Zip壓縮文件與解壓（MFC文件操作四）

寂靜如河 2012-08-06

展開全文

一、壓縮文件

我們的程序要用到了zip壓縮，就需要自己將幾個(gè)zip相關(guān)文件加入到工程中

zlib.h zconf.h zlib.lib 這些可以自己上網(wǎng)下載 http://d.download.csdn.net/down/2344459/mryeze

在程序中要將兩個(gè).h文件 add to project。然后聲明引入lib

[c-sharp] view plain copy ?

#include "zlib.h"http://壓縮文件相關(guān)
#include "zconf.h"
#pragma comment(lib,"zlib.lib")

這些工作只是為了使程序中的關(guān)鍵函數(shù)compress 能夠使用

之后就寫我們的代碼了，源代碼是網(wǎng)上找的，自己在做的時(shí)候，對(duì)其做了一點(diǎn)修改，使其能直接運(yùn)行。

[cpp] view plain copy ?

HANDLE hFile, hFileToWrite;
CString strFilePath = "C:/aaa.txt"; //要壓縮的文件的路徑
// 下載的源代碼中后綴名為rar,經(jīng)測(cè)試無法打開
//打開要進(jìn)行壓縮的文件
hFile = CreateFile(strFilePath, // file name
GENERIC_READ, // open for reading
FILE_SHARE_READ, // share for reading
NULL, // no security
OPEN_EXISTING, // existing file only
FILE_ATTRIBUTE_NORMAL, // normal file
NULL
); // no attr. template
if (hFile == INVALID_HANDLE_VALUE)
{
AfxMessageBox("Could not open file to read"); // process error
return;
}
HANDLE hMapFile, hMapFileToWrite;
//創(chuàng)建一個(gè)文件映射
hMapFile = CreateFileMapping(hFile, // Current file handle.
NULL, // Default security.
PAGE_READONLY, // Read/write permission.
0, // Max. object size.
0, // Size of hFile.
"ZipTestMappingObjectForRead"
); // Name of mapping object.
if (hMapFile == NULL)
{
AfxMessageBox("Could not create file mapping object");
return;
}
LPVOID lpMapAddress, lpMapAddressToWrite;
//創(chuàng)建一個(gè)文件映射的視圖用來作為source
lpMapAddress = MapViewOfFile(hMapFile, // Handle to mapping object.
FILE_MAP_READ, // Read/write permission
0, // Max. object size.
0, // Size of hFile.
0); // Map entire file.
if (lpMapAddress == NULL)
{
AfxMessageBox("Could not map view of file");
return;
}
DWORD dwFileLength,dwFileLengthToWrite;
dwFileLength = GetFileSize(hFile, NULL); //獲取文件的大小
/ m_dwSourceFileLength = dwFileLength;
//因?yàn)閴嚎s函數(shù)的輸出緩沖必須比輸入大0.1% + 12 然后一個(gè)DWORD 用來保存壓縮前的大小，
// 解壓縮的時(shí)候用，當(dāng)然還可以保存更多的信息，這里用不到
dwFileLengthToWrite = (double)dwFileLength*1.001 + 12 +sizeof(DWORD);
//以下是創(chuàng)建一個(gè)文件，用來保存壓縮后的文件
hFileToWrite = CreateFile("C:/demoFile.txt", // demoFile.rar
GENERIC_WRITE|GENERIC_READ, // open for writing
0, // do not share
NULL, // no security
CREATE_ALWAYS, // overwrite existing
FILE_ATTRIBUTE_NORMAL , // normal file
NULL); // no attr. template
if (hFileToWrite == INVALID_HANDLE_VALUE)
{
AfxMessageBox("Could not open file to write"); // process error
return;
}
//為輸出文件創(chuàng)建一個(gè)文件映射
hMapFileToWrite = CreateFileMapping(hFileToWrite, // Current file handle.
NULL, // Default security.
PAGE_READWRITE, // Read/write permission.
0, // Max. object size.
dwFileLengthToWrite, // Size of hFile.
"ZipTestMappingObjectForWrite"); // Name of mapping object.
if (hMapFileToWrite == NULL)
{
AfxMessageBox("Could not create file mapping object for write");
return;
}
//為輸出文件創(chuàng)建一個(gè)文件映射視圖
lpMapAddressToWrite = MapViewOfFile(hMapFileToWrite, //Handle to mapping
FILE_MAP_WRITE, // Read/write permission 0, // Max. object size.
0, // Size of hFile.
0,
0
); // Map entire file.
if (lpMapAddressToWrite == NULL)
{
AfxMessageBox("Could not map view of file");
return;
}
//這里是將壓縮前的大小保存在文件的第一個(gè)DWORD 里面
LPVOID pBuf = lpMapAddressToWrite;
(*(DWORD*)pBuf) = dwFileLength;
pBuf = (DWORD*)pBuf + 1;
//這里就是最重要的，zlib 里面提供的一個(gè)方法，將源緩存的數(shù)據(jù)壓縮至目的緩存
//原形如下：
//int compress (Bytef *dest, uLongf *destLen, const Bytef*source, uLong sourceLen);
//參數(shù)destLen 返回實(shí)際壓縮后的文件大小。
compress((Bytef*)pBuf,&dwFileLengthToWrite, (Bytef*)lpMapAddress, dwFileLength);
UnmapViewOfFile(lpMapAddress);
CloseHandle(hMapFile);
CloseHandle(hFile);
UnmapViewOfFile(lpMapAddressToWrite);
CloseHandle(hMapFileToWrite);
//這里將文件大小重新設(shè)置一下
SetFilePointer(hFileToWrite,dwFileLengthToWrite + sizeof(DWORD) ,NULL,FILE_BEGIN);
SetEndOfFile(hFileToWrite);
CloseHandle(hFileToWrite);

