/*
* C11 <threads.h> emulation library
*
* (C) Copyright yohhoy 2012.
* Distributed under the Boost Software License, Version 1.0.
*
* Permission is hereby granted, free of charge, to any person or organization
* obtaining a copy of the software and accompanying documentation covered by
* this license (the "Software") to use, reproduce, display, distribute,
* execute, and transmit the Software, and to prepare [[derivative work]]s of the
* Software, and to permit third-parties to whom the Software is furnished to
* do so, all subject to the following:
*
* The copyright notices in the Software and this entire statement, including
* the above license grant, this restriction and the following disclaimer,
* must be included in all copies of the Software, in whole or in part, and
* all derivative works of the Software, unless such copies or derivative
* works are solely in the form of machine-executable object code generated by
* a source language processor.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
* SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
* FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#ifndef assert
#include <assert.h>
#endif
#include <limits.h>
#include <errno.h>
#include <process.h> // MSVCRT
#include <stdlib.h>
/*
Configuration macro:
EMULATED_THREADS_USE_NATIVE_CALL_ONCE
Use native WindowsAPI one-time initialization function.
(requires WinVista or later)
Otherwise emulate by mtx_trylock() + *busy loop* for WinXP.
EMULATED_THREADS_USE_NATIVE_CV
Use native WindowsAPI condition variable object.
(requires WinVista or later)
Otherwise use emulated implementation for WinXP.
EMULATED_THREADS_TSS_DTOR_SLOTNUM
Max registerable TSS dtor number.
*/
// XXX: Retain XP compatability
#if 0
#if _WIN32_WINNT >= 0x0600
// Prefer native WindowsAPI on newer environment.
#if !defined(__MINGW32__)
#define EMULATED_THREADS_USE_NATIVE_CALL_ONCE
#endif
#define EMULATED_THREADS_USE_NATIVE_CV
#endif
#endif
#define EMULATED_THREADS_TSS_DTOR_SLOTNUM 64 // see TLS_MINIMUM_AVAILABLE
#include <windows.h>
// check configuration
#if defined(EMULATED_THREADS_USE_NATIVE_CALL_ONCE) && (_WIN32_WINNT < 0x0600)
#error EMULATED_THREADS_USE_NATIVE_CALL_ONCE requires _WIN32_WINNT>=0x0600
#endif
#if defined(EMULATED_THREADS_USE_NATIVE_CV) && (_WIN32_WINNT < 0x0600)
#error EMULATED_THREADS_USE_NATIVE_CV requires _WIN32_WINNT>=0x0600
#endif
/*---------------------------- macros ----------------------------*/
#ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
#define ONCE_FLAG_INIT INIT_ONCE_STATIC_INIT
#else
#define ONCE_FLAG_INIT {0}
#endif
#define TSS_DTOR_ITERATIONS 1
// FIXME: temporary non-standard hack to ease transition
#define _MTX_INITIALIZER_NP {(PCRITICAL_SECTION_DEBUG)-1, -1, 0, 0, 0, 0}
/*---------------------------- types ----------------------------*/
typedef struct cnd_t {
#ifdef EMULATED_THREADS_USE_NATIVE_CV
CONDITION_VARIABLE condvar;
#else
int blocked;
int gone;
int to_unblock;
HANDLE sem_queue;
HANDLE sem_gate;
CRITICAL_SECTION monitor;
#endif
} cnd_t;
typedef HANDLE thrd_t;
typedef DWORD tss_t;
typedef CRITICAL_SECTION mtx_t;
#ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
typedef INIT_ONCE once_flag;
#else
typedef struct once_flag_t {
volatile LONG status;
} once_flag;
#endif
static inline void * tss_get(tss_t key);
static inline void thrd_yield(void);
static inline int mtx_trylock(mtx_t *mtx);
static inline int mtx_lock(mtx_t *mtx);
static inline int mtx_unlock(mtx_t *mtx);
/*
Implementation limits:
- Conditionally emulation for "Initialization functions"
(see EMULATED_THREADS_USE_NATIVE_CALL_ONCE macro)
- Emulated `mtx_timelock()' with mtx_trylock() + *busy loop*
*/
static void impl_tss_dtor_invoke(void); // forward decl.
