Handle case of get_bits(0)

[libav.git] / libavutil / internal.h

/*
 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file internal.h
 * common internal api header.
 */

#ifndef INTERNAL_H
#define INTERNAL_H

#if ( defined(__PIC__) || defined(__pic__) ) && ! defined(PIC)
#    define PIC
#endif

#    ifndef ENODATA
#        define ENODATA  61
#    endif

#include "bswap.h"

#include <stddef.h>
#ifndef offsetof
# define offsetof(T,F) ((unsigned int)((char *)&((T *)0)->F))
#endif

#ifdef __MINGW32__
#    ifdef _DEBUG
#        define DEBUG
#    endif

#    define snprintf _snprintf
#    define vsnprintf _vsnprintf

#    ifdef CONFIG_WINCE
#        define perror(a)
#    endif

/* __MINGW32__ end */
#elif defined (CONFIG_OS2)
/* OS/2 EMX */

#include <float.h>

#endif /* !__MINGW32__ && CONFIG_OS2 */

#    ifdef USE_FASTMEMCPY
#        include "libvo/fastmemcpy.h"
#    endif

// Use rip-relative addressing if compiling PIC code on x86-64.
#    if defined(__MINGW32__) || defined(__CYGWIN__) || \
        defined(__OS2__) || (defined (__OpenBSD__) && !defined(__ELF__))
#        if defined(ARCH_X86_64) && defined(PIC)
#            define MANGLE(a) "_" #a"(%%rip)"
#        else
#            define MANGLE(a) "_" #a
#        endif
#    else
#        if defined(ARCH_X86_64) && defined(PIC)
#            define MANGLE(a) #a"(%%rip)"
#        elif defined(CONFIG_DARWIN)
#            define MANGLE(a) "_" #a
#        else
#            define MANGLE(a) #a
#        endif
#    endif

/* debug stuff */

#    if !defined(DEBUG) && !defined(NDEBUG)
#        define NDEBUG
#    endif
#    include <assert.h>

/* dprintf macros */
#    ifdef DEBUG
#        define dprintf(fmt,...) av_log(NULL, AV_LOG_DEBUG, fmt, __VA_ARGS__)
#    else
#        define dprintf(fmt,...)
#    endif

#    ifdef CONFIG_WINCE
#            define abort()
#    endif

#    define av_abort()      do { av_log(NULL, AV_LOG_ERROR, "Abort at %s:%d\n", __FILE__, __LINE__); abort(); } while (0)

extern const uint32_t inverse[256];

#if defined(ARCH_X86) || defined(ARCH_X86_64)
#    define FASTDIV(a,b) \
    ({\
        int ret,dmy;\
        asm volatile(\
            "mull %3"\
            :"=d"(ret),"=a"(dmy)\
            :"1"(a),"g"(inverse[b])\
            );\
        ret;\
    })
#elif defined(CONFIG_FASTDIV)
#    define FASTDIV(a,b)   ((uint32_t)((((uint64_t)a)*inverse[b])>>32))
#else
#    define FASTDIV(a,b)   ((a)/(b))
#endif

/* math */
extern FF_IMPORT_ATTR const uint8_t ff_sqrt_tab[128];

static inline int ff_sqrt(int a)
{
    int ret=0;
    int s;
    int ret_sq=0;

    if(a<128) return ff_sqrt_tab[a];

    for(s=15; s>=0; s--){
        int b= ret_sq + (1<<(s*2)) + (ret<<s)*2;
        if(b<=a){
            ret_sq=b;
            ret+= 1<<s;
        }
    }
    return ret;
}

#if defined(ARCH_X86) || defined(ARCH_X86_64)
#define MASK_ABS(mask, level)\
            asm volatile(\
                "cdq                    \n\t"\
                "xorl %1, %0            \n\t"\
                "subl %1, %0            \n\t"\
                : "+a" (level), "=&d" (mask)\
            );
#else
#define MASK_ABS(mask, level)\
            mask= level>>31;\
            level= (level^mask)-mask;
#endif

#if __CPU__ >= 686 && !defined(RUNTIME_CPUDETECT)
#define COPY3_IF_LT(x,y,a,b,c,d)\
asm volatile (\
    "cmpl %0, %3        \n\t"\
    "cmovl %3, %0       \n\t"\
    "cmovl %4, %1       \n\t"\
    "cmovl %5, %2       \n\t"\
    : "+r" (x), "+r" (a), "+r" (c)\
    : "r" (y), "r" (b), "r" (d)\
);
#else
#define COPY3_IF_LT(x,y,a,b,c,d)\
if((y)<(x)){\
     (x)=(y);\
     (a)=(b);\
     (c)=(d);\
}
#endif

/* avoid usage of various functions */
#define malloc please_use_av_malloc
#define free please_use_av_free
#define realloc please_use_av_realloc
#define time time_is_forbidden_due_to_security_issues
#define rand rand_is_forbidden_due_to_state_trashing
#define srand srand_is_forbidden_due_to_state_trashing
#define sprintf sprintf_is_forbidden_due_to_security_issues_use_snprintf
#define strcat strcat_is_forbidden_due_to_security_issues_use_pstrcat
#if !(defined(LIBAVFORMAT_BUILD) || defined(_FRAMEHOOK_H))
#define printf please_use_av_log
#define fprintf please_use_av_log
#endif

#define CHECKED_ALLOCZ(p, size)\
{\
    p= av_mallocz(size);\
    if(p==NULL && (size)!=0){\
        perror("malloc");\
        goto fail;\
    }\
}

#ifndef HAVE_LRINTF
/* XXX: add ISOC specific test to avoid specific BSD testing. */
/* better than nothing implementation. */
/* btw, rintf() is existing on fbsd too -- alex */
static always_inline long int lrintf(float x)
{
#ifdef __MINGW32__
#  ifdef ARCH_X86
    int32_t i;
    asm volatile(
        "fistpl %0\n\t"
        : "=m" (i) : "t" (x) : "st"
    );
    return i;
#  else
    /* XXX: incorrect, but make it compile */
    return (int)(x + (x < 0 ? -0.5 : 0.5));
#  endif /* ARCH_X86 */
#else
    return (int)(rint(x));
#endif /* __MINGW32__ */
}
#endif /* HAVE_LRINTF */

#endif /* INTERNAL_H */