php_json_escape_string() optimization

1 files changed, 60 insertions, 35 deletions

diff --git a/ext/json/json_encoder.c b/ext/json/json_encoder.c
index b3d0b57a7e..c79e694f26 100644
--- a/ext/json/json_encoder.c
+++ b/ext/json/json_encoder.c
@@ -33,7 +33,7 @@
 static const char digits[] = "0123456789abcdef";
 
 static int php_json_escape_string(
-		smart_str *buf,	char *s, size_t len,
+		smart_str *buf,	const char *s, size_t len,
 		int options, php_json_encoder *encoder);
 
 static int php_json_determine_array_type(zval *val) /* {{{ */
@@ -250,12 +250,13 @@ static int php_json_encode_array(smart_str *buf, zval *val, int options, php_jso
 /* }}} */
 
 static int php_json_escape_string(
-		smart_str *buf, char *s, size_t len,
+		smart_str *buf, const char *s, size_t len,
 		int options, php_json_encoder *encoder) /* {{{ */
 {
 	int status;
 	unsigned int us;
 	size_t pos, checkpoint;
+	char *dst;
 
 	if (len == 0) {
 		smart_str_appendl(buf, "\"\"", 2);
@@ -287,72 +288,89 @@ static int php_json_escape_string(
 
 	do {
 		us = (unsigned char)s[pos];
-		if (us >= 0x80) {
-			int utf8_sub = 0;
-			size_t prev_pos = pos;
-
+		if (UNEXPECTED(us >= 0x80)) {
+			if (pos) {
+				smart_str_appendl(buf, s, pos);
+				s += pos;
+				pos = 0;
+			}
 			us = php_next_utf8_char((unsigned char *)s, len, &pos, &status);
+			len -= pos;
 
 			/* check whether UTF8 character is correct */
-			if (status != SUCCESS) {
+			if (UNEXPECTED(status != SUCCESS)) {
+				s += pos;
+				pos = 0;
 				if (options & PHP_JSON_INVALID_UTF8_IGNORE) {
 					/* ignore invalid UTF8 character */
 					continue;
 				} else if (options & PHP_JSON_INVALID_UTF8_SUBSTITUTE) {
 					/* Use Unicode character 'REPLACEMENT CHARACTER' (U+FFFD) */
-					us = 0xfffd;
-					utf8_sub = 1;
-				} else {
-					if (buf->s) {
-						ZSTR_LEN(buf->s) = checkpoint;
+					if (options & PHP_JSON_UNESCAPED_UNICODE) {
+						smart_str_appendl(buf, "\xef\xbf\xbd", 3);
+					} else {
+						smart_str_appendl(buf, "\\ufffd", 6);
 					}
+					continue;
+				} else {
+					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;
 				}
-			}
 
 			/* 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)
+			} else if ((options & PHP_JSON_UNESCAPED_UNICODE)
 			    && ((options & PHP_JSON_UNESCAPED_LINE_TERMINATORS)
 					|| us < 0x2028 || us > 0x2029)) {
-				if (utf8_sub) {
-					smart_str_appendl(buf, "\xef\xbf\xbd", 3);
-				} else {
-					smart_str_appendl(buf, s + prev_pos, pos - prev_pos);
-				}
+				smart_str_appendl(buf, s, pos);
+				s += pos;
+				pos = 0;
 				continue;
 			}
 			/* From http://en.wikipedia.org/wiki/UTF16 */
 			if (us >= 0x10000) {
 				unsigned int next_us;
+
 				us -= 0x10000;
 				next_us = (unsigned short)((us & 0x3ff) | 0xdc00);
 				us = (unsigned short)((us >> 10) | 0xd800);
-				smart_str_appendl(buf, "\\u", 2);
-				smart_str_appendc(buf, digits[(us & 0xf000) >> 12]);
-				smart_str_appendc(buf, digits[(us & 0xf00)  >> 8]);
-				smart_str_appendc(buf, digits[(us & 0xf0)   >> 4]);
-				smart_str_appendc(buf, digits[(us & 0xf)]);
+				dst = smart_str_extend(buf, 6);
+				dst[0] = '\\';
+				dst[1] = 'u';
+				dst[2] = digits[(us >> 12) & 0xf];
+				dst[3] = digits[(us >> 8) & 0xf];
+				dst[4] = digits[(us >> 4) & 0xf];
+				dst[5] = digits[us & 0xf];
 				us = next_us;
 			}
-			smart_str_appendl(buf, "\\u", 2);
-			smart_str_appendc(buf, digits[(us & 0xf000) >> 12]);
-			smart_str_appendc(buf, digits[(us & 0xf00)  >> 8]);
-			smart_str_appendc(buf, digits[(us & 0xf0)   >> 4]);
-			smart_str_appendc(buf, digits[(us & 0xf)]);
+			dst = smart_str_extend(buf, 6);
+			dst[0] = '\\';
+			dst[1] = 'u';
+			dst[2] = digits[(us >> 12) & 0xf];
+			dst[3] = digits[(us >> 8) & 0xf];
+			dst[4] = digits[(us >> 4) & 0xf];
+			dst[5] = digits[us & 0xf];
+			s += pos;
+			pos = 0;
 		} else {
 			static const uint32_t charmap[4] = {
 				0xffffffff, 0x500080c4, 0x10000000, 0x00000000};
 
-			pos++;
+			len--;
 			if (EXPECTED(!ZEND_BIT_TEST(charmap, us))) {
-				smart_str_appendc(buf, (unsigned char) us);
+				pos++;
 			} else {
+				if (pos) {
+					smart_str_appendl(buf, s, pos);
+					s += pos;
+					pos = 0;
+				}
+				s++;
 				switch (us) {
 					case '"':
 						if (options & PHP_JSON_HEX_QUOT) {
@@ -428,15 +446,22 @@ static int php_json_escape_string(
 
 					default:
 						ZEND_ASSERT(us < ' ');
-						smart_str_appendl(buf, "\\u00", sizeof("\\u00")-1);
-						smart_str_appendc(buf, digits[(us & 0xf0)   >> 4]);
-						smart_str_appendc(buf, digits[(us & 0xf)]);
+						dst = smart_str_extend(buf, 6);
+						dst[0] = '\\';
+						dst[1] = 'u';
+						dst[2] = '0';
+						dst[3] = '0';
+						dst[4] = digits[(us >> 4) & 0xf];
+						dst[5] = digits[us & 0xf];
 						break;
 				}
 			}
 		}
-	} while (pos < len);
+	} while (len);
 
+	if (EXPECTED(pos)) {
+		smart_str_appendl(buf, s, pos);
+	}
 	smart_str_appendc(buf, '"');
 
 	return SUCCESS;