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php json_encode application analysis

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Release： 2016-07-25 09:04:22
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  2. static PHP_FUNCTION(json_encode)
  3. {
  4. zval *parameter;
  5. smart_str buf = {0};
  6. long options = 0;
  8. if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z|l", ¶meter, &options) == FAILURE) {
  9. return;
  10. }
  12. JSON_G(error_code) = PHP_JSON_ERROR_NONE;
  14. php_json_encode(&buf, parameter, options TSRMLS_CC);
  16. ZVAL_STRINGL(return_value, buf.c, buf. len, 1);
  18. smart_str_free(&buf);
  19. }
Copy code

JSON_G(error_code) = PHP_JSON_ERROR_NONE; It is a defined json error. This error can be obtained through the json_last_error function. Have you used it? I haven't used it anyway. php_json_encode is the main operation

  2. PHP_JSON_API void php_json_encode(smart_str *buf, zval *val, int options TSRMLS_DC) /* {{{ */
  3. {
  4. switch (Z_TYPE_P(val))
  5. {
  6. case IS_NULL:
  7. smart_str_append l(buf, "null", 4); //Output NULL
  8. break;
  10. case IS_BOOL:
  11. if (Z_BVAL_P(val)) {
  12. smart_str_appendl(buf, "true", 4); //Output true
  13. } else {
  14. smart_str_appendl (buf, "false", 5);//Output false
  15. }
  16. break;
  18. case IS_LONG:
  19. smart_str_append_long(buf, Z_LVAL_P(val));//Output the value of long integer
  20. break;
  22. case IS_DOUBLE:
  23. {
  24. char *d = NULL;
  25. int len;
  26. double dbl = Z_DVAL_P(val);
  28. if (!zend_isinf(dbl) && !zend_isnan(dbl)) {//Non-infinite
  29. len = spprintf(&d , 0, "%.*k", (int) EG(precision), dbl);
  30. smart_str_appendl(buf, d, len);
  31. efree(d);
  32. } else {
  33. php_error_docref(NULL TSRMLS_CC, E_WARNING, " double %.9g does not conform to the JSON spec, encoded as 0", dbl);
  34. smart_str_appendc(buf, '0');
  35. }
  36. }
  37. break;
  39. case IS_STRING://string
  40. json_escape_string(buf , Z_STRVAL_P(val), Z_STRLEN_P(val), options TSRMLS_CC);
  41. break;
  43. case IS_ARRAY://Arrays and objects
  44. case IS_OBJECT:
  45. json_encode_array(buf, &val, options TSRMLS_CC);
  46. break;
  48. default:
  49. php_error_docref(NULL TSRMLS_CC, E_WARNING, "type is unsupported, encoded as null");
  50. smart_str_appendl(buf, "null", 4);
  51. break;
  52. }
  54. return;
  55. }
Copy code

Obviously, there will be corresponding cases according to 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 and the comments are written directly in the code.

