path: root/Alc/helpers.c

/**
 * OpenAL cross platform audio library
 * Copyright (C) 2011 by authors.
 * This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the
 *  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 *  Boston, MA  02111-1307, USA.
 * Or go to http://www.gnu.org/copyleft/lgpl.html
 */

#ifdef _WIN32
#ifdef __MINGW32__
#define _WIN32_IE 0x501
#else
#define _WIN32_IE 0x400
#endif
#endif

#include "config.h"

#include <stdlib.h>
#include <time.h>
#include <errno.h>
#include <stdarg.h>
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif

#ifndef AL_NO_UID_DEFS
#if defined(HAVE_GUIDDEF_H) || defined(HAVE_INITGUID_H)
#define INITGUID
#include <windows.h>
#ifdef HAVE_GUIDDEF_H
#include <guiddef.h>
#else
#include <initguid.h>
#endif

DEFINE_GUID(KSDATAFORMAT_SUBTYPE_PCM,        0x00000001, 0x0000, 0x0010, 0x80,0x00, 0x00,0xaa,0x00,0x38,0x9b,0x71);
DEFINE_GUID(KSDATAFORMAT_SUBTYPE_IEEE_FLOAT, 0x00000003, 0x0000, 0x0010, 0x80,0x00, 0x00,0xaa,0x00,0x38,0x9b,0x71);

DEFINE_GUID(IID_IDirectSoundNotify,   0xb0210783, 0x89cd, 0x11d0, 0xaf,0x08, 0x00,0xa0,0xc9,0x25,0xcd,0x16);

DEFINE_GUID(CLSID_MMDeviceEnumerator, 0xbcde0395, 0xe52f, 0x467c, 0x8e,0x3d, 0xc4,0x57,0x92,0x91,0x69,0x2e);
DEFINE_GUID(IID_IMMDeviceEnumerator,  0xa95664d2, 0x9614, 0x4f35, 0xa7,0x46, 0xde,0x8d,0xb6,0x36,0x17,0xe6);
DEFINE_GUID(IID_IAudioClient,         0x1cb9ad4c, 0xdbfa, 0x4c32, 0xb1,0x78, 0xc2,0xf5,0x68,0xa7,0x03,0xb2);
DEFINE_GUID(IID_IAudioRenderClient,   0xf294acfc, 0x3146, 0x4483, 0xa7,0xbf, 0xad,0xdc,0xa7,0xc2,0x60,0xe2);

#ifdef HAVE_MMDEVAPI
#include <devpropdef.h>
DEFINE_DEVPROPKEY(DEVPKEY_Device_FriendlyName, 0xa45c254e, 0xdf1c, 0x4efd, 0x80,0x20, 0x67,0xd1,0x46,0xa8,0x50,0xe0, 14);
#endif
#endif
#endif /* AL_NO_UID_DEFS */

#ifdef HAVE_DLFCN_H
#include <dlfcn.h>
#endif
#ifdef HAVE_CPUID_H
#include <cpuid.h>
#endif
#ifdef HAVE_SYS_SYSCONF_H
#include <sys/sysconf.h>
#endif
#ifdef HAVE_FLOAT_H
#include <float.h>
#endif
#ifdef HAVE_IEEEFP_H
#include <ieeefp.h>
#endif

#ifdef _WIN32_IE
#include <shlobj.h>
#endif

#include "alMain.h"
#include "atomic.h"
#include "uintmap.h"
#include "vector.h"
#include "alstring.h"
#include "compat.h"


extern inline RefCount IncrementRef(volatile RefCount *ptr);
extern inline RefCount DecrementRef(volatile RefCount *ptr);
extern inline int ExchangeInt(volatile int *ptr, int newval);
extern inline void *ExchangePtr(XchgPtr *ptr, void *newval);
extern inline int CompExchangeInt(volatile int *ptr, int oldval, int newval);
extern inline void *CompExchangePtr(XchgPtr *ptr, void *oldval, void *newval);

extern inline void LockUIntMapRead(UIntMap *map);
extern inline void UnlockUIntMapRead(UIntMap *map);
extern inline void LockUIntMapWrite(UIntMap *map);
extern inline void UnlockUIntMapWrite(UIntMap *map);

extern inline ALuint NextPowerOf2(ALuint value);
extern inline ALint fastf2i(ALfloat f);
extern inline ALuint fastf2u(ALfloat f);


