Function decodeZstandardFrame [src]

Decode a Zstandard frame from src into dest, returning the number of bytes read from src and written to dest. The first four bytes of src must be the magic number for a Zstandard frame. Error returned: error.UnknownContentSizeUnsupported if the frame does not declare the uncompressed content size error.ContentTooLarge if dest is smaller than the uncompressed data size declared by the frame header error.WindowSizeUnknown if the frame does not have a valid window size error.DictionaryIdFlagUnsupported if the frame uses a dictionary error.ContentSizeTooLarge if the frame header indicates a content size that is larger than std.math.maxInt(usize) error.ChecksumFailure if verify_checksum is true and the frame contains a checksum that does not match the checksum of the decompressed data error.ReservedBitSet if the reserved bit of the frame header is set error.EndOfStream if src does not contain a complete frame an error in block.Error if there are errors decoding a block error.BadContentSize if the content size declared by the frame does not equal the actual size of decompressed data

Prototype

 pub fn decodeZstandardFrame( dest: []u8, src: []const u8, verify_checksum: bool, ) (error{ UnknownContentSizeUnsupported, ContentTooLarge, ContentSizeTooLarge, WindowSizeUnknown, DictionaryIdFlagUnsupported, } || FrameError)!ReadWriteCount

Parameters

dest: []u8src: []const u8verify_checksum: bool

Source

  pub fn decodeZstandardFrame(
    dest: []u8,
    src: []const u8,
    verify_checksum: bool,
) (error{
    UnknownContentSizeUnsupported,
    ContentTooLarge,
    ContentSizeTooLarge,
    WindowSizeUnknown,
    DictionaryIdFlagUnsupported,
} || FrameError)!ReadWriteCount {
    assert(std.mem.readInt(u32, src[0..4], .little) == frame.Zstandard.magic_number);
    var consumed_count: usize = 4;

    var frame_context = context: {
        var fbs = std.io.fixedBufferStream(src[consumed_count..]);
        const source = fbs.reader();
        const frame_header = try decodeZstandardHeader(source);
        consumed_count += fbs.pos;
        break :context FrameContext.init(
            frame_header,
            std.math.maxInt(usize),
            verify_checksum,
        ) catch |err| switch (err) {
            error.WindowTooLarge => unreachable,
            inline else => |e| return e,
        };
    };
    const counts = try decodeZStandardFrameBlocks(
        dest,
        src[consumed_count..],
        &frame_context,
    );
    return ReadWriteCount{
        .read_count = counts.read_count + consumed_count,
        .write_count = counts.write_count,
    };
}  