Advanced Params

examples/advanced_params.zig — CompressionOptions and getCompressionParameters.

Client Code

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

pub fn main() !void {
    var gpa = std.heap.DebugAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();
    const data = "Advanced parameters example: custom window, checksum, and strategy tuning. " ** 30;
    var base = zstd.getCompressionParameters(12, data.len, 20);
    base.checksum = true;
    const compressed = try zstd.compressWithOptions(allocator, data, base);
    defer allocator.free(compressed);
    std.debug.print("Advanced compress: {d} -> {d} (strategy={s}, window_log={d})\n", .{ data.len, compressed.len, @tagName(base.strategy), base.window_log });
    const hdr = try zstd.getFrameHeader(compressed);
    std.debug.assert(hdr.checksum_flag);
    std.debug.assert(hdr.window_size >= data.len);
    const decompressed = try zstd.decompress(allocator, compressed);
    defer allocator.free(decompressed);
    std.debug.assert(std.mem.eql(u8, data, decompressed));
    std.debug.print("Decompressed {d} bytes, checksum validated\n", .{decompressed.len});
}

Output

Advanced compress: 2250 -> 2264 (strategy=btlazy2, window_log=20)
Decompressed 2250 bytes, checksum validated

Explanation

• getCompressionParameters(12, len, 20) returns tuned window_log, hash_log, chain_log, search_log, target_length, strategy for level 12.
• Setting checksum=true adds Content_Checksum (XXH64 low 32) validated on decompress.
• getFrameHeader confirms checksum_flag and window_size.

Run:

zig build run-advanced_params