Json_encode analysis in PHP _ PHP Tutorial

Json_encode analysis of PHP. I don't need to mention the advantages of json. I have a habit. when I output json, I like to use sprintf to splice it into json format. I was told by a friend that it was not standard two days ago, the json_encode must be used to generate the advantage of json,

I like to use sprintf to spell json format when outputting json,

Two days ago, I was told that it was not standard. The standard json format must be generated using json_encode. of course, I am very depressed,

After so many years of use, I just learned that this is not a standard. since I am not a standard, is the above standard json format?

{A: 'ABC '}

{'A': 'ABC '}

{A: "abc "}

{"A": "abc "}

We all know that only the fourth type is the standard json format.

I am doing this

$ Ret_json = '{"% s": "% s "}';

Echo json_encode ($ ret_json, "a", "abc ");

It must also comply with standards.

In this case, I have to answer the question. what is the difference in the json format generated by json_encode?

Code on

Static PHP_FUNCTION (json_encode)

{

Zval * parameter;

Smart_str buf = {0 };

Long options = 0;

If (zend_parse_parameters (ZEND_NUM_ARGS () TSRMLS_CC, "z | l", & parameter, & options) = FAILURE ){

Return;

}

JSON_G (error_code) = PHP_JSON_ERROR_NONE;

Php_json_encode (& buf, parameter, options TSRMLS_CC );

ZVAL_STRINGL (return_value, buf. c, buf. len, 1 );

Smart_str_free (& buf );

}

JSON_G (error_code) = PHP_JSON_ERROR_NONE;

Is a defined json error. This error can be obtained through the json_last_error function. have you used this error? I have never used it.

Php_json_encode is the main operation

PHP_JSON_API void php_json_encode (smart_str * buf, zval * val, int options TSRMLS_DC )/*{{{*/

{

Switch (Z_TYPE_P (val ))

{

Case IS_NULL:

Smart_str_appendl (buf, "null", 4); // output NULL

Break;

Case IS_BOOL:

If (Z_BVAL_P (val )){

Smart_str_appendl (buf, "true", 4); // outputs true

} Else {

Smart_str_appendl (buf, "false", 5); // outputs false

}

Break;

Case IS_LONG:

Smart_str_append_long (buf, Z_LVAL_P (val); // output the value of the long integer.

Break;

Case IS_DOUBLE:

{

Char * d = NULL;

Int len;

Double dbl = Z_DVAL_P (val );

If (! Zend_isinf (dbl )&&! Zend_isnan (dbl) {// non-endless

Len = spprintf (& d, 0, "%. * k", (int) EG (precision), dbl );

Smart_str_appendl (buf, d, len );

Efree (d );

} Else {

Php_error_docref (NULL TSRMLS_CC, E_WARNING, "double %. 9g does not conform to the JSON spec, encoded as 0", dbl );

Smart_str_appendc (buf, '0 ');

}

}

Break;

Case IS_STRING: // string

Json_escape_string (buf, Z_STRVAL_P (val), Z_STRLEN_P (val), options TSRMLS_CC );

Break;

Case IS_ARRAY: // array and object

Case IS_OBJECT:

Json_encode_array (buf, & val, options TSRMLS_CC );

Break;

Default:

Php_error_docref (NULL TSRMLS_CC, E_WARNING, "type is unsupported, encoded as null ");

Smart_str_appendl (buf, "null", 4 );

Break;

}

Return;

}

Obviously, there will be corresponding cases based on different types.

The most complex types are string, array, and object. arrays and objects are the same operation.

Let's take a look at the string first. it's very long. comments are directly written in the code.

// Options should be supported only after version 5.3. the binary mask composed of the following constants: JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, signature, JSON_NUMERIC_CHECK, signature, expires, JSON_FORCE_OBJECT, and signature. although I have never used it...

Static void json_escape_string (smart_str * buf, char * s, int len, int options TSRMLS_DC )/*{{{*/

{

Int pos = 0;

Unsigned short us;

Unsigned short * utf16;

If (len = 0) {// if the length is 0, double quotation marks are returned directly ""

Smart_str_appendl (buf, "\" \ "", 2 );

Return;

}

If (options & PHP_JSON_NUMERIC_CHECK) {// check whether the number is 0-9. if it is a number, the data is directly returned as long or double.

