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std.compress.zstd: keep frame state between blocks
This commit is contained in:
Andrew Kelley
parent
13e08ea6f0
commit
7f43f78b5b
1 changed files with 32 additions and 42 deletions
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@ -23,6 +23,7 @@ const State = union(enum) {
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frame: Frame,
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checksum: ?u32,
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decompressed_size: usize,
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decode: Frame.Zstandard.Decode,
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};
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};
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@ -138,6 +139,7 @@ fn initFrame(d: *Decompress, window_size_max: usize, magic: Frame.Magic) !void {
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.frame = try Frame.init(header, window_size_max, d.verify_checksum),
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.checksum = null,
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.decompressed_size = 0,
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.decode = .init,
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} };
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},
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.skippable => {
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@ -168,16 +170,13 @@ fn readInFrame(d: *Decompress, w: *Writer, limit: Limit, state: *State.InFrame)
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bytes_written = block_size;
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},
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.compressed => {
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var literal_fse_buffer: [zstd.table_size_max.literal]Table.Fse = undefined;
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var match_fse_buffer: [zstd.table_size_max.match]Table.Fse = undefined;
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var offset_fse_buffer: [zstd.table_size_max.offset]Table.Fse = undefined;
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var literals_buffer: [zstd.block_size_max]u8 = undefined;
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var sequence_buffer: [zstd.block_size_max]u8 = undefined;
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var decode: Frame.Zstandard.Decode = .init(&literal_fse_buffer, &match_fse_buffer, &offset_fse_buffer, window_len);
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var remaining: Limit = .limited(block_size);
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const literals = try LiteralsSection.decode(in, &remaining, &literals_buffer);
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const sequences_header = try SequencesSection.Header.decode(in, &remaining);
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const decode = &state.decode;
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try decode.prepare(in, &remaining, literals, sequences_header);
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{
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@ -370,16 +369,15 @@ pub const Frame = struct {
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};
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pub const Decode = struct {
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window_len: u32,
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repeat_offsets: [3]u32,
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offset: StateData(8),
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match: StateData(9),
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literal: StateData(9),
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offset_fse_buffer: []Table.Fse,
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match_fse_buffer: []Table.Fse,
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literal_fse_buffer: []Table.Fse,
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literal_fse_buffer: [zstd.table_size_max.literal]Table.Fse,
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match_fse_buffer: [zstd.table_size_max.match]Table.Fse,
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offset_fse_buffer: [zstd.table_size_max.offset]Table.Fse,
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fse_tables_undefined: bool,
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@ -401,38 +399,30 @@ pub const Frame = struct {
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};
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}
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pub fn init(
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literal_fse_buffer: []Table.Fse,
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match_fse_buffer: []Table.Fse,
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offset_fse_buffer: []Table.Fse,
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window_len: u32,
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) Decode {
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return .{
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.window_len = window_len,
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.repeat_offsets = .{
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zstd.start_repeated_offset_1,
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zstd.start_repeated_offset_2,
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zstd.start_repeated_offset_3,
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},
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const init: Decode = .{
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.repeat_offsets = .{
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zstd.start_repeated_offset_1,
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zstd.start_repeated_offset_2,
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zstd.start_repeated_offset_3,
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},
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.offset = undefined,
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.match = undefined,
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.literal = undefined,
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.offset = undefined,
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.match = undefined,
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.literal = undefined,
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.literal_fse_buffer = literal_fse_buffer,
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.match_fse_buffer = match_fse_buffer,
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.offset_fse_buffer = offset_fse_buffer,
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.literal_fse_buffer = undefined,
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.match_fse_buffer = undefined,
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.offset_fse_buffer = undefined,
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.fse_tables_undefined = true,
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.fse_tables_undefined = true,
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.literal_written_count = 0,
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.literal_header = undefined,
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.literal_streams = undefined,
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.literal_stream_reader = undefined,
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.literal_stream_index = undefined,
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.huffman_tree = null,
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};
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}
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.literal_written_count = 0,
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.literal_header = undefined,
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.literal_streams = undefined,
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.literal_stream_reader = undefined,
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.literal_stream_index = undefined,
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.huffman_tree = null,
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};
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pub const PrepareError = error{
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/// the (reversed) literal bitstream's first byte does not have any bits set
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@ -514,12 +504,12 @@ pub const Frame = struct {
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return self.repeat_offsets[0];
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}
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const DataType = enum { offset, match, literal };
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const WhichFse = enum { offset, match, literal };
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/// TODO: don't use `@field`
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fn updateState(
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self: *Decode,
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comptime choice: DataType,
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comptime choice: WhichFse,
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bit_reader: *ReverseBitReader,
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) error{ MalformedFseBits, EndOfStream }!void {
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switch (@field(self, @tagName(choice)).table) {
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@ -549,7 +539,7 @@ pub const Frame = struct {
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self: *Decode,
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in: *Reader,
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remaining: *Limit,
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comptime choice: DataType,
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comptime choice: WhichFse,
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mode: SequencesSection.Header.Mode,
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) !void {
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const field_name = @tagName(choice);
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@ -576,10 +566,10 @@ pub const Frame = struct {
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&bit_reader,
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@field(zstd.table_symbol_count_max, field_name),
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@field(zstd.table_accuracy_log_max, field_name),
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@field(self, field_name ++ "_fse_buffer"),
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&@field(self, field_name ++ "_fse_buffer"),
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);
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@field(self, field_name).table = .{
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.fse = @field(self, field_name ++ "_fse_buffer")[0..table_size],
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.fse = (&@field(self, field_name ++ "_fse_buffer"))[0..table_size],
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};
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@field(self, field_name).accuracy_log = std.math.log2_int_ceil(usize, table_size);
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in.toss(bit_reader.index);
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@ -762,7 +752,7 @@ pub const Frame = struct {
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}
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/// TODO: don't use `@field`
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fn getCode(self: *Decode, comptime choice: DataType) u32 {
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fn getCode(self: *Decode, comptime choice: WhichFse) u32 {
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return switch (@field(self, @tagName(choice)).table) {
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.rle => |value| value,
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.fse => |table| table[@field(self, @tagName(choice)).state].symbol,
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