Thu Jul 9 13:41:33 2009

Asterisk developer's documentation


stringfields.h File Reference

String fields in structures. More...

#include "asterisk/inline_api.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_ptr_build(&(x)->__field_mgr, &(x)->__field_mgr_pool, (ast_string_field *) &(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_ptr_build_va(&(x)->__field_mgr, &(x)->__field_mgr_pool, (ast_string_field *) &(x)->field, fmt, args1, args2)
 Set a field to a complex (built) value.
#define ast_string_field_free_memory(x)   __ast_string_field_init(&(x)->__field_mgr, &(x)->__field_mgr_pool, -1, __FILE__, __LINE__, __PRETTY_FUNCTION__)
 free all memory - to be called before destroying the object
#define ast_string_field_init(x, size)   __ast_string_field_init(&(x)->__field_mgr, &(x)->__field_mgr_pool, size, __FILE__, __LINE__, __PRETTY_FUNCTION__)
 Initialize a field pool and fields.
#define ast_string_field_ptr_build(x, ptr, fmt, args...)   __ast_string_field_ptr_build(&(x)->__field_mgr, &(x)->__field_mgr_pool, (ast_string_field *) ptr, fmt, args)
 Set a field to a complex (built) value.
#define ast_string_field_ptr_build_va(x, ptr, fmt, args1, args2)   __ast_string_field_ptr_build_va(&(x)->__field_mgr, &(x)->__field_mgr_pool, (ast_string_field *) ptr, fmt, args1, args2)
 Set a field to a complex (built) value with prebuilt va_lists.
#define ast_string_field_ptr_set(x, ptr, data)
 Set a field to a simple string value.
#define ast_string_field_set(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, struct ast_string_field_pool **pool_head, size_t needed)
int __ast_string_field_init (struct ast_string_field_mgr *mgr, struct ast_string_field_pool **pool_head, int needed, const char *file, int lineno, const char *func)
void __ast_string_field_ptr_build (struct ast_string_field_mgr *mgr, struct ast_string_field_pool **pool_head, ast_string_field *ptr, const char *format,...)
void __ast_string_field_ptr_build_va (struct ast_string_field_mgr *mgr, struct ast_string_field_pool **pool_head, ast_string_field *ptr, const char *format, va_list a1, va_list a2)
int __ast_string_field_ptr_grow (struct ast_string_field_mgr *mgr, size_t needed, const ast_string_field *ptr)

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(foo);
        AST_STRING_FIELD(bar);
        AST_STRING_FIELD(blah);
     );
     long x2;
  };

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

  struct sample_fields *x;
  
  x = ast_calloc(1, sizeof(*x));
  if (x == NULL || ast_string_field_init(x, 252)) {
   if (x)
      ast_free(x);
   x = NULL;
   ... handle error
  }

Fields will default to pointing to an empty string, and will revert to that when ast_string_field_set() is called with a NULL argument. A string field will never contain NULL (this feature is not used in this code, but comes from external requirements).

ast_string_field_init(x, 0) will reset fields to the initial value while keeping the pool allocated.

Reading the fields is much like using 'const char * const' fields in the structure: you cannot write to the field or to the memory it points to (XXX perhaps the latter is too much of a restriction since values are not shared).

Writing to the fields must be done using the wrapper macros listed below; and assignments are always by value (i.e. strings are copied): ast_string_field_set() stores a simple value; ast_string_field_build() builds the string using a printf-style; ast_string_field_build_va() is the varargs version of the above (for portability reasons it uses two vararg); variants of these function allow passing a pointer to the field as an argument.

  ast_string_field_set(x, foo, "infinite loop");
  ast_string_field_set(x, foo, NULL); // set to an empty string
  ast_string_field_ptr_set(x, &x->bar, "right way");

  ast_string_field_build(x, blah, "%d %s", zipcode, city);
  ast_string_field_ptr_build(x, &x->blah, "%d %s", zipcode, city);

  ast_string_field_build_va(x, bar, fmt, args1, args2)
  ast_string_field_ptr_build_va(x, &x->bar, fmt, args1, args2)

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

  ast_string_field_free_memory(x);
  ast_free(x);

This completes the API description.

Definition in file stringfields.h.


