c++ - 如何在C++中使用LZMA SDK？

Question

我在我的应用程序中使用 LZMA SDK 时遇到困难。

我想创建一种单文件压缩工具。我不需要任何目录支持，只需要 LZMA2 流。但我不知道如何使用 LZMA SDK。

谁能给我一个关于如何在 C++ 下使用 LZMA SDK 的小例子？

Answer 1

我认为这是一个使用 LZMA SDK 的小例子。

/* LzmaUtil.c -- Test application for LZMA compression  
2008-08-05  
Igor Pavlov  
public domain */   

#define _CRT_SECURE_NO_WARNINGS   

#include <stdio.h>   
#include <stdlib.h>   
#include <string.h>   

#include "../LzmaDec.h"   
#include "../LzmaEnc.h"   
#include "../Alloc.h"   

const char *kCantReadMessage = "Can not read input file";   
const char *kCantWriteMessage = "Can not write output file";   
const char *kCantAllocateMessage = "Can not allocate memory";   
const char *kDataErrorMessage = "Data error";   

static void *SzAlloc(void *p, size_t size) { p = p; return MyAlloc(size); }   
static void SzFree(void *p, void *address) {  p = p; MyFree(address); }   
static ISzAlloc g_Alloc = { SzAlloc, SzFree };   

#define kInBufferSize (1 << 15)   
#define kOutBufferSize (1 << 15)   

unsigned char g_InBuffer[kInBufferSize];   
unsigned char g_OutBuffer[kOutBufferSize];   

size_t MyReadFile(FILE *file, void *data, size_t size)   
  { return fread(data, 1, size, file); }   

int MyReadFileAndCheck(FILE *file, void *data, size_t size)   
  { return (MyReadFile(file, data, size) == size); }   

size_t MyWriteFile(FILE *file, const void *data, size_t size)   
{   
  if (size == 0)   
    return 0;   
  return fwrite(data, 1, size, file);   
}   

int MyWriteFileAndCheck(FILE *file, const void *data, size_t size)   
  { return (MyWriteFile(file, data, size) == size); }   

long MyGetFileLength(FILE *file)   
{   
  long length;   
  fseek(file, 0, SEEK_END);   
  length = ftell(file);   
  fseek(file, 0, SEEK_SET);   
  return length;   
}   

void PrintHelp(char *buffer)   
{   
  strcat(buffer, "\nLZMA Utility 4.58 Copyright (c) 1999-2008 Igor Pavlov  2008-04-11\n"   
      "\nUsage:  lzma <e|d> inputFile outputFile\n"   
             "  e: encode file\n"   
             "  d: decode file\n");   
}   

int PrintError(char *buffer, const char *message)   
{   
  strcat(buffer, "\nError: ");   
  strcat(buffer, message);   
  strcat(buffer, "\n");   
  return 1;   
}   

int PrintErrorNumber(char *buffer, SRes val)   
{   
  sprintf(buffer + strlen(buffer), "\nError code: %x\n", (unsigned)val);   
  return 1;   
}   

int PrintUserError(char *buffer)   
{   
  return PrintError(buffer, "Incorrect command");   
}   

#define IN_BUF_SIZE (1 << 16)   
#define OUT_BUF_SIZE (1 << 16)   

static int Decode(FILE *inFile, FILE *outFile, char *rs)   
{   
  UInt64 unpackSize;   
  int thereIsSize; /* = 1, if there is uncompressed size in headers */   
  int i;   
  int res = 0;   

  CLzmaDec state;   

  /* header: 5 bytes of LZMA properties and 8 bytes of uncompressed size */   
  unsigned char header[LZMA_PROPS_SIZE + 8];   

  /* Read and parse header */   

  if (!MyReadFileAndCheck(inFile, header, sizeof(header)))   
    return PrintError(rs, kCantReadMessage);   

  unpackSize = 0;   
  thereIsSize = 0;   
  for (i = 0; i < 8; i++)   
  {   
    unsigned char b = header[LZMA_PROPS_SIZE + i];   
    if (b != 0xFF)   
      thereIsSize = 1;   
    unpackSize += (UInt64)b << (i * 8);   
  }   

  LzmaDec_Construct(&state);   
  res = LzmaDec_Allocate(&state, header, LZMA_PROPS_SIZE, &g_Alloc);   
  if (res != SZ_OK)   
    return res;   
  {   
    Byte inBuf[IN_BUF_SIZE];   
    Byte outBuf[OUT_BUF_SIZE];   
    size_t inPos = 0, inSize = 0, outPos = 0;   
    LzmaDec_Init(&state);   
    for (;;)   
    {   
      if (inPos == inSize)   
      {   
        inSize = MyReadFile(inFile, inBuf, IN_BUF_SIZE);   
        inPos = 0;   
      }   
      {   
        SizeT inProcessed = inSize - inPos;   
        SizeT outProcessed = OUT_BUF_SIZE - outPos;   
        ELzmaFinishMode finishMode = LZMA_FINISH_ANY;   
        ELzmaStatus status;   
        if (thereIsSize && outProcessed > unpackSize)   
        {   
          outProcessed = (SizeT)unpackSize;   
          finishMode = LZMA_FINISH_END;   
        }   

        res = LzmaDec_DecodeToBuf(&state, outBuf + outPos, &outProcessed,   
            inBuf + inPos, &inProcessed, finishMode, &status);   
        inPos += (UInt32)inProcessed;   
        outPos += outProcessed;   
        unpackSize -= outProcessed;   

        if (outFile != 0)   
          MyWriteFile(outFile, outBuf, outPos);   
        outPos = 0;   

        if (res != SZ_OK || thereIsSize && unpackSize == 0)   
          break;   

        if (inProcessed == 0 && outProcessed == 0)   
        {   
          if (thereIsSize || status != LZMA_STATUS_FINISHED_WITH_MARK)   
            res = SZ_ERROR_DATA;   
          break;   
        }   
      }   
    }   
  }   

