Skip to content

Add str_extend() #20527

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 1 commit into
base: master
Choose a base branch
from
+90 −11
Open

Add str_extend() #20527

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
42 changes: 33 additions & 9 deletions Zend/zend_alloc.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1671,7 +1671,10 @@ static zend_never_inline void *zend_mm_realloc_huge(zend_mm_heap *heap, void *pt
return zend_mm_realloc_slow(heap, ptr, size, MIN(old_size, copy_size) ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}

static zend_always_inline void *zend_mm_realloc_heap(zend_mm_heap *heap, void *ptr, size_t size, bool use_copy_size, size_t copy_size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC)
#define EREALLOC_DEFAULT 0
#define EREALLOC_COPY 1
#define EREALLOC_NOSHRINK 2
Comment on lines -1674 to +1676
Copy link
Member

@dstogov dstogov Nov 24, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

EREALLOC_COPY doesn't keep the explanation of semantic of use_copy_size.
In case use_copy_size is set, erealloc() copies only the size specified in copy_size argument.

Copy link
Member

@dstogov dstogov Nov 24, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

EREALLOC_NOSHRINK also embraces use_copy_size mode. Probably mode should be represented as a bitset.

static zend_always_inline void *zend_mm_realloc_heap(zend_mm_heap *heap, void *ptr, size_t size, int mode, size_t copy_size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC)
{
size_t page_offset;
size_t old_size;
Expand All @@ -1686,6 +1689,12 @@ static zend_always_inline void *zend_mm_realloc_heap(zend_mm_heap *heap, void *p
if (EXPECTED(ptr == NULL)) {
return _zend_mm_alloc(heap, size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
} else {
if (mode == EREALLOC_NOSHRINK) {
old_size = zend_mm_get_huge_block_size(heap, ptr ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
Copy link
Member

@dstogov dstogov Nov 24, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Why do you use huge_block_size?

if (EXPECTED(size <= old_size)) {
return ptr;
}
}
return zend_mm_realloc_huge(heap, ptr, size, copy_size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}
} else {
Expand Down Expand Up @@ -1713,10 +1722,10 @@ static zend_always_inline void *zend_mm_realloc_heap(zend_mm_heap *heap, void *p
/* Check if requested size fits into current bin */
if (size <= old_size) {
/* Check if truncation is necessary */
if (old_bin_num > 0 && size < bin_data_size[old_bin_num - 1]) {
if (mode != EREALLOC_NOSHRINK && old_bin_num > 0 && size < bin_data_size[old_bin_num - 1]) {
/* truncation */
ret = zend_mm_alloc_small(heap, ZEND_MM_SMALL_SIZE_TO_BIN(size) ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
copy_size = use_copy_size ? MIN(size, copy_size) : size;
copy_size = mode != EREALLOC_DEFAULT ? MIN(size, copy_size) : size;
memcpy(ret, ptr, copy_size);
zend_mm_free_small(heap, ptr, old_bin_num);
} else {
Expand All @@ -1731,7 +1740,7 @@ static zend_always_inline void *zend_mm_realloc_heap(zend_mm_heap *heap, void *p
size_t orig_peak = heap->peak;
#endif
ret = zend_mm_alloc_small(heap, ZEND_MM_SMALL_SIZE_TO_BIN(size) ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
copy_size = use_copy_size ? MIN(old_size, copy_size) : old_size;
copy_size = mode != EREALLOC_DEFAULT ? MIN(old_size, copy_size) : old_size;
memcpy(ret, ptr, copy_size);
zend_mm_free_small(heap, ptr, old_bin_num);
#if ZEND_MM_STAT
Expand Down Expand Up @@ -1759,7 +1768,7 @@ static zend_always_inline void *zend_mm_realloc_heap(zend_mm_heap *heap, void *p
old_size = ZEND_MM_LRUN_PAGES(info) * ZEND_MM_PAGE_SIZE;
if (size > ZEND_MM_MAX_SMALL_SIZE && size <= ZEND_MM_MAX_LARGE_SIZE) {
new_size = ZEND_MM_ALIGNED_SIZE_EX(size, ZEND_MM_PAGE_SIZE);
if (new_size == old_size) {
if (mode == EREALLOC_NOSHRINK ? new_size <= old_size : (new_size == old_size)) {
#if ZEND_DEBUG
dbg = zend_mm_get_debug_info(heap, ptr);
dbg->size = real_size;
Expand Down Expand Up @@ -2579,12 +2588,17 @@ ZEND_API void ZEND_FASTCALL _zend_mm_free(zend_mm_heap *heap, void *ptr ZEND_FIL

void* ZEND_FASTCALL _zend_mm_realloc(zend_mm_heap *heap, void *ptr, size_t size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC)
{
return zend_mm_realloc_heap(heap, ptr, size, 0, size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
return zend_mm_realloc_heap(heap, ptr, size, EREALLOC_DEFAULT, size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}

void* ZEND_FASTCALL _zend_mm_realloc2(zend_mm_heap *heap, void *ptr, size_t size, size_t copy_size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC)
{
return zend_mm_realloc_heap(heap, ptr, size, 1, copy_size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
return zend_mm_realloc_heap(heap, ptr, size, EREALLOC_COPY, copy_size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}

void* ZEND_FASTCALL _zend_mm_realloc3(zend_mm_heap *heap, void *ptr, size_t size, size_t copy_size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC)
{
return zend_mm_realloc_heap(heap, ptr, size, EREALLOC_NOSHRINK, copy_size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}