Define Documentation

#define AST_DECLARE_STRING_FIELDS ( field_list   ) 

Value:

struct ast_string_field_pool *__field_mgr_pool; \
   field_list              \
   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. Internally, string fields are stored as a pointer to the head of the pool, followed by individual string fields, and then a struct ast_string_field_mgr which describes the space allocated. We split the two variables so they can be used as markers around the field_list, and this allows us to determine how many entries are in the field, and play with them. In particular, for writing to the fields, we rely on __field_mgr_pool to be a non-const pointer, so we know it has the same size as ast_string_field, and we can use it to locate the fields.

Definition at line 227 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 212 of file stringfields.h.

#define ast_string_field_build ( x,
field,
fmt,
args...   )     __ast_string_field_ptr_build(&(x)->__field_mgr, &(x)->__field_mgr_pool, (ast_string_field *) &(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 308 of file stringfields.h.

Referenced by __ast_channel_alloc_ap(), build_callid_pvt(), build_callid_registry(), build_contact(), build_rpid(), build_user(), check_auth(), create_addr_from_peer(), handle_request_subscribe(), handle_response(), mgcp_new(), parse_moved_contact(), parse_register_contact(), pri_fixup_principle(), sip_sendhtml(), sip_sipredirect(), transmit_fake_auth_response(), unistim_new(), and update_name().

#define ast_string_field_build_va ( x,
field,
fmt,
args1,
args2   )     __ast_string_field_ptr_build_va(&(x)->__field_mgr, &(x)->__field_mgr_pool, (ast_string_field *) &(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
args1 argument one
args2 argument two
Returns:
nothing

Definition at line 332 of file stringfields.h.

Referenced by __ast_channel_alloc_ap().

#define ast_string_field_free_memory (  )     __ast_string_field_init(&(x)->__field_mgr, &(x)->__field_mgr_pool, -1, __FILE__, __LINE__, __PRETTY_FUNCTION__)

free all memory - to be called before destroying the object

Definition at line 245 of file stringfields.h.

Referenced by __ast_channel_alloc_ap(), ast_channel_free(), ast_unregister_groups(), build_user(), delete_file(), delete_user(), destroy_jack_data(), destroy_mailbox_mapping(), destroy_queue(), destroy_station(), destroy_trunk(), exception_store_free(), load_module(), peer_destructor(), profile_destructor(), pvt_destructor(), route_destructor(), sip_alloc(), sip_registry_destroy(), tds_unload_module(), temp_pvt_cleanup(), and user_destructor().

#define ast_string_field_init ( x,
size   )     __ast_string_field_init(&(x)->__field_mgr, &(x)->__field_mgr_pool, size, __FILE__, __LINE__, __PRETTY_FUNCTION__)

Initialize a field pool and fields.

Parameters:
x Pointer to a structure containing fields
size Amount of storage to allocate. Use 0 to reset fields to the default value, and release all but the most recent pool. size<0 (used internally) means free all pools.
Returns:
0 on success, non-zero on failure

Definition at line 241 of file stringfields.h.

Referenced by __ast_channel_alloc_ap(), alloc_queue(), append_mailbox_mapping(), build_peer(), build_profile(), build_route(), build_user(), init_pvt(), jack_data_alloc(), load_module(), new_iax(), pbx_builtin_raise_exception(), register_group(), register_group_feature(), sip_alloc(), sip_register(), sla_build_station(), sla_build_trunk(), tds_load_module(), temp_pvt_init(), and transmit_response_using_temp().

#define ast_string_field_ptr_build ( x,
ptr,
fmt,
args...   )     __ast_string_field_ptr_build(&(x)->__field_mgr, &(x)->__field_mgr_pool, (ast_string_field *) ptr, fmt, args)

Set a field to a complex (built) value.

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

Definition at line 297 of file stringfields.h.

#define ast_string_field_ptr_build_va ( x,
ptr,
fmt,
args1,
args2   )     __ast_string_field_ptr_build_va(&(x)->__field_mgr, &(x)->__field_mgr_pool, (ast_string_field *) ptr, fmt, args1, args2)

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

Parameters:
x Pointer to a structure containing fields
ptr Pointer to a 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 320 of file stringfields.h.

#define ast_string_field_ptr_set ( x,
ptr,
data   ) 

Set a field to a simple string value.

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

Definition at line 262 of file stringfields.h.

Referenced by reply_digest().

#define ast_string_field_set ( x,
field,
data   ) 

Value:

do {     \
   ast_string_field_ptr_set(x, &(x)->field, data);    \
   } while (0)
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 285 of file stringfields.h.

