/*

* Copyright (C) 2012 Yee Young Han <[email protected]> (http://blog.naver.com/websearch)

*

* This program is free software; you can redistribute it and/or modify

* it under the terms of the GNU General Public License as published by

* the Free Software Foundation; either version 3 of the License, or

* (at your option) any later version.

*

* This program 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 General Public License for more details.

*

* You should have received a copy of the GNU General Public License

* along with this program; if not, write to the Free Software

* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

*/

#include "Http2HuffmanCode.h"

#include <stdio.h>

#include "Http2HuffmanCodeEncode.hpp"

#include "Http2HuffmanCodeDecode.hpp"

/**

* @ingroup HttpParser

* @brief Huffman code 인코딩 함수

* @param pszInput [in] 평문

* @param iInputLen [in] pszInput 변수의 길이

* @param pszOutput [out] Huffman code 인코딩된 데이터를 저장할 버퍼

* @param iOutputSize [in] pszOutput 변수의 크기

* @returns 성공하면 Huffman code 인코딩된 데이터의 길이를 리턴하고 그렇지 않으면 -1 를 리턴한다.

*/

int HuffmanCodeEncode( const uint8_t * pszInput, uint32_t iInputLen, uint8_t * pszOutput, uint32_t iOutputSize )

{

HuffmanEncode * psttCode;

uint32_t iOutput = 0;

uint32_t iBitPos = 0, iBitRemain, iOutputPos = 0;

for( uint32_t i = 0; i < iInputLen; ++i )

{

psttCode = &garrHuffmanEncode[pszInput[i]];

if( ( psttCode->iBit + iBitPos ) < 32 )

{

iOutput <<= psttCode->iBit;

iOutput |= psttCode->iCode;

iBitPos += psttCode->iBit;

continue;

}

if( iOutputPos + 4 > iOutputSize )

{

return -1;

}

iBitRemain = 32 - iBitPos;

iOutput <<= iBitRemain;

iBitPos = psttCode->iBit - iBitRemain;

iOutput |= psttCode->iCode >> iBitPos;

pszOutput[iOutputPos++] = iOutput >> 24;

pszOutput[iOutputPos++] = iOutput >> 16;

pszOutput[iOutputPos++] = iOutput >> 8;

pszOutput[iOutputPos++] = iOutput;

iOutput = psttCode->iCode;

}

if( iBitPos )

{

iBitRemain = 32 - iBitPos;

iOutput <<= iBitRemain;

iOutput |= 0xFFFFFFFF >> iBitPos;

pszOutput[iOutputPos++] = iOutput >> 24;

if( iBitPos > 8 ) pszOutput[iOutputPos++] = iOutput >> 16;

if( iBitPos > 16 ) pszOutput[iOutputPos++] = iOutput >> 8;

if( iBitPos > 24 ) pszOutput[iOutputPos++] = iOutput;

}

return iOutputPos;

}

static void PrintDebug( const char * pszName, uint32_t iCode, int iBitPos, int iBitRemain, uint8_t cInput, int iInputBitRemain )

{

printf( "%s code[", pszName );

for( int i = 0; i < iBitPos; ++i )

{

printf( "%d", ( iCode >> ( 32 - i - 1 ) ) & 0x01 );

}

printf( "] pos[%d] remain[%d] input[", iBitPos, iBitRemain );

for( int i = 0; i < 8; ++i )

{

printf( "%d", ( cInput >> ( 8 - i - 1 ) ) & 0x01 );

}

printf( "] input remain[%d]\n", iInputBitRemain );

}

/**

* @ingroup HttpParser

* @brief Huffman code 디코더 함수

* @param pszInput [in] Huffman code 로 인코딩된 데이터를 저장하는 버퍼

* @param iInputLen [in] pszInput 변수의 길이

* @param pszOutput [out] Huffman code 로 디코딩된 문자열을 저장할 버퍼

* @param iOutputSize [in] pszOutput 변수의 크기

* @returns 성공하면 Huffman code 로 디코딩된 문자열의 길이를 리턴하고 그렇지 않으면 -1 를 리턴한다.

*/

int HuffmanCodeDecode( const uint8_t * pszInput, uint32_t iInputLen, uint8_t * pszOutput, uint32_t iOutputSize )

{

int iInputPos = 0, iInputBitRemain = 0;

int iOutputPos = 0;

int iBitPos = 0, iBitRemain, iDecode, i;

uint32_t iCode = 0, iCodeInput = 0, iTest;

bool bFound;

while( iInputPos < (int)iInputLen || iBitPos >= 5 )

{

if( iBitPos < 32 )

{

iBitRemain = 32 - iBitPos;

if( iInputBitRemain )

{

// 입력 문자에서 남은 값만 변수에 저장한다.

switch( iInputBitRemain )

{

case 1: iCodeInput = pszInput[iInputPos] & 0x01; break;

case 2: iCodeInput = pszInput[iInputPos] & 0x03; break;

case 3: iCodeInput = pszInput[iInputPos] & 0x07; break;

case 4: iCodeInput = pszInput[iInputPos] & 0x0F; break;

case 5: iCodeInput = pszInput[iInputPos] & 0x1F; break;

case 6: iCodeInput = pszInput[iInputPos] & 0x3F; break;

case 7: iCodeInput = pszInput[iInputPos] & 0x7F; break;

}

if( iBitRemain >= iInputBitRemain )

{

// 남은 값을 모두 저장한다.

iCode |= iCodeInput << ( iBitRemain - iInputBitRemain );

iBitPos += iInputBitRemain;

iBitRemain -= iInputBitRemain;

iInputBitRemain = 0;

++iInputPos;

}

else

{

// 남은 값의 일부만 저장한다.

iCode |= iCodeInput >> ( iInputBitRemain - iBitRemain );

iBitPos += iBitRemain;

iInputBitRemain -= iBitRemain;

iBitRemain = 0;

}

}

for( ; iBitRemain > 0 && iInputPos < (int)iInputLen; iBitRemain -= 8 )

{

if( iBitRemain >= 8 )

{

// 8bit 저장한다.

iCode |= pszInput[iInputPos++] << ( iBitRemain - 8 );

iBitPos += 8;

}

else

{

// 일부만 저장한다.

iCode |= pszInput[iInputPos] >> ( 8 - iBitRemain );

iBitPos += iBitRemain;

iInputBitRemain = 8 - iBitRemain;

}

}

}

if( iBitPos < 5 )

{

break;

}

bFound = false;

// 코드 테이블에서 검색한다.

for( iDecode = 0; garrHuffmanDecodeInfo[iDecode].psttDecode; ++iDecode )

{

if( iBitPos < garrHuffmanDecodeInfo[iDecode].iBit ) break;

iTest = iCode >> ( 32 - garrHuffmanDecodeInfo[iDecode].iBit );

for( i = 0; i < garrHuffmanDecodeInfo[iDecode].iCount; ++i )

{

if( garrHuffmanDecodeInfo[iDecode].psttDecode[i].iCode == iTest )

{

pszOutput[iOutputPos++] = garrHuffmanDecodeInfo[iDecode].psttDecode[i].cChar;

iCode <<= garrHuffmanDecodeInfo[iDecode].iBit;

iBitPos -= garrHuffmanDecodeInfo[iDecode].iBit;

bFound = true;

break;

}

}

if( bFound ) break;

}

if( bFound == false )

{

break;

}

if( iOutputPos >= (int)iOutputSize )

{

return -1;

}

}

return iOutputPos;

}