From e8f4dc86cb87b38ee19b8574dadbbe6629f35ef0 Mon Sep 17 00:00:00 2001
From: Joey Adams
Date: Mon, 14 Jun 2010 02:29:58 -0400
Subject: Implemented/tested parser for basic JSONPath(ish) patterns.

---
 json.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 49 insertions(+), 21 deletions(-)

(limited to 'json.c')

diff --git a/json.c b/json.c
index d530edd..1cc8628 100644
--- a/json.c
+++ b/json.c
@@ -349,9 +349,10 @@ ascend:
 
 static json_node *decode_leaf(const char **sp);
 static json_node *decode_number(const char **sp);
-static char *decode_string(const char **sp, size_t *length);
-/* decode_string has a different signature than its friends
-   because it's also used to parse object member keys. */
+char *json_decode_string(const char **sp, size_t *length, bool strict);
+/* json_decode_string has a different signature than its friends
+   because it's also used to parse object member keys.
+   It's also useful outside of json.c, such as in jsonpath.c . */
 
 bool json_validate(const char *str)
 {
@@ -382,7 +383,7 @@ item: /* Expect a value */
 	
 	if (parent && parent->type == JSON_OBJECT) {
 		/* Parse member key string. */
-		key = decode_string(&s, &key_length);
+		key = json_decode_string(&s, &key_length, true);
 		if (!key)
 			goto failed;
 		
@@ -482,7 +483,7 @@ static json_node *decode_leaf(const char **sp)
 	
 	if (c == '"') {
 		size_t length;
-		char *str = decode_string(sp, &length);
+		char *str = json_decode_string(sp, &length, true);
 		
 		if (str) {
 			json_node *node = json_mknode(JSON_STRING);
@@ -573,24 +574,32 @@ static json_node *decode_number(const char **sp)
 	return json_mknumber(start, end - start);
 }
 
-static char *decode_string(const char **sp, size_t *length)
+char *json_decode_string(const char **sp, size_t *length, bool strict)
 {
 	const char *s = *sp;
 	String(ret);
 	char *out;
 	size_t size;
+	char quote;
+
+	Assert(length != NULL);
 	
-	if (*s++ != '"')
-		return NULL;
-	
-	while (*s && *s != '"') {
+	quote = *s++;
+	if (strict) {
+		if (quote != '"')
+			return NULL;
+	} else {
+		if (quote != '"' && quote != '\'')
+			return NULL;
+	}
+
+	while (*s && *s != quote) {
 		unsigned char c = *s++;
 		unsigned int uc, lc;
 		
 		if (c == '\\') {
 			c = *s++;
 			switch (c) {
-				case '"':
 				case '\\':
 				case '/':
 					break;
@@ -635,7 +644,11 @@ static char *decode_string(const char **sp, size_t *length)
 					continue; /* Continue the enclosing while loop to skip
 					             the str_append below. */
 				default: /* Invalid escape */
-					goto failed;
+					if (c == quote)
+						break;
+					if (!strict && (c == '"' || c == '\''))
+						break;
+					goto failed; /* Invalid escape */
 			}
 		} else if (c <= 0x1F) {
 			/* Control characters not allowed in string literals. */
@@ -693,22 +706,21 @@ json_type json_text_type(const char *str, size_t nbytes)
 
 /****************************** Encoding *****************************/
 
-static bool encode_string(String out, const char *string, size_t length)
+static bool encode_string(String out, const char *string, size_t length, char quote)
 {
 	const char *s = string;
 	const char *e = s + length;
-	
-	if (!utf8_validate(string, length))
+
+	if (!utf8_validate(string, length) || quote == '\\')
 		return false;
-	
-	string_append_char(out, '"');
+
+	string_append_char(out, quote);
 	
 	while (s < e) {
 		unsigned char c = *s++;
 		unsigned char e;
 		
 		switch (c) {
-			case '"': e = '"'; break;
 			case '\\': e = '\\'; break;
 			case '\b': e = 'b'; break;
 			case '\f': e = 'f'; break;
@@ -716,6 +728,10 @@ static bool encode_string(String out, const char *string, size_t length)
 			case '\r': e = 'r'; break;
 			case '\t': e = 't'; break;
 			default: {
+				if (c == quote) {
+					e = quote;
+					break;
+				}
 				if (c < 0x1F || (c >= 0x80 && json_escape_unicode)) {
 					/* Encode using \u.... */
 					unsigned int uc, lc;
@@ -754,7 +770,7 @@ static bool encode_string(String out, const char *string, size_t length)
 			string_append_char(out, e);
 	}
 	
-	string_append_char(out, '"');
+	string_append_char(out, quote);
 	
 	return true;
 }
@@ -799,7 +815,7 @@ begin: /* Encode entire node, or (if it's an array or object)
           the beginning of it. */
 	
 	if (node->key) {
-		if (!encode_string(ret, node->key, node->key_length))
+		if (!encode_string(ret, node->key, node->key_length, '"'))
 			goto failed;
 		string_append_char(ret, ':');
 	}
@@ -819,7 +835,7 @@ begin_nokey:
 				txt = "false";
 			break;
 		case JSON_STRING:
-			if (!encode_string(ret, node->v.string.str, node->v.string.length))
+			if (!encode_string(ret, node->v.string.str, node->v.string.length, '"'))
 				goto failed;
 			break;
 		case JSON_NUMBER:
@@ -870,6 +886,18 @@ failed: /* Handle error. */
 	return NULL;
 }
 
+char *json_encode_string(const char *str, size_t length, char quote)
+{
+	String(ret);
+
+	if (!encode_string(ret, str, length, quote)) {
+		string_free(ret);
+		return NULL;
+	}
+
+	return string_buffer(ret);
+}
+
 
 /************************ Liberal JSON support ***********************/
 
-- 
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