ALuint CPUCapFlags = 0;


void FillCPUCaps(ALuint capfilter)
{
    ALuint caps = 0;

/* FIXME: We really should get this for all available CPUs in case different
 * CPUs have different caps (is that possible on one machine?). */
#if defined(HAVE_CPUID_H) && (defined(__i386__) || defined(__x86_64__) || \
                              defined(_M_IX86) || defined(_M_X64))
    union {
        unsigned int regs[4];
        char str[sizeof(unsigned int[4])];
    } cpuinf[3];

    if(!__get_cpuid(0, &cpuinf[0].regs[0], &cpuinf[0].regs[1], &cpuinf[0].regs[2], &cpuinf[0].regs[3]))
        ERR("Failed to get CPUID\n");
    else
    {
        unsigned int maxfunc = cpuinf[0].regs[0];
        unsigned int maxextfunc = 0;

        if(__get_cpuid(0x80000000, &cpuinf[0].regs[0], &cpuinf[0].regs[1], &cpuinf[0].regs[2], &cpuinf[0].regs[3]))
            maxextfunc = cpuinf[0].regs[0];
        TRACE("Detected max CPUID function: 0x%x (ext. 0x%x)\n", maxfunc, maxextfunc);

        TRACE("Vendor ID: \"%.4s%.4s%.4s\"\n", cpuinf[0].str+4, cpuinf[0].str+12, cpuinf[0].str+8);
        if(maxextfunc >= 0x80000004 &&
           __get_cpuid(0x80000002, &cpuinf[0].regs[0], &cpuinf[0].regs[1], &cpuinf[0].regs[2], &cpuinf[0].regs[3]) &&
           __get_cpuid(0x80000003, &cpuinf[1].regs[0], &cpuinf[1].regs[1], &cpuinf[1].regs[2], &cpuinf[1].regs[3]) &&
           __get_cpuid(0x80000004, &cpuinf[2].regs[0], &cpuinf[2].regs[1], &cpuinf[2].regs[2], &cpuinf[2].regs[3]))
            TRACE("Name: \"%.16s%.16s%.16s\"\n", cpuinf[0].str, cpuinf[1].str, cpuinf[2].str);

        if(maxfunc >= 1 &&
           __get_cpuid(1, &cpuinf[0].regs[0], &cpuinf[0].regs[1], &cpuinf[0].regs[2], &cpuinf[0].regs[3]))
        {
            if((cpuinf[0].regs[3]&(1<<25)))
            {
                caps |= CPU_CAP_SSE;
                if((cpuinf[0].regs[3]&(1<<26)))
                    caps |= CPU_CAP_SSE2;
            }
        }
    }
#elif defined(HAVE_WINDOWS_H)
    HMODULE k32 = GetModuleHandleA("kernel32.dll");
    BOOL (WINAPI*IsProcessorFeaturePresent)(DWORD ProcessorFeature);
    IsProcessorFeaturePresent = (BOOL(WINAPI*)(DWORD))GetProcAddress(k32, "IsProcessorFeaturePresent");
    if(!IsProcessorFeaturePresent)
        ERR("IsProcessorFeaturePresent not available; CPU caps not detected\n");
    else
    {
        if(IsProcessorFeaturePresent(PF_XMMI_INSTRUCTIONS_AVAILABLE))
        {
            caps |= CPU_CAP_SSE;
            if(IsProcessorFeaturePresent(PF_XMMI64_INSTRUCTIONS_AVAILABLE))
                caps |= CPU_CAP_SSE2;
        }
    }
#endif
#ifdef HAVE_NEON
    /* Assume Neon support if compiled with it */
    caps |= CPU_CAP_NEON;
#endif

