Zig

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.

Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    const str_hex = "54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A54686520717569636B2062726F776E20666F78206A756D706564206F76657220746865206C617A7920646F672E0D0A0D0A";

    const compress = try chilkat.Compression.init();
    defer compress.deinit();
    compress.setAlgorithm("deflate");

    const bin_dat = try chilkat.BinData.init();
    defer bin_dat.deinit();
    // Load the hex string into a BinData object.
    // This decodes the hexidecimal. The decoded bytes will be contained in the BinData.
    bin_dat.appendEncoded(str_hex, "hex") catch {};

    // Compress the BinData.
    compress.compressBd(bin_dat) catch {};

    // Get the compressed data in hex format:
    const compressed_hex = try bin_dat.getEncoded(alloc, "hex");
    std.debug.print("compressed hex:\n", .{});
    std.debug.print("{s}\n", .{compressed_hex});

    // The compressed hex is: 0BC94855282CCD4CCE56482ACA2FCF5348CBAF50C82ACD2D484D51C82F4B2D522801CAE72456552AA4E4A7EBF172850C61E5BC5C00

    // Even better, get the compressed data in base64 format:
    // (base64url and modbase64 are other valid choices...)
    const compressed_base64 = try bin_dat.getEncoded(alloc, "base64");
    std.debug.print("compressed base64:\n", .{});
    std.debug.print("{s}\n", .{compressed_base64});

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

    // Now decompress:
    bin_dat.clear() catch {};
    bin_dat.appendEncoded(compressed_hex, "hex") catch {};
    compress.decompressBd(bin_dat) catch {};

    const decompressed_hex = try bin_dat.getEncoded(alloc, "hex");
    std.debug.print("decompressed hex:\n", .{});
    std.debug.print("{s}\n", .{decompressed_hex});

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