Added fabled hex2bin() function

NEWS

@@ -130,6 +130,7 @@ PHP                                                                        NEWS
 - Improved core functions:
   . number_format() no longer truncates multibyte decimal points and thousand
     separators to the first byte. FR #53457. (Adam)
+  . Added hex2bin() function. (Scott)
 
 - Improved CURL extension:
   . Added support for CURLOPT_MAX_RECV_SPEED_LARGE and

UPGRADING

@@ -358,10 +358,11 @@ UPGRADE NOTES - PHP X.Y
 
        - Core:
          - get_declared_traits()
+         - hex2bin()
          - http_response_code()
-         - trait_exists()
          - stream_set_chunk_size()
          - socket_import_stream()
+         - trait_exists()
 
        - LDAP:
          - ldap_control_paged_results()

ext/standard/basic_functions.c

@@ -2142,6 +2142,10 @@ ZEND_BEGIN_ARG_INFO(arginfo_bin2hex, 0)
 	ZEND_ARG_INFO(0, data)
 ZEND_END_ARG_INFO()
 
+ZEND_BEGIN_ARG_INFO(arginfo_hex2bin, 0)
+	ZEND_ARG_INFO(0, data)
+ZEND_END_ARG_INFO()
+
 ZEND_BEGIN_ARG_INFO_EX(arginfo_strspn, 0, 0, 2)
 	ZEND_ARG_INFO(0, str)
 	ZEND_ARG_INFO(0, mask)
@@ -2682,6 +2686,7 @@ ZEND_END_ARG_INFO()
 const zend_function_entry basic_functions[] = { /* {{{ */
 	PHP_FE(constant,														arginfo_constant)
 	PHP_FE(bin2hex,															arginfo_bin2hex)
+	PHP_FE(hex2bin,															arginfo_hex2bin)
 	PHP_FE(sleep,															arginfo_sleep)
 	PHP_FE(usleep,															arginfo_usleep)
 #if HAVE_NANOSLEEP

ext/standard/php_string.h

@@ -78,6 +78,7 @@ PHP_FUNCTION(chunk_split);
 PHP_FUNCTION(parse_str);
 PHP_FUNCTION(str_getcsv);
 PHP_FUNCTION(bin2hex);
+PHP_FUNCTION(hex2bin);
 PHP_FUNCTION(similar_text);
 PHP_FUNCTION(strip_tags);
 PHP_FUNCTION(str_repeat);

ext/standard/string.c

@@ -146,6 +146,46 @@ static char *php_bin2hex(const unsigned char *old, const size_t oldlen, size_t *
 }
 /* }}} */
 
+/* {{{ php_hex2bin
+ */
+static char *php_hex2bin(const unsigned char *old, const size_t oldlen, size_t *newlen)
+{
+	size_t target_length = oldlen >> 1;
+	register unsigned char *str = (unsigned char *)safe_emalloc(target_length, sizeof(char), 1);
+	size_t i, j;
+	for (i = j = 0; i < target_length; i++) {
+		char c = old[j++];
+		if (c >= '0' && c <= '9') {
+			str[i] = (c - '0') << 4;
+		} else if (c >= 'a' && c <= 'f') {
+			str[i] = (c - 'a' + 10) << 4;
+		} else if (c >= 'A' && c <= 'F') {
+			str[i] = (c - 'A' + 10) << 4;
+		} else {
+			efree(str);
+			return NULL;
+		}
+		c = old[j++];
+		if (c >= '0' && c <= '9') {
+			str[i] |= c - '0';
+		} else if (c >= 'a' && c <= 'f') {
+			str[i] |= c - 'a' + 10;
+		} else if (c >= 'A' && c <= 'F') {
+			str[i] |= c - 'A' + 10;
+		} else {
+			efree(str);
+			return NULL;
+		}
+	}
+	str[target_length] = '\0';
+	
+	if (newlen) 
+		*newlen = target_length;
+
+	return (char *)str;
+}
+/* }}} */
+
 #ifdef HAVE_LOCALECONV
 /* {{{ localeconv_r
  * glibc's localeconv is not reentrant, so lets make it so ... sorta */
@@ -214,6 +254,28 @@ PHP_FUNCTION(bin2hex)
 }
 /* }}} */
 
+/* {{{ proto string hex2bin(string data)
+   Converts the hex representation of data to binary */
+PHP_FUNCTION(hex2bin)
+{
+	char *result, *data;
+	size_t newlen;
+	int datalen;
+
+	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &data, &datalen) == FAILURE) {
+		return;
+	}
+
+	result = php_hex2bin((unsigned char *)data, datalen, &newlen);
+	
+	if (!result) {
+		RETURN_FALSE;
+	}
+
+	RETURN_STRINGL(result, newlen, 0);
+}
+/* }}} */
+
 static void php_spn_common_handler(INTERNAL_FUNCTION_PARAMETERS, int behavior) /* {{{ */
 {
 	char *s11, *s22;