    TRACE("Got caps:%s%s%s%s\n", ((caps&CPU_CAP_SSE)?((capfilter&CPU_CAP_SSE)?" SSE":" (SSE)"):""),
                                 ((caps&CPU_CAP_SSE2)?((capfilter&CPU_CAP_SSE2)?" SSE2":" (SSE2)"):""),
                                 ((caps&CPU_CAP_NEON)?((capfilter&CPU_CAP_NEON)?" Neon":" (Neon)"):""),
                                 ((!caps)?" -none-":""));
    CPUCapFlags = caps & capfilter;
}


void *al_malloc(size_t alignment, size_t size)
{
#if defined(HAVE_ALIGNED_ALLOC)
    size = (size+(alignment-1))&~(alignment-1);
    return aligned_alloc(alignment, size);
#elif defined(HAVE_POSIX_MEMALIGN)
    void *ret;
    if(posix_memalign(&ret, alignment, size) == 0)
        return ret;
    return NULL;
#elif defined(HAVE__ALIGNED_MALLOC)
    return _aligned_malloc(size, alignment);
#else
    char *ret = malloc(size+alignment);
    if(ret != NULL)
    {
        *(ret++) = 0x00;
        while(((ALintptrEXT)ret&(alignment-1)) != 0)
            *(ret++) = 0x55;
    }
    return ret;
#endif
}

void *al_calloc(size_t alignment, size_t size)
{
    void *ret = al_malloc(alignment, size);
    if(ret) memset(ret, 0, size);
    return ret;
}

void al_free(void *ptr)
{
#if defined(HAVE_ALIGNED_ALLOC) || defined(HAVE_POSIX_MEMALIGN)
    free(ptr);
#elif defined(HAVE__ALIGNED_MALLOC)
    _aligned_free(ptr);
#else
    if(ptr != NULL)
    {
        char *finder = ptr;
        do {
            --finder;
        } while(*finder == 0x55);
        free(finder);
    }
#endif
}


#if (defined(HAVE___CONTROL87_2) || defined(HAVE__CONTROLFP)) && (defined(__x86_64__) || defined(_M_X64))
/* Win64 doesn't allow us to set the precision control. */
#undef _MCW_PC
#define _MCW_PC 0
#endif

void SetMixerFPUMode(FPUCtl *ctl)
{
#ifdef HAVE_FENV_H
    fegetenv(STATIC_CAST(fenv_t, ctl));
#if defined(__GNUC__) && defined(HAVE_SSE)
    if((CPUCapFlags&CPU_CAP_SSE))
        __asm__ __volatile__("stmxcsr %0" : "=m" (*&ctl->sse_state));
#endif

#ifdef FE_TOWARDZERO
    fesetround(FE_TOWARDZERO);
#endif
#if defined(__GNUC__) && defined(HAVE_SSE)
    if((CPUCapFlags&CPU_CAP_SSE))
    {
        int sseState = ctl->sse_state;
        sseState |= 0x6000; /* set round-to-zero */
        sseState |= 0x8000; /* set flush-to-zero */
        if((CPUCapFlags&CPU_CAP_SSE2))
            sseState |= 0x0040; /* set denormals-are-zero */
        __asm__ __volatile__("ldmxcsr %0" : : "m" (*&sseState));
    }
#endif

#elif defined(HAVE___CONTROL87_2)

    int mode;
    __control87_2(0, 0, &ctl->state, NULL);
    __control87_2(_RC_CHOP|_PC_24, _MCW_RC|_MCW_PC, &mode, NULL);
#ifdef HAVE_SSE
    if((CPUCapFlags&CPU_CAP_SSE))
    {
        __control87_2(0, 0, NULL, &ctl->sse_state);
        __control87_2(_RC_CHOP|_DN_FLUSH, _MCW_RC|_MCW_DN, NULL, &mode);
    }
#endif

#elif defined(HAVE__CONTROLFP)

    ctl->state = _controlfp(0, 0);
    (void)_controlfp(_RC_CHOP|_PC_24, _MCW_RC|_MCW_PC);
#endif
}

void RestoreFPUMode(const FPUCtl *ctl)
{
#ifdef HAVE_FENV_H
    fesetenv(STATIC_CAST(fenv_t, ctl));
#if defined(__GNUC__) && defined(HAVE_SSE)
    if((CPUCapFlags&CPU_CAP_SSE))
        __asm__ __volatile__("ldmxcsr %0" : : "m" (*&ctl->sse_state));
#endif

