gem5/ext/iostream3/zfstream.h
Andreas Hansson 7661f1c2bf ext: Replace gzstream with iostream3 from zlib to avoid LGPL
This patch replaces the gzstream zlib wrapper with the iostream3
wrapper provided as part of zlib contributions. The main reason for
the switch is to avoid including LGPL in the default gem5
build. iostream3 is provided under a more permissive license:

The code is provided "as is", with the permission to use, copy,
modify, distribute and sell it for any purpose without fee.
2016-01-11 05:52:18 -05:00

466 lines
12 KiB
C++

/*
* A C++ I/O streams interface to the zlib gz* functions
*
* by Ludwig Schwardt <schwardt@sun.ac.za>
* original version by Kevin Ruland <kevin@rodin.wustl.edu>
*
* This version is standard-compliant and compatible with gcc 3.x.
*/
#ifndef ZFSTREAM_H
#define ZFSTREAM_H
#include <istream> // not iostream, since we don't need cin/cout
#include <ostream>
#include "zlib.h"
/*****************************************************************************/
/**
* @brief Gzipped file stream buffer class.
*
* This class implements basic_filebuf for gzipped files. It doesn't yet support
* seeking (allowed by zlib but slow/limited), putback and read/write access
* (tricky). Otherwise, it attempts to be a drop-in replacement for the standard
* file streambuf.
*/
class gzfilebuf : public std::streambuf
{
public:
// Default constructor.
gzfilebuf();
// Destructor.
virtual
~gzfilebuf();
/**
* @brief Set compression level and strategy on the fly.
* @param comp_level Compression level (see zlib.h for allowed values)
* @param comp_strategy Compression strategy (see zlib.h for allowed values)
* @return Z_OK on success, Z_STREAM_ERROR otherwise.
*
* Unfortunately, these parameters cannot be modified separately, as the
* previous zfstream version assumed. Since the strategy is seldom changed,
* it can default and setcompression(level) then becomes like the old
* setcompressionlevel(level).
*/
int
setcompression(int comp_level,
int comp_strategy = Z_DEFAULT_STRATEGY);
/**
* @brief Check if file is open.
* @return True if file is open.
*/
bool
is_open() const { return (file != NULL); }
/**
* @brief Open gzipped file.
* @param name File name.
* @param mode Open mode flags.
* @return @c this on success, NULL on failure.
*/
gzfilebuf*
open(const char* name,
std::ios_base::openmode mode);
/**
* @brief Attach to already open gzipped file.
* @param fd File descriptor.
* @param mode Open mode flags.
* @return @c this on success, NULL on failure.
*/
gzfilebuf*
attach(int fd,
std::ios_base::openmode mode);
/**
* @brief Close gzipped file.
* @return @c this on success, NULL on failure.
*/
gzfilebuf*
close();
protected:
/**
* @brief Convert ios open mode int to mode string used by zlib.
* @return True if valid mode flag combination.
*/
bool
open_mode(std::ios_base::openmode mode,
char* c_mode) const;
/**
* @brief Number of characters available in stream buffer.
* @return Number of characters.
*
* This indicates number of characters in get area of stream buffer.
* These characters can be read without accessing the gzipped file.
*/
virtual std::streamsize
showmanyc();
/**
* @brief Fill get area from gzipped file.
* @return First character in get area on success, EOF on error.
*
* This actually reads characters from gzipped file to stream
* buffer. Always buffered.
*/
virtual int_type
underflow();
/**
* @brief Write put area to gzipped file.
* @param c Extra character to add to buffer contents.
* @return Non-EOF on success, EOF on error.
*
* This actually writes characters in stream buffer to
* gzipped file. With unbuffered output this is done one
* character at a time.
*/
virtual int_type
overflow(int_type c = traits_type::eof());
/**
* @brief Installs external stream buffer.
* @param p Pointer to char buffer.
* @param n Size of external buffer.
* @return @c this on success, NULL on failure.
