From a7941b92e29f90b071139efa87c01dc379597fcf Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Mon, 15 Feb 2016 22:53:39 +0100
Subject: [PATCH] added BitReader::readUnsignedExpGolombCodedBits() and
 BitReader::readSignedExpGolombCodedBits()

---
 CMakeLists.txt    |  4 ++--
 c++utilities.pro  |  2 +-
 io/binaryreader.h |  4 ++--
 io/bitreader.h    | 37 ++++++++++++++++++++++++++++++++++++-
 tests/iotests.cpp |  8 ++++++--
 5 files changed, 47 insertions(+), 8 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 05eefec..ea10920 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -66,8 +66,8 @@ set(META_APP_AUTHOR "Martchus")
 set(META_APP_URL "https://github.com/${META_APP_AUTHOR}/${META_PROJECT_NAME}")
 set(META_APP_DESCRIPTION "Common C++ classes and routines used by my applications such as argument parser, IO and conversion utilities.")
 set(META_VERSION_MAJOR 3)
-set(META_VERSION_MINOR 1)
-set(META_VERSION_PATCH 1)
+set(META_VERSION_MINOR 2)
+set(META_VERSION_PATCH 0)
 set(META_APP_VERSION ${META_VERSION_MAJOR}.${META_VERSION_MINOR}.${META_VERSION_PATCH})
 
 # stringification of meta data
diff --git a/c++utilities.pro b/c++utilities.pro
index b5390d1..f12b7a2 100644
--- a/c++utilities.pro
+++ b/c++utilities.pro
@@ -3,7 +3,7 @@ projectname = c++utilities
 appname = "C++ Utilities"
 appauthor = Martchus
 QMAKE_TARGET_DESCRIPTION = "Common C++ classes and routines used by my applications such as argument parser, IO and conversion utilities."
-VERSION = 3.1.1
+VERSION = 3.2.0
 
 # include ../../common.pri when building as part of a subdirs project; otherwise include general.pri
 !include(../../common.pri) {
diff --git a/io/binaryreader.h b/io/binaryreader.h
index 9424a1b..0804b05 100644
--- a/io/binaryreader.h
+++ b/io/binaryreader.h
@@ -160,7 +160,7 @@ inline bool BinaryReader::fail() const
  */
 inline bool BinaryReader::eof() const
 {
-    return m_stream ? m_stream->eof() : false;
+    return m_stream && m_stream->eof();
 }
 
 /*!
@@ -168,7 +168,7 @@ inline bool BinaryReader::eof() const
  */
 inline bool BinaryReader::canRead() const
 {
-    return m_stream ? !(m_stream->fail() || m_stream->eof()) : false;
+    return m_stream && m_stream->good();
 }
 
 /*!
diff --git a/io/bitreader.h b/io/bitreader.h
index 2dabde6..10721be 100644
--- a/io/bitreader.h
+++ b/io/bitreader.h
@@ -5,8 +5,8 @@
 #include "../application/global.h"
 
 #include <ios>
-
 #include <iostream>
+#include <type_traits>
 
 namespace IoUtilities {
 
@@ -18,6 +18,8 @@ public:
 
     template<typename intType> intType readBits(byte bitCount);
     byte readBit();
+    template<typename intType> intType readUnsignedExpGolombCodedBits();
+    template<typename intType> intType readSignedExpGolombCodedBits();
     template<typename intType> intType showBits(byte bitCount);
     void skipBits(std::size_t bitCount);
     void align();
@@ -88,6 +90,39 @@ inline byte BitReader::readBit()
     return readBits<byte>(1) == 1;
 }
 
+/*!
+ * \brief Reads "Exp-Golomb coded" bits (unsigned).
+ * \tparam intType Specifies the type of the returned value.
+ * \remarks Does not check whether intType is big enough to hold result.
+ * \throws Throws ios_base::failure if the end of the buffer is exceeded.
+ *         The reader becomes invalid in that case.
+ * \sa https://en.wikipedia.org/wiki/Exponential-Golomb_coding
+ */
+template<typename intType>
+intType BitReader::readUnsignedExpGolombCodedBits()
+{
+    byte count = 0;
+    while(!readBit()) {
+        ++count;
+    }
+    return count ? (((1 << count) | readBits<intType>(count)) - 1) : 0;
+}
+
+/*!
+ * \brief Reads "Exp-Golomb coded" bits (signed).
+ * \tparam intType Specifies the type of the returned value which should be signed (obviously).
+ * \remarks Does not check whether intType is big enough to hold result.
+ * \throws Throws ios_base::failure if the end of the buffer is exceeded.
+ *         The reader becomes invalid in that case.
+ * \sa https://en.wikipedia.org/wiki/Exponential-Golomb_coding
+ */
+template<typename intType>
+intType BitReader::readSignedExpGolombCodedBits()
+{
+    auto value = readUnsignedExpGolombCodedBits<typename std::make_unsigned<intType>::type>();
+    return (value % 2) ? static_cast<intType>((value + 1) / 2) : (-static_cast<intType>(value / 2));
+}
+
 /*!
  * \brief Reads the specified number of bits from the buffer without advancing the current position.
  */
diff --git a/tests/iotests.cpp b/tests/iotests.cpp
index 061faca..d9b9a8a 100644
--- a/tests/iotests.cpp
+++ b/tests/iotests.cpp
@@ -181,8 +181,8 @@ void IoTests::testBinaryWriter()
  */
 void IoTests::testBitReader()
 {
-    byte testData[] = {0x81, 0x90, 0x3C, 0x44, 0x28, 0x00, 0x44};
-    BitReader reader(reinterpret_cast<char *>(testData), sizeof(testData));
+    const byte testData[] = {0x81, 0x90, 0x3C, 0x44, 0x28, 0x00, 0x44, 0x10, 0x20};
+    BitReader reader(reinterpret_cast<const char *>(testData), sizeof(testData));
     CPPUNIT_ASSERT(reader.readBit() == 1);
     reader.skipBits(6);
     CPPUNIT_ASSERT(reader.showBits<byte>(2) == 3);
@@ -190,6 +190,10 @@ void IoTests::testBitReader()
     CPPUNIT_ASSERT(reader.readBits<uint32>(32) == (0x103C4428 << 1));
     reader.align();
     CPPUNIT_ASSERT(reader.readBits<byte>(8) == 0x44);
+    CPPUNIT_ASSERT(reader.readUnsignedExpGolombCodedBits<byte>() == 7);
+    CPPUNIT_ASSERT(reader.readSignedExpGolombCodedBits<sbyte>() == 4);
+    CPPUNIT_ASSERT(reader.readBit() == 0);
+    CPPUNIT_ASSERT(reader.readBit() == 0);
     CPPUNIT_ASSERT_THROW(reader.readBit(), std::ios_base::failure);
 }