#elif defined(HAVE___CONTROL87_2)

    int mode;
    __control87_2(ctl->state, _MCW_RC|_MCW_PC, &mode, NULL);
#ifdef HAVE_SSE
    if((CPUCapFlags&CPU_CAP_SSE))
        __control87_2(ctl->sse_state, _MCW_RC|_MCW_DN, NULL, &mode);
#endif

#elif defined(HAVE__CONTROLFP)

    _controlfp(ctl->state, _MCW_RC|_MCW_PC);
#endif
}


#ifdef _WIN32
extern inline int alsched_yield(void);

void althread_once(althread_once_t *once, void (*callback)(void))
{
    LONG ret;
    while((ret=InterlockedExchange(once, 1)) == 1)
        alsched_yield();
    if(ret == 0)
        callback();
    InterlockedExchange(once, 2);
}


int althread_key_create(althread_key_t *key, void (*callback)(void*))
{
    *key = TlsAlloc();
    if(callback)
        InsertUIntMapEntry(&TlsDestructor, *key, callback);
    return 0;
}

int althread_key_delete(althread_key_t key)
{
    InsertUIntMapEntry(&TlsDestructor, key, NULL);
    TlsFree(key);
    return 0;
}

void *althread_getspecific(althread_key_t key)
{ return TlsGetValue(key); }

int althread_setspecific(althread_key_t key, void *val)
{
    TlsSetValue(key, val);
    return 0;
}


void *LoadLib(const char *name)
{ return LoadLibraryA(name); }
void CloseLib(void *handle)
{ FreeLibrary((HANDLE)handle); }
void *GetSymbol(void *handle, const char *name)
{
    void *ret;

    ret = (void*)GetProcAddress((HANDLE)handle, name);
    if(ret == NULL)
        ERR("Failed to load %s\n", name);
    return ret;
}

WCHAR *strdupW(const WCHAR *str)
{
    const WCHAR *n;
    WCHAR *ret;
    size_t len;

    n = str;
    while(*n) n++;
    len = n - str;

    ret = calloc(sizeof(WCHAR), len+1);
    if(ret != NULL)
        memcpy(ret, str, sizeof(WCHAR)*len);
    return ret;
}

static WCHAR *FromUTF8(const char *str)
{
    WCHAR *out = NULL;
    int len;

    if((len=MultiByteToWideChar(CP_UTF8, 0, str, -1, NULL, 0)) > 0)
    {
        out = calloc(sizeof(WCHAR), len);
        MultiByteToWideChar(CP_UTF8, 0, str, -1, out, len);
    }
    return out;
}

FILE *al_fopen(const char *fname, const char *mode)
{
    WCHAR *wname=NULL, *wmode=NULL;
    FILE *file = NULL;

    wname = FromUTF8(fname);
    wmode = FromUTF8(mode);
    if(!wname)
        ERR("Failed to convert UTF-8 filename: \"%s\"\n", fname);
    else if(!wmode)
        ERR("Failed to convert UTF-8 mode: \"%s\"\n", mode);
    else
        file = _wfopen(wname, wmode);

    free(wname);
    free(wmode);

    return file;
}

#else

#include <pthread.h>
#ifdef HAVE_PTHREAD_NP_H
#include <pthread_np.h>
#endif
#include <sched.h>
#include <time.h>
#include <sys/time.h>

void InitializeCriticalSection(CRITICAL_SECTION *cs)
{
    pthread_mutexattr_t attrib;
    int ret;

    ret = pthread_mutexattr_init(&attrib);
    assert(ret == 0);

    ret = pthread_mutexattr_settype(&attrib, PTHREAD_MUTEX_RECURSIVE);
#ifdef HAVE_PTHREAD_NP_H
    if(ret != 0)
        ret = pthread_mutexattr_setkind_np(&attrib, PTHREAD_MUTEX_RECURSIVE);
#endif
    assert(ret == 0);
    ret = pthread_mutex_init(cs, &attrib);
    assert(ret == 0);

    pthread_mutexattr_destroy(&attrib);
}
void DeleteCriticalSection(CRITICAL_SECTION *cs)
{
    int ret;
    ret = pthread_mutex_destroy(cs);
    assert(ret == 0);
}
void EnterCriticalSection(CRITICAL_SECTION *cs)
{
    int ret;
    ret = pthread_mutex_lock(cs);
    assert(ret == 0);
}
void LeaveCriticalSection(CRITICAL_SECTION *cs)
{
    int ret;
    ret = pthread_mutex_unlock(cs);
    assert(ret == 0);
}