ZEND_API size_t ZEND_FASTCALL _zend_mm_block_size(zend_mm_heap *heap, void *ptr ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC)
Expand Down Expand Up @@ -2801,7 +2815,7 @@ ZEND_API void* ZEND_FASTCALL _erealloc(void *ptr, size_t size ZEND_FILE_LINE_DC
return AG(mm_heap)->custom_heap._realloc(ptr, size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}
#endif
return zend_mm_realloc_heap(AG(mm_heap), ptr, size, 0, size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
return zend_mm_realloc_heap(AG(mm_heap), ptr, size, EREALLOC_DEFAULT, size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}

ZEND_API void* ZEND_FASTCALL _erealloc2(void *ptr, size_t size, size_t copy_size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC)
Expand All @@ -2811,7 +2825,17 @@ ZEND_API void* ZEND_FASTCALL _erealloc2(void *ptr, size_t size, size_t copy_size
return AG(mm_heap)->custom_heap._realloc(ptr, size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}
#endif
return zend_mm_realloc_heap(AG(mm_heap), ptr, size, 1, copy_size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
return zend_mm_realloc_heap(AG(mm_heap), ptr, size, EREALLOC_COPY, copy_size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}

ZEND_API void* ZEND_FASTCALL _erealloc3(void *ptr, size_t size, size_t copy_size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC)
{
#if ZEND_MM_CUSTOM
if (UNEXPECTED(AG(mm_heap)->use_custom_heap)) {
return AG(mm_heap)->custom_heap._realloc(ptr, size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}
#endif
return zend_mm_realloc_heap(AG(mm_heap), ptr, size, EREALLOC_NOSHRINK, copy_size ZEND_FILE_LINE_RELAY_CC ZEND_FILE_LINE_ORIG_RELAY_CC);
}

