文件打包代码更新使用json记录打包文件信息

时间：2016-06-08 15:37:27 阅读：273 评论：0 收藏：0 [点我收藏+]

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经过之前的几次试验决定使用json记录打包文件信息

#include "Package.h"
#include "json/json.h"
#include <string>
#include <iostream>
 
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bool Package::CreatePackage(const char* packFileName) {
    bool bRet = false;
 
    fpPackage_ = fopen(packFileName,"wb+");
    if (NULL == fpPackage_)
        return bRet;
 
    bRet = true;
    return bRet;
}
 
void Package::AddFileToList(const char* fileName) {
    fileList.push_back(fileName);
}
 
bool Package::OpenPackageForUnPack(const char* packFileName) {
    if (NULL != fpPackage_)
        fclose(fpPackage_);
 
    fpPackage_ = fopen(packFileName, "rb");
    if (NULL == fpPackage_)
        return false;
 
    return true;
}
 
bool Package::CopyFileContent(FILE* src, FILE* dsc) {
    char* buf = new char[CopyBufSize];
    if (NULL == buf)
        return false;
 
    while (1) {
        int nReadBytes = fread(buf,1, CopyBufSize, src);
        //写入包裹
        fwrite(buf, 1, nReadBytes, dsc);
        //如果读取到的数据比缓冲区小，那么说明读取结束了
        if (nReadBytes < sizeof(buf))
        {
            break;
        }
    }
    //fflush是确保我们的数据写入到磁盘上了
    fflush(dsc);
    return true;
}
 
bool  Package::PackageOneFile(const char*name)
{
    bool bRet = false;
 
    FILE* fp = fopen(name, "rb");
    if (NULL == fp)
    return bRet;
 
    //获取文件长度
    _fseeki64(fp, 0, SEEK_END); //定位到文件末 
    __int64 filelength = _ftelli64(fp);
    _fseeki64(fp, 0, SEEK_SET);
 
    //获取PACKAGE文件当前偏移
    __int64 currentOffset = _ftelli64(fpPackage_);
 
    //开始打包
    CopyFileContent(fp, fpPackage_);
 
    FILEINFO fileInfo;
    fileInfo.filename = name;
    fileInfo.fileSize = filelength;
    fileInfo.offsetInPackFile = currentOffset;
 
    fileInfoList.push_back(fileInfo);
    fclose(fp);
    return bRet;
}
 
bool Package::GetUnpackFileInfo() {
    fileInfoList.clear();
    __int64 jsonOffset = 0;
    fread(&jsonOffset,1,sizeof(jsonOffset), fpPackage_);
 
    //获取文件长度
    _fseeki64(fpPackage_, 0, SEEK_END); //定位到文件末 
    __int64 filelength = _ftelli64(fpPackage_);
    _fseeki64(fpPackage_, 0, SEEK_SET);
 
    _fseeki64(fpPackage_, jsonOffset, SEEK_SET);
    char* jsonBuf = new char[filelength - jsonOffset];
    if (NULL == jsonBuf)
        return false;
    fread(jsonBuf,filelength - jsonOffset,1, fpPackage_);
 
    //解析json字符串
    Json::Reader pJsonParser;;
    Json::Value tempVal;
 
    if (!pJsonParser.parse(jsonBuf, tempVal))
    {
        std::cout << "parse error" << std::endl;
        delete[] jsonBuf;
        return false;
    }
 
    Json::Value array = tempVal["array"];
    for (int i = 0; i < array.size(); i++) {
        std::cout << array[i]["Filename"].asString() << std::endl;
        std::cout << array[i]["FileSize"].asInt64() << std::endl;
        std::cout << array[i]["Offset"].asInt64() << std::endl;
    }
 
    delete[] jsonBuf;
    return true;
}
 
 
bool Package::WriteFileInfoToPackFile() {
 
    //获取PACKAGE文件当前偏移 写入JSON文件信息的偏移
    __int64 currentOffset = _ftelli64(fpPackage_);
    //生成JSON
    Json::Value root;
    Json::Value array;
    Json::FastWriter writer;
    Json::Value fileInfo;
 
    for (std::deque<FILEINFO>::iterator it = fileInfoList.begin();
        it != fileInfoList.end(); it++) {
        fileInfo["Filename"] = it->filename;
        fileInfo["FileSize"] = it->fileSize;
        fileInfo["Offset"] = it->offsetInPackFile;
        array.append(fileInfo);
    }
    root["array"] = array;
     
    std::string s = writer.write(root);
 
    //写入文件信息
    fwrite(s.c_str(),1,s.size(), fpPackage_);
 
    //跳转到文件头 写入JOSN偏移
    _fseeki64(fpPackage_, 0, SEEK_SET);
    fwrite(&currentOffset,1,sizeof(currentOffset), fpPackage_);
    fflush(fpPackage_);
    return true;
}
 
bool Package::PackFile() {
    bool bRet = false;
    //预留 打包文件的信息的偏移位置
    __int64 jsonOffset = 0;
    fwrite(&jsonOffset, 1, sizeof(jsonOffset), fpPackage_);
    for (std::deque<std::string>::iterator it = fileList.begin();
        it != fileList.end(); it++) {
        std::string fileName = *it;
        PackageOneFile(fileName.c_str());
    }
    fileList.clear();
    WriteFileInfoToPackFile();
 
    return bRet;
}