mirror of
https://github.com/php/php-src.git
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298 lines
9.3 KiB
C
298 lines
9.3 KiB
C
/*
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+----------------------------------------------------------------------+
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| Zend Engine |
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+----------------------------------------------------------------------+
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| Copyright (c) 1998-2014 Zend Technologies Ltd. (http://www.zend.com) |
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+----------------------------------------------------------------------+
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| This source file is subject to version 2.00 of the Zend license, |
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| that is bundled with this package in the file LICENSE, and is |
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| available through the world-wide-web at the following url: |
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| http://www.zend.com/license/2_00.txt. |
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| If you did not receive a copy of the Zend license and are unable to |
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| obtain it through the world-wide-web, please send a note to |
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| license@zend.com so we can mail you a copy immediately. |
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+----------------------------------------------------------------------+
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| Authors: Dmitry Stogov <dmitry@zend.com> |
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+----------------------------------------------------------------------+
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*/
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/* $Id: $ */
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#ifndef ZEND_STRING_H
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#define ZEND_STRING_H
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#include "zend.h"
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BEGIN_EXTERN_C()
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ZEND_API extern zend_string *(*zend_new_interned_string)(zend_string *str TSRMLS_DC);
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ZEND_API extern void (*zend_interned_strings_snapshot)(TSRMLS_D);
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ZEND_API extern void (*zend_interned_strings_restore)(TSRMLS_D);
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ZEND_API zend_ulong zend_hash_func(const char *str, uint len);
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void zend_interned_strings_init(TSRMLS_D);
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void zend_interned_strings_dtor(TSRMLS_D);
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END_EXTERN_C()
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#define IS_INTERNED(s) (GC_FLAGS(s) & IS_STR_INTERNED)
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#define STR_HASH_VAL(s) zend_str_hash_val(s)
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#define STR_FORGET_HASH_VAL(s) zend_str_forget_hash_val(s)
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#define STR_REFCOUNT(s) zend_str_refcount(s)
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#define STR_ADDREF(s) zend_str_addref(s)
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#define STR_DELREF(s) zend_str_delref(s)
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#define STR_ALLOC(len, persistent) zend_str_alloc(len, persistent)
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#define STR_SAFE_ALLOC(n, m, l, p) zend_str_safe_alloc(n, m, l, p)
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#define STR_INIT(str, len, persistent) zend_str_init(str, len, persistent)
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#define STR_COPY(s) zend_str_copy(s)
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#define STR_DUP(s, persistent) zend_str_dup(s, persistent)
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#define STR_REALLOC(s, len, persistent) zend_str_realloc(s, len, persistent)
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#define STR_SAFE_REALLOC(s, n, m, l, p) zend_str_safe_realloc(s, n, m, l, p)
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#define STR_FREE(s) zend_str_free(s)
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#define STR_RELEASE(s) zend_str_release(s)
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#define STR_EMPTY_ALLOC() CG(empty_string)
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#define _STR_HEADER_SIZE XtOffsetOf(zend_string, val)
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#define STR_ALLOCA_ALLOC(str, _len, use_heap) do { \
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(str) = (zend_string *)do_alloca(_STR_HEADER_SIZE + (_len) + 1, (use_heap)); \
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GC_REFCOUNT(str) = 1; \
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(str)->h = 0; \
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(str)->len = (_len); \
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} while (0)
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#define STR_ALLOCA_INIT(str, s, len, use_heap) do { \
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STR_ALLOCA_ALLOC(str, len, use_heap); \
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memcpy((str)->val, (s), (len)); \
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(str)->val[(len)] = '\0'; \
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} while (0)
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#define STR_ALLOCA_FREE(str, use_heap) free_alloca(str, use_heap)
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static zend_always_inline zend_ulong zend_str_hash_val(zend_string *s)
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{
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if (!s->h) {
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s->h = zend_hash_func(s->val, s->len);
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}
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return s->h;
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}
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static zend_always_inline void zend_str_forget_hash_val(zend_string *s)
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{
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s->h = 0;
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}
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static zend_always_inline zend_uint zend_str_refcount(zend_string *s)
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{
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if (!IS_INTERNED(s)) {
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return GC_REFCOUNT(s);
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}
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return 1;
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}
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static zend_always_inline zend_uint zend_str_addref(zend_string *s)
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{
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if (!IS_INTERNED(s)) {
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return ++GC_REFCOUNT(s);
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}
