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這篇文章將為大家詳細(xì)講解有關(guān)PHP源碼之implode函數(shù)源碼怎么用，小編覺得挺實(shí)用的，因此分享給大家做個(gè)參考，希望大家閱讀完這篇文章后可以有所收獲。
// 方法1 implode ( string $glue , array $pieces ) : string // 方法2 implode ( array $pieces ) : string
$pieces = [
123,
',是一個(gè)',
'number!',
];
$str1 = implode($pieces);
$str2 = implode('', $pieces);
var_dump($str1, $str2);
/*
string(20) "123,是一個(gè)number!"
string(20) "123,是一個(gè)number!"
*/PHP_FUNCTION(implode) 可以找到，該函數(shù)定義于 \ext\standard\string.c 文件中的 1288 行if (arg2 == NULL) {
if (Z_TYPE_P(arg1) != IS_ARRAY) {
php_error_docref(NULL, E_WARNING, "Argument must be an array");
return;
}
glue = ZSTR_EMPTY_ALLOC();
tmp_glue = NULL;
pieces = arg1;
} else {
if (Z_TYPE_P(arg1) == IS_ARRAY) {
glue = zval_get_tmp_string(arg2, &tmp_glue);
pieces = arg1;
} else if (Z_TYPE_P(arg2) == IS_ARRAY) {
glue = zval_get_tmp_string(arg1, &tmp_glue);
pieces = arg2;
} else {
php_error_docref(NULL, E_WARNING, "Invalid arguments passed");
return;
}
}arg2 == NULL，主要是對參數(shù)的一些處理php_implode(glue, pieces, return_value);PHP源碼中 return_value，找到了答案。PHP_FUNCTION(implode) 來聲明的。而 PHP_FUNCTION 的定義是:#define PHP_FUNCTION ZEND_FUNCTION // 對應(yīng)的 ZEND_FUNCTION 定義如下 #define ZEND_FUNCTION(name) ZEND_NAMED_FUNCTION(ZEND_FN(name)) // 對應(yīng)的 ZEND_NAMED_FUNCTION 定義如下 #define ZEND_NAMED_FUNCTION(name) void ZEND_FASTCALL name(INTERNAL_FUNCTION_PARAMETERS) // 對應(yīng)的 ZEND_FN 定義如下 #define ZEND_FN(name) zif_##name // 對應(yīng)的 ZEND_FASTCALL 定義如下 # define ZEND_FASTCALL __attribute__((fastcall))
void zif_implode(int ht, zval *return_value, zval **return_value_ptr, zval *this_ptr, int return_value_used TSRMLS_DC)
ALLOCA_FLAG(use_heap) 進(jìn)行標(biāo)識，如果申請內(nèi)存，則申請的是堆內(nèi)存numelems = zend_hash_num_elements(Z_ARRVAL_P(pieces)); 獲取 pieces 參數(shù)的單元數(shù)量，如果是空數(shù)組，則直接返回空字符串ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(zend_array), tmp) {
// ...
} ZEND_HASH_FOREACH_END();在循環(huán)內(nèi)，對數(shù)組單元分為三類：
struct {
zend_string *str;
zend_long lval;
} *strings, *ptr;// tmp 是循環(huán)中的單元值 ptr->str = Z_STR_P(tmp); len += ZSTR_LEN(ptr->str); ptr->lval = 0; ptr++;
len += ZSTR_LEN(ptr->str);Z_TYPE_P(tmp) == IS_LONG。一旦知道當(dāng)前的數(shù)據(jù)類型是 zend_long，則將其賦值給 ptr 的 lval 結(jié)構(gòu)體成員。然后 ptr 指針后移一個(gè)單位長度。len += ZSTR_LEN(val); 的方式獲取其字符長度。對于 zend_long，有什么好的方法呢？while (val) {
val /= 10;
len++;
}if (val <= 0) {
len++;
}str = zend_string_safe_alloc(numelems - 1, ZSTR_LEN(glue), len, 0);，用于存放單元字符串總長度加上連接字符的總長度，即 (n-1)glue + len。因?yàn)?n 個(gè)數(shù)組單元，只需要 n-1 個(gè) glue 字符串。然后，將這段內(nèi)存的尾地址，賦值給 cptr，為什么要指向尾部呢？看下一部分，你就會(huì)明白了。ptr--;，然后針對 ptr->str 的判斷 if (EXPECTED(ptr->str))，看了一下此處的 EXPECTED 的作用，可以參考這里?？梢院唵蔚膶⑵淅斫庖环N匯編層面的優(yōu)化，當(dāng)實(shí)際執(zhí)行的情況更偏向于當(dāng)前條件下的分支而非 else 的分支時(shí)，就用 EXPECTED 宏將其包裝起來：EXPECTED(ptr->str)。我敢說，當(dāng)你調(diào)用 implode 傳遞的數(shù)組中都是數(shù)字而非字符串，那么這里的 EXPECTED 作用就會(huì)失效。cptr -= ZSTR_LEN(ptr->str); memcpy(cptr, ZSTR_VAL(ptr->str), ZSTR_LEN(ptr->str));
