h>
 #include <math.h>
@@ -33,7 +33,9 @@ static void minFunc(sqlite_func *context, int argc, const char **argv){
 
   if( argc==0 ) return;
   zBest = argv[0];
+  if( zBest==0 ) return;
   for(i=1; i<argc; i++){
+    if( argv[i]==0 ) return;
     if( sqliteCompare(argv[i], zBest)<0 ){
       zBest = argv[i];
     }
@@ -46,7 +48,9 @@ static void maxFunc(sqlite_func *context, int argc, const char **argv){
 
   if( argc==0 ) return;
   zBest = argv[0];
+  if( zBest==0 ) return;
   for(i=1; i<argc; i++){
+    if( argv[i]==0 ) return;
     if( sqliteCompare(argv[i], zBest)>0 ){
       zBest = argv[i];
     }
@@ -63,15 +67,12 @@ static void lengthFunc(sqlite_func *context, int argc, const char **argv){
 
   assert( argc==1 );
   z = argv[0];
-  if( z==0 ){
-    len = 0;
-  }else{
+  if( z==0 ) return;
 #ifdef SQLITE_UTF8
-    for(len=0; *z; z++){ if( (0xc0&*z)!=0x80 ) len++; }
+  for(len=0; *z; z++){ if( (0xc0&*z)!=0x80 ) len++; }
 #else
-    len = strlen(z);
+  len = strlen(z);
 #endif
-  }
   sqlite_set_result_int(context, len);
 }
 
@@ -82,7 +83,8 @@ static void absFunc(sqlite_func *context, int argc, const char **argv){
   const char *z;
   assert( argc==1 );
   z = argv[0];
-  if( z && z[0]=='-' && isdigit(z[1]) ) z++;
+  if( z==0 ) return;
+  if( z[0]=='-' && isdigit(z[1]) ) z++;
   sqlite_set_result_string(context, z, -1);
 }
 
@@ -142,10 +144,11 @@ static void roundFunc(sqlite_func *context, int argc, const char **argv){
   double r;
   char zBuf[100];
   assert( argc==1 || argc==2 );
-  n = argc==2 && argv[1] ? atoi(argv[1]) : 0;
+  if( argv[0]==0 || (argc==2 && argv[1]==0) ) return;
+  n = argc==2 ? atoi(argv[1]) : 0;
   if( n>30 ) n = 30;
   if( n<0 ) n = 0;
-  r = argv[0] ? atof(argv[0]) : 0.0;
+  r = atof(argv[0]);
   sprintf(zBuf,"%.*f",n,r);
   sqlite_set_result_string(context, zBuf, -1);
 }
@@ -215,8 +218,8 @@ static void last_insert_rowid(sqlite_func *context, int arg, const char **argv){
 ** is implemented as like(A,B).
 */
 static void likeFunc(sqlite_func *context, int arg, const char **argv){
-  sqlite_set_result_int(context, 
-     sqliteLikeCompare(argv[0] ? argv[0] : "",argv[1] ? argv[1] : ""));
+  if( argv[0]==0 || argv[1]==0 ) return;
+  sqlite_set_result_int(context, sqliteLikeCompare(argv[0], argv[1]));
 }
 
 /*
@@ -229,8 +232,19 @@ static void likeFunc(sqlite_func *context, int arg, const char **argv){
 ** is implemented as glob(A,B).
 */
 static void globFunc(sqlite_func *context, int arg, const char **argv){
-  sqlite_set_result_int(context,
-    sqliteGlobCompare(argv[0] ? argv[0] : "",argv[1] ? argv[1] : ""));
+  if( argv[0]==0 || argv[1]==0 ) return;
+  sqlite_set_result_int(context, sqliteGlobCompare(argv[0], argv[1]));
+}
+
+/*
+** Implementation of the NULLIF(x,y) function.  The result is the first
+** argument if the arguments are different.  The result is NULL if the
+** arguments are equal to each other.
+*/
+static void nullifFunc(sqlite_func *context, int argc, const char **argv){
+  if( argv[0]!=0 && sqliteCompare(argv[0],argv[1])!=0 ){
+    sqlite_set_result_string(context, argv[0], -1);
+  }
 }
 