/* NOTE: This wrapper isn't quite accurate as it returns an ALuint, as opposed
 * to the expected DWORD. Both are defined as unsigned 32-bit types, however.
 * Additionally, Win32 is supposed to measure the time since Windows started,
 * as opposed to the actual time. */
ALuint timeGetTime(void)
{
#if _POSIX_TIMERS > 0
    struct timespec ts;
    int ret = -1;

#if defined(_POSIX_MONOTONIC_CLOCK) && (_POSIX_MONOTONIC_CLOCK >= 0)
#if _POSIX_MONOTONIC_CLOCK == 0
    static int hasmono = 0;
    if(hasmono > 0 || (hasmono == 0 &&
                       (hasmono=sysconf(_SC_MONOTONIC_CLOCK)) > 0))
#endif
        ret = clock_gettime(CLOCK_MONOTONIC, &ts);
#endif
    if(ret != 0)
        ret = clock_gettime(CLOCK_REALTIME, &ts);
    assert(ret == 0);

    return ts.tv_nsec/1000000 + ts.tv_sec*1000;
#else
    struct timeval tv;
    int ret;

    ret = gettimeofday(&tv, NULL);
    assert(ret == 0);

    return tv.tv_usec/1000 + tv.tv_sec*1000;
#endif
}

void Sleep(ALuint t)
{
    struct timespec tv, rem;
    tv.tv_nsec = (t*1000000)%1000000000;
    tv.tv_sec = t/1000;

    while(nanosleep(&tv, &rem) == -1 && errno == EINTR)
        tv = rem;
}

#ifdef HAVE_DLFCN_H

void *LoadLib(const char *name)
{
    const char *err;
    void *handle;

    dlerror();
    handle = dlopen(name, RTLD_NOW);
    if((err=dlerror()) != NULL)
        handle = NULL;
    return handle;
}
void CloseLib(void *handle)
{ dlclose(handle); }
void *GetSymbol(void *handle, const char *name)
{
    const char *err;
    void *sym;

    dlerror();
    sym = dlsym(handle, name);
    if((err=dlerror()) != NULL)
    {
        WARN("Failed to load %s: %s\n", name, err);
        sym = NULL;
    }
    return sym;
}

#endif
#endif


void al_print(const char *type, const char *func, const char *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    fprintf(LogFile, "AL lib: %s %s: ", type, func);
    vfprintf(LogFile, fmt, ap);
    va_end(ap);

    fflush(LogFile);
}

#ifdef _WIN32
FILE *OpenDataFile(const char *fname, const char *subdir)
{
    static const int ids[2] = { CSIDL_APPDATA, CSIDL_COMMON_APPDATA };
    WCHAR *wname=NULL, *wsubdir=NULL;
    int i;

    /* If the path is absolute, open it directly. */
    if(fname[0] != '\0' && fname[1] == ':' && (fname[2] == '\\' || fname[2] == '/'))
    {
        FILE *f;
        if((f=al_fopen(fname, "rb")) != NULL)
        {
            TRACE("Opened %s\n", fname);
            return f;
        }
        WARN("Could not open %s\n", fname);
        return NULL;
    }

    wname = FromUTF8(fname);
    wsubdir = FromUTF8(subdir);
    if(!wname)
        ERR("Failed to convert UTF-8 filename: \"%s\"\n", fname);
    else if(!wsubdir)
        ERR("Failed to convert UTF-8 subdir: \"%s\"\n", subdir);
    else for(i = 0;i < 2;i++)
    {
        WCHAR buffer[PATH_MAX];
        size_t len;
        FILE *f;

        if(SHGetSpecialFolderPathW(NULL, buffer, ids[i], FALSE) == FALSE)
            continue;

        len = lstrlenW(buffer);
        if(len > 0 && (buffer[len-1] == '\\' || buffer[len-1] == '/'))
            buffer[--len] = '\0';
        _snwprintf(buffer+len, PATH_MAX-len, L"/%ls/%ls", wsubdir, wname);
        len = lstrlenW(buffer);
        while(len > 0)
        {
            --len;
            if(buffer[len] == '/')
                buffer[len] = '\\';
        }

