Function decompress [src]

Decompresses the given data from reader into writer. Stops early if more than uncompressed_size bytes are processed and verifies that exactly that number of bytes are decompressed. Returns the CRC-32 of the uncompressed data. writer can be anything with a writeAll(self: *Self, chunk: []const u8) anyerror!void method.

Prototype

pub fn decompress( method: CompressionMethod, uncompressed_size: u64, reader: anytype, writer: anytype, ) !u32

Parameters

method: CompressionMethoduncompressed_size: u64

Source

  pub fn decompress(
    method: CompressionMethod,
    uncompressed_size: u64,
    reader: anytype,
    writer: anytype,
) !u32 {
    var hash = std.hash.Crc32.init();

    var total_uncompressed: u64 = 0;
    switch (method) {
        .store => {
            var buf: [4096]u8 = undefined;
            while (true) {
                const len = try reader.read(&buf);
                if (len == 0) break;
                try writer.writeAll(buf[0..len]);
                hash.update(buf[0..len]);
                total_uncompressed += @intCast(len);
            }
        },
        .deflate => {
            var br = std.io.bufferedReader(reader);
            var decompressor = std.compress.flate.decompressor(br.reader());
            while (try decompressor.next()) |chunk| {
                try writer.writeAll(chunk);
                hash.update(chunk);
                total_uncompressed += @intCast(chunk.len);
                if (total_uncompressed > uncompressed_size)
                    return error.ZipUncompressSizeTooSmall;
            }
            if (br.end != br.start)
                return error.ZipDeflateTruncated;
        },
        _ => return error.UnsupportedCompressionMethod,
    }
    if (total_uncompressed != uncompressed_size)
        return error.ZipUncompressSizeMismatch;

    return hash.final();
}  