libmkv/EbmlBufferWriter.c

//#include <strmif.h>
#include "EbmlBufferWriter.h"
#include "EbmlWriter.h"
//#include <cassert>
//#include <limits>
//#include <malloc.h>  //_alloca
#include <stdlib.h>
#include <wchar.h>
#include <string.h>

void Ebml_Write(EbmlGlobal *glob, const void *buffer_in, unsigned long len)
{
    unsigned char *src = glob->buf;
    src += glob->offset;
    memcpy(src, buffer_in, len);
    glob->offset += len;
}

static void _Serialize(EbmlGlobal *glob, const unsigned char *p, const unsigned char *q)
{
    while (q != p)
    {
        --q;

        unsigned long cbWritten;
        memcpy(&(glob->buf[glob->offset]), q, 1);
        glob->offset ++;
    }
}

void Ebml_Serialize(EbmlGlobal *glob, const void *buffer_in, unsigned long len)
{
    //assert(buf);

    const unsigned char *const p = (const unsigned char *)(buffer_in);
    const unsigned char *const q = p + len;

    _Serialize(glob, p, q);
}


void Ebml_StartSubElement(EbmlGlobal *glob, EbmlLoc *ebmlLoc, unsigned long class_id)
{
    Ebml_WriteID(glob, class_id);
    ebmlLoc->offset = glob->offset;
    //todo this is always taking 8 bytes, this may need later optimization
    unsigned long long unknownLen =  0x01FFFFFFFFFFFFFFLLU;
    Ebml_Serialize(glob, (void *)&unknownLen, 8); //this is a key that says lenght unknown
}

void Ebml_EndSubElement(EbmlGlobal *glob, EbmlLoc *ebmlLoc)
{
    unsigned long long size = glob->offset - ebmlLoc->offset - 8;
    unsigned long long curOffset = glob->offset;
    glob->offset = ebmlLoc->offset;
    size |=  0x0100000000000000LLU;
    Ebml_Serialize(glob, &size, 8);
    glob->offset = curOffset;
}