  2. //options should be supported only after version 5.3, a binary mask composed of the following constants: JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_NUMERIC_CHECK, JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_FORCE_ OBJECT, JSON_UNESCAPED_UNICODE. Although I have not used it. . .
  3. static void json_escape_string(smart_str *buf, char *s, int len, int options TSRMLS_DC) /* {{{ */
  4. {
  5. int pos = 0;
  6. unsigned short us;
  7. unsigned short *utf16;
  9. if ( len == 0) {//If the length is 0, directly return double quotes ""
  10. smart_str_appendl(buf, """", 2);
  11. return;
  12. }
  14. if (options & PHP_JSON_NUMERIC_CHECK) {//Detection Is it a number from 0 to 9? If it is a number, the data will be returned directly as a long or double type.
  15. double d;
  16. int type;
  17. long p;
  19. if ((type = is_numeric_string(s, len, &p, &d, 0)) != 0) {
  20. if (type == IS_LONG) {
  21. smart_str_append_long(buf , p);
  22. } else if (type == IS_DOUBLE) {
  23. if (!zend_isinf(d) && !zend_isnan(d)) {
  24. char *tmp;
  25. int l = spprintf(&tmp, 0, "%.* k", (int) EG(precision), d);
  26. smart_str_appendl(buf, tmp, l);
  27. efree(tmp);
  28. } else {
  29. php_error_docref(NULL TSRMLS_CC, E_WARNING, "double %.9g does not conform to the JSON spec, encoded as 0", d);
  30. smart_str_appendc(buf, '0');
  31. }
  32. }
  33. return;
  34. }
  36. }
  38. utf16 = (unsigned short *) safe_emalloc(len, sizeof( unsigned short), 0);
  39. len = utf8_to_utf16(utf16, s, len); //The value you input will be processed once and converted into the corresponding Dec code. For example, 1 is 49 and a is 97. Save it to in utf16.
  40. if (len <= 0) {//If len is less than 0, an error has occurred. If you use json_encode to process GBK encoding, it will hang up here.
  41. if (utf16) {
  42. efree(utf16);
  43. }
  44. if (len < 0) {
  45. JSON_G(error_code) = PHP_JSON_ERROR_UTF8;
  46. if (!PG(display_errors)) {
  47. php_error_docref(NULL TSRMLS_CC, E_WARNING, " Invalid UTF-8 sequence in argument");
  48. }
  49. smart_str_appendl(buf, "null", 4);
  50. } else {
  51. smart_str_appendl(buf, """", 2);
  52. }
  53. return;
  54. }
  56. smart_str_appendc(buf, '"'); //Enter "
  58. //The following code is to escape some special characters such as double quotes, backslashes, etc.
  59. while (pos < len)
  60. {
  61. us = utf16[pos++];
  63. switch (us)
  64. {
  65. case '"':
  66. if (options & PHP_JSON_HEX_QUOT) {
  67. smart_str_appendl(buf, "\u0022", 6);
  68. } else {
  69. smart_str_appendl(buf, " \"", 2);
  70. }
  71. break;
  73. case '\':
  74. smart_str_appendl(buf, "\\", 2);
  75. break;
  76. case '/':
  77. smart_str_appendl(buf, "\/" , 2);
  78. break;
  80. case 'b':
  81. smart_str_appendl(buf, "\b", 2);
  82. break;
  84. case 'f':
  85. smart_str_appendl(buf, "\f", 2);
  86. break;
  88. case 'n':
  89. smart_str_appendl(buf, "\n", 2);
  90. break;
  92. case 'r':
  93. smart_str_appendl(buf, "\r", 2);
  94. break;
  96. case 't':
  97. smart_str_appendl(buf, "\t", 2);
  98. break;
  100. case '<':
  101. if (options & PHP_JSON_HEX_TAG) {
  102. smart_str_appendl(buf, "\u003C", 6) ;
  103. } else {
  104. smart_str_appendc(buf, '<');
  105. }
  106. break;
  108. case '>':
  109. if (options & PHP_JSON_HEX_TAG) {
  110. smart_str_appendl(buf, "\u003E", 6);
  111. } else {
  112. smart_str_appendc(buf, '>');
  113. }
  114. break;
  116. case '&':
  117. if (options & PHP_JSON_HEX_AMP) {
  118. smart_str_appendl(buf, "\u0026", 6);
  119. } else {
  120. smart_str_appendc(buf, '&');
  121. }
  122. break;
  124. case ''':
  125. if (options & PHP_JSON_HEX_APOS) {
  126. smart_str_appendl(buf, "\u0027", 6);
  127. } else {
  128. smart_str_appendc(buf, ''');
  129. }
  130. break;
  132. default: //Up to here, the value will be appended to buf without special characters
  133. if (us >= ' ' && (us & 127) == us) {
  134. smart_str_appendc(buf, (unsigned char) us);
  135. }else {
  136. smart_str_appendl(buf, "\u", 2);
  137. us = REVERSE16(us);
  139. smart_str_appendc(buf, digits[us & ((1 << 4) - 1)]);
  140. us >>= 4;
  141. smart_str_appendc(buf, digits[us & ((1 << 4) - 1)]);
  142. us >>= 4;
  143. smart_str_appendc(buf, digits[us & ((1 << 4) - 1)]);
  144. us >>= 4;
  145. smart_str_appendc(buf, digits[us & ((1 << 4) - 1)]);
  146. }
  147. break;
  148. }
  149. }
  150. smart_str_appendc(buf, '"'); //结束 双引号。
  151. efree(utf16);
  152. }
复制代码

Let’s take a look at arrays and objects. It’s also very simple.

  2. static void json_encode_array(smart_str *buf, zval **val, int options TSRMLS_DC) /* {{{ */
  3. {
  4. int i, r;
  5. HashTable *myht;
  7. if (Z_TYPE_PP(val) == IS_ARRAY) {
  8. myht = HASH_OF(*val);
  9. r = (options & PHP_JSON_FORCE_OBJECT) ? PHP_JSON_OUTPUT_OBJECT : json_determine_array_type(val TSRMLS_CC);
  10. } else {
  11. myht = Z_OBJPROP_PP(val);
  12. r = PHP_JSON_OUTPUT_OBJECT;
  13. }
  15. if (myht && myht->nApplyCount > 1) {
  16. php_error_docref(NULL TSRMLS_CC, E_WARNING, "recursion detected");
  17. smart_str_appendl(buf, "null", 4);
  18. return;
  19. }
  20. //开始标签
  21. if (r == PHP_JSON_OUTPUT_ARRAY) {
  22. smart_str_appendc(buf, '[');
  23. } else {
  24. smart_str_appendc(buf, '{');
  25. }
  27. i = myht ? zend_hash_num_elements(myht) : 0;
  29. if (i > 0)
  30. {
  31. char *key;
  32. zval **data;
  33. ulong index;
  34. uint key_len;
  35. HashPosition pos;
  36. HashTable *tmp_ht;
  37. int need_comma = 0;
  39. zend_hash_internal_pointer_reset_ex(myht, &pos);
  40. //便利哈希表
  41. for (;; zend_hash_move_forward_ex(myht, &pos)) {
  42. i = zend_hash_get_current_key_ex(myht, &key, &key_len, &index, 0, &pos);
  43. if (i == HASH_KEY_NON_EXISTANT)
  44. break;
  46. if (zend_hash_get_current_data_ex(myht, (void **) &data, &pos) == SUCCESS) {
  47. tmp_ht = HASH_OF(*data);
  48. if (tmp_ht) {
  49. tmp_ht->nApplyCount++;
  50. }
  52. if (r == PHP_JSON_OUTPUT_ARRAY) {
  53. if (need_comma) {
  54. smart_str_appendc(buf, ',');
  55. } else {
  56. need_comma = 1;
  57. }
  58. //将值append到 buf中
  59. php_json_encode(buf, *data, options TSRMLS_CC);
  60. } else if (r == PHP_JSON_OUTPUT_OBJECT) {
  61. if (i == HASH_KEY_IS_STRING) {
  62. if (key[0] == '
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php json_encode应用分析
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