Octane v1.01.20 - The Open Compression Toolkit for C++

http://octane.sourceforge.net/

bitwriter Class Reference
[bitio]

#include <bitwriter.hpp>

Inheritance diagram for bitwriter:

List of all members.

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Detailed Description

Base class for bit output wrappers.

The bitwriter class is a wrapper which provides bit output functionality to anything supporting output of 8-bit chars (bytes). It attempts to be as clean and transparent as possible, while maintaining a fairly decent efficiency.

The base class contains functions for handling the output by collecting bits in a temporary store (a byte), writing them out when the store is full.

It is used by creating a sub-class and implementing the write_next_byte() member function.

The destructor of the derived class should call finalize().

Definition at line 40 of file bitwriter.hpp.

Public Member Functions
	bitwriter ()
	Constructor.
virtual	~bitwriter ()
	Destructor.
virtual bool	error () const
	Check for error.
void	align_byte ()
	Align bitwriter on a byte boundary.
Size Functions
size_t	bits_done () const
	Return the number of bits written.
size_t	bytes_done () const
	Return the number of bytes written.
size_t	tell_bit () const
	Return the current bit position within the bit stream.
size_t	tell_byte () const
	Return the current byte position within the bit stream.
Output Functions
void	put_bit (bool v)
	Write one bit to the output.
void	put_byte (unsigned char v)
	Write one byte (8-bit unsigned value).
void	put_word (unsigned short v)
	Write one word (16-bit unsigned value).
void	put_dword (unsigned long v)
	Write one dword (32-bit unsigned value).
void	put_float (float v)
	Write one float.
void	put_double (double v)
	Write one double.
void	put_string (std::string &s)
	Write a string.
void	write (const char *buffer, size_t length)
	Copy bytes from an array to the bitwriter.
Polymorphic Output Function Wrappers
void	put (bool v)
void	put (char v)
void	put (unsigned char v)
void	put (short v)
void	put (unsigned short v)
void	put (int v)
void	put (unsigned int v)
void	put (long v)
void	put (unsigned long v)
void	put (float v)
void	put (double v)
void	put (std::string &s)
Protected Member Functions
void	finalize ()
	Perform cleanup.
virtual void	write_next_byte (char c)=0
	Defines the method of writing a single byte of output.
Protected Attributes
size_t	num
	Number of bytes written.

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Constructor & Destructor Documentation

virtual bitwriter::~bitwriter (   )  [inline, virtual]

Destructor. Derived classes should implement a destructor which calls the finalize() member function. Definition at line 48 of file bitwriter.hpp. { ; }

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Member Function Documentation

virtual bool bitwriter::error (   )  const [inline, virtual]

Check for error. Returns: true if an error occurred. Reimplemented in file_bitwriter. Definition at line 53 of file bitwriter.hpp. { return false; }

size_t bitwriter::bits_done (   )  const [inline]

Return the number of bits written. Returns: the number of bits written by the bitwriter. Definition at line 72 of file bitwriter.hpp. References num. Referenced by tell_bit(). { return 8*num + 8 - log2_tab[mask]; }

size_t bitwriter::bytes_done (   )  const [inline]

Return the number of bytes written. Returns: the number of bytes written by the bitwriter. Definition at line 75 of file bitwriter.hpp. References num. Referenced by tell_byte(). { return num; }

size_t bitwriter::tell_bit (   )  const [inline]

Return the current bit position within the bit stream. Returns: the current bit position. Definition at line 79 of file bitwriter.hpp. References bits_done(). { return bits_done(); }

size_t bitwriter::tell_byte (   )  const [inline]

Return the current byte position within the bit stream. Returns: the current byte position. Definition at line 83 of file bitwriter.hpp. References bytes_done(). Referenced by OctaneCompressor::Compress(), OctaneCompressor::Decompress(), and OctaneCompressor::Save(). { return bytes_done(); }

void bitwriter::put_bit (  bool  v  )  [inline]

