Thu Oct 1 13:10:19 2009

Asterisk developer's documentation


stringfields.h File Reference

String fields in structures. More...

#include <string.h>
#include <stdarg.h>
#include <stddef.h>
#include "asterisk/inline_api.h"
#include "asterisk/compiler.h"
#include "asterisk/compat.h"

Go to the source code of this file.

Data Structures

struct  ast_string_field_mgr
struct  ast_string_field_pool

Defines

#define AST_DECLARE_STRING_FIELDS(field_list)
 Declare the fields needed in a structure.
#define AST_STRING_FIELD(name)   const ast_string_field name
 Declare a string field.
#define ast_string_field_build(x, field, fmt, args...)   ast_string_field_index_build(x, ast_string_field_index(x, field), fmt, args)
 Set a field to a complex (built) value.
#define ast_string_field_build_va(x, field, fmt, args1, args2)   ast_string_field_index_build_va(x, ast_string_field_index(x, field), fmt, args1, args2)
 Set a field to a complex (built) value.
#define ast_string_field_count(x)   (offsetof(typeof(*(x)), __end_field) - offsetof(typeof(*(x)), __begin_field)) / sizeof(ast_string_field)
 Get the number of string fields in a structure.
#define ast_string_field_free(x, field)   ast_string_field_index_free(x, ast_string_field_index(x, field))
 Free a field's value.
#define ast_string_field_free_memory(x)
 Free the stringfield storage pools attached to a structure.
#define ast_string_field_index(x, field)   (offsetof(typeof(*x), field) - offsetof(typeof(*x), __begin_field)) / sizeof(ast_string_field)
 Get the index of a field in a structure.
#define ast_string_field_index_build(x, index, fmt, args...)   __ast_string_field_index_build(&(x)->__field_mgr, &(x)->__begin_field[0], ast_string_field_count(x), index, fmt, args)
 Set a field to a complex (built) value.
#define ast_string_field_index_build_va(x, index, fmt, args1, args2)   __ast_string_field_index_build_va(&(x)->__field_mgr, &(x)->__begin_field[0], ast_string_field_count(x), index, fmt, args1, args2)
 Set a field to a complex (built) value with prebuilt va_lists.
#define ast_string_field_index_free(x, index)
 Free a field's value.
#define ast_string_field_index_logset(x, index, data, logstr)
#define ast_string_field_index_set(x, index, data)
 Set a field to a simple string value.
#define ast_string_field_init(x, size)   __ast_string_field_init(&(x)->__field_mgr, size, &(x)->__begin_field[0], ast_string_field_count(x))
 Initialize a field pool and fields.
#define ast_string_field_logset(x, field, data, logstr)   ast_string_field_index_logset(x, ast_string_field_index(x, field), data, logstr)
#define ast_string_field_reset_all(x)
 Free the stringfields in a structure.
#define ast_string_field_set(x, field, data)   ast_string_field_index_set(x, ast_string_field_index(x, field), data)
 Set a field to a simple string value.

Typedefs

typedef const char * ast_string_field

Functions

ast_string_field __ast_string_field_alloc_space (struct ast_string_field_mgr *mgr, size_t needed, ast_string_field *fields, int num_fields)
void __ast_string_field_index_build (struct ast_string_field_mgr *mgr, ast_string_field *fields, int num_fields, int index, const char *format,...)
void __ast_string_field_index_build_va (struct ast_string_field_mgr *mgr, ast_string_field *fields, int num_fields, int index, const char *format, va_list a1, va_list a2)
int __ast_string_field_init (struct ast_string_field_mgr *mgr, size_t size, ast_string_field *fields, int num_fields)

Variables

const char __ast_string_field_empty []


Detailed Description

String fields in structures.

This file contains objects and macros used to manage string fields in structures without requiring them to be allocated as fixed-size buffers or requiring individual allocations for for each field.

Using this functionality is quite simple... an example structure with three fields is defined like this:

  struct sample_fields {
     int x1;
     AST_DECLARE_STRING_FIELDS(
        AST_STRING_FIELD(name);
        AST_STRING_FIELD(address);
        AST_STRING_FIELD(password);
     );
     long x2;
  };

When an instance of this structure is allocated, the fields (and the pool of storage for them) must be initialized:

  struct sample_fields *sample;
  
  sample = calloc(1, sizeof(*sample));
  if (sample) {
     if (ast_string_field_init(sample, 256)) {
        free(sample);
        sample = NULL;
     }
  }
  
  if (!sample) {
  ...
  }

Fields will default to pointing to an empty string, and will revert to that when ast_string_field_free() is called. This means that a string field will never contain NULL.

