Thread: Reading data from volumes

Don't be discouraged. Salem's just pulling your leg.

Here's a bit of a rewrite for you. I tried to make the "CreateArchive" function able to create either an archive with volumes or without, depending on whether volSize is 0 or not. I haven't tested it, though, so you may have to fix a few things.

Code:

#define MIN_ARGS 4
#define BUFFER_SIZE 4096

FILE *OpenVolumeFile(char *volumeName, int volume) {
    char volumeName[256];
    FILE *fArchive;
    if (volume > 0)
        sprintf(volumeName, "%s-%d", archiveName, volume);
    else
        sprintf(volumeName, "%s", archiveName);
    if (!(fArchive = fopen(volumeName, "wb", fArchive))
        Error("No file handle\n");
    return fArchive;
}

size_t ReadBuffer(FILE *fin, char *buffer, size_t bytesToRead) {
    size_t bytesRead;
    bytesRead = fread(buffer, 1, bytesToRead, fData);
    if(bytesRead < bytesToRead) Error("fread failure");
    return bytesRead;
}

size_t WriteArchiveHeader(FILE *fArchive, size_t volSize, int numFiles,
                          char *fileNames, size_t *fileSizes);
{
    size_t headerSize = sizeof numFiles + sizeof volSize +
                 numFiles * (sizeof *fileSizes + sizeof (size_t));
    if( fwrite(&numFiles, sizeof(numFiles), 1, fArchive) != 1)
        Error("Error writing number of files to bin\n");
    if( fwrite(&volSize, sizeof(volSize), 1, fArchive) != 1)
        Error("Error writing volume size to bin\n");
    for(i = 0; i < numFiles; i++)
    {
        size_t fileNameLen = strlen(fileNames[i]);
        WriteArchiveHeaderRecord(fArchive, fileNames[i], fileNameLen, fileSizes[i]);
        headerSize += fileNameLen;
    }
    printf("Wrote file header -> Size: %d\n\n", headerSize);
    return headerSize;
}

void CreateArchive(
    char   *archiveName,
    size_t  volSize,
    int     numFiles,
    char   *fileNames)
{
    FILE   *fArchive;
    size_t  volBytesLeft;
    size_t  headerSize;
    size_t  fileSizes[numFiles]; // I got rid of the "file" struct
    int     i;
    int     volume = 0;

    for(i = 0; i < numFiles; i++)
        fileSizes[i] = GetFileSize(fileNames[i]);

    fArchive = OpenVolumeFile(archiveName, volSize>0 ? ++volume : 0);
    headerSize = WriteArchiveHeader(fArchive, volSize, numFiles, fileNames, fileSizes);
    if (volSize > 0)
        volBytesLeft = volSize - headerSize;
    else
        volBytesLeft = BUFFER_SIZE + 1; // ensure that it's greater than buffer size

    for(i = 0; i < numFiles; i++)
    {
        size_t fileBytesLeft = fileSizes[i];

        FILE *fData = fopen(fileNames[i], "rb");
        if(fData == NULL)  Error("Error opening file\n");

        printf("File %i: %.2f MB\n", i + 1, (double)fileSizes[i] / 1024 / 1024);

        do
        {
            char buffer[BUFFER_SIZE];
            size_t bytesToRead, bytesRead;

            if(volBytesLeft == 0)
            {
                fclose(fArchive);
                fArchive = OpenVolumeFile(archiveName, ++volume);
                volBytesLeft = volSize;
            }

            bytesRead = ReadBuffer(fData, buffer,
                            min3(sizeof buffer, fileBytesLeft, volBytesLeft));
            WriteBuffer(fArchive, buffer, bytesRead);

            fileBytesLeft -= bytesRead;
            if (volSize > 0)
                volBytesLeft -= bytesRead;
        }
        while(fileBytesLeft > 0);

        fclose(fData);
        printf("Wrote file %i: %s\n\n", i + 1, argv[i + MIN_ARGS - 1]);
    }

    fclose(fArchive);
    printf("Success!");
}

// Call from main:
   CreateArchive(
       &argv[2],
       (size_t)atoi(argv[1])*1024*1024,
       argc - MIN_ARGS + 1,
       &argv[3]);

Yes. I remember one of them was called WriteChunkBin (I think that's what I called WriteBuffer). I can't remember what the other was called, but it writes the file size, name length, and name to the header.