Implement bitstream

2 files changed, 159 insertions, 0 deletions

diff --git a/tests/tbitstream.nim b/tests/tbitstream.nim
new file mode 100644
index 0000000..2292049
--- /dev/null
+++ b/tests/tbitstream.nim
@@ -0,0 +1,131 @@
+# "à-la-gzip" 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 unittest, streams, sugar, sequtils
+import integers, bitstream
+
+suite "bitstream":
+  test "chunks iterator":
+    check toSeq(chunks(70, uint32)) == @[(0, 32), (1, 32), (2, 6)]
+    check toSeq(chunks(32, uint16)) == @[(0, 16), (1, 16)]
+
+  test "flush":
+    let stream = newStringStream()
+    defer: stream.close()
+    let bitStream = stream.bitStream()
+
+    bitStream.writeBool(true)
+    stream.setPosition(0)
+    expect IOError: discard stream.peekUint8()
+  
+    bitStream.flush()
+    stream.setPosition(0)
+    check stream.readUint8() == 0x01'u8
+    check stream.atEnd()
+
+    bitStream.flush()
+    check stream.atEnd()
+
+  test "readBool":
+    let stream = newStringStream()
+    defer: stream.close()
+    stream.write(0b1001_1111'u8)
+    stream.write(0b0110_0000'u8)
+    stream.setPosition(0)
+    
+    let bitStream = stream.bitStream()
+    check lc[bitStream.readBool() | (_ <- 0..<16), bool] == @[
+      true, true, true, true, true, false, false, true,
+      false, false, false, false, false, true, true, false]
+
+    expect IOError: discard bitStream.readBool()
+    check bitStream.atEnd()
+
+  test "readBits":
+    let stream = newStringStream()
+    defer: stream.close()
+    stream.write(0xF00F'u16)
+    stream.write(0x0FFF'u16)
+    stream.setPosition(0)
+
+    let bitStream = stream.bitStream()
+    check bitStream.readBits(8, uint8) == 0x0F'u8
+    check bitStream.readBits(16, uint16) == 0xFFF0'u16
+    check bitStream.readBits(8, uint8) == 0x0F'u8
+
+    expect RangeError: discard bitStream.readBits(9, uint8)
+    expect IOError: discard bitStream.readBits(16, uint16)
+    check bitStream.atEnd()
+
+  test "readSeq":
+    let stream = newStringStream()
+    defer: stream.close()
+    stream.write(0x0F00_F0FF_F0F0_F0F0'u64)
+    stream.setPosition(0)
+
+    let bitStream = stream.bitStream()
+    check bitStream.readSeq(32, uint16) == (32, @[0xF0F0'u16, 0xF0F0])
+    check bitStream.readSeq(40, uint8) == (32, @[0xFF'u8, 0xF0, 0x00, 0x0F])
+    check bitStream.atEnd()
+
+  test "writeBool":
+    let stream = newStringStream()
+    defer: stream.close()
+
+    let bitStream = stream.bitStream()
+    let booleanValues = @[
+      true, true, true, true, true, false, false, true,
+      false, false, false, false, false, true, true, false,
+      true, true, false, true]
+    for b in booleanValues: bitStream.writeBool(b)
+    bitStream.flush()
+
+    stream.setPosition(0)
+    check stream.readUint8() == 0b1001_1111'u8
+    check stream.readUint8() == 0b0110_0000'u8
+    check stream.readUint8() == 0b0000_1011'u8
+    expect IOError: discard stream.readUint8()
+    check stream.atEnd()
+
+  test "writeBits":
+    let stream = newStringStream()
+    defer: stream.close()
+
+    let bitStream = stream.bitStream()
+    bitStream.writeBits(4, 0xF00F'u16)
+    bitStream.writeBits(16, 0xF00F'u16)
+    bitStream.writeBits(16, 0xFFFF'u16)
+    bitStream.flush()
+
+    stream.setPosition(0)
+    check stream.readUint16() == 0x00FF'u16
+    check stream.readUint16() == 0xFFFF'u16
+    check stream.readUint8() == 0x0F'u8
+    expect IOError: discard stream.readUint8()
+    check stream.atEnd()
+
+  test "writeSeq":
+    let stream = newStringStream()
+    defer: stream.close()
+
+    let bitStream = stream.bitStream()
+    bitStream.writeSeq(32, @[0xF0F0'u16, 0xF0F0])
+    bitStream.writeSeq(28, @[0xFF'u8, 0xF0, 0x00, 0xFF])
+    bitStream.flush()
+
+    stream.setPosition(0)
+    check stream.readUint64() == 0x0F00_F0FF_F0F0_F0F0'u64
+    check stream.atEnd()
diff --git a/tests/tintegers.nim b/tests/tintegers.nim
new file mode 100644
index 0000000..720677e
--- /dev/null
+++ b/tests/tintegers.nim
@@ -0,0 +1,28 @@
+# "à-la-gzip" 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 unittest
+import integers
+
+suite "integers":
+  test "Round-up integer division":
+    check 42 /^ 2 == 21
+    check 43 /^ 2 == 22
+
+  test "truncateToUint8":
+    check truncateToUint8(0xFA'u8) == 0xFA'u8
+    check truncateToUint8(0x00FA'u16) == 0xFA'u8
+    check truncateToUint8(0xFFFA'u16) == 0xFA'u8