os.h

OGG文件格式音频数解压缩SDK.现在OGG文件格式在一些游戏开发中使用的比较多.

#ifndef _OS_H
#define _OS_H
/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
 *                                                                  *
 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
 * by the XIPHOPHORUS Company http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: #ifdef jail to whip a few platforms into the UNIX ideal.
 last mod: $Id: os.h,v 1.32 2002/07/11 06:40:49 xiphmont Exp $

 ********************************************************************/

#include <math.h>
#include <ogg/os_types.h>

#include "misc.h"

#ifndef _V_IFDEFJAIL_H_
#  define _V_IFDEFJAIL_H_

#  ifdef __GNUC__
#    define STIN static __inline__
#  elif _WIN32
#    define STIN static __inline
#else
#  define STIN static
#endif

#ifndef M_PI
#  define M_PI (3.1415926536f)
#endif

#ifdef _WIN32
#  include <malloc.h>
#  define rint(x)   (ogg_floor((x)+0.5f)) 
#  define NO_FLOAT_MATH_LIB
#  define FAST_HYPOT(a, b) ogg_sqrt((a)*(a) + (b)*(b))
#endif

#ifndef FAST_HYPOT
#  define FAST_HYPOT hypot
#endif

#endif

#ifdef HAVE_ALLOCA_H
#  include <alloca.h>
#endif

#ifdef USE_MEMORY_H
#  include <memory.h>
#endif

#ifndef min
#  define min(x,y)  ((x)>(y)?(y):(x))
#endif

#ifndef max
#  define max(x,y)  ((x)<(y)?(y):(x))
#endif

#if defined(__i386__) && defined(__GNUC__) && !defined(__BEOS__)
    #  define VORBIS_FPU_CONTROL
    /* both GCC and MSVC are kinda stupid about rounding/casting to int.
       Because of encapsulation constraints (GCC can't see inside the asm
       block and so we end up doing stupid things like a store/load that
       is collectively a noop), we do it this way */

    /* we must set up the fpu before this works!! */

    typedef ogg_int16_t vorbis_fpu_control;

    static inline void vorbis_fpu_setround(vorbis_fpu_control *fpu){
      ogg_int16_t ret;
      ogg_int16_t temp;
      __asm__ __volatile__("fnstcw %0\n\t"
	      "movw %0,%%dx\n\t"
	      "orw $62463,%%dx\n\t"
	      "movw %%dx,%1\n\t"
	      "fldcw %1\n\t":"=m"(ret):"m"(temp): "dx");
      *fpu=ret;
    }

    static inline void vorbis_fpu_restore(vorbis_fpu_control fpu){
      __asm__ __volatile__("fldcw %0":: "m"(fpu));
    }

    /* assumes the FPU is in round mode! */
    static inline int vorbis_ftoi(double f){  /* yes, double!  Otherwise,
                                                 we get extra fst/fld to
                                                 truncate precision */
      int i;
      __asm__("fistl %0": "=m"(i) : "t"(f));
      return(i);
    }

    #define ogg_cos cosf
    #define ogg_sin sinf
    #define ogg_sqrt sqrtf
    #define ogg_fabs fabsf
    #define ogg_ceil ceilf
    #define ogg_floor floorf
    #define ogg_exp expf
    #define ogg_log logf
    #define ogg_ldexp ldexpf
    #define ogg_frexp frexpf
    #define ogg_atan atanf
    #define ogg_pow powf
    #define ogg_rint(_x) (ogg_floor((_x)+0.5f)) /* rintf doesnt work.  causes horrible corruption.  bug in compiler i think */
#endif


#if defined(R5900)
    #  define VORBIS_FPU_CONTROL

    typedef int vorbis_fpu_control;

    static __inline int vorbis_ftoi(float val)
    {   
        register int result;                                       
	    register float tmp = 0;
        __asm__ volatile ( 
            "cvt.w.s %2,%1\n"   	
		    "mfc1    %0,%2\n"
            : "=r" (result)   
            : "f" (val),"f" (tmp)
		    );  
	    return result;
    }
    static __inline int vorbis_ftoipcm(float val)
    {   
        register int result;                                       
	    register float tmp = 0;
        __asm__ volatile ( 
        	"addi	 $4, $0, -32768\n"
        	"addi	 $5, $0,  32767\n"
            "cvt.w.s %2,%1\n"   	
		    "mfc1    %0,%2\n"
            "pmaxw   %0, %0, $4\n"
            "pminw   %0, %0, $5\n"
            : "=r" (result)   
            : "f" (val),"f" (tmp)
            : "$4", "$5"
		    );  
	    return result;
    }
    #  define vorbis_fpu_setround(vorbis_fpu_control) {}
    #  define vorbis_fpu_restore(vorbis_fpu_control) {}

    #define ogg_cos cosf
    #define ogg_sin sinf
    #define ogg_sqrt sqrtf
    #define ogg_fabs fabsf
    #define ogg_ceil ceilf
    #define ogg_floor floorf
    #define ogg_exp expf
    #define ogg_log logf
    #define ogg_ldexp ldexpf
    #define ogg_frexp frexpf
    #define ogg_atan atanf
    #define ogg_pow powf
    #define ogg_rint(_x) (ogg_floor((_x)+0.5f)) /* rintf doesnt work.  causes horrible corruption.  bug in compiler i think */
#endif

#if defined(_WIN32) && !defined(__GNUC__) && !defined(__BORLANDC__) && !defined(AMD64)
    #define VORBIS_FPU_CONTROL

    typedef ogg_int16_t vorbis_fpu_control;

    static __inline int vorbis_ftoi(double f){
	    int i;
	    __asm{
		    fld f
		    fistp i
	    }
	    return i;
    }
    static __inline void vorbis_fpu_setround(vorbis_fpu_control *fpu){
    }
    static __inline void vorbis_fpu_restore(vorbis_fpu_control fpu){
    }
    #define ogg_cos (float)cos
    #define ogg_sin (float)sin
    #define ogg_sqrt (float)sqrt
    #define ogg_fabs (float)fabs
    #define ogg_ceil (float)ceil
    #define ogg_floor (float)floor
    #define ogg_exp (float)exp
    #define ogg_log (float)log
    #define ogg_ldexp (float)ldexp
    #define ogg_frexp (float)frexp
    #define ogg_atan (float)atan
    #define ogg_pow (float)pow
    #define ogg_rint (float)rint
#endif


#ifndef VORBIS_FPU_CONTROL

    typedef int vorbis_fpu_control;

    #define ogg_cos (float)cos
    #define ogg_sin (float)sin
    #define ogg_sqrt (float)sqrt
    #define ogg_fabs (float)fabs
    #define ogg_ceil (float)ceil
    #define ogg_floor (float)floor
    #define ogg_exp (float)exp
    #define ogg_log (float)log
    #define ogg_ldexp (float)ldexp
    #define ogg_frexp (float)frexp
    #define ogg_atan (float)atan
    #define ogg_pow (float)pow
    #define ogg_rint (float)rint

    static int vorbis_ftoi(float f)
    {
      return (int)(f+0.5f);
    }

    /* We don't have special code for this compiler/arch, so do it the slow way */
    #  define vorbis_fpu_setround(vorbis_fpu_control) {}
    #  define vorbis_fpu_restore(vorbis_fpu_control) {}
   
#endif

#include <string.h>
#define ogg_strlen strlen
#define ogg_strcpy strcpy
#define ogg_strcat strcat

#endif /* _OS_H */