Annotation of embedaddon/php/README.PARAMETER_PARSING_API, revision 1.1.1.3
1.1 misho 1: New parameter parsing functions
2: ===============================
3:
4: It should be easier to parse input parameters to an extension function.
5: Hence, borrowing from Python's example, there are now a set of functions
6: that given the string of type specifiers, can parse the input parameters
7: and store the results in the user specified variables. This avoids most
8: of the IS_* checks and convert_to_* conversions. The functions also
9: check for the appropriate number of parameters, and try to output
10: meaningful error messages.
11:
12:
13: Prototypes
14: ----------
15: /* Implemented. */
16: int zend_parse_parameters(int num_args TSRMLS_DC, char *type_spec, ...);
17: int zend_parse_parameters_ex(int flags, int num_args TSRMLS_DC, char *type_spec, ...);
18:
19: The zend_parse_parameters() function takes the number of parameters
20: passed to the extension function, the type specifier string, and the
21: list of pointers to variables to store the results in. The _ex() version
22: also takes 'flags' argument -- current only ZEND_PARSE_PARAMS_QUIET can
23: be used as 'flags' to specify that the function should operate quietly
24: and not output any error messages.
25:
26: Both functions return SUCCESS or FAILURE depending on the result.
27:
28: The auto-conversions are performed as necessary. Arrays, objects, and
29: resources cannot be auto-converted.
30:
31:
32: Type specifiers
33: ---------------
34: The following list shows the type specifier, its meaning and the parameter
1.1.1.3 ! misho 35: types that need to be passed by address. All passed parameters are set
1.1 misho 36: if the PHP parameter is non optional and untouched if optional and the
37: parameter is not present. The only exception is O where the zend_class_entry*
38: has to be provided on input and is used to verify the PHP parameter is an
39: instance of that class.
40:
41: a - array (zval*)
42: A - array or object (zval *)
43: b - boolean (zend_bool)
44: C - class (zend_class_entry*)
45: d - double (double)
46: f - function or array containing php method call info (returned as
47: zend_fcall_info and zend_fcall_info_cache)
48: h - array (returned as HashTable*)
49: H - array or HASH_OF(object) (returned as HashTable*)
50: l - long (long)
51: L - long, limits out-of-range numbers to LONG_MAX/LONG_MIN (long)
52: o - object of any type (zval*)
53: O - object of specific type given by class entry (zval*, zend_class_entry)
1.1.1.2 misho 54: p - valid path (string without null bytes in the middle) and its length (char*, int)
1.1 misho 55: r - resource (zval*)
56: s - string (with possible null bytes) and its length (char*, int)
57: z - the actual zval (zval*)
58: Z - the actual zval (zval**)
59: * - variable arguments list (0 or more)
60: + - variable arguments list (1 or more)
61:
62: The following characters also have a meaning in the specifier string:
63: | - indicates that the remaining parameters are optional, they
64: should be initialized to default values by the extension since they
65: will not be touched by the parsing function if they are not
66: passed to it.
67: / - use SEPARATE_ZVAL_IF_NOT_REF() on the parameter it follows
68: ! - the parameter it follows can be of specified type or NULL (applies
69: to all specifiers except for 'b', 'l', and 'd'). If NULL is passed, the
70: results pointer is set to NULL as well.
71:
72:
73: Note on 64bit compatibility
74: ---------------------------
75: Please do not forget that int and long are two different things on 64bit
76: OSes (int is 4 bytes and long is 8 bytes), so make sure you pass longs to "l"
77: and ints to strings length (i.e. for "s" you need to pass char * and int),
78: not the other way round!
79: Remember: "l" is the only case when you need to pass long (and that's why
80: it's "l", not "i" btw).
81:
82: Both mistakes cause memory corruptions and segfaults on 64bit OSes:
83: 1)
84: char *str;
85: long str_len; /* XXX THIS IS WRONG!! Use int instead. */
86: zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len)
87:
88: 2)
89: int num; /* XXX THIS IS WRONG!! Use long instead. */
90: zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &num)
91:
92: If you're in doubt, use check_parameters.php script to the parameters
93: and their types (it can be found in ./scripts/dev/ directory of PHP sources):
94:
95: # php ./scripts/dev/check_parameters.php /path/to/your/sources/
96:
97:
98: Examples
99: --------
100: /* Gets a long, a string and its length, and a zval */
101: long l;
102: char *s;
103: int s_len;
104: zval *param;
105: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "lsz",
106: &l, &s, &s_len, ¶m) == FAILURE) {
107: return;
108: }
109:
110:
111: /* Gets an object of class specified by my_ce, and an optional double. */
112: zval *obj;
113: double d = 0.5;
114: zend_class_entry *my_ce;
115: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "O|d",
116: &obj, my_ce, &d) == FAILURE) {
117: return;
118: }
119:
120:
121: /* Gets an object or null, and an array.
122: If null is passed for object, obj will be set to NULL. */
123: zval *obj;
124: zval *arr;
125: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "o!a",
126: &obj, &arr) == FAILURE) {
127: return;
128: }
129:
130:
131: /* Gets a separated array which can also be null. */
132: zval *arr;
133: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a/!",
134: &arr) == FAILURE) {
135: return;
136: }
137:
138: /* Get either a set of 3 longs or a string. */
139: long l1, l2, l3;
140: char *s;
141: /*
142: * The function expects a pointer to a integer in this case, not a long
143: * or any other type. If you specify a type which is larger
144: * than a 'int', the upper bits might not be initialized
145: * properly, leading to random crashes on platforms like
146: * Tru64 or Linux/Alpha.
147: */
148: int length;
149:
150: if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC,
151: "lll", &l1, &l2, &l3) == SUCCESS) {
152: /* manipulate longs */
153: } else if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC,
154: "s", &s, &length) == SUCCESS) {
155: /* manipulate string */
156: } else {
157: /* output error */
158:
159: return;
160: }
161:
162:
163: /* Function that accepts only varargs (0 or more) */
164:
165: int i, num_varargs;
166: zval ***varargs = NULL;
167:
168:
169: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "*", &varargs, &num_varargs) == FAILURE) {
170: return;
171: }
172:
173: for (i = 0; i < num_varargs; i++) {
174: /* do something with varargs[i] */
175: }
176:
177: if (varargs) {
178: efree(varargs);
179: }
180:
181:
182: /* Function that accepts a string, followed by varargs (1 or more) */
183:
184: char *str;
185: int str_len;
186: int i, num_varargs;
187: zval ***varargs = NULL;
188:
189: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s+", &str, &str_len, &varargs, &num_varargs) == FAILURE) {
190: return;
191: }
192:
193: for (i = 0; i < num_varargs; i++) {
194: /* do something with varargs[i] */
195: }
196:
197: if (varargs) {
198: efree(varargs);
199: }
200:
201:
202: /* Function that takes an array, followed by varargs, and ending with a long */
203: long num;
204: zval *array;
205: int i, num_varargs;
206: zval ***varargs = NULL;
207:
208: if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a*l", &array, &varargs, &num_varargs, &num) == FAILURE) {
209: return;
210: }
211:
212: for (i = 0; i < num_varargs; i++) {
213: /* do something with varargs[i] */
214: }
215:
216: if (varargs) {
217: efree(varargs);
218: }
219:
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