1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
|
# gzip-like LZSS compressor
# Copyright (C) 2018 Pacien TRAN-GIRARD
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import integers, bitio/bitreader, bitio/bitwriter
const maxDataBitLength = high(uint16).int
const bitLengthFieldBitLength = 2 * wordBitLength
type RawBlock* = object
bitLength: int
data: seq[uint8]
proc readSerialised*(bitReader: BitReader): RawBlock =
let bitLength = bitReader.readBits(bitLengthFieldBitLength, uint16).int
let data = bitReader.readSeq(bitLength, uint8)
RawBlock(bitLength: bitLength, data: data.data)
proc writeSerialisedTo*(rawBlock: RawBlock, bitWriter: BitWriter) =
bitWriter.writeBits(bitLengthFieldBitLength, rawBlock.bitLength.uint16)
bitWriter.writeSeq(rawBlock.bitLength, rawBlock.data)
proc readRaw*(bitReader: BitReader, bits: int = maxDataBitLength): RawBlock =
let data = bitReader.readSeq(bits, uint8)
RawBlock(bitLength: data.bitLength, data: data.data)
proc writeRawTo*(rawBlock: RawBlock, bitWriter: BitWriter) =
bitWriter.writeSeq(rawBlock.bitLength, rawBlock.data)
|