adding (optional) j0g set of utilities, safer handling of index pointer, and can be dropped into arduino projects as a lib easily now

Author: quartzjer

Makefile

@@ -1,2 +1,2 @@
 all:
-	gcc -Wall -o js0n_test js0n_test.c js0n.c 
+	gcc -Wall -o js0n_test test/js0n_test.c js0n.c j0g.c

README

@@ -8,5 +8,6 @@ Parsing this:
 
 Would result in:
 
-2,3,8,3,14,6,22,7,30,3,35,9
+2,3,8,3,14,6,22,7,30,3,35,9,0
 
+Also includes a collection utility functions for handy ways of using js0n quickly/easily.

j0g.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "js0n.h"
+#include "j0g.h"
+
+// dumbed down parser, expects null terminated json, if fails the *index is 0 (and safe to pass into j0g_*)
+char *j0g(char *json, unsigned short *index, int ilen)
+{
+  int ret, len;
+  if(!json) return NULL;
+  len = strlen(json);
+  ret = js0n((unsigned char*)json, len, index, ilen);
+  if(ret) *index = 0;
+  return json;
+}
+
+// return the null-terminated string value matching the given key
+char *j0g_str(char *key, char *json, unsigned short *index)
+{
+  char *str, *cursor;
+  int val = j0g_val(key, json, index);
+  if(!val) return NULL;
+  *(json+(index[val]+index[val+1])) = 0; // null terminate
+  // unescape stuff
+  for(cursor=str=json+index[val]; *cursor; cursor++,str++)
+  {
+    if(*cursor == '\\' && *(cursor+1) == 'n')
+    {
+      *str = '\n';
+      cursor++;
+    }else if(*cursor == '\\' && *(cursor+1) == '"'){
+      *str = '"';
+      cursor++;
+    }else{
+      *str = *cursor;
+    }
+  }
+  *str = *cursor; // copy null terminator too
+  return (char*)json+index[val];
+}
+
+// return 1 if the value is the bool value true, number 1, or even the string "true", false otherwise
+int j0g_test(char *key, char *json, unsigned short *index)
+{
+  char *val = j0g_str(key, json, index);
+  if(!val) return 0;
+  if(strcmp(val, "true") == 0) return 1;
+  if(strcmp(val, "1") == 0) return 1;
+  return 0;
+}
+
+// return the index offset of the value matching the given key
+int j0g_val(char *key, char *json, unsigned short *index)
+{
+  if(!key || !json) return 0;
+  int i, klen = strlen(key);
+	for(i=0;index[i];i+=4)
+	{
+    if(klen == index[i+1] && strncmp(key,(char*)json+index[i],klen) == 0) return i+2;
+	}
+  return 0;
+}
+

j0g.h

@@ -0,0 +1,20 @@
+// these are handy utility functions to make working with js0n easier
+
+// dumbed down parser, expects null terminated json, if fails the *index is 0 (and safe to pass into j0g_*)
+// returns json, for chaining
+char *j0g(char *json, unsigned short *index, int ilen);
+
+// for the rest -
+// first arg is the key to find in the json
+// second is the original json passed to js0n
+// third is the array returned by js0n
+// these functions will modify the json arg in place (to null terminate strings)
+
+// return the null-terminated string value matching the given key
+char *j0g_str(char *key, char *json, unsigned short *index);
+
+// return 1 if the value is the bool value true, number 1, or even the string "true", false otherwise
+int j0g_test(char *key, char *json, unsigned short *index);
+
+// return the index offset of the value matching the given key
+int j0g_val(char *key, char *json, unsigned short *index);

js0n.c

@@ -5,9 +5,9 @@
 #define PUSH(i) if(depth == 1) prev = *out++ = ((cur+i) - js)
 #define CAP(i) if(depth == 1) prev = *out++ = ((cur+i) - (js + prev) + 1)
 
-int js0n(unsigned char *js, unsigned int len, unsigned short *out)
+int js0n(unsigned char *js, unsigned int len, unsigned short *out, unsigned int olen)
 {
-	unsigned short prev = 0;
+	unsigned short prev = 0, *oend;
 	unsigned char *cur, *end;
 	int depth=0;
 	int utf8_remain=0;
@@ -55,12 +55,13 @@ int js0n(unsigned char *js, unsigned int len, unsigned short *out)
 	};
 	static void **go = gostruct;
 
-	for(cur=js,end=js+len; cur<end; cur++)
+	for(cur=js,end=js+len,oend=out+olen; cur<end && out<oend; cur++)
 	{
 			goto *go[*cur];
 			l_loop:;
 	}
 
+  if(out < oend) *out = 0;
 	return depth; // 0 if successful full parse, >0 for incomplete data
 
 	l_bad:

js0n.h

@@ -1,6 +1,3 @@
-
-// pass it a raw json string and length, it will return an array of unsigned shorts, see js0n.c for more
-int js0n(unsigned char *js, unsigned int len, unsigned short *out);
-
-// TODO: decode a string value, copy into new while unescaping things and unicode stuffs
-// int js0n(unsigned char *in, unsigned int len, unsigned char *out); 
+// pass it a raw json string and length, and it will tag all the key/value offsets in the out argument (size it same as js to be safe)
+// returns 0 if successful, >0 if not
+int js0n(unsigned char *js, unsigned int len, unsigned short *out, unsigned int olen);

test.js

@@ -3,5 +3,6 @@
 	"bar":[1,2,3],
 	"baz":{"a":"b"},
 	"num":123.45,
-	"obj":{"true":false}
+	"key":"value\n\"newline\"",
+	"obj":{"true":true}
 }

js0n_test.c test/js0n_test.cjs0n_test.c renamed to test/js0n_test.c

@@ -1,7 +1,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include "js0n.h"
+#include "../js0n.h"
+#include "../j0g.h"
 
 int main(int argc, char **argv)
 {
@@ -24,13 +25,18 @@ int main(int argc, char **argv)
 	fclose(f);
 	printf("got[%.*s]\n",lastlen,json);
 	res = malloc(lastlen); // way more than enough
-	memset(res,0,lastlen);
-	ret = js0n(json,lastlen,res);
+	ret = js0n(json,lastlen,res,lastlen);
 	printf("returned %d\n",ret);
 	for(i=0;res[i];i+=2)
 	{
 		printf("%d: at %d len %d is %.*s\n",i,res[i],res[i+1],res[i+1],json+res[i]);
 	}
+	
+	// j0g tests
+  printf("j0g_val 'key' val offset %d\n", j0g_val("key",(char*)json,res));
+  printf("j0g_str 'key' val '%s'\n", j0g_str("key",(char*)json,res));
+  printf("j0g_str 'num' val '%0.2f'\n", (j0g_str("num",(char*)json,res)!=NULL)?strtof(j0g_str("num",(char*)json,res), NULL):0);
+  printf("j0g_test obj->true %d\n", j0g_test("true",j0g(j0g_str("obj",(char*)json,res),res,16),res));
 	return 0;
 }