Simplifications to the upper() and lower() SQL functions.

Updates to documentation on sqlite3_bind_text() and sqlite3_result_text()
to make it clear that users should not try to create strings with
embedded NULs and that if they do the result of expression on those strings
is undefined.  Ticket [57c971fc74524a]

FossilOrigin-Name: 9984cc20ca70b7fb39c0b99580a1317a7b0c9c85

manifest

@@ -1,5 +1,5 @@
-C Handle\supdating\sthe\sonly\srow\sof\san\sFTS\stable\scorrectly.\sFix\sfor\s[9fd058691].
-D 2011-10-13T17:16:45.272
+C Simplifications\sto\sthe\supper()\sand\slower()\sSQL\sfunctions.\nUpdates\sto\sdocumentation\son\ssqlite3_bind_text()\sand\ssqlite3_result_text()\nto\smake\sit\sclear\sthat\susers\sshould\snot\stry\sto\screate\sstrings\swith\nembedded\sNULs\sand\sthat\sif\sthey\sdo\sthe\sresult\sof\sexpression\son\sthose\sstrings\nis\sundefined.\s\sTicket\s[57c971fc74524a]
+D 2011-10-13T18:00:11.063
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in a162fe39e249b8ed4a65ee947c30152786cfe897
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -136,7 +136,7 @@ F src/delete.c ff68e5ef23aee08c0ff528f699a19397ed8bbed8
 F src/expr.c 1a7970a0c5c72a76c6929896ac109f04e194619b
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c 9f00ea98f6b360d477b5a78b5b59a1fbde82431c
-F src/func.c 59bb046d7e3df1ab512ac339ccb0a6f996a17cb7
+F src/func.c 6261ce00aad9c63cd5b4219249b05683979060e9
 F src/global.c e230227de13601714b29f9363028514aada5ae2f
 F src/hash.c 458488dcc159c301b8e7686280ab209f1fb915af
 F src/hash.h 2894c932d84d9f892d4b4023a75e501f83050970
@@ -181,7 +181,7 @@ F src/resolve.c 36368f44569208fa074e61f4dd0b6c4fb60ca2b4
 F src/rowset.c 69afa95a97c524ba6faf3805e717b5b7ae85a697
 F src/select.c 94b375306bfb4590fdfd76581ae663f57e94808f
 F src/shell.c e30e20107fda14260640191a51aa527d8f209671
-F src/sqlite.h.in 821027573c481e45ba276b078a3ae9ebaeb9bb92
+F src/sqlite.h.in 5ec7488ef4c124ae905286600a9f2d64250aebb1
 F src/sqlite3ext.h 1a1a4f784aa9c3b00edd287940197de52487cd93
 F src/sqliteInt.h 6f8e592fc28d16160d017684966b3528833a46c1
 F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
@@ -969,7 +969,7 @@ F tool/symbols.sh fec58532668296d7c7dc48be9c87f75ccdb5814f
 F tool/tostr.awk e75472c2f98dd76e06b8c9c1367f4ab07e122d06
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
-P c3cb7f4fad725d5fa4d5acd9da63fc4538ce8e13
-R ec95a62db79b84d7111fda3a8be06ca9
-U dan
-Z 25dbdd79336e5688c7ffd1d8a10e1ab3
+P 7e24645be2fe0ffe092212e7bcfa5b4500305811
+R 70d5d750704aa84a6b8318ba5f4ea9e5
+U drh
+Z 36fd6a9db851f3c203fcf94c8d8271d9

manifest.uuid

@@ -1 +1 @@
-7e24645be2fe0ffe092212e7bcfa5b4500305811
+9984cc20ca70b7fb39c0b99580a1317a7b0c9c85

src/func.c

@@ -332,16 +332,15 @@ static void upperFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   if( z2 ){
     z1 = contextMalloc(context, ((i64)n)+1);
     if( z1 ){
-      memcpy(z1, z2, n+1);
-      for(i=0; z1[i]; i++){
-        z1[i] = (char)sqlite3Toupper(z1[i]);
+      for(i=0; i<n; i++){
+        z1[i] = (char)sqlite3Toupper(z2[i]);
       }
-      sqlite3_result_text(context, z1, -1, sqlite3_free);
+      sqlite3_result_text(context, z1, n, sqlite3_free);
     }
   }
 }
 static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
-  u8 *z1;
+  char *z1;
   const char *z2;
   int i, n;
   UNUSED_PARAMETER(argc);
@@ -352,11 +351,10 @@ static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   if( z2 ){
     z1 = contextMalloc(context, ((i64)n)+1);
     if( z1 ){
-      memcpy(z1, z2, n+1);
-      for(i=0; z1[i]; i++){
-        z1[i] = sqlite3Tolower(z1[i]);
+      for(i=0; i<n; i++){
+        z1[i] = sqlite3Tolower(z2[i]);
       }
-      sqlite3_result_text(context, (char *)z1, -1, sqlite3_free);
+      sqlite3_result_text(context, z1, n, sqlite3_free);
     }
   }
 }

src/sqlite.h.in

@@ -2799,7 +2799,8 @@ int sqlite3_limit(sqlite3*, int id, int newVal);
 ** that the supplied string is nul-terminated, then there is a small
 ** performance advantage to be gained by passing an nByte parameter that
 ** is equal to the number of bytes in the input string <i>including</i>
-** the nul-terminator bytes.
+** the nul-terminator bytes as this saves SQLite from having to
+** make a copy of the input string.
 **
 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
 ** past the end of the first SQL statement in zSql.  These routines only
@@ -3020,6 +3021,13 @@ typedef struct sqlite3_context sqlite3_context;
 ** number of <u>bytes</u> in the value, not the number of characters.)^
 ** ^If the fourth parameter is negative, the length of the string is
 ** the number of bytes up to the first zero terminator.
+** If a non-negative fourth parameter is provided to sqlite3_bind_text()
+** or sqlite3_bind_text16() then that parameter must be the byte offset
+** where the NUL terminator would occur assuming the string were NUL
+** terminated.  If any NUL characters occur at byte offsets less than 
+** the value of the fourth parameter then the resulting string value will
+** contain embedded NULs.  The result of expressions involving strings
+** with embedded NULs is undefined.
 **
 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
@@ -4038,7 +4046,12 @@ typedef void (*sqlite3_destructor_type)(void*);
 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
 ** is non-negative, then as many bytes (not characters) of the text
 ** pointed to by the 2nd parameter are taken as the application-defined
-** function result.
+** function result.  If the 3rd parameter is non-negative, then it
+** must be the byte offset into the string where the NUL terminator would
+** appear if the string where NUL terminated.  If any NUL characters occur
+** in the string at a byte offset that is less than the value of the 3rd
+** parameter, then the resulting string will contain embedded NULs and the
+** result of expressions operating on strings with embedded NULs is undefined.
 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
 ** function as the destructor on the text or BLOB result when it has