*
* Call setbuf(0,0) to enable unbuffered output.
*/
virtual std::streambuf*
setbuf(char_type* p,
std::streamsize n);
/**
* @brief Flush stream buffer to file.
* @return 0 on success, -1 on error.
*
* This calls underflow(EOF) to do the job.
*/
virtual int
sync();
//
// Some future enhancements
//
// virtual int_type uflow();
// virtual int_type pbackfail(int_type c = traits_type::eof());
// virtual pos_type
// seekoff(off_type off,
// std::ios_base::seekdir way,
// std::ios_base::openmode mode = std::ios_base::in|std::ios_base::out);
// virtual pos_type
// seekpos(pos_type sp,
// std::ios_base::openmode mode = std::ios_base::in|std::ios_base::out);
private:
/**
* @brief Allocate internal buffer.
*
* This function is safe to call multiple times. It will ensure
* that a proper internal buffer exists if it is required. If the
* buffer already exists or is external, the buffer pointers will be
* reset to their original state.
*/
void
enable_buffer();
/**
* @brief Destroy internal buffer.
*
* This function is safe to call multiple times. It will ensure
* that the internal buffer is deallocated if it exists. In any
* case, it will also reset the buffer pointers.
*/
void
disable_buffer();
/**
* Underlying file pointer.
*/
gzFile file;
/**
* Mode in which file was opened.
*/
std::ios_base::openmode io_mode;
/**
* @brief True if this object owns file descriptor.
*
* This makes the class responsible for closing the file
* upon destruction.
*/
bool own_fd;
/**
* @brief Stream buffer.
*
* For simplicity this remains allocated on the free store for the
* entire life span of the gzfilebuf object, unless replaced by setbuf.
*/
char_type* buffer;
/**
* @brief Stream buffer size.
*
* Defaults to system default buffer size (typically 8192 bytes).
* Modified by setbuf.
*/
std::streamsize buffer_size;
/**
* @brief True if this object owns stream buffer.
*
* This makes the class responsible for deleting the buffer
* upon destruction.
*/
bool own_buffer;
};
/*****************************************************************************/
/**
* @brief Gzipped file input stream class.
*
* This class implements ifstream for gzipped files. Seeking and putback
* is not supported yet.
*/
class gzifstream : public std::istream
{
public:
// Default constructor
gzifstream();
/**
* @brief Construct stream on gzipped file to be opened.
* @param name File name.
* @param mode Open mode flags (forced to contain ios::in).
*/
explicit
gzifstream(const char* name,
std::ios_base::openmode mode = std::ios_base::in);
/**
* @brief Construct stream on already open gzipped file.
* @param fd File descriptor.
* @param mode Open mode flags (forced to contain ios::in).
*/
explicit
gzifstream(int fd,
std::ios_base::openmode mode = std::ios_base::in);
/**
* Obtain underlying stream buffer.
*/
gzfilebuf*
rdbuf() const
{ return const_cast<gzfilebuf*>(&sb); }
/**
* @brief Check if file is open.
* @return True if file is open.
*/
bool
is_open() { return sb.is_open(); }
/**
* @brief Open gzipped file.
* @param name File name.
* @param mode Open mode flags (forced to contain ios::in).
*
* Stream will be in state good() if file opens successfully;
* otherwise in state fail(). This differs from the behavior of
* ifstream, which never sets the state to good() and therefore
* won't allow you to reuse the stream for a second file unless
* you manually clear() the state. The choice is a matter of
* convenience.
*/
void
open(const char* name,
std::ios_base::openmode mode = std::ios_base::in);
/**
* @brief Attach to already open gzipped file.
* @param fd File descriptor.
* @param mode Open mode flags (forced to contain ios::in).
*
* Stream will be in state good() if attach succeeded; otherwise
* in state fail().
*/
void
attach(int fd,
std::ios_base::openmode mode = std::ios_base::in);
/**
* @brief Close gzipped file.
*
* Stream will be in state fail() if close failed.
