274 lines
6.9 KiB
C
274 lines
6.9 KiB
C
/* runtime/weak dynamic JACK linking
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*
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* (C) 2014 Robin Gareus <robin@gareus.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include "weak_libjack.h"
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#ifndef USE_WEAK_JACK
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int have_libjack (void) {
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return 0;
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}
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#else
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#include <stdio.h>
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#include <string.h>
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#include <assert.h>
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#ifdef PLATFORM_WINDOWS
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#include <windows.h>
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#else
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#include <dlfcn.h>
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#endif
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static void* lib_open(const char* const so) {
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#ifdef PLATFORM_WINDOWS
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return (void*) LoadLibraryA(so);
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#else
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return dlopen(so, RTLD_NOW|RTLD_LOCAL);
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#endif
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}
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static void* lib_symbol(void* const lib, const char* const sym) {
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#ifdef PLATFORM_WINDOWS
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return (void*) GetProcAddress((HMODULE)lib, sym);
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#else
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return dlsym(lib, sym);
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#endif
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}
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#ifdef COMPILER_MSVC
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typedef void * pvoid_t;
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#define MAPSYM(SYM, FAIL) _j._ ## SYM = (func_t)lib_symbol(lib, "jack_" # SYM); \
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if (!_j._ ## SYM) err |= FAIL;
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#elif defined NDEBUG
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typedef void * __attribute__ ((__may_alias__)) pvoid_t;
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#define MAPSYM(SYM, FAIL) *(pvoid_t *)(&_j._ ## SYM) = lib_symbol(lib, "jack_" # SYM); \
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if (!_j._ ## SYM) err |= FAIL;
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#else
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typedef void * __attribute__ ((__may_alias__)) pvoid_t;
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#define MAPSYM(SYM, FAIL) *(pvoid_t *)(&_j._ ## SYM) = lib_symbol(lib, "jack_" # SYM); \
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if (!_j._ ## SYM) { \
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if (FAIL) { \
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fprintf(stderr, "*** WEAK-JACK: required symbol 'jack_%s' was not found\n", "" # SYM); \
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} \
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err |= FAIL; \
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}
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#endif
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typedef void (* func_t) (void);
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/* function pointers to the real jack API */
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static struct WeakJack {
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func_t _client_open; // special case due to varargs
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#define JCFUN(ERR, RTYPE, NAME, RVAL) func_t _ ## NAME ;
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#define JPFUN(ERR, RTYPE, NAME, DEF, ARGS, RVAL) func_t _ ## NAME ;
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#define JXFUN(ERR, RTYPE, NAME, DEF, ARGS, CODE) func_t _ ## NAME ;
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#define JVFUN(ERR, NAME, DEF, ARGS, CODE) func_t _ ## NAME ;
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#include "weak_libjack.def"
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#undef JCFUN
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#undef JPFUN
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#undef JXFUN
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#undef JVFUN
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} _j;
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static int _status = -1;
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__attribute__((constructor))
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static void init_weak_jack(void)
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{
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void* lib;
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int err = 0;
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#ifndef NDEBUG
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fprintf(stderr, "*** WEAK-JACK: initializing\n");
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#endif
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memset(&_j, 0, sizeof(_j));
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#ifdef __APPLE__
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lib = lib_open("libjack.dylib");
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if (!lib) {
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lib = lib_open("/usr/local/lib/libjack.dylib");
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}
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#elif (defined PLATFORM_WINDOWS)
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# if ( defined(__x86_64__) || defined(_M_X64) )
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lib = lib_open("libjack64.dll");
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# else
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lib = lib_open("libjack.dll");
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# endif
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#else
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lib = lib_open("libjack.so.0");
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#endif
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if (!lib) {
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#ifndef NDEBUG
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fprintf(stderr, "*** WEAK-JACK: libjack was not found\n");
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#endif
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_status = -2;
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return;
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}
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/* found library, now lookup functions */
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MAPSYM(client_open, 2)
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#define JCFUN(ERR, RTYPE, NAME, RVAL) MAPSYM(NAME, ERR)
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#define JPFUN(ERR, RTYPE, NAME, DEF, ARGS, RVAL) MAPSYM(NAME, ERR)
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#define JXFUN(ERR, RTYPE, NAME, DEF, ARGS, CODE) MAPSYM(NAME, ERR)
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#define JVFUN(ERR, NAME, DEF, ARGS, CODE) MAPSYM(NAME, ERR)
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#include "weak_libjack.def"
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#undef JCFUN
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#undef JPFUN
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#undef JXFUN
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#undef JVFUN
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/* if a required symbol is not found, disable JACK completly */
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if (err) {
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_j._client_open = NULL;
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}
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_status = err;
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#ifndef NDEBUG
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fprintf(stderr, "*** WEAK-JACK: %s. (%d)\n", err ? "jack is not available" : "OK", _status);
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#endif
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}
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int have_libjack (void) {
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if (_status == -1) {
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init_weak_jack();
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}
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return _status;
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}
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/*******************************************************************************
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* helper macros
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*/
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#if defined(__GNUC__) && (__GNUC__ > 2) && !defined(NDEBUG)
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#define likely(expr) (__builtin_expect (!!(expr), 1))
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#else
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#define likely(expr) (expr)
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#endif
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#ifndef NDEBUG
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# define WJACK_WARNING(NAME) \
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fprintf(stderr, "*** WEAK-JACK: function 'jack_%s' ignored\n", "" # NAME);
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#else
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# define WJACK_WARNING(NAME) ;
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#endif
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/******************************************************************************
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* JACK API wrapper functions.