Referenced by __ast_channel_alloc_ap(), __find_callno(), __oh323_new(), acf_channel_write(), agent_new(), alloc_queue(), 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_channel(), build_peer(), build_profile(), build_route(), build_rpid(), build_user(), cache_get_callno_locked(), check_access(), check_peer_ok(), check_user_full(), check_user_ok(), conf_start_moh(), console_new(), create_addr(), create_addr_from_peer(), dahdi_new(), dial_exec_full(), do_forward(), extract_uri(), features_call(), get_also_info(), get_destination(), get_rdnis(), gtalk_new(), handle_incoming(), handle_options(), handle_request_bye(), handle_request_invite(), handle_request_options(), handle_request_refer(), handle_response(), handle_response_invite(), iax2_call(), iax2_request(), init_pvt(), init_queue(), initreqprep(), jingle_new(), load_module(), local_call(), mgcp_new(), monitor_dial(), nbs_new(), new_iax(), oss_new(), parse_moved_contact(), parse_ok_contact(), parse_register_contact(), pbx_builtin_raise_exception(), phone_new(), queue_set_param(), read_config(), register_group(), register_group_feature(), register_verify(), registry_authrequest(), replace_cid(), reply_digest(), reqprep(), respprep(), rpt_call(), save_osptoken(), set_moh_exec(), set_pvt_defaults(), sip_alloc(), sip_call(), sip_new(), sip_poke_peer(), sip_register(), sip_request_call(), sip_set_redirstr(), skinny_new(), sla_build_station(), sla_build_trunk(), socket_process(), store_callerid(), tds_load_module(), transmit_refer(), transmit_register(), transmit_response_using_temp(), unistim_new(), usbradio_new(), and vm_execmain().


Typedef Documentation

typedef const char* ast_string_field

Definition at line 114 of file stringfields.h.


Function Documentation

ast_string_field __ast_string_field_alloc_space ( struct ast_string_field_mgr mgr,
struct ast_string_field_pool **  pool_head,
size_t  needed 
)

Definition at line 1459 of file utils.c.

References add_string_pool(), ast_string_field_mgr::last_alloc, ast_string_field_mgr::size, and ast_string_field_mgr::used.

01461 {
01462    char *result = NULL;
01463    size_t space = mgr->size - mgr->used;
01464 
01465    if (__builtin_expect(needed > space, 0)) {
01466       size_t new_size = mgr->size * 2;
01467 
01468       while (new_size < needed)
01469          new_size *= 2;
01470 
01471 #if defined(__AST_DEBUG_MALLOC)
01472       if (add_string_pool(mgr, pool_head, new_size, mgr->owner_file, mgr->owner_line, mgr->owner_func))
01473          return NULL;
01474 #else
01475       if (add_string_pool(mgr, pool_head, new_size, __FILE__, __LINE__, __FUNCTION__))
01476          return NULL;
01477 #endif
01478    }
01479 
01480    result = (*pool_head)->base + mgr->used;
01481    mgr->used += needed;
01482    mgr->last_alloc = result;
01483    return result;
01484 }

int __ast_string_field_init ( struct ast_string_field_mgr mgr,
struct ast_string_field_pool **  pool_head,
int  needed,
const char *  file,
int  lineno,
const char *  func 
)

Definition at line 1405 of file utils.c.

References add_string_pool(), ast_free, ast_log(), ast_string_field_mgr::last_alloc, LOG_WARNING, ast_string_field_pool::prev, and ast_string_field_mgr::used.

01407 {
01408    const char **p = (const char **) pool_head + 1;
01409    struct ast_string_field_pool *cur = NULL;
01410    struct ast_string_field_pool *preserve = NULL;
01411 
01412    /* clear fields - this is always necessary */
01413    while ((struct ast_string_field_mgr *) p != mgr)
01414       *p++ = __ast_string_field_empty;
01415    mgr->last_alloc = NULL;
01416 #if defined(__AST_DEBUG_MALLOC)
01417    mgr->owner_file = file;
01418    mgr->owner_func = func;
01419    mgr->owner_line = lineno;
01420 #endif
01421    if (needed > 0) {    /* allocate the initial pool */
01422       *pool_head = NULL;
01423       return add_string_pool(mgr, pool_head, needed, file, lineno, func);
01424    }
01425    if (needed < 0) {    /* reset all pools */
01426       if (*pool_head == NULL) {
01427          ast_log(LOG_WARNING, "trying to reset empty pool\n");
01428          return -1;
01429       }
01430       cur = *pool_head;
01431    } else {       /* preserve the last pool */
01432       if (*pool_head == NULL) {
01433          ast_log(LOG_WARNING, "trying to reset empty pool\n");
01434          return -1;
01435       }
01436       mgr->used = 0;
01437       preserve = *pool_head;
01438       cur = preserve->prev;
01439    }
01440 
01441    if (preserve) {
01442       preserve->prev = NULL;
01443    }
01444 
01445    while (cur) {
01446       struct ast_string_field_pool *prev = cur->prev;
01447 
01448       if (cur != preserve) {
01449          ast_free(cur);
01450       }
01451       cur = prev;
01452    }
01453 
01454    *pool_head = preserve;
01455 
01456    return 0;
01457 }

