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-rw-r--r--src/rawblock.nim40
-rw-r--r--tests/trawblock.nim57
2 files changed, 97 insertions, 0 deletions
diff --git a/src/rawblock.nim b/src/rawblock.nim
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+++ b/src/rawblock.nim
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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
17import integers, bitstream
18
19const maxDataBitLength = 100_000_000 * wordBitLength # 100MB
20const bitLengthFieldBitLength = 2 * wordBitLength
21
22type RawBlock* = object
23 bitLength: int
24 data: seq[uint8]
25
26proc 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
31proc writeSerialisedTo*(rawBlock: RawBlock, bitStream: BitStream) =
32 bitStream.writeBits(bitLengthFieldBitLength, rawBlock.bitLength.uint16)
33 writeSeq(bitStream, rawBlock.bitLength, rawBlock.data)
34
35proc readRaw*(bitStream: BitStream, bits: int = maxDataBitLength): RawBlock =
36 let data = readSeq(bitStream, bits, uint8)
37 RawBlock(bitLength: data.bitLength, data: data.data)
38
39proc 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
17import unittest, streams
18import bitstream, rawblock
19
20suite "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()