  LzmaDec_Free(&state, &g_Alloc);   
  return res;   
}   

typedef struct _CFileSeqInStream   
{   
  ISeqInStream funcTable;   
  FILE *file;   
} CFileSeqInStream;   

static SRes MyRead(void *p, void *buf, size_t *size)   
{   
  if (*size == 0)   
    return SZ_OK;   
  *size = MyReadFile(((CFileSeqInStream*)p)->file, buf, *size);   
  /*  
  if (*size == 0)  
    return SZE_FAIL;  
  */   
  return SZ_OK;   
}   

typedef struct _CFileSeqOutStream   
{   
  ISeqOutStream funcTable;   
  FILE *file;   
} CFileSeqOutStream;   

static size_t MyWrite(void *pp, const void *buf, size_t size)   
{   
  return MyWriteFile(((CFileSeqOutStream *)pp)->file, buf, size);   
}   

static SRes Encode(FILE *inFile, FILE *outFile, char *rs)   
{   
  CLzmaEncHandle enc;   
  SRes res;   
  CFileSeqInStream inStream;   
  CFileSeqOutStream outStream;   
  CLzmaEncProps props;   

  enc = LzmaEnc_Create(&g_Alloc);   
  if (enc == 0)   
    return SZ_ERROR_MEM;   

  inStream.funcTable.Read = MyRead;   
  inStream.file = inFile;   
  outStream.funcTable.Write = MyWrite;   
  outStream.file = outFile;   

  LzmaEncProps_Init(&props);   
  res = LzmaEnc_SetProps(enc, &props);   

  if (res == SZ_OK)   
  {   
    Byte header[LZMA_PROPS_SIZE + 8];   
    size_t headerSize = LZMA_PROPS_SIZE;   
    UInt64 fileSize;   
    int i;   

    res = LzmaEnc_WriteProperties(enc, header, &headerSize);   
    fileSize = MyGetFileLength(inFile);   
    for (i = 0; i < 8; i++)   
      header[headerSize++] = (Byte)(fileSize >> (8 * i));   
    if (!MyWriteFileAndCheck(outFile, header, headerSize))   
      return PrintError(rs, "writing error");   

    if (res == SZ_OK)   
      res = LzmaEnc_Encode(enc, &outStream.funcTable, &inStream.funcTable,   
        NULL, &g_Alloc, &g_Alloc);   
  }   
  LzmaEnc_Destroy(enc, &g_Alloc, &g_Alloc);   
  return res;   
}   

int main2(int numArgs, const char *args[], char *rs)   
{   
  FILE *inFile = 0;   
  FILE *outFile = 0;   
  char c;   
  int res;   
  int encodeMode;   

  if (numArgs == 1)   
  {   
    PrintHelp(rs);   
    return 0;   
  }   

  if (numArgs < 3 || numArgs > 4 || strlen(args[1]) != 1)   
    return PrintUserError(rs);   

  c = args[1][0];   
  encodeMode = (c == 'e' || c == 'E');   
  if (!encodeMode && c != 'd' && c != 'D')   
    return PrintUserError(rs);   

  {   
    size_t t4 = sizeof(UInt32);   
    size_t t8 = sizeof(UInt64);   
    if (t4 != 4 || t8 != 8)   
      return PrintError(rs, "LZMA UTil needs correct UInt32 and UInt64");   
  }   

  inFile = fopen(args[2], "rb");   
  if (inFile == 0)   
    return PrintError(rs, "Can not open input file");   

  if (numArgs > 3)   
  {   
    outFile = fopen(args[3], "wb+");   
    if (outFile == 0)   
      return PrintError(rs, "Can not open output file");   
  }   
  else if (encodeMode)   
    PrintUserError(rs);   

  if (encodeMode)   
  {   
    res = Encode(inFile, outFile, rs);   
  }   
  else   
  {   
    res = Decode(inFile, outFile, rs);   
  }   

  if (outFile != 0)   
    fclose(outFile);   
  fclose(inFile);   

  if (res != SZ_OK)   
  {   
    if (res == SZ_ERROR_MEM)   
      return PrintError(rs, kCantAllocateMessage);   
    else if (res == SZ_ERROR_DATA)   
      return PrintError(rs, kDataErrorMessage);   
    else   
      return PrintErrorNumber(rs, res);   
  }   
  return 0;   
}   

int MY_CDECL main(int numArgs, const char *args[])   
{   
  char rs[800] = { 0 };   
  int res = main2(numArgs, args, rs);   
  printf(rs);   
  return res;   
}

您还可以在以下位置看到它:

http://read.pudn.com/downloads151/sourcecode/zip/656407/7z460/C/LzmaUtil/LzmaUtil.c__.htm

http://read.pudn.com/downloads157/sourcecode/zip/698262/LZMA/LzmaUtil.c__.htm