#pragma once

#include "Types.h"
#include "JpgEvent.h"
#include "Utils.h"

//-------------------------------------------------------------------------------------------------------------------------------
// Bit input-output stream (BitIO)
//-------------------------------------------------------------------------------------------------------------------------------

//-------------------------------------------------------------------------------------------------------------------------------
// Вспомогательные функции
//-------------------------------------------------------------------------------------------------------------------------------
static int  BitIO_ByteOut(BitIO *pBIO) 
{
	pBIO->nBuffer = (pBIO->nBuffer << 8) & 0xffff;
	pBIO->nValidBitsCount = pBIO->nBuffer == 0xff00 ? 7 : 8;

	if ( pBIO->pCurPos >= pBIO->pEnd ) 
	{
		return 1;
	}
	*pBIO->pCurPos++ = pBIO->nBuffer >> 8;
	return 0;
}

static int  BitIO_ByteIn (BitIO *pBIO) 
{
	pBIO->nBuffer = (pBIO->nBuffer << 8) & 0xffff;
	pBIO->nValidBitsCount = pBIO->nBuffer == 0xff00 ? 7 : 8;

	if ( pBIO->pCurPos >= pBIO->pEnd ) 
	{
		return 1;
	}
	pBIO->nBuffer |= *pBIO->pCurPos++;
	return 0;
}

static void BitIO_PutBit (BitIO *pBIO, int nBit) 
{
	if ( 0 == pBIO->nValidBitsCount ) 
	{
		BitIO_ByteOut( pBIO );
	}
	pBIO->nValidBitsCount--;
	pBIO->nBuffer |= nBit << pBIO->nValidBitsCount;
}

static int  BitIO_GetBit (BitIO *pBIO) 
{
	if ( 0 == pBIO->nValidBitsCount ) 
	{
		BitIO_ByteIn( pBIO );
	}
	pBIO->nValidBitsCount--;
	return ( pBIO->nBuffer >> pBIO->nValidBitsCount ) & 1;
}


//-------------------------------------------------------------------------------------------------------------------------------
// Основные функции
//-------------------------------------------------------------------------------------------------------------------------------
BitIO* BitIO_Create()
{
	BitIO *pBIO = (BitIO*)Malloc(HEAP_ZERO_MEMORY,  sizeof(BitIO) );
	return pBIO;
}

void   BitIO_Destroy(BitIO *pBIO)
{
	RELEASEHEAP(pBIO);
}

int    BitIO_WrittenBytesCount(BitIO *pBIO) 
{
	return (pBIO->pCurPos - pBIO->pStart);
}

void   BitIO_InitEncoder(BitIO *pBIO, unsigned char *pBuffer, int nLen)
{
	pBIO->pStart  = pBuffer;
	pBIO->pEnd    = pBuffer + nLen;
	pBIO->pCurPos = pBuffer;
	pBIO->nBuffer = 0;
	pBIO->nValidBitsCount = 8;
}
void   BitIO_InitDecoder(BitIO *pBIO, unsigned char *pBuffer, int nLen)
{
	pBIO->pStart  = pBuffer;
	pBIO->pEnd    = pBuffer + nLen;
	pBIO->pCurPos = pBuffer;
	pBIO->nBuffer = 0;
	pBIO->nValidBitsCount = 0;
}

void   BitIO_Write(BitIO *pBIO, int nValue, int nLen) 
{
	for ( int nIndex = nLen - 1; nIndex >= 0; nIndex-- ) 
	{
		BitIO_PutBit( pBIO, (nValue >> nIndex) & 1 );
	}
}

int    BitIO_Read(BitIO *pBIO, int nLen) 
{
	int nResult = 0;
	for ( int nIndex = nLen - 1; nIndex >= 0; nIndex-- ) 
	{
		nResult += BitIO_GetBit( pBIO ) << nIndex;
	}
	return nResult;
}

int    BitIO_Flush(BitIO *pBIO) 
{
	pBIO->nValidBitsCount = 0;

	if ( BitIO_ByteOut( pBIO ) ) 
	{
		return 1;
	}
	if ( 7 == pBIO->nValidBitsCount ) 
	{
		pBIO->nValidBitsCount = 0;
		if ( BitIO_ByteOut( pBIO ) ) 
		{
			return 1;
		}
	}
	return 0;
}
int    BitIO_InAlign(BitIO *pBIO) 
{
	pBIO->nValidBitsCount = 0;
	
	if ( ( pBIO->nBuffer & 0xff ) == 0xff ) 
	{
		if ( BitIO_ByteIn( pBIO ) ) 
		{
			return 1;
		}
		pBIO->nValidBitsCount = 0;
	}
	return 0;
}