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-rw-r--r-- | src/rawblock.nim | 40 | ||||
-rw-r--r-- | tests/trawblock.nim | 57 |
2 files changed, 97 insertions, 0 deletions
diff --git a/src/rawblock.nim b/src/rawblock.nim new file mode 100644 index 0000000..bdbfc71 --- /dev/null +++ b/src/rawblock.nim | |||
@@ -0,0 +1,40 @@ | |||
1 | # "à-la-gzip" gzip-like LZSS compressor | ||
2 | # Copyright (C) 2018 Pacien TRAN-GIRARD | ||
3 | # | ||
4 | # This program is free software: you can redistribute it and/or modify | ||
5 | # it under the terms of the GNU Affero General Public License as | ||
6 | # published by the Free Software Foundation, either version 3 of the | ||
7 | # License, or (at your option) any later version. | ||
8 | # | ||
9 | # This program is distributed in the hope that it will be useful, | ||
10 | # but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
11 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
12 | # GNU Affero General Public License for more details. | ||
13 | # | ||
14 | # You should have received a copy of the GNU Affero General Public License | ||
15 | # along with this program. If not, see <https://www.gnu.org/licenses/>. | ||
16 | |||
17 | import integers, bitstream | ||
18 | |||
19 | const maxDataBitLength = 100_000_000 * wordBitLength # 100MB | ||
20 | const bitLengthFieldBitLength = 2 * wordBitLength | ||
21 | |||
22 | type RawBlock* = object | ||
23 | bitLength: int | ||
24 | data: seq[uint8] | ||
25 | |||
26 | proc readSerialised*(bitStream: BitStream): RawBlock = | ||
27 | let bitLength = bitStream.readBits(bitLengthFieldBitLength, uint16).int | ||
28 | let data = readSeq(bitStream, bitLength, uint8) | ||
29 | RawBlock(bitLength: bitLength, data: data.data) | ||
30 | |||
31 | proc writeSerialisedTo*(rawBlock: RawBlock, bitStream: BitStream) = | ||
32 | bitStream.writeBits(bitLengthFieldBitLength, rawBlock.bitLength.uint16) | ||
33 | writeSeq(bitStream, rawBlock.bitLength, rawBlock.data) | ||
34 | |||
35 | proc readRaw*(bitStream: BitStream, bits: int = maxDataBitLength): RawBlock = | ||
36 | let data = readSeq(bitStream, bits, uint8) | ||
37 | RawBlock(bitLength: data.bitLength, data: data.data) | ||
38 | |||
39 | proc writeRawTo*(rawBlock: RawBlock, bitStream: BitStream) = | ||
40 | writeSeq(bitStream, rawBlock.bitLength, rawBlock.data) | ||
diff --git a/tests/trawblock.nim b/tests/trawblock.nim new file mode 100644 index 0000000..1e92c60 --- /dev/null +++ b/tests/trawblock.nim | |||
@@ -0,0 +1,57 @@ | |||
1 | # "à-la-gzip" gzip-like LZSS compressor | ||
2 | # Copyright (C) 2018 Pacien TRAN-GIRARD | ||
3 | # | ||
4 | # This program is free software: you can redistribute it and/or modify | ||
5 | # it under the terms of the GNU Affero General Public License as | ||
6 | # published by the Free Software Foundation, either version 3 of the | ||
7 | # License, or (at your option) any later version. | ||
8 | # | ||
9 | # This program is distributed in the hope that it will be useful, | ||
10 | # but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
11 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
12 | # GNU Affero General Public License for more details. | ||
13 | # | ||
14 | # You should have received a copy of the GNU Affero General Public License | ||
15 | # along with this program. If not, see <https://www.gnu.org/licenses/>. | ||
16 | |||
17 | import unittest, streams | ||
18 | import bitstream, rawblock | ||
19 | |||
20 | suite "rawblock": | ||
21 | test "serialise": | ||
22 | let rawStream = newStringStream() | ||
23 | defer: rawStream.close() | ||
24 | rawStream.write(0xFEDC_BA98_7654_3210'u64) | ||
25 | rawStream.setPosition(0) | ||
26 | let rawBitStream = rawStream.bitStream() | ||
27 | let rawBlock = rawblock.readRaw(rawBitStream) | ||
28 | |||
29 | let outputStream = newStringStream() | ||
30 | defer: outputStream.close() | ||
31 | let outputBitStream = outputStream.bitStream() | ||
32 | rawBlock.writeSerialisedTo(outputBitStream) | ||
33 | outputBitStream.flush() | ||
34 | |||
35 | outputStream.setPosition(0) | ||
36 | check outputStream.readUint16() == 64 | ||
37 | check outputStream.readUint64() == 0xFEDC_BA98_7654_3210'u64 | ||
38 | check outputStream.atEnd() | ||
39 | |||
40 | test "deserialise": | ||
41 | let serialisedStream = newStringStream() | ||
42 | defer: serialisedStream.close() | ||
43 | serialisedStream.write(60'u16) | ||
44 | serialisedStream.write(0xFEDC_BA98_7654_3210'u64) | ||
45 | serialisedStream.setPosition(0) | ||
46 | let serialisedBitStream = serialisedStream.bitStream() | ||
47 | let rawBlock = rawBlock.readSerialised(serialisedBitStream) | ||
48 | |||
49 | let outputStream = newStringStream() | ||
50 | defer: outputStream.close() | ||
51 | let outputBitStream = outputStream.bitStream() | ||
52 | rawBlock.writeRawTo(outputBitStream) | ||
53 | outputBitStream.flush() | ||
54 | |||
55 | outputStream.setPosition(0) | ||
56 | check outputStream.readUint64 == 0x0EDC_BA98_7654_3210'u64 | ||
57 | check outputStream.atEnd() | ||