292 lines
		
	
	
		
			7.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			292 lines
		
	
	
		
			7.3 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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| 
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| #include "weak_libjack.h"
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| 
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| #define NDEBUG
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| 
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| #ifndef USE_WEAK_JACK
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| 
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| int have_libjack (void) {
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| 	return 0;
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| }
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| 
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| #else
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| 
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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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| 
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| #ifdef _WIN32
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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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| 
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| static void* lib_open(const char* const so) {
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| #ifdef _WIN32
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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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| 
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| static void* lib_symbol(void* const lib, const char* const sym) {
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| #ifdef _WIN32
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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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| 
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| #if defined _MSC_VER  && ! defined __INTEL_COMPILER
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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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| 
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| typedef void (* func_t) (void);
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| 
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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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| 
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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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| 
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| #include "weak_libjack.def"
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| 
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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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| 
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| static int _status = -1;
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| #if !defined _MSC_VER || defined __INTEL_COMPILER
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| __attribute__((constructor))
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| #endif
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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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| 
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| 	memset(&_j, 0, sizeof(_j));
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| 
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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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| 	if (!lib) {
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| 		/* New Homebrew location */
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| 		lib = lib_open("/opt/homebrew/lib/libjack.dylib");
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| 		if (lib) {
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| 			fprintf(stderr, "*** WEAK-JACK: using Homebrew\n");
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| 		}
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| 	}
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| 	if (!lib) {
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| 		/* MacPorts location */
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| 		lib = lib_open("/opt/local/lib/libjack.dylib");
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| 		if (lib) {
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| 			fprintf(stderr, "*** WEAK-JACK: using MacPorts\n");
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| 		}
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| 	}
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| 
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| #elif (defined _WIN32)
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| # if defined(__x86_64__) || defined(_M_X64) || defined(__amd64__)
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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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| 
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| 	/* found library, now lookup functions */
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| 	MAPSYM(client_open, 2)
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| 
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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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| 
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| #include "weak_libjack.def"
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| 
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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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| 
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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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| 
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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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| /*******************************************************************************
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|  * helper macros
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|  */
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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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| 
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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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| /******************************************************************************
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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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| 
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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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| 
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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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| /*******************************************************************************
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|  * Macros to wrap jack API
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|  */
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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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| 
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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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| 
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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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| 
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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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| 
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| #include "weak_libjack.def"
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| 
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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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| 
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| #endif // end USE_WEAK_JACK
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