Use interned empty and "one char" strings.

Author: dstogov

Zend/zend_operators.c

@@ -537,7 +537,7 @@ ZEND_API void ZEND_FASTCALL _convert_to_string(zval *op ZEND_FILE_LINE_DC) /* {{
 			break;
 		}
 		case IS_LONG: {
-			ZVAL_NEW_STR(op, zend_long_to_str(Z_LVAL_P(op)));
+			ZVAL_STR(op, zend_long_to_str(Z_LVAL_P(op)));
 			break;
 		}
 		case IS_DOUBLE: {
@@ -2856,9 +2856,13 @@ ZEND_API void ZEND_FASTCALL zend_locale_sprintf_double(zval *op ZEND_FILE_LINE_D
 
 ZEND_API zend_string* ZEND_FASTCALL zend_long_to_str(zend_long num) /* {{{ */
 {
-	char buf[MAX_LENGTH_OF_LONG + 1];
-	char *res = zend_print_long_to_buf(buf + sizeof(buf) - 1, num);
-	return zend_string_init(res, buf + sizeof(buf) - 1 - res, 0);
+	if ((zend_ulong)num <= 9) {
+		return ZSTR_CHAR((zend_uchar)'0' + (zend_uchar)num);
+	} else {
+		char buf[MAX_LENGTH_OF_LONG + 1];
+		char *res = zend_print_long_to_buf(buf + sizeof(buf) - 1, num);
+		return zend_string_init(res, buf + sizeof(buf) - 1 - res, 0);
+	}
 }
 /* }}} */
 

ext/mysqlnd/mysqlnd_wireprotocol.c

@@ -1766,6 +1766,10 @@ php_mysqlnd_rowp_read_text_protocol_aux(MYSQLND_MEMORY_POOL_CHUNK * row_buffer,
 				} else if (Z_TYPE_P(current_field) == IS_STRING) {
 					/* nothing to do here, as we want a string and ps_fetch_from_1_to_8_bytes() has given us one */
 				}
+			} else if (len == 0) {
+				ZVAL_EMPTY_STRING(current_field);
+			} else if (len == 1) {
+				ZVAL_INTERNED_STR(current_field, ZSTR_CHAR((zend_uchar)*(char *)p));
 			} else {
 				ZVAL_STRINGL(current_field, (char *)p, len);
 			}

ext/standard/array.c

@@ -3807,19 +3807,19 @@ static inline void php_array_merge_or_replace_wrapper(INTERNAL_FUNCTION_PARAMETE
 		Z_PARAM_VARIADIC('+', args, argc)
 	ZEND_PARSE_PARAMETERS_END();
 
-	for (i = 0; i < argc; i++) {
-		zval *arg = args + i;
-
-		if (Z_TYPE_P(arg) != IS_ARRAY) {
-			php_error_docref(NULL, E_WARNING, "Argument #%d is not an array", i + 1);
-			RETURN_NULL();
-		}
-	}
-
 
 	if (replace) {
 		HashTable *dest;
 
+		for (i = 0; i < argc; i++) {
+			zval *arg = args + i;
+
+			if (Z_TYPE_P(arg) != IS_ARRAY) {
+				php_error_docref(NULL, E_WARNING, "Argument #%d is not an array", i + 1);
+				RETURN_NULL();
+			}
+		}
+
 		/* copy first array */
 		arg = args;
 		dest = zend_array_dup(Z_ARRVAL_P(arg));
@@ -3838,11 +3838,22 @@ static inline void php_array_merge_or_replace_wrapper(INTERNAL_FUNCTION_PARAMETE
 	} else {
 		zval *src_entry;
 		HashTable *src, *dest;
+		uint32_t count = 0;
+
+		for (i = 0; i < argc; i++) {
+			zval *arg = args + i;
+
+			if (Z_TYPE_P(arg) != IS_ARRAY) {
+				php_error_docref(NULL, E_WARNING, "Argument #%d is not an array", i + 1);
+				RETURN_NULL();
+			}
+			count += zend_hash_num_elements(Z_ARRVAL_P(arg));
+		}
 
