Improve and simplify UTF-8 validation in JSON

diff --git a/ext/json/json_encoder.c b/ext/json/json_encoder.c
index 545d229f35f82ffc8f7fd94c43cdbac6dffec992..6b55a83ca1f9d7cda71977740fd47d4fcbd39d99 100644 (file)
--- a/ext/json/json_encoder.c
+++ b/ext/json/json_encoder.c
@@ -246,33 +246,13 @@ static int php_json_encode_array(smart_str *buf, zval *val, int options, php_jso
 }
 /* }}} */
 
-static int php_json_valid_utf8(char utf8[], size_t len) /* {{{ */
-{
-       size_t pos = 0, us;
-       int status;
-
-       while (pos < len) {
-               us = (unsigned char)utf8[pos];
-               if (us < 0x80) {
-                       pos++;
-               } else {
-                       us = php_next_utf8_char((const unsigned char *)utf8, len, &pos, &status);
-                       if (status != SUCCESS) {
-                               return 0;
-                       }
-               }
-       }
-       return 1;
-}
-/* }}} */
-
 static int php_json_escape_string(
                smart_str *buf, char *s, size_t len,
                int options, php_json_encoder *encoder) /* {{{ */
 {
        int status;
        unsigned int us;
-       size_t pos, checkpoint;
+       size_t prev_pos, pos, checkpoint;
 
        if (len == 0) {
                smart_str_appendl(buf, "\"\"", 2);
@@ -295,18 +275,6 @@ static int php_json_escape_string(
                }
 
        }
-
-       if (options & PHP_JSON_UNESCAPED_UNICODE) {
-               /* validate UTF-8 string first */
-               if (!php_json_valid_utf8(s, len)) {
-                       encoder->error_code = PHP_JSON_ERROR_UTF8;
-                       if (options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR) {
-                               smart_str_appendl(buf, "null", 4);
-                       }
-                       return FAILURE;
-               }
-       }
-
        pos = 0;
        checkpoint = buf->s ? ZSTR_LEN(buf->s) : 0;
 
@@ -315,27 +283,27 @@ static int php_json_escape_string(
        smart_str_appendc(buf, '"');
 
        do {
-               us = (unsigned char)s[pos];
-               if (us >= 0x80 && (!(options & PHP_JSON_UNESCAPED_UNICODE) || us == 0xE2)) {
-                       /* UTF-8 character */
-                       us = php_next_utf8_char((const unsigned char *)s, len, &pos, &status);
-                       if (status != SUCCESS) {
-                               if (buf->s) {
-                                       ZSTR_LEN(buf->s) = checkpoint;
-                               }
-                               encoder->error_code = PHP_JSON_ERROR_UTF8;
-                               if (options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR) {
-                                       smart_str_appendl(buf, "null", 4);
-                               }
-                               return FAILURE;
+               prev_pos = pos;
+               us = php_next_utf8_char((unsigned char *)s, len, &pos, &status);
+               /* check whether UTF8 character is correct */
+               if (status != SUCCESS) {
+                       if (buf->s) {
+                               ZSTR_LEN(buf->s) = checkpoint;
                        }
+                       encoder->error_code = PHP_JSON_ERROR_UTF8;
+                       if (options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR) {
+                               smart_str_appendl(buf, "null", 4);
+                       }
+                       return FAILURE;
+               }
+               if (us >= 0x80 && (!(options & PHP_JSON_UNESCAPED_UNICODE) || (unsigned char)s[prev_pos] == 0xE2)) {
                        /* Escape U+2028/U+2029 line terminators, UNLESS both
                           JSON_UNESCAPED_UNICODE and
                           JSON_UNESCAPED_LINE_TERMINATORS were provided */
                        if ((options & PHP_JSON_UNESCAPED_UNICODE)
                                && ((options & PHP_JSON_UNESCAPED_LINE_TERMINATORS)
                                        || us < 0x2028 || us > 0x2029)) {
-                               smart_str_appendl(buf, &s[pos - 3], 3);
+                               smart_str_appendl(buf, &s[prev_pos], 3);
                                continue;
                        }
                        /* From http://en.wikipedia.org/wiki/UTF16 */
@@ -357,8 +325,6 @@ static int php_json_escape_string(
                        smart_str_appendc(buf, digits[(us & 0xf0)   >> 4]);
                        smart_str_appendc(buf, digits[(us & 0xf)]);
                } else {
-                       pos++;
-
                        switch (us) {
                                case '"':
                                        if (options & PHP_JSON_HEX_QUOT) {
@@ -434,7 +400,7 @@ static int php_json_escape_string(
 
                                default:
                                        if (us >= ' ') {
-                                               smart_str_appendc(buf, (unsigned char) us);
+                                               smart_str_appendl(buf, s + prev_pos, pos - prev_pos);
                                        } else {
                                                smart_str_appendl(buf, "\\u00", sizeof("\\u00")-1);
                                                smart_str_appendc(buf, digits[(us & 0xf0)   >> 4]);