Double d;

Int type;

Long p;

If (type = is_numeric_string (s, len, & p, & d, 0 ))! = 0 ){

If (type = IS_LONG ){

Smart_str_append_long (buf, p );

} Else if (type = IS_DOUBLE ){

If (! Zend_isinf (d )&&! Zend_isnan (d )){

Char * tmp;

Int l = spprintf (& tmp, 0, "%. * k", (int) EG (precision), d );

Smart_str_appendl (buf, tmp, l );

Efree (tmp );

} Else {

Php_error_docref (NULL TSRMLS_CC, E_WARNING, "double %. 9g does not conform to the JSON spec, encoded as 0", d );

Smart_str_appendc (buf, '0 ');

}

}

Return;

}

}

Utf16 = (unsigned short *) safe_emalloc (len, sizeof (unsigned short), 0 );

Len = utf8_to_utf16 (utf16, s, len); // the input value is converted to the corresponding Dec code once, for example, 1 is 49 and a is 97, save it to utf16.

If (len <= 0) {// if len is smaller than 0, an error occurs. If you use json_encode to process GBK encoding, it will be suspended here.

If (utf16 ){

Efree (utf16 );

}

If (len <0 ){

JSON_G (error_code) = PHP_JSON_ERROR_UTF8;

If (! PG (display_errors )){

Php_error_docref (NULL TSRMLS_CC, E_WARNING, "Invalid UTF-8 sequence in argument ");

}

Smart_str_appendl (buf, "null", 4 );

} Else {

Smart_str_appendl (buf, "\" \ "", 2 );

}

Return;

}

Smart_str_appendc (buf, '"'); // input \"

// The following code escapes special characters, such as double quotation marks and backslash.

While (pos <len)

{

Us = utf16 [pos ++];

Switch (us)

{

Case '"':

If (options & PHP_JSON_HEX_QUOT ){

Smart_str_appendl (buf, "\ u0022", 6 );

} Else {

Smart_str_appendl (buf, "\\\" ", 2 );

}

Break;

Case '\\':

Smart_str_appendl (buf, "\\\\", 2 );

Break;

Case '/':

Smart_str_appendl (buf, "\\/", 2 );

Break;

Case '\ B ':

Smart_str_appendl (buf, "\ B", 2 );

Break;

Case '\ f ':

Smart_str_appendl (buf, "\ f", 2 );

Break;

Case '\ n ':

Smart_str_appendl (buf, "\ n", 2 );

Break;

Case '\ r ':

Smart_str_appendl (buf, "\ r", 2 );

Break;

Case '\ t ':

Smart_str_appendl (buf, "\ t", 2 );

Break;

Case '<':

If (options & PHP_JSON_HEX_TAG ){

Smart_str_appendl (buf, "\ u003C", 6 );

} Else {

Smart_str_appendc (buf, '<');

}

Break;

Case '> ':

If (options & PHP_JSON_HEX_TAG ){

Smart_str_appendl (buf, "\ u003E", 6 );

} Else {

Smart_str_appendc (buf, '> ');

}

Break;

Case '&':

If (options & PHP_JSON_HEX_AMP ){

Smart_str_appendl (buf, "\ u0026", 6 );

} Else {

Smart_str_appendc (buf ,'&');

}

Break;

Case '\'':

If (options & PHP_JSON_HEX_APOS ){

Smart_str_appendl (buf, "\ u0027", 6 );

} Else {

Smart_str_appendc (buf ,'\'');

}

Break;

Default: // until here, the value will be appended to the buf without special characters

If (us> = ''& (us & 127) = us ){

Smart_str_appendc (buf, (unsigned char) us );

} Else {

Smart_str_appendl (buf, "\ u", 2 );

Us = REVERSE16 (us );

Smart_str_appendc (buf, digits [us & (1 <4)-1)]);

Us> = 4;

Smart_str_appendc (buf, digits [us & (1 <4)-1)]);

Us> = 4;

Smart_str_appendc (buf, digits [us & (1 <4)-1)]);

Us> = 4;

Smart_str_appendc (buf, digits [us & (1 <4)-1)]);

}

Break;

}

}

Smart_str_appendc (buf, '"'); // End double quotation marks.