Write one bit to the output. Parameters: v  - bit value to write (true for 1, false for 0). Definition at line 93 of file bitwriter.hpp. References num, and write_next_byte(). Referenced by HuffNode_Leaf::AddBitsToBitWriter(). { if (v) current |= mask; if (!(mask >>= 1)) { ++num; write_next_byte(current); current = 0; mask = 0x80; } }

void bitwriter::put_byte (  unsigned char  v  )  [inline]

Write one byte (8-bit unsigned value). Parameters: v  - byte value to write. Definition at line 106 of file bitwriter.hpp. References num, and write_next_byte(). Referenced by zleCompressor::DoProtectedCompress(), SampleCompressor::DoProtectedCompress(), mtfllCompressor::DoProtectedCompress(), zleCompressor::DoProtectedDecompress(), SampleCompressor::DoProtectedDecompress(), mtfllCompressor::DoProtectedDecompress(), put_dword(), put_word(), OctaneCompressor::SaveCompressionHeader(), OctaneCompressor::SaveGUID(), and write(). { ++num; if (mask == 0x80) { write_next_byte(v); return; } unsigned char ml = log2_tab[mask]; current |= v >> (8 - ml); write_next_byte(current); current = v << ml; }

void bitwriter::put_word (  unsigned short  v  )  [inline]

Write one word (16-bit unsigned value). Parameters: v  - word value to write. Definition at line 120 of file bitwriter.hpp. References put_byte(). Referenced by put_string(). { put_byte((v >> 8) & 0x00ff); put_byte((v ) & 0x00ff); }

void bitwriter::put_dword (  unsigned long  v  )  [inline]

Write one dword (32-bit unsigned value). Parameters: v  - dword value to write. Definition at line 128 of file bitwriter.hpp. References put_byte(). Referenced by put_string(). { put_byte((unsigned char) ((v >> 24) & 0x00ff)); put_byte((unsigned char) ((v >> 16) & 0x00ff)); put_byte((unsigned char) ((v >> 8 ) & 0x00ff)); put_byte((unsigned char) ((v ) & 0x00ff)); }

void bitwriter::put_float (  float  v  )  [inline]

Write one float. Parameters: v  - float value to write. Warning: Experimental, not portable. Todo: Experimental, not portable. Definition at line 140 of file bitwriter.hpp. References write(). { write((char*)&v, sizeof(float)); }

void bitwriter::put_double (  double  v  )  [inline]

Write one double. Parameters: v  - double value to write. Warning: Experimental, not portable. Todo: Experimental, not portable. Definition at line 146 of file bitwriter.hpp. References write(). { write((char*)&v, sizeof(double)); }

void bitwriter::put_string (  std::string &  s  )  [inline]

Write a string. Parameters: s  - the string to write. Definition at line 150 of file bitwriter.hpp. References put_dword(), put_word(), and write(). { size_t len = s.length(); if ((len > 0x0000ffff) || (len == 0)) { put_word(0); put_dword(len); } else { put_word(len); } write(s.c_str(), len); }

void bitwriter::write (  const char *  buffer, size_t  length )  [inline]

Copy bytes from an array to the bitwriter. Parameters: buffer  - pointer to where the bytes should be read. length  - the number of bytes to copy. Definition at line 168 of file bitwriter.hpp. References put_byte(). Referenced by put_double(), put_float(), put_string(), and SubstringParser::WriteSymbolText(). { for ( ; length; --length) put_byte(*buffer++); }

void bitwriter::finalize (   )  [inline, protected]

Perform cleanup. Derived classes should call this method from their destructor. Definition at line 203 of file bitwriter.hpp. References align_byte(). { align_byte(); }

virtual void bitwriter::write_next_byte (  char  c  )  [protected, pure virtual]

Defines the method of writing a single byte of output. Derived classes should implement this function. Parameters: c  - the 8 bits to write to the output. Implemented in null_bitwriter, stream_bitwriter, vector_bitwriter, string_bitwriter, array_bitwriter, and file_bitwriter. Referenced by align_byte(), put_bit(), and put_byte().

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The documentation for this class was generated from the following files:

• bitio/bitwriter.hpp
• bitio/bitwriter.cpp

 

Generated on 20 May 2004 by doxygen 1.3.3