#pragma once


#if defined(__cplusplus)
extern "C"
#endif

#if defined(MP4ISTRUNC_IMPL)
#if defined(_WIN32) || defined(WIN32)

#else
#define _FILE_OFFSET_BITS=64
#endif
#endif

#include <stdio.h>

#define MP4TRUNC_OK 0
#define MP4TRUNC_TRUNC 1

int mp4trunc_istruncf(FILE* f);
int mp4trunc_istrunc(const char* path);


#if defined(MP4ISTRUNC_IMPL)
#include <string.h>

int mp4trunc_istruncf(FILE* f)
{
    #if defined(_WIN32) || defined(WIN32)

    #if defined(MP4TRUNC_LEGACYWIN32)
    fseek(f,0L,SEEK_END);
    long long len = (long long)ftell(f);
    rewind(f);
    #else
    _fseeki64(f,0L,SEEK_END);
    long long len = (long long)_ftelli64(f);
    rewind(f);
    #endif
    #else
    fseeko(f,0L,SEEK_END);
    long long len = (long long)ftello(f);
    rewind(f);
    #endif
    

    unsigned long long fileSizeToThisPoint = 0;

    int hadWide = 0;

    while(!feof(f))
    {
        unsigned char hdr[1024];
        

        if(fread(hdr,1,8,f) != 8) return MP4TRUNC_TRUNC;

        fileSizeToThisPoint += 8;

        unsigned long long atom_len = (unsigned int)hdr[0] << 24 |
            (unsigned int)hdr[1] << 16 |
            (unsigned int)hdr[2] << 8 |
            (unsigned int)hdr[3];
        
        
        
        if(atom_len == 0) return MP4TRUNC_OK;


        

        if(memcmp(hdr+4,"wide",4) == 0)
        {
            hadWide = 1;
            continue;
        }
        int isBig=0;

        if(hadWide && atom_len == 1) {
            hadWide=0;
            isBig=1;
            if(fread(hdr+8,1,8,f) != 8) return MP4TRUNC_TRUNC;
            fileSizeToThisPoint+=8;
            atom_len = (unsigned long)hdr[8] << 56 | 
            (unsigned long long)hdr[9] << 48 |
            (unsigned long long)hdr[10] << 40 |
            (unsigned long long)hdr[11] << 32 |
            (unsigned long long)hdr[12] << 24 |
            (unsigned long long)hdr[13] << 16 |
            (unsigned long long)hdr[14] << 8 |
            (unsigned long long)hdr[15];
        }
    
        if(memcmp(hdr+4,"mdat",4) == 0)
        {
            if((unsigned long long)len < (atom_len + fileSizeToThisPoint-(isBig?16:8))) return MP4TRUNC_TRUNC;
            return MP4TRUNC_OK;
        } else {
            size_t left = atom_len-(isBig?16:8);
            size_t read = 0;
            do {
                size_t toRead = sizeof(hdr);
                if(left < toRead) toRead = left;

                read = fread(hdr,1,toRead,f);

                left -= read;
                fileSizeToThisPoint += read;

                if(feof(f) && left != 0) return MP4TRUNC_TRUNC;
                
            } while(read != 0);


        }
    }


    return MP4TRUNC_OK;
}
int mp4trunc_istrunc(const char* path)
{
    FILE* f = fopen(path,"rb");
    int res = mp4trunc_istruncf(f);
    fclose(f);
    return res;
}
#endif

#if defined(__cplusplus)
}
#endif