        if((f=_wfopen(buffer, L"rb")) != NULL)
        {
            TRACE("Opened %ls\n", buffer);
            return f;
        }
        WARN("Could not open %ls\n", buffer);
    }
    free(wname);
    free(wsubdir);

    return NULL;
}
#else
FILE *OpenDataFile(const char *fname, const char *subdir)
{
    char buffer[PATH_MAX] = "";
    const char *str, *next;
    FILE *f;

    if(fname[0] == '/')
    {
        if((f=al_fopen(fname, "rb")) != NULL)
        {
            TRACE("Opened %s\n", fname);
            return f;
        }
        WARN("Could not open %s\n", fname);
        return NULL;
    }

    if((str=getenv("XDG_DATA_HOME")) != NULL && str[0] != '\0')
        snprintf(buffer, sizeof(buffer), "%s/%s/%s", str, subdir, fname);
    else if((str=getenv("HOME")) != NULL && str[0] != '\0')
        snprintf(buffer, sizeof(buffer), "%s/.local/share/%s/%s", str, subdir, fname);
    if(buffer[0])
    {
        if((f=al_fopen(buffer, "rb")) != NULL)
        {
            TRACE("Opened %s\n", buffer);
            return f;
        }
        WARN("Could not open %s\n", buffer);
    }

    if((str=getenv("XDG_DATA_DIRS")) == NULL || str[0] == '\0')
        str = " /usr/local/share/:/usr/share/";

    next = str;
    while((str=next) != NULL && str[0] != '\0')
    {
        size_t len;
        next = strchr(str, ':');

        if(!next)
            len = strlen(str);
        else
        {
            len = next - str;
            next++;
        }

        if(len > sizeof(buffer)-1)
            len = sizeof(buffer)-1;
        strncpy(buffer, str, len);
        buffer[len] = '\0';
        snprintf(buffer+len, sizeof(buffer)-len, "/%s/%s", subdir, fname);

        if((f=al_fopen(buffer, "rb")) != NULL)
        {
            TRACE("Opened %s\n", buffer);
            return f;
        }
        WARN("Could not open %s\n", buffer);
    }

    return NULL;
}
#endif


void SetRTPriority(void)
{
    ALboolean failed = AL_FALSE;

#ifdef _WIN32
    if(RTPrioLevel > 0)
        failed = !SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);
#elif defined(HAVE_PTHREAD_SETSCHEDPARAM) && !defined(__OpenBSD__)
    if(RTPrioLevel > 0)
    {
        struct sched_param param;
        /* Use the minimum real-time priority possible for now (on Linux this
         * should be 1 for SCHED_RR) */
        param.sched_priority = sched_get_priority_min(SCHED_RR);
        failed = !!pthread_setschedparam(pthread_self(), SCHED_RR, &param);
    }
#else
    /* Real-time priority not available */
    failed = (RTPrioLevel>0);
#endif
    if(failed)
        ERR("Failed to set priority level for thread\n");
}


static void Lock(volatile ALenum *l)
{
    while(ExchangeInt(l, AL_TRUE) == AL_TRUE)
        alsched_yield();
}

static void Unlock(volatile ALenum *l)
{
    ExchangeInt(l, AL_FALSE);
}

void RWLockInit(RWLock *lock)
{
    lock->read_count = 0;
    lock->write_count = 0;
    lock->read_lock = AL_FALSE;
    lock->read_entry_lock = AL_FALSE;
    lock->write_lock = AL_FALSE;
}

void ReadLock(RWLock *lock)
{
    Lock(&lock->read_entry_lock);
    Lock(&lock->read_lock);
    if(IncrementRef(&lock->read_count) == 1)
        Lock(&lock->write_lock);
    Unlock(&lock->read_lock);
    Unlock(&lock->read_entry_lock);
}

void ReadUnlock(RWLock *lock)
{
    if(DecrementRef(&lock->read_count) == 0)
        Unlock(&lock->write_lock);
}

void WriteLock(RWLock *lock)
{
    if(IncrementRef(&lock->write_count) == 1)
        Lock(&lock->read_lock);
    Lock(&lock->write_lock);
}

void WriteUnlock(RWLock *lock)
{
    Unlock(&lock->write_lock);
    if(DecrementRef(&lock->write_count) == 0)
        Unlock(&lock->read_lock);
}