Efree (utf16 );

}

Let's take a look at Arrays and objects, which is also very simple,

Static void json_encode_array (smart_str * buf, zval ** val, int options TSRMLS_DC )/*{{{*/

{

Int I, r;

HashTable * myht;

If (Z_TYPE_PP (val) = IS_ARRAY ){

Myht = HASH_OF (* val );

R = (options & PHP_JSON_FORCE_OBJECT )? PHP_JSON_OUTPUT_OBJECT: json_determine_array_type (val TSRMLS_CC );

} Else {

Myht = Z_OBJPROP_PP (val );

R = PHP_JSON_OUTPUT_OBJECT;

}

If (myht & myht-> nApplyCount> 1 ){

Php_error_docref (NULL TSRMLS_CC, E_WARNING, "recursion detected ");

Smart_str_appendl (buf, "null", 4 );

Return;

}

// Start tag

If (r = PHP_JSON_OUTPUT_ARRAY ){

Smart_str_appendc (buf ,'[');

} Else {

Smart_str_appendc (buf ,'{');

}

I = myht? Zend_hash_num_elements (myht): 0;

If (I> 0)

{

Char * key;

Zval ** data;

Ulong index;

Uint key_len;

HashPosition pos;

HashTable * tmp_ht;

Int need_comma = 0;

Zend_hash_internal_pointer_reset_ex (myht, & pos );

// Convenient hash table

For (; zend_hash_move_forward_ex (myht, & pos )){

I = zend_hash_get_current_key_ex (myht, & key, & key_len, & index, 0, & pos );

If (I = HASH_KEY_NON_EXISTANT)

Break;

If (zend_hash_get_current_data_ex (myht, (void **) & data, & pos) = SUCCESS ){

Tmp_ht = HASH_OF (* data );

If (tmp_ht ){

Tmp_ht-> nApplyCount ++;

}

If (r = PHP_JSON_OUTPUT_ARRAY ){

If (need_comma ){

Smart_str_appendc (buf ,',');

} Else {

Need_comma = 1;

}

// Append the value to the buf

Php_json_encode (buf, * data, options TSRMLS_CC );

} Else if (r = PHP_JSON_OUTPUT_OBJECT ){

If (I = HASH_KEY_IS_STRING ){

If (key [0] = '\ 0' & Z_TYPE_PP (val) = IS_OBJECT ){

/* Skip protected and private members .*/

If (tmp_ht ){

Tmp_ht-> nApplyCount --;

}

Continue;

}

If (need_comma ){

Smart_str_appendc (buf ,',');

} Else {

Need_comma = 1;

}

Json_escape_string (buf, key, key_len-1, options &~ PHP_JSON_NUMERIC_CHECK TSRMLS_CC );

Smart_str_appendc (buf ,':');

Php_json_encode (buf, * data, options TSRMLS_CC );

} Else {

If (need_comma ){

Smart_str_appendc (buf ,',');

} Else {

Need_comma = 1;

}

Smart_str_appendc (buf ,'"');

Smart_str_append_long (buf, (long) index );

Smart_str_appendc (buf ,'"');

Smart_str_appendc (buf ,':');

Php_json_encode (buf, * data, options TSRMLS_CC );

}

}

If (tmp_ht ){

Tmp_ht-> nApplyCount --;

}

}

}

}

// End tag

If (r = PHP_JSON_OUTPUT_ARRAY ){

Smart_str_appendc (buf, ']');

} Else {

Smart_str_appendc (buf ,'}');

}

}

After a simple analysis, it is proved that the sprintf method is the same as that used above, and all of them are concatenated strings,

Parser. I like to use sprintf to splice the json format when outputting json. I was told by a friend two days ago that it was not standard and that json_encode must be used to generate the standard...