void __ast_string_field_ptr_build ( struct ast_string_field_mgr mgr,
struct ast_string_field_pool **  pool_head,
ast_string_field ptr,
const char *  format,
  ... 
)

Definition at line 1565 of file utils.c.

References __ast_string_field_ptr_build_va().

01568 {
01569    va_list ap1, ap2;
01570 
01571    va_start(ap1, format);
01572    va_start(ap2, format);     /* va_copy does not exist on FreeBSD */
01573 
01574    __ast_string_field_ptr_build_va(mgr, pool_head, ptr, format, ap1, ap2);
01575 
01576    va_end(ap1);
01577    va_end(ap2);
01578 }

void __ast_string_field_ptr_build_va ( struct ast_string_field_mgr mgr,
struct ast_string_field_pool **  pool_head,
ast_string_field ptr,
const char *  format,
va_list  a1,
va_list  a2 
)

Definition at line 1509 of file utils.c.

References add_string_pool(), available(), ast_string_field_mgr::last_alloc, ast_string_field_mgr::size, and ast_string_field_mgr::used.

Referenced by __ast_string_field_ptr_build().

01512 {
01513    size_t needed;
01514    size_t available;
01515    size_t space = mgr->size - mgr->used;
01516    char *target;
01517 
01518    /* if the field already has space allocated, try to reuse it;
01519       otherwise, use the empty space at the end of the current
01520       pool
01521    */
01522    if ((*ptr)[0] != '\0') {
01523       target = (char *) *ptr;
01524       available = strlen(target) + 1;
01525    } else {
01526       target = (*pool_head)->base + mgr->used;
01527       available = space;
01528    }
01529 
01530    needed = vsnprintf(target, available, format, ap1) + 1;
01531 
01532    va_end(ap1);
01533 
01534    if (needed > available) {
01535       /* if the space needed can be satisfied by using the current
01536          pool (which could only occur if we tried to use the field's
01537          allocated space and failed), then use that space; otherwise
01538          allocate a new pool
01539       */
01540       if (needed > space) {
01541          size_t new_size = mgr->size * 2;
01542 
01543          while (new_size < needed)
01544             new_size *= 2;
01545          
01546 #if defined(__AST_DEBUG_MALLOC)
01547          if (add_string_pool(mgr, pool_head, new_size, mgr->owner_file, mgr->owner_line, mgr->owner_func))
01548             return;
01549 #else
01550          if (add_string_pool(mgr, pool_head, new_size, NULL, 0, NULL))
01551             return;
01552 #endif
01553       }
01554 
01555       target = (*pool_head)->base + mgr->used;
01556       vsprintf(target, format, ap2);
01557    }
01558 
01559    if (*ptr != target) {
01560       mgr->last_alloc = *ptr = target;
01561       mgr->used += needed;
01562    }
01563 }

int __ast_string_field_ptr_grow ( struct ast_string_field_mgr mgr,
size_t  needed,
const ast_string_field ptr 
)

Definition at line 1486 of file utils.c.

References ast_string_field_mgr::last_alloc, ast_string_field_mgr::size, and ast_string_field_mgr::used.

01488 {
01489    int grow = needed - (strlen(*ptr) + 1);
01490    size_t space = mgr->size - mgr->used;
01491 
01492    if (grow <= 0) {
01493       return 0;
01494    }
01495 
01496    if (*ptr != mgr->last_alloc) {
01497       return 1;
01498    }
01499 
01500    if (space < grow) {
01501       return 1;
01502    }
01503 
01504    mgr->used += grow;
01505 
01506    return 0;
01507 }


Variable Documentation

const char __ast_string_field_empty[]

the empty string

Definition at line 1365 of file utils.c.


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