運(yùn)行程序后，將aaa.txt文件壓縮成功了。

二、解壓文件

解壓文件的思路和壓縮差不多，其中的區(qū)別就是

1. 輸出文件緩沖區(qū)大小的設(shè)定

zip為：

[c-sharp] view plain copy ?

//因?yàn)閴嚎s函數(shù)的輸出緩沖必須比輸入大0.1% + 12 然后一個(gè)DWORD 用來保存壓縮前的大小，
// 解壓縮的時(shí)候用，當(dāng)然還可以保存更多的信息，這里用不到
dwFileLengthToWrite = (double)dwFileLength*1.001 + 12 +sizeof(DWORD);

upzip為：

[c-sharp] view plain copy ?

dwFileLengthToWrite = (*(DWORD*)lpMapAddress);

2 compress 與 uncompress函數(shù)

這個(gè)是必須的了！

[c-sharp] view plain copy ?

compress((Bytef*)pBuf,&dwFileLengthToWrite, (Bytef*)lpMapAddress, dwFileLength);

[c-sharp] view plain copy ?

uncompress((Bytef*)pBuf,&dwFileLengthToWrite, (Bytef*)pSourceBuf, dwFileLength);

還是提供源代碼

[c-sharp] view plain copy ?

HANDLE hFile, hFileToWrite;
CString strFilePath="C:/demoFile.txt";
//打開要進(jìn)行解壓縮的文件
hFile = CreateFile(strFilePath, // file name
GENERIC_READ, // open for reading
FILE_SHARE_READ, // share for reading
NULL, // no security
OPEN_EXISTING, // existing file only
FILE_ATTRIBUTE_NORMAL, // normal file
NULL
); // no attr. template
if (hFile == INVALID_HANDLE_VALUE)
{
AfxMessageBox("Could not open file to read"); // process error
return;
}
HANDLE hMapFile, hMapFileToWrite;
//創(chuàng)建一個(gè)文件映射
hMapFile = CreateFileMapping(hFile, // Current file handle.
NULL, // Default security.
PAGE_READONLY, // Read/write permission.
0, // Max. object size.
0, // Size of hFile.
"ZipTestMappingObjectForRead"); // Name of mapping object.
if (hMapFile == NULL)
{
AfxMessageBox("Could not create file mapping object");
return;
}
LPVOID lpMapAddress, lpMapAddressToWrite;
//創(chuàng)建一個(gè)文件映射的視圖用來作為source
lpMapAddress = MapViewOfFile(hMapFile, // Handle to mapping
FILE_MAP_READ, // Read/write permission
0, // Max. object size.
0, // Size of hFile.
0); // Map entire file.
if (lpMapAddress == NULL)
{
AfxMessageBox("Could not map view of file");
return;
}
DWORD dwFileLength,dwFileLengthToWrite;
dwFileLength = GetFileSize(hFile, NULL) - sizeof(DWORD);
//因?yàn)閴嚎s函數(shù)的輸出緩沖必須比輸入大0.1% + 12 然后一個(gè)DWORD 用來保存壓縮前的大小，