 		arg = args;
 		src  = Z_ARRVAL_P(arg);
 		/* copy first array */
-		array_init_size(return_value, zend_hash_num_elements(src));
+		array_init_size(return_value, count);
 		dest = Z_ARRVAL_P(return_value);
 		if (src->u.flags & HASH_FLAG_PACKED) {
 			zend_hash_real_init(dest, 1);

ext/standard/basic_functions.c

@@ -5320,7 +5320,7 @@ PHP_FUNCTION(highlight_string)
 PHP_FUNCTION(ini_get)
 {
 	char *varname, *str;
-	size_t varname_len;
+	size_t varname_len, len;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
 		Z_PARAM_STRING(varname, varname_len)
@@ -5332,7 +5332,13 @@ PHP_FUNCTION(ini_get)
 		RETURN_FALSE;
 	}
 
-	RETURN_STRING(str);
+	len = strlen(str);
+	if (len == 0) {
+		RETURN_EMPTY_STRING();
+	} else if (len == 1) {
+		RETURN_INTERNED_STR(ZSTR_CHAR((zend_uchar)str[0]));
+	}
+	RETURN_STRINGL(str, len);
 }
 /* }}} */
 
@@ -5443,7 +5449,15 @@ PHP_FUNCTION(ini_set)
 
 	/* copy to return here, because alter might free it! */
 	if (old_value) {
-		RETVAL_STRING(old_value);
+		size_t len = strlen(old_value);
+
+		if (len == 0) {
+			RETVAL_EMPTY_STRING();
+		} else if (len == 1) {
+			RETVAL_INTERNED_STR(ZSTR_CHAR((zend_uchar)old_value[0]));
+		} else {
+			RETVAL_STRINGL(old_value, len);
+		}
 	} else {
 		RETVAL_FALSE;
 	}

ext/standard/string.c

@@ -1094,7 +1094,15 @@ PHPAPI void php_explode(const zend_string *delim, zend_string *str, zval *return
 		zend_hash_next_index_insert_new(Z_ARRVAL_P(return_value), &tmp);
 	} else {
 		do {
-			ZVAL_STRINGL(&tmp, p1, p2 - p1);
+			size_t l = p2 - p1;
+
+			if (l == 0) {
+				ZVAL_EMPTY_STRING(&tmp);
+			} else if (l == 1) {
+				ZVAL_INTERNED_STR(&tmp, ZSTR_CHAR((zend_uchar)(*p1)));
+			} else {
+				ZVAL_STRINGL(&tmp, p1, p2 - p1);
+			}
 			zend_hash_next_index_insert_new(Z_ARRVAL_P(return_value), &tmp);
 			p1 = p2 + ZSTR_LEN(delim);
 			p2 = (char *) php_memnstr(p1, ZSTR_VAL(delim), ZSTR_LEN(delim), endp);
@@ -2420,6 +2428,14 @@ PHP_FUNCTION(substr)
 		l = ZSTR_LEN(str) - f;
 	}
 
+	if (l == 0) {
+		RETURN_EMPTY_STRING();
+	} else if (l == 1) {
+		RETURN_INTERNED_STR(ZSTR_CHAR((zend_uchar)(ZSTR_VAL(str)[f])));
+	} else if (l == ZSTR_LEN(str)) {
+		RETURN_STR_COPY(str);
+	}
+
 	RETURN_STRINGL(ZSTR_VAL(str) + f, l);
 }
 /* }}} */
@@ -3227,7 +3243,14 @@ static zend_string *php_str_to_str_ex(zend_string *haystack,
 nothing_todo:
 		return zend_string_copy(haystack);
 	} else {
-		new_str = zend_string_init(str, str_len, 0);
+		if (str_len == 0) {
+			new_str = ZSTR_EMPTY_ALLOC();
+		} else if (str_len == 1) {
+			new_str = ZSTR_CHAR((zend_uchar)(*str));
+		} else {
+			new_str = zend_string_init(str, str_len, 0);
+		}
+
 		(*replace_count)++;
 		return new_str;
 	}