Using the fields is much like using regular 'char *' fields in the structure, except that writing into them must be done using wrapper macros defined in this file.

Storing simple values into fields can be done using ast_string_field_set(); more complex values (using printf-style format strings) can be stored using ast_string_field_build().

When the structure instance is no longer needed, the fields and their storage pool must be freed:

  ast_string_field_free_memory(sample);
  free(sample);

Definition in file stringfields.h.


Define Documentation

#define AST_DECLARE_STRING_FIELDS ( field_list   ) 

Value:

ast_string_field __begin_field[0]; \
   field_list \
   ast_string_field __end_field[0]; \
   struct ast_string_field_mgr __field_mgr
Declare the fields needed in a structure.

Parameters:
field_list The list of fields to declare, using AST_STRING_FIELD() for each one

Definition at line 196 of file stringfields.h.

#define AST_STRING_FIELD ( name   )     const ast_string_field name

Declare a string field.

Parameters:
name The field name

Definition at line 190 of file stringfields.h.

#define ast_string_field_build ( x,
field,
fmt,
args...   )     ast_string_field_index_build(x, ast_string_field_index(x, field), fmt, args)

Set a field to a complex (built) value.

Parameters:
x Pointer to a structure containing fields
field Name of the field to set
fmt printf-style format string
args Arguments for format string
Returns:
nothing

Definition at line 316 of file stringfields.h.

Referenced by build_callid_pvt(), build_callid_registry(), build_contact(), build_rpid(), build_user(), create_addr_from_peer(), handle_request_subscribe(), handle_response(), mgcp_new(), parse_moved_contact(), parse_register_contact(), pri_fixup_principle(), set_nonce_randdata(), sip_sipredirect(), and update_name().

#define ast_string_field_build_va ( x,
field,
fmt,
args1,
args2   )     ast_string_field_index_build_va(x, ast_string_field_index(x, field), fmt, args1, args2)

Set a field to a complex (built) value.

Parameters:
x Pointer to a structure containing fields
field Name of the field to set
fmt printf-style format string
argslist a va_list of the args
Returns:
nothing

Definition at line 327 of file stringfields.h.

#define ast_string_field_count (  )     (offsetof(typeof(*(x)), __end_field) - offsetof(typeof(*(x)), __begin_field)) / sizeof(ast_string_field)

Get the number of string fields in a structure.

Parameters:
x Pointer to a structure containing fields
Returns:
the number of fields in the structure's definition

Definition at line 207 of file stringfields.h.

#define ast_string_field_free ( x,
field   )     ast_string_field_index_free(x, ast_string_field_index(x, field))

Free a field's value.

Parameters:
x Pointer to a structure containing fields
field Name of the field to free
Returns:
nothing
Note:
Because of the storage pool used, the memory occupied by the field's value is not recovered; the field pointer is just changed to point to an empty string.

Definition at line 354 of file stringfields.h.

Referenced by check_user_full(), handle_request_invite(), handle_response_invite(), sip_request_call(), and transmit_register().

#define ast_string_field_free_memory (  ) 

Free the stringfield storage pools attached to a structure.

Parameters:
x Pointer to a structure containing fields
Returns:
nothing
After calling this macro, fields can no longer be accessed in structure; it should only be called immediately before freeing the structure itself.

Definition at line 366 of file stringfields.h.

Referenced by ast_channel_free(), build_user(), destroy_mailbox_mapping(), destroy_station(), destroy_trunk(), peer_destructor(), pvt_destructor(), sip_alloc(), sip_registry_destroy(), temp_pvt_cleanup(), and user_destructor().

#define ast_string_field_index ( x,
field   )     (offsetof(typeof(*x), field) - offsetof(typeof(*x), __begin_field)) / sizeof(ast_string_field)

Get the index of a field in a structure.

Parameters:
x Pointer to a structure containing fields
field Name of the field to locate
Returns:
the position (index) of the field within the structure's array of fields

Definition at line 217 of file stringfields.h.

Referenced by reply_digest().

#define ast_string_field_index_build ( x,
index,
fmt,
args...   )     __ast_string_field_index_build(&(x)->__field_mgr, &(x)->__begin_field[0], ast_string_field_count(x), index, fmt, args)

Set a field to a complex (built) value.