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return 1;
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}
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static zend_always_inline zend_uint zend_str_delref(zend_string *s)
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{
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if (!IS_INTERNED(s)) {
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return --GC_REFCOUNT(s);
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}
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return 1;
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}
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static zend_always_inline zend_string *zend_str_alloc(int len, int persistent)
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{
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zend_string *ret = (zend_string *)pemalloc(_STR_HEADER_SIZE + len + 1, persistent);
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GC_REFCOUNT(ret) = 1;
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#if 1
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/* optimized single assignment */
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GC_TYPE_INFO(ret) = IS_STRING | ((persistent ? IS_STR_PERSISTENT : 0) << 8);
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#else
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GC_TYPE(ret) = IS_STRING;
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GC_FLAGS(ret) = (persistent ? IS_STR_PERSISTENT : 0);
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GC_INFO(ret) = 0;
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#endif
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ret->h = 0;
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ret->len = len;
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return ret;
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}
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static zend_always_inline zend_string *zend_str_safe_alloc(size_t n, size_t m, size_t l, int persistent)
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{
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zend_string *ret = (zend_string *)safe_pemalloc(n, m, _STR_HEADER_SIZE + l + 1, persistent);
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GC_REFCOUNT(ret) = 1;
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#if 1
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/* optimized single assignment */
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GC_TYPE_INFO(ret) = IS_STRING | ((persistent ? IS_STR_PERSISTENT : 0) << 8);
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#else
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GC_TYPE(ret) = IS_STRING;
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GC_FLAGS(ret) = (persistent ? IS_STR_PERSISTENT : 0);
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GC_INFO(ret) = 0;
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#endif
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ret->h = 0;
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ret->len = (n * m) + l;
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return ret;
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}
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static zend_always_inline zend_string *zend_str_init(const char *str, int len, int persistent)
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{
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zend_string *ret = STR_ALLOC(len, persistent);
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memcpy(ret->val, str, len);
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ret->val[len] = '\0';
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return ret;
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}
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static zend_always_inline zend_string *zend_str_copy(zend_string *s)
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{
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if (!IS_INTERNED(s)) {
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STR_ADDREF(s);
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}
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return s;
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}
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static zend_always_inline zend_string *zend_str_dup(zend_string *s, int persistent)
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{
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if (IS_INTERNED(s)) {
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return s;
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} else {
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return STR_INIT(s->val, s->len, persistent);
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}
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}
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static zend_always_inline zend_string *zend_str_realloc(zend_string *s, int len, int persistent)
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{
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zend_string *ret;
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if (IS_INTERNED(s)) {
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ret = STR_ALLOC(len, persistent);
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memcpy(ret->val, s->val, (len > s->len ? s->len : len) + 1);
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} else if (EXPECTED(STR_REFCOUNT(s) == 1)) {
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ret = (zend_string *)perealloc(s, _STR_HEADER_SIZE + len + 1, persistent);
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ret->len = len;
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STR_FORGET_HASH_VAL(ret);
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} else {
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ret = STR_ALLOC(len, persistent);
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memcpy(ret->val, s->val, (len > s->len ? s->len : len) + 1);
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STR_DELREF(s);
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}
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return ret;
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}
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static zend_always_inline zend_string *zend_str_safe_realloc(zend_string *s, size_t n, size_t m, size_t l, int persistent)
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{
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zend_string *ret;
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if (IS_INTERNED(s)) {
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ret = STR_SAFE_ALLOC(n, m, l, persistent);
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memcpy(ret->val, s->val, ((n * m) + l > s->len ? s->len : ((n * m) + l)) + 1);
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} else if (STR_REFCOUNT(s) == 1) {
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ret = (zend_string *)safe_perealloc(s, n, m, _STR_HEADER_SIZE + l + 1, persistent);
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ret->len = (n * m) + l;
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STR_FORGET_HASH_VAL(ret);
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} else {
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ret = STR_SAFE_ALLOC(n, m, l, persistent);
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memcpy(ret->val, s->val, ((n * m) + l > s->len ? s->len : ((n * m) + l)) + 1);