 /*
@@ -334,6 +348,7 @@ static void countFinalize(sqlite_func *context){
 */
 typedef struct MinMaxCtx MinMaxCtx;
 struct MinMaxCtx {
+  int isNull;      /* True if the result should be NULL */
   char *z;         /* The best so far */
   char zBuf[28];   /* Space that can be used for storage */
 };
@@ -345,50 +360,52 @@ static void minStep(sqlite_func *context, int argc, const char **argv){
   MinMaxCtx *p;
   p = sqlite_aggregate_context(context, sizeof(*p));
   if( p==0 || argc<1 ) return;
+  if( argv[0]==0 || p->isNull ){
+    p->isNull = 1;
+    return;
+  }
   if( sqlite_aggregate_count(context)==1 || sqliteCompare(argv[0],p->z)<0 ){
+    int len;
     if( p->z && p->z!=p->zBuf ){
       sqliteFree(p->z);
     }
-    if( argv[0] ){
-      int len = strlen(argv[0]);
-      if( len < sizeof(p->zBuf) ){
-        p->z = p->zBuf;
-      }else{
-        p->z = sqliteMalloc( len+1 );
-        if( p->z==0 ) return;
-      }
-      strcpy(p->z, argv[0]);
+    len = strlen(argv[0]);
+    if( len < sizeof(p->zBuf) ){
+      p->z = p->zBuf;
     }else{
-      p->z = 0;
+      p->z = sqliteMalloc( len+1 );
+      if( p->z==0 ) return;
     }
+    strcpy(p->z, argv[0]);
   }
 }
 static void maxStep(sqlite_func *context, int argc, const char **argv){
   MinMaxCtx *p;
   p = sqlite_aggregate_context(context, sizeof(*p));
   if( p==0 || argc<1 ) return;
+  if( argv[0]==0 || p->isNull ){
+    p->isNull = 1;
+    return;
+  }
   if( sqlite_aggregate_count(context)==1 || sqliteCompare(argv[0],p->z)>0 ){
+    int len;
     if( p->z && p->z!=p->zBuf ){
       sqliteFree(p->z);
     }
-    if( argv[0] ){
-      int len = strlen(argv[0]);
-      if( len < sizeof(p->zBuf) ){
-        p->z = p->zBuf;
-      }else{
-        p->z = sqliteMalloc( len+1 );
-        if( p->z==0 ) return;
-      }
-      strcpy(p->z, argv[0]);
+    len = strlen(argv[0]);
+    if( len < sizeof(p->zBuf) ){
+      p->z = p->zBuf;
     }else{
-      p->z = 0;
+      p->z = sqliteMalloc( len+1 );
+      if( p->z==0 ) return;
     }
+    strcpy(p->z, argv[0]);
   }
 }
 static void minMaxFinalize(sqlite_func *context){
   MinMaxCtx *p;
   p = sqlite_aggregate_context(context, sizeof(*p));
-  if( p && p->z ){
+  if( p && p->z && !p->isNull ){
     sqlite_set_result_string(context, p->z, strlen(p->z));
   }
   if( p && p->z && p->z!=p->zBuf ){
@@ -424,6 +441,7 @@ void sqliteRegisterBuildinFunctions(sqlite *db){
     { "random",    -1, randomFunc },
     { "like",       2, likeFunc   },
     { "glob",       2, globFunc   },
+    { "nullif",     2, nullifFunc },
   };
   static struct {
     char *zName;

diff --git a/src/util.c b/src/util.c
index a13b92af596ce9b6598549f19cd5fe514d66d419..536f15816f8b646bc8d44541b60c7ea8f1b4b1e1 100644 (file)
--- a/src/util.c
+++ b/src/util.c
@@ -14,7 +14,7 @@
 ** This file contains functions for allocating memory, comparing
 ** strings, and stuff like that.
 **
-** $Id: util.c,v 1.43 2002/05/10 13:14:07 drh Exp $
+** $Id: util.c,v 1.44 2002/05/26 21:34:58 drh Exp $
 */
 #include "sqliteInt.h"
 #include <stdarg.h>
@@ -665,7 +665,7 @@ int sqliteCompare(const char *atext, const char *btext){
   int result;
   int isNumA, isNumB;
   if( atext==0 ){
-    return -(btext!=0);
+    return -1;
   }else if( btext==0 ){
     return 1;
   }