cocos lua解压zip文件(支持源文件非zip格式)

最近遇到需要在cocos中解压zip的需求就了解了下

以下代码摘自: http://www.cocoachina.com/bbs/read.php?tid=212537

    // Open the zip file
    std::string outFileName = filename;
    unzFile zipfile = unzOpen(outFileName.c_str());
    if (!zipfile){
        CCLOG("can not open downloaded zip file %s", outFileName.c_str());
        return false;
    }
 
    // Get info about the zip file
    unz_global_info global_info;
    if (unzGetGlobalInfo(zipfile, &global_info) != UNZ_OK){
        CCLOG("can not read file global info of %s", outFileName.c_str());
        unzClose(zipfile);
        return false;
    }
 
    const int BUFFER_SIZE = 8192;
    const int MAX_FILENAME = 512;

    // Buffer to hold data read from the zip file
    char readBuffer[BUFFER_SIZE];
 
    // Loop to extract all files.
    uLong i;
    for (i = 0; i < global_info.number_entry; ++i){
        // Get info about current file.
        unz_file_info fileInfo;
        char fileName[MAX_FILENAME];
        if (unzGetCurrentFileInfo(zipfile, &fileInfo, fileName, MAX_FILENAME, NULL, 0, NULL, 0) != UNZ_OK){
            CCLOG("can not read file info");
            unzClose(zipfile);
            return false;
        }
 
        std::string storagePath = destPath;
        std::string fullPath = storagePath + fileName;
 
        // Check if this entry is a directory or a file.
        const size_t filenameLength = strlen(fileName);
        if (fileName[filenameLength - 1] == '/'){
            // get all dir
            std::string fileNameStr = std::string(fileName);
            size_t position = 0;
            while ((position = fileNameStr.find_first_of("/", position)) != std::string::npos){
                std::string dirPath = storagePath + fileNameStr.substr(0, position);
                // Entry is a direcotry, so create it.
                // If the directory exists, it will failed scilently.
                if (!createDirectory(dirPath.c_str())){
                    CCLOG("can not create directory %s", dirPath.c_str());
                    //unzClose(zipfile);
                    //return false;
                }
                position++;
            }
        } else {
            // Entry is a file, so extract it.
            // Open current file.
            if (unzOpenCurrentFile(zipfile) != UNZ_OK) {
                CCLOG("can not open file %s", fileName);
                unzClose(zipfile);
                return false;
            }
 
            // Create a file to store current file.
            FILE *out = fopen(fullPath.c_str(), "wb");
            if (!out) {
                CCLOG("can not open destination file %s", fullPath.c_str());
                unzCloseCurrentFile(zipfile);
                unzClose(zipfile);
                return false;
            }
 
            // Write current file content to destinate file.
            int error = UNZ_OK;
            do {
                error = unzReadCurrentFile(zipfile, readBuffer, BUFFER_SIZE);
                if (error < 0) {
                    CCLOG("can not read zip file %s, error code is %d", fileName, error);
                    unzCloseCurrentFile(zipfile);
                    unzClose(zipfile);
                    return false;
                }
 
                if (error > 0) {
                    fwrite(readBuffer, error, 1, out);
                }
            } while (error > 0);
            fclose(out);
        }
 
        unzCloseCurrentFile(zipfile);
 
        // Goto next entry listed in the zip file.
        if ((i + 1) < global_info.number_entry) {
            if (unzGoToNextFile(zipfile) != UNZ_OK) {
                CCLOG("can not read next file");
                unzClose(zipfile);
                return false;
            }
        }
    }

使用zlib 的上层封装 minizip 的接口，但是在ios上会出现非zip后缀的文件，无法读取的尴尬，主要问题出在unzOpen方法。

看了下可以使用unzOpenBuffer方法就能避免掉这个问题。就变成了:

    std::string outFileName = filename;    
    ssize_t size = 0;
    unsigned char *zipFileData = FileUtils::getInstance()->getFileData(outFileName, "rb", &size);　　  
    unzFile zipfile = unzOpenBuffer(zipFileData, size);
    ......

或者直接用cocos封装好的 ZipFile ，也就是:

ZipFile *zip = nullptr;
if (zipFileData) {
    zip = ZipFile::createWithBuffer(zipFileData, size);
}

1	`这样就ok。同时了解了下zip格式：`

Offset	Bytes	Contents	Descriptor
LOCAL FILE HEADER
00000000	4	50 4B 03 04	文件头标识(0x04034b50)
00000004	2	0A 00	解压文件所需 pkware最低版本
00000006	2	00 00	通用比特标志位
00000008	2	08 00	压缩方式
0000000A	2	E1 5D	文件最后修改时间
0000000C	2	CC 48	文件最后修改日期
0000000E	4	61 D3 72 09	crc-32校验码
00000012	4	08 00 00 00	压缩后的大小
00000016	4	06 00 00 00	未压缩的大小
0000001A	2	07 00	文件名长度
0000001C	2	00 00	扩展区长度
0000001E	6	31 32 33 2E 74 78 74	文件名 123.txt
FILE DATA
00000025	8	33 34 32 36 31 35 03 00	压缩文件数据，此处就是压缩文本文件123.txt压缩后的数据
Central Directory Header
0000002D	4	50 4B 01 02	核心目录文件header标识=（0x02014b50）
00000031	2	0A 00	压缩所用的pkware版本
00000033	2	0A 00	解压所需pkware的最低版本
00000035	2	00 00	通用位标记
00000037	2	08 00	压缩方法
00000039	2	E1 5D	文件最后修改时间
0000003B	2	CC 48	文件最后修改日期
0000003D	4	61 D3 72 09	CRC-32校验码
00000041	4	08 00 00 00	压缩后的大小
00000045	4	06 00 00 00	未压缩的大小
00000049	2	07 00	文件名长度
0000004B	2	00 00	扩展域长度
0000004D	2	00 00	文件注释长度
0000004F	2	00 00	文件开始位置的磁盘编号
00000051	2	00 00	内部文件属性
00000053	4	20 00 00 00	外部文件属性
00000057	4	00 00 00 00	本地文件header的相对位移
0000005B	7	31 32 33 2E 74 78 74	目录文件名
End of central directory record
00000062	4	50 4B 05 06	核心目录结束标记（0x06054b50）
00000066	2	00 00	当前磁盘编号
00000068	2	00 00	核心目录开始位置的磁盘编号
0000006A	2	01 00	该磁盘上所记录的核心目录数量
0000006C	2	01 00	核心目录结构总数
0000006E	4	35 00 00 00	核心目录的大小
00000072	4	2D 00 00 00	核心目录开始位置相对于archive开始的位移
00000076	2	00 00	注释长度