C

Compress and Decompress Hex String

See more Compression Examples

Imagine we have data represented as a hex string. This example demonstrates how to decode, compress, and re-encode to a smaller hex string representing the compressed data. An even better choice is to re-encode to a more compact encoding such as base64.

Note: This example requires Chilkat v9.5.0.66 or greater.

C

#include <C_CkCompression.h>
#include <C_CkBinData.h>

void ChilkatSample(void)
    {
    BOOL success;
    const char *strHex;
    HCkCompression compress;
    HCkBinData binDat;
    const char *compressedHex;
    const char *compressedBase64;
    const char *decompressedHex;

    success = FALSE;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    strHex = "54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A0D0A";

    compress = CkCompression_Create();
    CkCompression_putAlgorithm(compress,"deflate");

    binDat = CkBinData_Create();
    // Load the hex string into a BinData object.
    // This decodes the hexidecimal. The decoded bytes will be contained in the BinData.
    CkBinData_AppendEncoded(binDat,strHex,"hex");

    // Compress the BinData.
    CkCompression_CompressBd(compress,binDat);

    // Get the compressed data in hex format:
    compressedHex = CkBinData_getEncoded(binDat,"hex");
    printf("compressed hex:\n");
    printf("%s\n",compressedHex);

    // The compressed hex is: 0BC94855282CCD4CCE56482ACA2FCF5348CBAF50C82ACD2D484D51C82F4B2D522801CAE72456552AA4E4A7EBF172850C61E5BC5C00

    // Even better, get the compressed data in base64 format:
    // (base64url and modbase64 are other valid choices...)
    compressedBase64 = CkBinData_getEncoded(binDat,"base64");
    printf("compressed base64:\n");
    printf("%s\n",compressedBase64);

    // The compressed base64 is: C8lIVSgszUzOVkgqyi/PU0jLr1DIKs0tSE1RyC9LLVIoAcrnJFZVKqTkp+vxcoUMYeW8XAA=

    // Now decompress:
    CkBinData_Clear(binDat);
    CkBinData_AppendEncoded(binDat,compressedHex,"hex");
    CkCompression_DecompressBd(compress,binDat);

    decompressedHex = CkBinData_getEncoded(binDat,"hex");
    printf("decompressed hex:\n");
    printf("%s\n",decompressedHex);

    // The output is the original hex string:
    // 54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A0D0A


    CkCompression_Dispose(compress);
    CkBinData_Dispose(binDat);

    }