ptr->str （某數(shù)組單元的值）通過 c 標(biāo)準(zhǔn)庫函數(shù) memcpy 拷貝到 cptr 內(nèi)存空間中。ptr == strings 滿足時(shí)，意味著 ptr 不再有可被復(fù)制的字符串/數(shù)字。因?yàn)?strings 是 ptr 所在區(qū)域的首地址。ptr->str 一樣處理 glue 即可。至少源碼中是這么做的。*cptr = 0，它的作用相當(dāng)于賦值空字符串。free_alloca(strings, use_heap); RETURN_NEW_STR(str);
free_alloca(strings, use_heap);。RETURN_NEW_STR 會(huì)將最終的返回值寫入 return_value 中debug/implode，可自行下載運(yùn)行，看看效果。static void su_php_implode(const zend_string *glue, zval *pieces, zval *return_value)
{
// 源碼內(nèi)容省略
}PHP_FUNCTION(su_test)
{
zval tmp;
zend_string *str, *glue, *tmp_glue;
zval *arg1, *arg2 = NULL, *pieces;
ZEND_PARSE_PARAMETERS_START(1, 2)
Z_PARAM_ZVAL(arg1)
Z_PARAM_OPTIONAL
Z_PARAM_ZVAL(arg2)
ZEND_PARSE_PARAMETERS_END();
glue = zval_get_tmp_string(arg1, &tmp_glue);
pieces = arg2;
su_php_implode(glue, pieces, return_value);
}// t1.php
$res = su_test('-', [
2019, '01', '01',
]);
var_dump($res);string(10) "2019-01-01"，這意味著，你已經(jīng)成功編寫了一個(gè)擴(kuò)展函數(shù)。別急，這只是邁出了第一步，別忘記我們的目標(biāo)：通過調(diào)試來學(xué)習(xí) implode 源碼。gdb php b zval_get_tmp_string r t1.php
b 即 break，表示打一個(gè)斷點(diǎn)r 即 run，表示運(yùn)行腳本s 即 step，表示一步一步調(diào)試，遇到方法調(diào)用，會(huì)進(jìn)入方法內(nèi)部單步調(diào)試n 即 next，表示一行一行調(diào)試。遇到方法，則調(diào)試直接略過直接執(zhí)行返回，調(diào)試不會(huì)進(jìn)入其內(nèi)部。p 即 print，表示打印當(dāng)前作用域中的一個(gè)變量r t1.php，則會(huì)定位到第一個(gè)斷點(diǎn)對應(yīng)的行，顯示如下：Breakpoint 1, zif_su_test (execute_data=0x7ffff1a1d0c0,
return_value=0x7ffff1a1d090)
at /home/www/clang/php-7.3.3/ext/su_dd/su_dd.c:179
179 glue = zval_get_tmp_string(arg1, &tmp_glue);n，顯示如下：184 su_php_implode(glue, pieces, return_value);
glue，pieces，return_valuepieces 的值。先使用命令：p pieces，此時(shí)在終端會(huì)顯示類似于如下內(nèi)容：$1 = (zval *) 0x7ffff1a1d120
pieces 是一個(gè) zval 類型的指針，0x7ffff1a1d120 是其地址，當(dāng)然，你運(yùn)行的時(shí)候?qū)?yīng)的也是一個(gè)地址，只不過跟我的這個(gè)會(huì)不太一樣。p 去打印存儲(chǔ)于改地址的變量內(nèi)容：p *$1,$1 可以認(rèn)為是一個(gè)臨時(shí)變量名，* 是取值運(yùn)算符。運(yùn)行完后，此時(shí)顯示如下：(gdb) p *$1
$2 = {value = {lval = 140737247576960, dval = 6.9533439118030153e-310,
counted = 0x7ffff1a60380, str = 0x7ffff1a60380, arr = 0x7ffff1a60380,
obj = 0x7ffff1a60380, res = 0x7ffff1a60380, ref = 0x7ffff1a60380,
ast = 0x7ffff1a60380, zv = 0x7ffff1a60380, ptr = 0x7ffff1a60380,
ce = 0x7ffff1a60380, func = 0x7ffff1a60380, ww = {w1 = 4054188928,
w2 = 32767}}, u1 = {v = {type = 7 '\a', type_flags = 1 '\001', u = {
call_info = 0, extra = 0}}, type_info = 263}, u2 = {next = 0,