ALboolean vector_reserve(void *ptr, size_t orig_count, size_t base_size, size_t obj_count, size_t obj_size, ALboolean exact)
{
    if(orig_count < obj_count)
    {
        vector_ *vecptr = ptr;
        void *temp;

        /* Limit vector sizes to the greatest power-of-two value that an
         * ALsizei can hold. */
        if(obj_count > (INT_MAX>>1)+1)
            return AL_FALSE;

        /* Use the next power-of-2 size if we don't need to allocate the exact
         * amount. This is preferred when regularly increasing the vector since
         * it means fewer reallocations. Though it means it also wastes some
         * memory. */
        if(exact == AL_FALSE)
            obj_count = NextPowerOf2((ALuint)obj_count);

        /* Need to be explicit with the caller type's base size, because it
         * could have extra padding before the start of the array (that is,
         * sizeof(*vector_) may not equal base_size). */
        temp = realloc(*vecptr, base_size + obj_size*obj_count);
        if(temp == NULL) return AL_FALSE;

        *vecptr = temp;
        (*vecptr)->Capacity = (ALsizei)obj_count;
    }
    return AL_TRUE;
}

ALboolean vector_resize(void *ptr, size_t base_size, size_t obj_count, size_t obj_size)
{
    vector_ *vecptr = ptr;
    if(!vector_reserve(vecptr, (*vecptr)->Capacity, base_size, obj_count, obj_size, AL_TRUE))
        return AL_FALSE;
    (*vecptr)->Size = (ALsizei)obj_count;
    return AL_TRUE;
}


extern inline ALsizei al_string_length(const_al_string str);
extern inline ALsizei al_string_empty(const_al_string str);
extern inline const al_string_char_type *al_string_get_cstr(const_al_string str);
extern inline int al_string_cmp(const_al_string str1, const_al_string str2);
extern inline int al_string_cmp_cstr(const_al_string str1, const al_string_char_type *str2);

void al_string_clear(al_string *str)
{
    /* Reserve one more character than the total size of the string. This is to
     * ensure we have space to add a null terminator in the string data so it
     * can be used as a C-style string. */
    VECTOR_RESERVE(*str, 1);
    VECTOR_RESIZE(*str, 0);
    *VECTOR_ITER_END(*str) = 0;
}

void al_string_copy(al_string *str, const_al_string from)
{
    ALsizei len = VECTOR_SIZE(from);
    VECTOR_RESERVE(*str, len+1);
    VECTOR_RESIZE(*str, len);
    memcpy(&VECTOR_FRONT(*str), &VECTOR_FRONT(from),
           len*sizeof(al_string_char_type));
    *VECTOR_ITER_END(*str) = 0;
}

void al_string_copy_cstr(al_string *str, const al_string_char_type *from)
{
    size_t len = strlen(from);
    VECTOR_RESERVE(*str, len+1);
    VECTOR_RESIZE(*str, len);
    memcpy(&VECTOR_FRONT(*str), from, len*sizeof(al_string_char_type));
    *VECTOR_ITER_END(*str) = 0;
}

void al_string_append_char(al_string *str, const al_string_char_type c)
{
    VECTOR_RESERVE(*str, al_string_length(*str)+2);
    VECTOR_PUSH_BACK(*str, c);
    *VECTOR_ITER_END(*str) = 0;
}

void al_string_append_cstr(al_string *str, const al_string_char_type *from)
{
    size_t len = strlen(from);
    if(len != 0)
    {
        VECTOR_RESERVE(*str, al_string_length(*str)+len+1);
        VECTOR_RESIZE(*str, al_string_length(*str)+len);
        memcpy(VECTOR_ITER_END(*str)-len, from, len);
        *VECTOR_ITER_END(*str) = 0;
    }
}

void al_string_append_range(al_string *str, const al_string_char_type *from, const al_string_char_type *to)
{
    ptrdiff_t len = to - from;
    if(len != 0)
    {
        VECTOR_RESERVE(*str, al_string_length(*str)+len+1);
        VECTOR_RESIZE(*str, al_string_length(*str)+len);
        memcpy(VECTOR_ITER_END(*str)-len, from, len);
        *VECTOR_ITER_END(*str) = 0;
    }
}