struct impl_thrd_param {
thrd_start_t func;
void *arg;
};
static unsigned __stdcall impl_thrd_routine(void *p)
{
struct impl_thrd_param pack;
int code;
memcpy(&pack, p, sizeof(struct impl_thrd_param));
free(p);
code = pack.func(pack.arg);
impl_tss_dtor_invoke();
return (unsigned)code;
}
static DWORD impl_xtime2msec(const xtime *xt)
{
return (DWORD)((xt->sec * 1000U) + (xt->nsec / 1000000L));
}
#ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
struct impl_call_once_param { void (*func)(void); };
static BOOL CALLBACK impl_call_once_callback(PINIT_ONCE InitOnce, PVOID Parameter, PVOID *Context)
{
struct impl_call_once_param *param = (struct impl_call_once_param*)Parameter;
(param->func)();
((void)InitOnce); ((void)Context); // suppress warning
return TRUE;
}
#endif // ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
#ifndef EMULATED_THREADS_USE_NATIVE_CV
/*
Note:
The implementation of condition variable is ported from Boost.Interprocess
See http://www.boost.org/boost/interprocess/sync/windows/condition.hpp
*/
static void impl_cond_do_signal(cnd_t *cond, int broadcast)
{
int nsignal = 0;
EnterCriticalSection(&cond->monitor);
if (cond->to_unblock != 0) {
if (cond->blocked == 0) {
LeaveCriticalSection(&cond->monitor);
return;
}
if (broadcast) {
cond->to_unblock += nsignal = cond->blocked;
cond->blocked = 0;
} else {
nsignal = 1;
cond->to_unblock++;
cond->blocked--;
}
} else if (cond->blocked > cond->gone) {
WaitForSingleObject(cond->sem_gate, INFINITE);
if (cond->gone != 0) {
cond->blocked -= cond->gone;
cond->gone = 0;
}
if (broadcast) {
nsignal = cond->to_unblock = cond->blocked;
cond->blocked = 0;
} else {
nsignal = cond->to_unblock = 1;
cond->blocked--;
}
}
LeaveCriticalSection(&cond->monitor);
if (0 < nsignal)
ReleaseSemaphore(cond->sem_queue, nsignal, NULL);
}
static int impl_cond_do_wait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
{
int nleft = 0;
int ngone = 0;
int timeout = 0;
DWORD w;
WaitForSingleObject(cond->sem_gate, INFINITE);
cond->blocked++;
ReleaseSemaphore(cond->sem_gate, 1, NULL);
mtx_unlock(mtx);
w = WaitForSingleObject(cond->sem_queue, xt ? impl_xtime2msec(xt) : INFINITE);
timeout = (w == WAIT_TIMEOUT);
EnterCriticalSection(&cond->monitor);
if ((nleft = cond->to_unblock) != 0) {
if (timeout) {
if (cond->blocked != 0) {
cond->blocked--;
} else {
cond->gone++;
}
}
if (--cond->to_unblock == 0) {
if (cond->blocked != 0) {
ReleaseSemaphore(cond->sem_gate, 1, NULL);
nleft = 0;
}
else if ((ngone = cond->gone) != 0) {
cond->gone = 0;
}
}
} else if (++cond->gone == INT_MAX/2) {
WaitForSingleObject(cond->sem_gate, INFINITE);
cond->blocked -= cond->gone;
ReleaseSemaphore(cond->sem_gate, 1, NULL);
cond->gone = 0;
}
LeaveCriticalSection(&cond->monitor);
if (nleft == 1) {
while (ngone--)
WaitForSingleObject(cond->sem_queue, INFINITE);
ReleaseSemaphore(cond->sem_gate, 1, NULL);
}
mtx_lock(mtx);
return timeout ? thrd_busy : thrd_success;
}
#endif // ifndef EMULATED_THREADS_USE_NATIVE_CV
static struct impl_tss_dtor_entry {
tss_t key;
tss_dtor_t dtor;
} impl_tss_dtor_tbl[EMULATED_THREADS_TSS_DTOR_SLOTNUM];
static int impl_tss_dtor_register(tss_t key, tss_dtor_t dtor)
{
int i;
for (i = 0; i < EMULATED_THREADS_TSS_DTOR_SLOTNUM; i++) {
if (!impl_tss_dtor_tbl[i].dtor)
break;
}
if (i == EMULATED_THREADS_TSS_DTOR_SLOTNUM)
return 1;
impl_tss_dtor_tbl[i].key = key;
impl_tss_dtor_tbl[i].dtor = dtor;
return 0;
}
static void impl_tss_dtor_invoke()
{
int i;
for (i = 0; i < EMULATED_THREADS_TSS_DTOR_SLOTNUM; i++) {
if (impl_tss_dtor_tbl[i].dtor) {
void* val = tss_get(impl_tss_dtor_tbl[i].key);
if (val)
(impl_tss_dtor_tbl[i].dtor)(val);
}
}
}
/*--------------- 7.25.2 Initialization functions ---------------*/
// 7.25.2.1
static inline void
call_once(once_flag *flag, void (*func)(void))
{
assert(flag && func);
#ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
{
struct impl_call_once_param param;
param.func = func;
InitOnceExecuteOnce(flag, impl_call_once_callback, (PVOID)¶m, NULL);
}
#else
if (InterlockedCompareExchange(&flag->status, 1, 0) == 0) {
(func)();
InterlockedExchange(&flag->status, 2);
} else {
while (flag->status == 1) {
// busy loop!
