[sqlite] json1.c: isalnum(), isspace(), and isdigit() usage

[Jan Nijtmans]

2015-08-26 19:03 GMT+02:00 Ralf Junker <ralfjunker at gmx.de>:
> ext/misc/json1.c uses the following functions from the C library:
>
> isalnum(): http://www.sqlite.org/src/artifact/541004e47235cefc?ln=564
> isspace(): http://www.sqlite.org/src/artifact/541004e47235cefc?ln=635
> isdigit(): http://www.sqlite.org/src/artifact/541004e47235cefc?ln=829

> Shouldn't json1.c avoid them for the same reasons?

Simpler is: cast the argument to (unsigned char), that
has the same effect (but is more efficient).

Proposed patch below.

Thanks!

Regards,
      Jan Nijtmans
==================================================
--- ext/misc/json1.c
+++ ext/misc/json1.c
@@ -583,18 +583,18 @@
   char c;
   u32 j;
   int iThis;
   int x;
   JsonNode *pNode;
-  while( isspace(pParse->zJson[i]) ){ i++; }
+  while( isspace((unsigned char)pParse->zJson[i]) ){ i++; }
   if( (c = pParse->zJson[i])==0 ) return 0;
   if( c=='{' ){
     /* Parse object */
     iThis = jsonParseAddNode(pParse, JSON_OBJECT, 0, 0);
     if( iThis<0 ) return -1;
     for(j=i+1;;j++){
-      while( isspace(pParse->zJson[j]) ){ j++; }
+      while( isspace((unsigned char)pParse->zJson[j]) ){ j++; }
       x = jsonParseValue(pParse, j);
       if( x<0 ){
         if( x==(-2) && pParse->nNode==(u32)iThis+1 ) return j+1;
         return -1;
       }
@@ -601,17 +601,17 @@
       if( pParse->oom ) return -1;
       pNode = &pParse->aNode[pParse->nNode-1];
       if( pNode->eType!=JSON_STRING ) return -1;
       pNode->jnFlags |= JNODE_LABEL;
       j = x;
-      while( isspace(pParse->zJson[j]) ){ j++; }
+      while( isspace((unsigned char)pParse->zJson[j]) ){ j++; }
       if( pParse->zJson[j]!=':' ) return -1;
       j++;
       x = jsonParseValue(pParse, j);
       if( x<0 ) return -1;
       j = x;
-      while( isspace(pParse->zJson[j]) ){ j++; }
+      while( isspace((unsigned char)pParse->zJson[j]) ){ j++; }
       c = pParse->zJson[j];
       if( c==',' ) continue;
       if( c!='}' ) return -1;
       break;
     }
@@ -620,18 +620,18 @@
   }else if( c=='[' ){
     /* Parse array */
     iThis = jsonParseAddNode(pParse, JSON_ARRAY, 0, 0);
     if( iThis<0 ) return -1;
     for(j=i+1;;j++){
-      while( isspace(pParse->zJson[j]) ){ j++; }
+      while( isspace((unsigned char)pParse->zJson[j]) ){ j++; }
       x = jsonParseValue(pParse, j);
       if( x<0 ){
         if( x==(-3) && pParse->nNode==(u32)iThis+1 ) return j+1;
         return -1;
       }
       j = x;
-      while( isspace(pParse->zJson[j]) ){ j++; }
+      while( isspace((unsigned char)pParse->zJson[j]) ){ j++; }
       c = pParse->zJson[j];
       if( c==',' ) continue;
       if( c!=']' ) return -1;
       break;
     }
@@ -656,21 +656,21 @@
     jsonParseAddNode(pParse, JSON_STRING, j+1-i, &pParse->zJson[i]);
     if( !pParse->oom ) pParse->aNode[pParse->nNode-1].jnFlags = jnFlags;
     return j+1;
   }else if( c=='n'
          && strncmp(pParse->zJson+i,"null",4)==0
-         && !isalnum(pParse->zJson[i+4]) ){
+         && !isalnum((unsigned char)pParse->zJson[i+4]) ){
     jsonParseAddNode(pParse, JSON_NULL, 0, 0);
     return i+4;
   }else if( c=='t'
          && strncmp(pParse->zJson+i,"true",4)==0
-         && !isalnum(pParse->zJson[i+4]) ){
+         && !isalnum((unsigned char)pParse->zJson[i+4]) ){
     jsonParseAddNode(pParse, JSON_TRUE, 0, 0);
     return i+4;
   }else if( c=='f'
          && strncmp(pParse->zJson+i,"false",5)==0
-         && !isalnum(pParse->zJson[i+5]) ){
+         && !isalnum((unsigned char)pParse->zJson[i+5]) ){
     jsonParseAddNode(pParse, JSON_FALSE, 0, 0);
     return i+5;
   }else if( c=='-' || (c>='0' && c<='9') ){
     /* Parse number */
     u8 seenDP = 0;
@@ -729,11 +729,11 @@
   if( zJson==0 ) return 1;
   pParse->zJson = zJson;
   i = jsonParseValue(pParse, 0);
   if( pParse->oom ) i = -1;
   if( i>0 ){
-    while( isspace(zJson[i]) ) i++;
+    while( isspace((unsigned char)zJson[i]) ) i++;
     if( zJson[i] ) i = -1;
   }
   if( i<=0 ){
     if( pCtx!=0 ){
       if( pParse->oom ){
@@ -860,15 +860,15 @@
         pRoot->jnFlags |= JNODE_APPEND;
         pParse->aNode[iLabel].jnFlags |= JNODE_RAW;
       }
       return pNode;
     }
-  }else if( zPath[0]=='[' && isdigit(zPath[1]) ){
+  }else if( zPath[0]=='[' && isdigit((unsigned char)zPath[1]) ){
     if( pRoot->eType!=JSON_ARRAY ) return 0;
     i = 0;
     zPath++;
-    while( isdigit(zPath[0]) ){
+    while( isdigit((unsigned char)zPath[0]) ){
       i = i*10 + zPath[0] - '0';
       zPath++;
     }
     if( zPath[0]!=']' ){
       *pzErr = zPath;