cache_slot = 0, opline_num = 0, lineno = 0, num_args = 0, fe_pos = 0,
fe_iter_idx = 0, access_flags = 0, property_guard = 0, constant_flags = 0,
extra = 0}}struct _zval_struct {
zend_value value; /* value */
union {
struct {
ZEND_ENDIAN_LOHI_3(
zend_uchar type, /* active type */
zend_uchar type_flags,
union {
uint16_t call_info; /* call info for EX(This) */
uint16_t extra; /* not further specified */
} u)
} v;
uint32_t type_info;
} u1;
union {
uint32_t next; /* hash collision chain */
uint32_t cache_slot; /* cache slot (for RECV_INIT) */
uint32_t opline_num; /* opline number (for FAST_CALL) */
uint32_t lineno; /* line number (for ast nodes) */
uint32_t num_args; /* arguments number for EX(This) */
uint32_t fe_pos; /* foreach position */
uint32_t fe_iter_idx; /* foreach iterator index */
uint32_t access_flags; /* class constant access flags */
uint32_t property_guard; /* single property guard */
uint32_t constant_flags; /* constant flags */
uint32_t extra; /* not further specified */
} u2;
};value，打印一下其中的內(nèi)容。打印結(jié)構(gòu)體成員可以使用 . 運(yùn)算符，例如：p $2.value，運(yùn)行這個(gè)命令，顯示如下：(gdb) p $2.value
$3 = {lval = 140737247576960, dval = 6.9533439118030153e-310,
counted = 0x7ffff1a60380, str = 0x7ffff1a60380, arr = 0x7ffff1a60380,
obj = 0x7ffff1a60380, res = 0x7ffff1a60380, ref = 0x7ffff1a60380,
ast = 0x7ffff1a60380, zv = 0x7ffff1a60380, ptr = 0x7ffff1a60380,
ce = 0x7ffff1a60380, func = 0x7ffff1a60380, ww = {w1 = 4054188928,
w2 = 32767}}typedef union _zend_value {
zend_long lval; /* long value */
double dval; /* double value */
zend_refcounted *counted;
zend_string *str;
zend_array *arr;
zend_object *obj;
zend_resource *res;
zend_reference *ref;
zend_ast_ref *ast;
zval *zv;
void *ptr;
zend_class_entry *ce;
zend_function *func;
struct {
uint32_t w1;
uint32_t w2;
} ww;
} zend_value;*arr 成員，它外表看起來就是一個(gè)指針，因此打印其內(nèi)容，需要使用 * 運(yùn)算符(gdb) p *$3.arr
$4 = {gc = {refcount = 2, u = {type_info = 23}}, u = {v = {flags = 28 '\034',
_unused = 0 '\000', nIteratorsCount = 0 '\000', _unused2 = 0 '\000'},
flags = 28}, nTableMask = 4294967294, arData = 0x7ffff1a67648,
nNumUsed = 3, nNumOfElements = 3, nTableSize = 8, nInternalPointer = 0,
nNextFreeElement = 3, pDestructor = 0x555555b6e200 <zval_ptr_dtor>}*arr 的類型是 zend_array：struct _zend_array {
zend_refcounted_h gc;
union {
struct {
ZEND_ENDIAN_LOHI_4(
zend_uchar flags,
zend_uchar _unused,
zend_uchar nIteratorsCount,
zend_uchar _unused2)
} v;
uint32_t flags;
} u;
uint32_t nTableMask;
Bucket *arData;
uint32_t nNumUsed;
uint32_t nNumOfElements;
uint32_t nTableSize;
uint32_t nInternalPointer;
zend_long nNextFreeElement;
dtor_func_t pDestructor;
};*arData，使用：p *$4.arDaa:(gdb) p *$4.arData
$5 = {val = {value = {lval = 2019, dval = 9.9751853895347677e-321,