Parameters:
x Pointer to a structure containing fields
index Index position of the field within the structure
fmt printf-style format string
args Arguments for format string
Returns:
nothing

Definition at line 293 of file stringfields.h.

#define ast_string_field_index_build_va ( x,
index,
fmt,
args1,
args2   )     __ast_string_field_index_build_va(&(x)->__field_mgr, &(x)->__begin_field[0], ast_string_field_count(x), index, fmt, args1, args2)

Set a field to a complex (built) value with prebuilt va_lists.

Parameters:
x Pointer to a structure containing fields
index Index position of the field within the structure
fmt printf-style format string
args1 Arguments for format string in va_list format
args2 a second copy of the va_list for the sake of bsd, with no va_list copy operation
Returns:
nothing

Definition at line 305 of file stringfields.h.

#define ast_string_field_index_free ( x,
index   ) 

Value:

do { \
   (x)->__begin_field[index] = __ast_string_field_empty; \
   } while(0)
Free a field's value.

Parameters:
x Pointer to a structure containing fields
index Index position of the field within the structure
Returns:
nothing
Note:
Because of the storage pool used, the memory occupied by the field's value is not recovered; the field pointer is just changed to point to an empty string.

Definition at line 340 of file stringfields.h.

#define ast_string_field_index_logset ( x,
index,
data,
logstr   ) 

Definition at line 254 of file stringfields.h.

#define ast_string_field_index_set ( x,
index,
data   ) 

Set a field to a simple string value.

Parameters:
x Pointer to a structure containing fields
index Index position of the field within the structure
data String value to be copied into the field
Returns:
nothing

Definition at line 236 of file stringfields.h.

Referenced by reply_digest().

#define ast_string_field_init ( x,
size   )     __ast_string_field_init(&(x)->__field_mgr, size, &(x)->__begin_field[0], ast_string_field_count(x))

Initialize a field pool and fields.

Parameters:
x Pointer to a structure containing fields
size Amount of storage to allocate
Returns:
0 on success, non-zero on failure

Definition at line 226 of file stringfields.h.

Referenced by append_mailbox_mapping(), ast_channel_alloc(), build_peer(), build_user(), load_module(), new_iax(), sip_alloc(), sip_register(), sla_build_station(), sla_build_trunk(), and transmit_response_using_temp().

#define ast_string_field_logset ( x,
field,
data,
logstr   )     ast_string_field_index_logset(x, ast_string_field_index(x, field), data, logstr)

Definition at line 282 of file stringfields.h.

#define ast_string_field_reset_all (  ) 

Free the stringfields in a structure.

Parameters:
x Pointer to a structure containing fields
Returns:
nothing
After calling this macro, the most recently allocated pool attached to the structure will be available for use by stringfields again.

Definition at line 383 of file stringfields.h.

Referenced by transmit_response_using_temp().

#define ast_string_field_set ( x,
field,
data   )     ast_string_field_index_set(x, ast_string_field_index(x, field), data)

Set a field to a simple string value.

Parameters:
x Pointer to a structure containing fields
field Name of the field to set
data String value to be copied into the field
Returns:
nothing

Definition at line 279 of file stringfields.h.

Referenced by __find_callno(), __oh323_new(), agent_new(), alsa_new(), append_mailbox_mapping(), ast_call_forward(), ast_cdr_setaccount(), ast_change_name(), ast_do_masquerade(), ast_feature_request_and_dial(), ast_iax2_new(), authenticate_reply(), authenticate_request(), authenticate_verify(), begin_dial(), build_peer(), build_rpid(), build_user(), cache_get_callno_locked(), check_access(), check_user_full(), create_addr(), create_addr_from_peer(), dahdi_new(), disa_exec(), extract_uri(), features_call(), get_also_info(), get_destination(), get_rdnis(), gtalk_new(), handle_request(), handle_request_bye(), handle_request_invite(), handle_request_options(), handle_request_refer(), handle_response(), iax2_call(), iax2_request(), initreqprep(), language_write(), load_module(), local_call(), mgcp_new(), moh2_exec(), moh_write(), nbs_new(), new_iax(), oss_new(), parse_moved_contact(), parse_ok_contact(), parse_register_contact(), phone_new(), read_config(), register_verify(), registry_authrequest(), reply_digest(), sip_alloc(), sip_call(), sip_new(), sip_poke_peer(), sip_register(), sip_request_call(), skinny_new(), sla_build_station(), sla_build_trunk(), socket_process(), transmit_refer(), transmit_register(), transmit_response_using_temp(), vm_execmain(), and wait_for_answer().