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STR_DELREF(s);
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}
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return ret;
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}
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static zend_always_inline void zend_str_free(zend_string *s)
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{
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if (!IS_INTERNED(s)) {
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ZEND_ASSERT(STR_REFCOUNT(s) <= 1);
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pefree(s, GC_FLAGS(s) & IS_STR_PERSISTENT);
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}
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}
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static zend_always_inline void zend_str_release(zend_string *s)
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{
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if (!IS_INTERNED(s)) {
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if (STR_DELREF(s) == 0) {
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pefree(s, GC_FLAGS(s) & IS_STR_PERSISTENT);
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}
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}
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}
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/*
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* DJBX33A (Daniel J. Bernstein, Times 33 with Addition)
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*
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* This is Daniel J. Bernstein's popular `times 33' hash function as
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* posted by him years ago on comp.lang.c. It basically uses a function
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* like ``hash(i) = hash(i-1) * 33 + str[i]''. This is one of the best
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* known hash functions for strings. Because it is both computed very
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* fast and distributes very well.
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*
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* The magic of number 33, i.e. why it works better than many other
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* constants, prime or not, has never been adequately explained by
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* anyone. So I try an explanation: if one experimentally tests all
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* multipliers between 1 and 256 (as RSE did now) one detects that even
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* numbers are not useable at all. The remaining 128 odd numbers
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* (except for the number 1) work more or less all equally well. They
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* all distribute in an acceptable way and this way fill a hash table
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* with an average percent of approx. 86%.
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*
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* If one compares the Chi^2 values of the variants, the number 33 not
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* even has the best value. But the number 33 and a few other equally
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* good numbers like 17, 31, 63, 127 and 129 have nevertheless a great
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* advantage to the remaining numbers in the large set of possible
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* multipliers: their multiply operation can be replaced by a faster
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* operation based on just one shift plus either a single addition
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* or subtraction operation. And because a hash function has to both
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* distribute good _and_ has to be very fast to compute, those few
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* numbers should be preferred and seems to be the reason why Daniel J.
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* Bernstein also preferred it.
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*
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*
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* -- Ralf S. Engelschall <rse@engelschall.com>
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*/
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static inline ulong zend_inline_hash_func(const char *str, uint len)
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{
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register ulong hash = 5381;
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/* variant with the hash unrolled eight times */
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for (; len >= 8; len -= 8) {
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hash = ((hash << 5) + hash) + *str++;
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hash = ((hash << 5) + hash) + *str++;
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hash = ((hash << 5) + hash) + *str++;
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hash = ((hash << 5) + hash) + *str++;
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hash = ((hash << 5) + hash) + *str++;
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hash = ((hash << 5) + hash) + *str++;
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hash = ((hash << 5) + hash) + *str++;
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hash = ((hash << 5) + hash) + *str++;
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}
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switch (len) {
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case 7: hash = ((hash << 5) + hash) + *str++; /* fallthrough... */
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case 6: hash = ((hash << 5) + hash) + *str++; /* fallthrough... */
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case 5: hash = ((hash << 5) + hash) + *str++; /* fallthrough... */
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case 4: hash = ((hash << 5) + hash) + *str++; /* fallthrough... */
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case 3: hash = ((hash << 5) + hash) + *str++; /* fallthrough... */
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case 2: hash = ((hash << 5) + hash) + *str++; /* fallthrough... */
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case 1: hash = ((hash << 5) + hash) + *str++; break;
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case 0: break;
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EMPTY_SWITCH_DEFAULT_CASE()
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}
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return hash;
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}
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#endif /* ZEND_STRING_H */
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/*
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* Local variables:
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* tab-width: 4
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* c-basic-offset: 4
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* indent-tabs-mode: t
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* End:
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*/
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