#ifdef _WIN32
void al_string_copy_wcstr(al_string *str, const wchar_t *from)
{
    int len;
    if((len=WideCharToMultiByte(CP_UTF8, 0, from, -1, NULL, 0, NULL, NULL)) > 0)
    {
        VECTOR_RESERVE(*str, len);
        VECTOR_RESIZE(*str, len-1);
        WideCharToMultiByte(CP_UTF8, 0, from, -1, &VECTOR_FRONT(*str), len, NULL, NULL);
        *VECTOR_ITER_END(*str) = 0;
    }
}
#endif


void InitUIntMap(UIntMap *map, ALsizei limit)
{
    map->array = NULL;
    map->size = 0;
    map->maxsize = 0;
    map->limit = limit;
    RWLockInit(&map->lock);
}

void ResetUIntMap(UIntMap *map)
{
    WriteLock(&map->lock);
    free(map->array);
    map->array = NULL;
    map->size = 0;
    map->maxsize = 0;
    WriteUnlock(&map->lock);
}

ALenum InsertUIntMapEntry(UIntMap *map, ALuint key, ALvoid *value)
{
    ALsizei pos = 0;

    WriteLock(&map->lock);
    if(map->size > 0)
    {
        ALsizei low = 0;
        ALsizei high = map->size - 1;
        while(low < high)
        {
            ALsizei mid = low + (high-low)/2;
            if(map->array[mid].key < key)
                low = mid + 1;
            else
                high = mid;
        }
        if(map->array[low].key < key)
            low++;
        pos = low;
    }

    if(pos == map->size || map->array[pos].key != key)
    {
        if(map->size == map->limit)
        {
            WriteUnlock(&map->lock);
            return AL_OUT_OF_MEMORY;
        }

        if(map->size == map->maxsize)
        {
            ALvoid *temp = NULL;
            ALsizei newsize;

            newsize = (map->maxsize ? (map->maxsize<<1) : 4);
            if(newsize >= map->maxsize)
                temp = realloc(map->array, newsize*sizeof(map->array[0]));
            if(!temp)
            {
                WriteUnlock(&map->lock);
                return AL_OUT_OF_MEMORY;
            }
            map->array = temp;
            map->maxsize = newsize;
        }

        if(pos < map->size)
            memmove(&map->array[pos+1], &map->array[pos],
                    (map->size-pos)*sizeof(map->array[0]));
        map->size++;
    }
    map->array[pos].key = key;
    map->array[pos].value = value;
    WriteUnlock(&map->lock);

    return AL_NO_ERROR;
}

ALvoid *RemoveUIntMapKey(UIntMap *map, ALuint key)
{
    ALvoid *ptr = NULL;
    WriteLock(&map->lock);
    if(map->size > 0)
    {
        ALsizei low = 0;
        ALsizei high = map->size - 1;
        while(low < high)
        {
            ALsizei mid = low + (high-low)/2;
            if(map->array[mid].key < key)
                low = mid + 1;
            else
                high = mid;
        }
        if(map->array[low].key == key)
        {
            ptr = map->array[low].value;
            if(low < map->size-1)
                memmove(&map->array[low], &map->array[low+1],
                        (map->size-1-low)*sizeof(map->array[0]));
            map->size--;
        }
    }
    WriteUnlock(&map->lock);
    return ptr;
}

ALvoid *LookupUIntMapKey(UIntMap *map, ALuint key)
{
    ALvoid *ptr = NULL;
    ReadLock(&map->lock);
    if(map->size > 0)
    {
        ALsizei low = 0;
        ALsizei high = map->size - 1;
        while(low < high)
        {
            ALsizei mid = low + (high-low)/2;
            if(map->array[mid].key < key)
                low = mid + 1;
            else
                high = mid;
        }
        if(map->array[low].key == key)
            ptr = map->array[low].value;
    }
    ReadUnlock(&map->lock);
    return ptr;
}