Typedef Documentation

typedef const char* ast_string_field

Definition at line 100 of file stringfields.h.


Function Documentation

ast_string_field __ast_string_field_alloc_space ( struct ast_string_field_mgr mgr,
size_t  needed,
ast_string_field fields,
int  num_fields 
)

Definition at line 1233 of file utils.c.

References add_string_pool(), ast_string_field_pool::base, ast_string_field_mgr::pool, ast_string_field_mgr::size, ast_string_field_mgr::space, and ast_string_field_mgr::used.

01235 {
01236    char *result = NULL;
01237 
01238    if (__builtin_expect(needed > mgr->space, 0)) {
01239       size_t new_size = mgr->size * 2;
01240 
01241       while (new_size < needed)
01242          new_size *= 2;
01243 
01244       if (add_string_pool(mgr, new_size))
01245          return NULL;
01246    }
01247 
01248    result = mgr->pool->base + mgr->used;
01249    mgr->used += needed;
01250    mgr->space -= needed;
01251    return result;
01252 }

void __ast_string_field_index_build ( struct ast_string_field_mgr mgr,
ast_string_field fields,
int  num_fields,
int  index,
const char *  format,
  ... 
)

Definition at line 1308 of file utils.c.

References __ast_string_field_index_build_va().

01311 {
01312    va_list ap1, ap2;
01313 
01314    va_start(ap1, format);
01315    va_start(ap2, format);     /* va_copy does not exist on FreeBSD */
01316 
01317    __ast_string_field_index_build_va(mgr, fields, num_fields, index, format, ap1, ap2);
01318 
01319    va_end(ap1);
01320    va_end(ap2);
01321 }

void __ast_string_field_index_build_va ( struct ast_string_field_mgr mgr,
ast_string_field fields,
int  num_fields,
int  index,
const char *  format,
va_list  a1,
va_list  a2 
)

Definition at line 1254 of file utils.c.

References add_string_pool(), available(), ast_string_field_pool::base, ast_string_field_mgr::pool, ast_string_field_mgr::size, ast_string_field_mgr::space, and ast_string_field_mgr::used.

Referenced by __ast_string_field_index_build().

01257 {
01258    size_t needed;
01259    size_t available;
01260    char *target;
01261 
01262    /* if the field already has space allocated, try to reuse it;
01263       otherwise, use the empty space at the end of the current
01264       pool
01265    */
01266    if (fields[index][0] != '\0') {
01267       target = (char *) fields[index];
01268       available = strlen(fields[index]) + 1;
01269    } else {
01270       target = mgr->pool->base + mgr->used;
01271       available = mgr->space;
01272    }
01273 
01274    needed = vsnprintf(target, available, format, ap1) + 1;
01275 
01276    va_end(ap1);
01277 
01278    if (needed > available) {
01279       /* if the space needed can be satisfied by using the current
01280          pool (which could only occur if we tried to use the field's
01281          allocated space and failed), then use that space; otherwise
01282          allocate a new pool
01283       */
01284       if (needed <= mgr->space) {
01285          target = mgr->pool->base + mgr->used;
01286       } else {
01287          size_t new_size = mgr->size * 2;
01288 
01289          while (new_size < needed)
01290             new_size *= 2;
01291          
01292          if (add_string_pool(mgr, new_size))
01293             return;
01294          
01295          target = mgr->pool->base + mgr->used;
01296       }
01297 
01298       vsprintf(target, format, ap2);
01299    }
01300 
01301    if (fields[index] != target) {
01302       fields[index] = target;
01303       mgr->used += needed;
01304       mgr->space -= needed;
01305    }
01306 }

int __ast_string_field_init ( struct ast_string_field_mgr mgr,
size_t  size,
ast_string_field fields,
int  num_fields 
)

Definition at line 1219 of file utils.c.

References add_string_pool().

01221 {
01222    int index;
01223 
01224    if (add_string_pool(mgr, size))
01225       return -1;
01226 
01227    for (index = 0; index < num_fields; index++)
01228       fields[index] = __ast_string_field_empty;
01229 
01230    return 0;
01231 }


Variable Documentation

const char __ast_string_field_empty[]

Definition at line 1201 of file utils.c.


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