counted = 0x7e3, str = 0x7e3, arr = 0x7e3, obj = 0x7e3, res = 0x7e3,
ref = 0x7e3, ast = 0x7e3, zv = 0x7e3, ptr = 0x7e3, ce = 0x7e3,
func = 0x7e3, ww = {w1 = 2019, w2 = 0}}, u1 = {v = {type = 4 '\004',
type_flags = 0 '\000', u = {call_info = 0, extra = 0}}, type_info = 4},
u2 = {next = 0, cache_slot = 0, opline_num = 0, lineno = 0, num_args = 0,
fe_pos = 0, fe_iter_idx = 0, access_flags = 0, property_guard = 0,
constant_flags = 0, extra = 0}}, h = 0, key = 0x0}lval = 2019。$res = implode('-', [
2019, '01', '01', [1,2]
]);
var_dump($res);PHP Notice: Array to string conversion in /path/to/t2.php on line 3 PHP Notice: Array to string conversion in /path/to/t2.php on line 3 string(16) "2019-01-01-Array"
PHPAPI void php_implode(const zend_string *glue, zval *pieces, zval *return_value)
{
zval *tmp;
int numelems;
zend_string *str;
char *cptr;
size_t len = 0;
struct {
zend_string *str;
zend_long lval;
} *strings, *ptr;
ALLOCA_FLAG(use_heap)
numelems = zend_hash_num_elements(Z_ARRVAL_P(pieces));
if (numelems == 0) {
RETURN_EMPTY_STRING();
} else if (numelems == 1) {
/* loop to search the first not undefined element... */
ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(pieces), tmp) {
RETURN_STR(zval_get_string(tmp));
} ZEND_HASH_FOREACH_END();
}
ptr = strings = do_alloca((sizeof(*strings)) * numelems, use_heap);
ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(pieces), tmp) {
if (EXPECTED(Z_TYPE_P(tmp) == IS_STRING)) {
ptr->str = Z_STR_P(tmp);
len += ZSTR_LEN(ptr->str);
ptr->lval = 0;
ptr++;
} else if (UNEXPECTED(Z_TYPE_P(tmp) == IS_LONG)) {
zend_long val = Z_LVAL_P(tmp);
ptr->str = NULL;
ptr->lval = val;
ptr++;
if (val <= 0) {
len++;
}
while (val) {
val /= 10;
len++;
}
} else {
ptr->str = zval_get_string_func(tmp);
len += ZSTR_LEN(ptr->str);
ptr->lval = 1;
ptr++;
}
} ZEND_HASH_FOREACH_END();
/* numelems can not be 0, we checked above */
str = zend_string_safe_alloc(numelems - 1, ZSTR_LEN(glue), len, 0);
cptr = ZSTR_VAL(str) + ZSTR_LEN(str);
*cptr = 0;
while (1) {
ptr--;
if (EXPECTED(ptr->str)) {
cptr -= ZSTR_LEN(ptr->str);
memcpy(cptr, ZSTR_VAL(ptr->str), ZSTR_LEN(ptr->str));
if (ptr->lval) {
zend_string_release_ex(ptr->str, 0);
}
} else {
char *oldPtr = cptr;
char oldVal = *cptr;
cptr = zend_print_long_to_buf(cptr, ptr->lval);
*oldPtr = oldVal;
}
if (ptr == strings) {
break;
}
cptr -= ZSTR_LEN(glue);
memcpy(cptr, ZSTR_VAL(glue), ZSTR_LEN(glue));
}
free_alloca(strings, use_heap);
RETURN_NEW_STR(str);
}static void su_php_implode(const zend_string *glue, zval *pieces, zval *return_value)ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(pieces), tmp) {
if (EXPECTED(Z_TYPE_P(tmp) == IS_STRING)) {
// ...