ZEND_API size_t ZEND_FASTCALL _zend_mem_block_size(void *ptr ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC)
Expand Down
3 changes: 3 additions & 0 deletions Zend/zend_alloc.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -71,6 +71,7 @@ ZEND_API void ZEND_FASTCALL _efree(void *ptr ZEND_FILE_LINE_DC ZEND_FILE_LINE_
ZEND_API ZEND_ATTRIBUTE_MALLOC void* ZEND_FASTCALL _ecalloc(size_t nmemb, size_t size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC) ZEND_ATTRIBUTE_ALLOC_SIZE2(1,2);
ZEND_API void* ZEND_FASTCALL _erealloc(void *ptr, size_t size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC) ZEND_ATTRIBUTE_ALLOC_SIZE(2);
ZEND_API void* ZEND_FASTCALL _erealloc2(void *ptr, size_t size, size_t copy_size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC) ZEND_ATTRIBUTE_ALLOC_SIZE(2);
ZEND_API void* ZEND_FASTCALL _erealloc3(void *ptr, size_t size, size_t copy_size ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC) ZEND_ATTRIBUTE_ALLOC_SIZE(2);
ZEND_API void* ZEND_FASTCALL _safe_erealloc(void *ptr, size_t nmemb, size_t size, size_t offset ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC);
ZEND_API void* ZEND_FASTCALL _safe_realloc(void *ptr, size_t nmemb, size_t size, size_t offset);
ZEND_API ZEND_ATTRIBUTE_MALLOC char* ZEND_FASTCALL _estrdup(const char *s ZEND_FILE_LINE_DC ZEND_FILE_LINE_ORIG_DC);
Expand Down Expand Up @@ -158,6 +159,7 @@ ZEND_API void ZEND_FASTCALL _efree_huge(void *, size_t size);
#define ecalloc(nmemb, size) _ecalloc((nmemb), (size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC)
#define erealloc(ptr, size) _erealloc((ptr), (size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC)
#define erealloc2(ptr, size, copy_size) _erealloc2((ptr), (size), (copy_size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC)
#define erealloc3(ptr, size, copy_size) _erealloc3((ptr), (size), (copy_size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC)
#define safe_erealloc(ptr, nmemb, size, offset) _safe_erealloc((ptr), (nmemb), (size), (offset) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC)
#define erealloc_recoverable(ptr, size) _erealloc((ptr), (size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC)
#define erealloc2_recoverable(ptr, size, copy_size) _erealloc2((ptr), (size), (copy_size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC)
Expand Down Expand Up @@ -200,6 +202,7 @@ ZEND_API ZEND_ATTRIBUTE_MALLOC char * __zend_strdup(const char *s);
#define pecalloc(nmemb, size, persistent) ((persistent)?__zend_calloc((nmemb), (size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC):ecalloc((nmemb), (size)))
#define perealloc(ptr, size, persistent) ((persistent)?__zend_realloc((ptr), (size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC):erealloc((ptr), (size)))
#define perealloc2(ptr, size, copy_size, persistent) ((persistent)?__zend_realloc((ptr), (size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC):erealloc2((ptr), (size), (copy_size)))
#define perealloc3(ptr, size, copy_size, persistent) ((persistent)?__zend_realloc((ptr), (size) ZEND_FILE_LINE_CC ZEND_FILE_LINE_EMPTY_CC):erealloc3((ptr), (size), (copy_size)))
#define safe_perealloc(ptr, nmemb, size, offset, persistent) ((persistent)?_safe_realloc((ptr), (nmemb), (size), (offset)):safe_erealloc((ptr), (nmemb), (size), (offset)))
#define perealloc_recoverable(ptr, size, persistent) ((persistent)?realloc((ptr), (size)):erealloc_recoverable((ptr), (size)))
#define perealloc2_recoverable(ptr, size, persistent) ((persistent)?realloc((ptr), (size)):erealloc2_recoverable((ptr), (size), (copy_size)))
Expand Down
2 changes: 1 addition & 1 deletion Zend/zend_string.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -261,7 +261,7 @@ static zend_always_inline zend_string *zend_string_extend(zend_string *s, size_t
ZEND_ASSERT(len >= ZSTR_LEN(s));
if (!ZSTR_IS_INTERNED(s)) {
if (EXPECTED(GC_REFCOUNT(s) == 1)) {
ret = (zend_string *)perealloc(s, ZEND_MM_ALIGNED_SIZE(_ZSTR_STRUCT_SIZE(len)), persistent);
ret = (zend_string *)perealloc3(s, ZEND_MM_ALIGNED_SIZE(_ZSTR_STRUCT_SIZE(len)), _ZSTR_STRUCT_SIZE(ZSTR_LEN(s)), persistent);
ZSTR_LEN(ret) = len;
zend_string_forget_hash_val(ret);
return ret;
Expand Down
5 changes: 5 additions & 0 deletions ext/standard/basic_functions.stub.php
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2448,6 +2448,11 @@ function substr_replace(array|string $string, array|string $replace, array|int $
*/
function quotemeta(string $string): string {}

/**
* @compile-time-eval
*/
function str_extend(string $string, int $size): string {}
Copy link
Member

@dstogov dstogov Nov 24, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm not sure if this is the best self-explainable name

Copy link
Member

@ndossche ndossche Nov 24, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I agree. The string does not become longer, so "extend" is the incorrect word. "reserve" may be better.


/** @compile-time-eval */
function ord(string $character): int {}

Expand Down
9 changes: 8 additions & 1 deletion ext/standard/basic_functions_arginfo.h
View file
Open in desktop

Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.

22 changes: 22 additions & 0 deletions ext/standard/string.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2643,6 +2643,28 @@ PHP_FUNCTION(quotemeta)
}
/* }}} */

PHP_FUNCTION(str_extend)
{
zend_string *str;
zend_long size;

ZEND_PARSE_PARAMETERS_START(2, 2)
Z_PARAM_STR(str)
Z_PARAM_LONG(size)
ZEND_PARSE_PARAMETERS_END();

size_t len = ZSTR_LEN(str);
if (len > size) {
zend_argument_value_error(2, "must not be smaller than the input string");
RETURN_THROWS();
}

ZVAL_UNDEF(ZEND_CALL_ARG(execute_data, 0)); // avoid copies, so that we may benefit from the RC=1 optimization
RETVAL_STR(zend_string_extend(str, size, 0));
Z_STRLEN_P(return_value) = len;
}
/* }}} */

/* {{{ Returns ASCII value of character
Warning: This function is special-cased by zend_compile.c and so is bypassed for constant string argument */
PHP_FUNCTION(ord)
Expand Down
18 changes: 18 additions & 0 deletions ext/standard/tests/strings/str_extend.phpt
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
--TEST--
Append to string allocated with str_extend()
--FILE--
<?php

$str = str_extend("a", 1 << 22);
for ($i = 0; $i < 1 << 21; ++$i) {
$str .= "a";
}

var_dump(array_filter(count_chars($str)));

?>
--EXPECT--
array(1) {
[97]=>
int(2097153)
}
Loading