thrd_yield();
}
}
#endif
}
/*------------- 7.25.3 Condition variable functions -------------*/
// 7.25.3.1
static inline int
cnd_broadcast(cnd_t *cond)
{
if (!cond) return thrd_error;
#ifdef EMULATED_THREADS_USE_NATIVE_CV
WakeAllConditionVariable(&cond->condvar);
#else
impl_cond_do_signal(cond, 1);
#endif
return thrd_success;
}
// 7.25.3.2
static inline void
cnd_destroy(cnd_t *cond)
{
assert(cond);
#ifdef EMULATED_THREADS_USE_NATIVE_CV
// do nothing
#else
CloseHandle(cond->sem_queue);
CloseHandle(cond->sem_gate);
DeleteCriticalSection(&cond->monitor);
#endif
}
// 7.25.3.3
static inline int
cnd_init(cnd_t *cond)
{
if (!cond) return thrd_error;
#ifdef EMULATED_THREADS_USE_NATIVE_CV
InitializeConditionVariable(&cond->condvar);
#else
cond->blocked = 0;
cond->gone = 0;
cond->to_unblock = 0;
cond->sem_queue = CreateSemaphore(NULL, 0, LONG_MAX, NULL);
cond->sem_gate = CreateSemaphore(NULL, 1, 1, NULL);
InitializeCriticalSection(&cond->monitor);
#endif
return thrd_success;
}
// 7.25.3.4
static inline int
cnd_signal(cnd_t *cond)
{
if (!cond) return thrd_error;
#ifdef EMULATED_THREADS_USE_NATIVE_CV
WakeConditionVariable(&cond->condvar);
#else
impl_cond_do_signal(cond, 0);
#endif
return thrd_success;
}
// 7.25.3.5
static inline int
cnd_timedwait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
{
if (!cond || !mtx || !xt) return thrd_error;
#ifdef EMULATED_THREADS_USE_NATIVE_CV
if (SleepConditionVariableCS(&cond->condvar, mtx, impl_xtime2msec(xt)))
return thrd_success;
return (GetLastError() == ERROR_TIMEOUT) ? thrd_busy : thrd_error;
#else
return impl_cond_do_wait(cond, mtx, xt);
#endif
}
// 7.25.3.6
static inline int
cnd_wait(cnd_t *cond, mtx_t *mtx)
{
if (!cond || !mtx) return thrd_error;
#ifdef EMULATED_THREADS_USE_NATIVE_CV
SleepConditionVariableCS(&cond->condvar, mtx, INFINITE);
#else
impl_cond_do_wait(cond, mtx, NULL);
#endif
return thrd_success;
}
/*-------------------- 7.25.4 Mutex functions --------------------*/
// 7.25.4.1
static inline void
mtx_destroy(mtx_t *mtx)
{
assert(mtx);
DeleteCriticalSection(mtx);
}
// 7.25.4.2
static inline int
mtx_init(mtx_t *mtx, int type)
{
if (!mtx) return thrd_error;
if (type != mtx_plain && type != mtx_timed && type != mtx_try
&& type != (mtx_plain|mtx_recursive)
&& type != (mtx_timed|mtx_recursive)
&& type != (mtx_try|mtx_recursive))
return thrd_error;
InitializeCriticalSection(mtx);
return thrd_success;
}
// 7.25.4.3
static inline int
mtx_lock(mtx_t *mtx)
{
if (!mtx) return thrd_error;
EnterCriticalSection(mtx);
return thrd_success;
}
// 7.25.4.4
static inline int
mtx_timedlock(mtx_t *mtx, const xtime *xt)
{
time_t expire, now;
if (!mtx || !xt) return thrd_error;
expire = time(NULL);
expire += xt->sec;
while (mtx_trylock(mtx) != thrd_success) {
now = time(NULL);
if (expire < now)
return thrd_busy;
// busy loop!