} else if (UNEXPECTED(Z_TYPE_P(tmp) == IS_LONG)) {
// ...
} else {
// ...
}
} ZEND_HASH_FOREACH_END();else if (UNEXPECTED(Z_TYPE_P(tmp) == IS_ARRAY))，其具體內(nèi)容如下：ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(pieces), tmp) {
if (EXPECTED(Z_TYPE_P(tmp) == IS_STRING)) {
// ...
} else if (UNEXPECTED(Z_TYPE_P(tmp) == IS_LONG)) {
// ...
} else if (UNEXPECTED(Z_TYPE_P(tmp) == IS_ARRAY)) {
// 如果值是數(shù)組，則調(diào)用 php_implode，將其使用 glue 連接成字符串
cptr = ZSTR_VAL(ptr->str);
zend_string* str2 = origin_php_implode(glue, tmp, tmp_val);
ptr->str = str2;
// 此時(shí)，要拿到拼接后的字符串長度
len += ZSTR_LEN(str2);
ptr++;
} else {
// ...
}
} ZEND_HASH_FOREACH_END();origin_php_implode：static zend_string* origin_php_implode(const zend_string *glue, zval *pieces, zval *return_value)
{
zval *tmp;
int numelems;
zend_string *str;
char *cptr;
size_t len = 0;
struct {
zend_string *str;
zend_long lval;
} *strings, *ptr;
ALLOCA_FLAG(use_heap)
numelems = zend_hash_num_elements(Z_ARRVAL_P(pieces));
if (numelems == 0) {
RETURN_EMPTY_STRING();
} else if (numelems == 1) {
/* loop to search the first not undefined element... */
ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(pieces), tmp) {
RETURN_STR(zval_get_string(tmp));
} ZEND_HASH_FOREACH_END();
}
ptr = strings = do_alloca((sizeof(*strings)) * numelems, use_heap);
ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(pieces), tmp) {
if (EXPECTED(Z_TYPE_P(tmp) == IS_STRING)) {
ptr->str = Z_STR_P(tmp);
len += ZSTR_LEN(ptr->str);
ptr->lval = 0;
ptr++;
} else if (UNEXPECTED(Z_TYPE_P(tmp) == IS_LONG)) {
zend_long val = Z_LVAL_P(tmp);
ptr->str = NULL;
ptr->lval = val;
ptr++;
if (val <= 0) {
len++;
}
while (val) {
val /= 10;
len++;
}
} else {
ptr->str = zval_get_string_func(tmp);
len += ZSTR_LEN(ptr->str);
ptr->lval = 1;
ptr++;
}
} ZEND_HASH_FOREACH_END();
/* numelems can not be 0, we checked above */
str = zend_string_safe_alloc(numelems - 1, ZSTR_LEN(glue), len, 0);
cptr = ZSTR_VAL(str) + ZSTR_LEN(str);
*cptr = 0;
while (1) {
ptr--;
if (EXPECTED(ptr->str)) {
cptr -= ZSTR_LEN(ptr->str);
memcpy(cptr, ZSTR_VAL(ptr->str), ZSTR_LEN(ptr->str));
if (ptr->lval) {
zend_string_release_ex(ptr->str, 0);
}
} else {
char *oldPtr = cptr;
char oldVal = *cptr;
cptr = zend_print_long_to_buf(cptr, ptr->lval);
*oldPtr = oldVal;
}
if (ptr == strings) {
break;
}
cptr -= ZSTR_LEN(glue);
memcpy(cptr, ZSTR_VAL(glue), ZSTR_LEN(glue));
}
free_alloca(strings, use_heap);
// RETURN_NEW_STR(str);
return str;
}PHP_FUNCTION(su_test)，功能實(shí)現(xiàn)的差不多了。我們?nèi)ゾ幾g看看：./configure sudo make sudo make install
$res = su_test('-', [
2019, '01', '01', ['1', '2',],
]);
var_dump($res);string(14) "2019-01-01-1-2"
關(guān)于PHP源碼之implode函數(shù)源碼怎么用就分享到這里了，希望以上內(nèi)容可以對大家有一定的幫助，可以學(xué)到更多知識。如果覺得文章不錯(cuò)，可以把它分享出去讓更多的人看到。
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