// 解壓縮的時(shí)候用，當(dāng)然還可以保存更多的信息，這里用不到
// dwFileLengthToWrite = (double)dwFileLength*1.001 + 12 +sizeof(DWORD);
dwFileLengthToWrite = (*(DWORD*)lpMapAddress);
LPVOID pSourceBuf = lpMapAddress;
pSourceBuf = (DWORD*)pSourceBuf + 1;
//以下是創(chuàng)建一個(gè)文件，用來保存壓縮后的文件
hFileToWrite = CreateFile("C:/UnZipFile.txt", // create demo.gz
GENERIC_WRITE|GENERIC_READ, // open for writing
0, // do not share
NULL, // no security
CREATE_ALWAYS, // overwrite existing
FILE_ATTRIBUTE_NORMAL , // normal file
NULL
); // no attr. template
if (hFileToWrite == INVALID_HANDLE_VALUE)
{
AfxMessageBox("Could not open file to write"); //process error
return;
}
hMapFileToWrite = CreateFileMapping(hFileToWrite, // Currentfile handle.
NULL, // Default security.
PAGE_READWRITE, // Read/write permission.
0, // Max. object size.
dwFileLengthToWrite, // Size of hFile.
"ZipTestMappingObjectForWrite"); // Name of mapping object.
if (hMapFileToWrite == NULL)
{
AfxMessageBox("Could not create file mapping object for write");
return;
}
lpMapAddressToWrite = MapViewOfFile(hMapFileToWrite, //Handle to mapping object.
FILE_MAP_WRITE, // Read/write permission
0, // Max. object size.
0, // Size of hFile.
0
); // Map entire file.
if (lpMapAddressToWrite == NULL)
{
AfxMessageBox("Could not map view of file");
return;
}
//這里是將壓縮前的大小保存在文件的第一個(gè)DWORD 里面
LPVOID pBuf = lpMapAddressToWrite;
//這里就是最重要的，zlib 里面提供的一個(gè)方法，將源緩存的數(shù)據(jù)壓縮至目的緩存
//原形如下：
//int compress (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen);
//參數(shù)destLen 返回實(shí)際壓縮后的文件大小。
uncompress((Bytef*)pBuf,&dwFileLengthToWrite, (Bytef*)pSourceBuf, dwFileLength);
UnmapViewOfFile(lpMapAddress);
CloseHandle(hMapFile);
CloseHandle(hFile);
UnmapViewOfFile(lpMapAddressToWrite);
CloseHandle(hMapFileToWrite);
//這里將文件大小重新設(shè)置一下
SetFilePointer(hFileToWrite,dwFileLengthToWrite,NULL,FILE_BEGIN);
SetEndOfFile(hFileToWrite);
CloseHandle(hFileToWrite);

運(yùn)行效果如下：

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