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*
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* if a function pointer is set in the static struct WeakJack _j,
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* the function is called directly.
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* Otherwise a dummy NOOP implementation is provided.
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* The latter is mainly for compile-time warnings.
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*
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* If libjack is not found, jack_client_open() will fail.
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* In that case the application should not call any other libjack
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* functions. Hence a real implementation is not needed.
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* (jack ringbuffer may be an exception for some apps)
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*/
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/* dedicated support for jack_client_open(,..) variable arg function macro */
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func_t WJACK_get_client_open(void) {
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if (_status == -1) {
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init_weak_jack();
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}
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return _j._client_open;
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}
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/* callback to set status */
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jack_client_t * WJACK_no_client_open (const char *client_name, jack_options_t options, jack_status_t *status, ...) {
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WJACK_WARNING(client_open);
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if (status) { *status = JackFailure; }
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return NULL;
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}
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/*******************************************************************************
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* Macros to wrap jack API
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*/
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/* abstraction for jack_client functions
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* rtype jack_function_name (jack_client_t *client) { return rval; }
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*/
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#define JCFUN(ERR, RTYPE, NAME, RVAL) \
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RTYPE WJACK_ ## NAME (jack_client_t *client) { \
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if likely(_j._ ## NAME) { \
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return ((RTYPE (*)(jack_client_t *client)) _j._ ## NAME)(client); \
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} else { \
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WJACK_WARNING(NAME) \
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return RVAL; \
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} \
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}
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/* abstraction for NOOP functions with return value
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* rtype jack_function_name (ARGS) { return rval; }
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*/
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#define JPFUN(ERR, RTYPE, NAME, DEF, ARGS, RVAL) \
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RTYPE WJACK_ ## NAME DEF { \
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if likely(_j._ ## NAME) { \
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return ((RTYPE (*)DEF) _j._ ## NAME) ARGS; \
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} else { \
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WJACK_WARNING(NAME) \
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return RVAL; \
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} \
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}
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/* abstraction for functions that need custom code.
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* e.g. functions with return-value-pointer args,
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* use CODE to initialize value
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*
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* rtype jack_function_name (ARGS) { CODE }
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*/
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#define JXFUN(ERR, RTYPE, NAME, DEF, ARGS, CODE) \
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RTYPE WJACK_ ## NAME DEF { \
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if likely(_j._ ## NAME) { \
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return ((RTYPE (*)DEF) _j._ ## NAME) ARGS; \
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} else { \
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WJACK_WARNING(NAME) \
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CODE \
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} \
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}
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/* abstraction for void functions with return-value-pointer args
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* void jack_function_name (ARGS) { CODE }
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*/
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#define JVFUN(ERR, NAME, DEF, ARGS, CODE) \
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void WJACK_ ## NAME DEF { \
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if likely(_j._ ## NAME) { \
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((void (*)DEF) _j._ ## NAME) ARGS; \
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} else { \
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WJACK_WARNING(NAME) \
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CODE \
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} \
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}
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#include "weak_libjack.def"
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#undef JCFUN
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#undef JPFUN
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#undef JXFUN
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#undef JVFUN
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#endif // end USE_WEAK_JACK
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