thrd_yield();
}
return thrd_success;
}
// 7.25.4.5
static inline int
mtx_trylock(mtx_t *mtx)
{
if (!mtx) return thrd_error;
return TryEnterCriticalSection(mtx) ? thrd_success : thrd_busy;
}
// 7.25.4.6
static inline int
mtx_unlock(mtx_t *mtx)
{
if (!mtx) return thrd_error;
LeaveCriticalSection(mtx);
return thrd_success;
}
/*------------------- 7.25.5 Thread functions -------------------*/
// 7.25.5.1
static inline int
thrd_create(thrd_t *thr, thrd_start_t func, void *arg)
{
struct impl_thrd_param *pack;
uintptr_t handle;
if (!thr) return thrd_error;
pack = (struct impl_thrd_param *)malloc(sizeof(struct impl_thrd_param));
if (!pack) return thrd_nomem;
pack->func = func;
pack->arg = arg;
handle = _beginthreadex(NULL, 0, impl_thrd_routine, pack, 0, NULL);
if (handle == 0) {
if (errno == EAGAIN || errno == EACCES)
return thrd_nomem;
return thrd_error;
}
*thr = (thrd_t)handle;
return thrd_success;
}
#if 0
// 7.25.5.2
static inline thrd_t
thrd_current(void)
{
HANDLE hCurrentThread;
BOOL bRet;
/* GetCurrentThread() returns a pseudo-handle, which is useless. We need
* to call DuplicateHandle to get a real handle. However the handle value
* will not match the one returned by thread_create.
*
* Other potential solutions would be:
* - define thrd_t as a thread Ids, but this would mean we'd need to OpenThread for many operations
* - use malloc'ed memory for thrd_t. This would imply using TLS for current thread.
*
* Neither is particularly nice.
*
* Life would be much easier if C11 threads had different abstractions for
* threads and thread IDs, just like C++11 threads does...
*/
bRet = DuplicateHandle(GetCurrentProcess(), // source process (pseudo) handle
GetCurrentThread(), // source (pseudo) handle
GetCurrentProcess(), // target process
&hCurrentThread, // target handle
0,
FALSE,
DUPLICATE_SAME_ACCESS);
assert(bRet);
if (!bRet) {
hCurrentThread = GetCurrentThread();
}
return hCurrentThread;
}
#endif
// 7.25.5.3
static inline int
thrd_detach(thrd_t thr)
{
CloseHandle(thr);
return thrd_success;
}
// 7.25.5.4
static inline int
thrd_equal(thrd_t thr0, thrd_t thr1)
{
return GetThreadId(thr0) == GetThreadId(thr1);
}
// 7.25.5.5
static inline void
thrd_exit(int res)
{
impl_tss_dtor_invoke();
_endthreadex((unsigned)res);
}
// 7.25.5.6
static inline int
thrd_join(thrd_t thr, int *res)
{
DWORD w, code;
w = WaitForSingleObject(thr, INFINITE);
if (w != WAIT_OBJECT_0)
return thrd_error;
if (res) {
if (!GetExitCodeThread(thr, &code)) {
CloseHandle(thr);
return thrd_error;
}
*res = (int)code;
}
CloseHandle(thr);
return thrd_success;
}
// 7.25.5.7
static inline void
thrd_sleep(const xtime *xt)
{
assert(xt);
Sleep(impl_xtime2msec(xt));
}
// 7.25.5.8
static inline void
thrd_yield(void)
{
SwitchToThread();
}
/*----------- 7.25.6 Thread-specific storage functions -----------*/
// 7.25.6.1
static inline int
tss_create(tss_t *key, tss_dtor_t dtor)
{
if (!key) return thrd_error;
*key = TlsAlloc();
if (dtor) {
if (impl_tss_dtor_register(*key, dtor)) {
TlsFree(*key);
return thrd_error;
}
}
return (*key != 0xFFFFFFFF) ? thrd_success : thrd_error;
}
// 7.25.6.2
static inline void
tss_delete(tss_t key)
{
TlsFree(key);
}
// 7.25.6.3
static inline void *
tss_get(tss_t key)
{
return TlsGetValue(key);
}
// 7.25.6.4
static inline int
tss_set(tss_t key, void *val)
{
return TlsSetValue(key, val) ? thrd_success : thrd_error;
}
/*-------------------- 7.25.7 Time functions --------------------*/
// 7.25.6.1
static inline int
xtime_get(xtime *xt, int base)
{
if (!xt) return 0;
if (base == TIME_UTC) {
xt->sec = time(NULL);
xt->nsec = 0;
return base;
}
return 0;
}