*/
void
close();
private:
/**
* Underlying stream buffer.
*/
gzfilebuf sb;
};
/*****************************************************************************/
/**
* @brief Gzipped file output stream class.
*
* This class implements ofstream for gzipped files. Seeking and putback
* is not supported yet.
*/
class gzofstream : public std::ostream
{
public:
// Default constructor
gzofstream();
/**
* @brief Construct stream on gzipped file to be opened.
* @param name File name.
* @param mode Open mode flags (forced to contain ios::out).
*/
explicit
gzofstream(const char* name,
std::ios_base::openmode mode = std::ios_base::out);
/**
* @brief Construct stream on already open gzipped file.
* @param fd File descriptor.
* @param mode Open mode flags (forced to contain ios::out).
*/
explicit
gzofstream(int fd,
std::ios_base::openmode mode = std::ios_base::out);
/**
* Obtain underlying stream buffer.
*/
gzfilebuf*
rdbuf() const
{ return const_cast<gzfilebuf*>(&sb); }
/**
* @brief Check if file is open.
* @return True if file is open.
*/
bool
is_open() { return sb.is_open(); }
/**
* @brief Open gzipped file.
* @param name File name.
* @param mode Open mode flags (forced to contain ios::out).
*
* Stream will be in state good() if file opens successfully;
* otherwise in state fail(). This differs from the behavior of
* ofstream, which never sets the state to good() and therefore
* won't allow you to reuse the stream for a second file unless
* you manually clear() the state. The choice is a matter of
* convenience.
*/
void
open(const char* name,
std::ios_base::openmode mode = std::ios_base::out);
/**
* @brief Attach to already open gzipped file.
* @param fd File descriptor.
* @param mode Open mode flags (forced to contain ios::out).
*
* Stream will be in state good() if attach succeeded; otherwise
* in state fail().
*/
void
attach(int fd,
std::ios_base::openmode mode = std::ios_base::out);
/**
* @brief Close gzipped file.
*
* Stream will be in state fail() if close failed.
*/
void
close();
private:
/**
* Underlying stream buffer.
*/
gzfilebuf sb;
};
/*****************************************************************************/
/**
* @brief Gzipped file output stream manipulator class.
*
* This class defines a two-argument manipulator for gzofstream. It is used
* as base for the setcompression(int,int) manipulator.
*/
template<typename T1, typename T2>
class gzomanip2
{
public:
// Allows insertor to peek at internals
template <typename Ta, typename Tb>
friend gzofstream&
operator<<(gzofstream&,
const gzomanip2<Ta,Tb>&);
// Constructor
gzomanip2(gzofstream& (*f)(gzofstream&, T1, T2),
T1 v1,
T2 v2);
private:
// Underlying manipulator function
gzofstream&
(*func)(gzofstream&, T1, T2);
// Arguments for manipulator function
T1 val1;
T2 val2;
};
/*****************************************************************************/
// Manipulator function thunks through to stream buffer
inline gzofstream&
setcompression(gzofstream &gzs, int l, int s = Z_DEFAULT_STRATEGY)
{
(gzs.rdbuf())->setcompression(l, s);
return gzs;
}
// Manipulator constructor stores arguments
template<typename T1, typename T2>
inline
gzomanip2<T1,T2>::gzomanip2(gzofstream &(*f)(gzofstream &, T1, T2),
T1 v1,
T2 v2)
: func(f), val1(v1), val2(v2)
{ }
// Insertor applies underlying manipulator function to stream
template<typename T1, typename T2>
inline gzofstream&
operator<<(gzofstream& s, const gzomanip2<T1,T2>& m)
{ return (*m.func)(s, m.val1, m.val2); }
// Insert this onto stream to simplify setting of compression level
inline gzomanip2<int,int>
setcompression(int l, int s = Z_DEFAULT_STRATEGY)
{ return gzomanip2<int,int>(&setcompression, l, s); }
#endif // ZFSTREAM_H