added way to estimate number of tokens before parsing

1 files changed, 21 insertions, 6 deletions

diff --git a/jsmn.c b/jsmn.c
index 2956230d3..e0644f57d 100644
--- a/jsmn.c
+++ b/jsmn.c
@@ -63,6 +63,10 @@ static jsmnerr_t jsmn_parse_primitive(jsmn_parser *parser, const char *js,
 #endif
 
 found:
+	if (tokens == NULL) {
+		parser->pos--;
+		return 0;
+	}
 	token = jsmn_alloc_token(parser, tokens, num_tokens);
 	if (token == NULL) {
 		parser->pos = start;
@@ -73,7 +77,7 @@ found:
 	token->parent = parser->toksuper;
 #endif
 	parser->pos--;
-	return JSMN_SUCCESS;
+	return 0;
 }
 
 /**
@@ -93,6 +97,9 @@ static jsmnerr_t jsmn_parse_string(jsmn_parser *parser, const char *js,
 
 		/* Quote: end of string */
 		if (c == '\"') {
+			if (tokens == NULL) {
+				return 0;
+			}
 			token = jsmn_alloc_token(parser, tokens, num_tokens);
 			if (token == NULL) {
 				parser->pos = start;
@@ -102,7 +109,7 @@ static jsmnerr_t jsmn_parse_string(jsmn_parser *parser, const char *js,
 #ifdef JSMN_PARENT_LINKS
 			token->parent = parser->toksuper;
 #endif
-			return JSMN_SUCCESS;
+			return 0;
 		}
 
 		/* Backslash: Quoted symbol expected */
@@ -148,6 +155,7 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, jsmntok_t *tokens,
 	jsmnerr_t r;
 	int i;
 	jsmntok_t *token;
+	int count = 0;
 
 	for (; js[parser->pos] != '\0'; parser->pos++) {
 		char c;
@@ -156,6 +164,10 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, jsmntok_t *tokens,
 		c = js[parser->pos];
 		switch (c) {
 			case '{': case '[':
+				if (tokens == NULL) {
+					count++;
+					break;
+				}
 				token = jsmn_alloc_token(parser, tokens, num_tokens);
 				if (token == NULL)
 					return JSMN_ERROR_NOMEM;
@@ -170,6 +182,8 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, jsmntok_t *tokens,
 				parser->toksuper = parser->toknext - 1;
 				break;
 			case '}': case ']':
+				if (tokens == NULL)
+					break;
 				type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
 #ifdef JSMN_PARENT_LINKS
 				if (parser->toknext < 1) {
@@ -216,7 +230,8 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, jsmntok_t *tokens,
 			case '\"':
 				r = jsmn_parse_string(parser, js, tokens, num_tokens);
 				if (r < 0) return r;
-				if (parser->toksuper != -1)
+				count++;
+				if (parser->toksuper != -1 && tokens != NULL)
 					tokens[parser->toksuper].size++;
 				break;
 			case '\t' : case '\r' : case '\n' : case ':' : case ',': case ' ': 
@@ -232,7 +247,8 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, jsmntok_t *tokens,
 #endif
 				r = jsmn_parse_primitive(parser, js, tokens, num_tokens);
 				if (r < 0) return r;
-				if (parser->toksuper != -1)
+				count++;
+				if (parser->toksuper != -1 && tokens != NULL)
 					tokens[parser->toksuper].size++;
 				break;
 
@@ -241,7 +257,6 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, jsmntok_t *tokens,
 			default:
 				return JSMN_ERROR_INVAL;
 #endif
-
 		}
 	}
 
@@ -252,7 +267,7 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, jsmntok_t *tokens,
 		}
 	}
 
-	return JSMN_SUCCESS;
+	return count;
 }
 
 /**