gem5/ext/iostream3/zfstream.cc
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

479 lines
13 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.
*/
#include "zfstream.h"
#include <cstring> // for strcpy, strcat, strlen (mode strings)
#include <cstdio> // for BUFSIZ
// Internal buffer sizes (default and "unbuffered" versions)
#define BIGBUFSIZE BUFSIZ
#define SMALLBUFSIZE 1
/*****************************************************************************/
// Default constructor
gzfilebuf::gzfilebuf()
: file(NULL), io_mode(std::ios_base::openmode(0)), own_fd(false),
buffer(NULL), buffer_size(BIGBUFSIZE), own_buffer(true)
{
// No buffers to start with
this->disable_buffer();
}
// Destructor
gzfilebuf::~gzfilebuf()
{
// Sync output buffer and close only if responsible for file
// (i.e. attached streams should be left open at this stage)
this->sync();
if (own_fd)
this->close();
// Make sure internal buffer is deallocated
this->disable_buffer();
}
// Set compression level and strategy
int
gzfilebuf::setcompression(int comp_level,
int comp_strategy)
{
return gzsetparams(file, comp_level, comp_strategy);
}
// Open gzipped file
gzfilebuf*
gzfilebuf::open(const char *name,
std::ios_base::openmode mode)
{
// Fail if file already open
if (this->is_open())
return NULL;
// Don't support simultaneous read/write access (yet)
if ((mode & std::ios_base::in) && (mode & std::ios_base::out))
return NULL;
// Build mode string for gzopen and check it [27.8.1.3.2]
char char_mode[6] = "\0\0\0\0\0";
if (!this->open_mode(mode, char_mode))
return NULL;
// Attempt to open file
if ((file = gzopen(name, char_mode)) == NULL)
return NULL;
// On success, allocate internal buffer and set flags
this->enable_buffer();
io_mode = mode;
own_fd = true;
return this;
}
// Attach to gzipped file
gzfilebuf*
gzfilebuf::attach(int fd,
std::ios_base::openmode mode)
{
// Fail if file already open
if (this->is_open())
return NULL;
// Don't support simultaneous read/write access (yet)
if ((mode & std::ios_base::in) && (mode & std::ios_base::out))
return NULL;
// Build mode string for gzdopen and check it [27.8.1.3.2]
char char_mode[6] = "\0\0\0\0\0";
if (!this->open_mode(mode, char_mode))
return NULL;
// Attempt to attach to file
if ((file = gzdopen(fd, char_mode)) == NULL)
return NULL;
// On success, allocate internal buffer and set flags
this->enable_buffer();
io_mode = mode;
own_fd = false;
return this;
}
// Close gzipped file
gzfilebuf*
gzfilebuf::close()
{
// Fail immediately if no file is open
if (!this->is_open())
return NULL;
// Assume success
gzfilebuf* retval = this;
// Attempt to sync and close gzipped file
if (this->sync() == -1)
retval = NULL;
if (gzclose(file) < 0)
retval = NULL;
// File is now gone anyway (postcondition [27.8.1.3.8])
file = NULL;
own_fd = false;
// Destroy internal buffer if it exists
this->disable_buffer();
return retval;
}
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
// Convert int open mode to mode string
bool
gzfilebuf::open_mode(std::ios_base::openmode mode,
char* c_mode) const
{
bool testb = mode & std::ios_base::binary;
bool testi = mode & std::ios_base::in;
bool testo = mode & std::ios_base::out;
bool testt = mode & std::ios_base::trunc;
bool testa = mode & std::ios_base::app;
// Check for valid flag combinations - see [27.8.1.3.2] (Table 92)
// Original zfstream hardcoded the compression level to maximum here...
// Double the time for less than 1% size improvement seems
// excessive though - keeping it at the default level
// To change back, just append "9" to the next three mode strings
if (!testi && testo && !testt && !testa)
strcpy(c_mode, "w");
if (!testi && testo && !testt && testa)
strcpy(c_mode, "a");
if (!testi && testo && testt && !testa)
strcpy(c_mode, "w");
if (testi && !testo && !testt && !testa)
strcpy(c_mode, "r");
// No read/write mode yet
// if (testi && testo && !testt && !testa)
// strcpy(c_mode, "r+");
// if (testi && testo && testt && !testa)
// strcpy(c_mode, "w+");
// Mode string should be empty for invalid combination of flags
if (strlen(c_mode) == 0)
return false;
if (testb)
strcat(c_mode, "b");
return true;
}
// Determine number of characters in internal get buffer
std::streamsize
gzfilebuf::showmanyc()
{
// Calls to underflow will fail if file not opened for reading
if (!this->is_open() || !(io_mode & std::ios_base::in))
return -1;
// Make sure get area is in use
if (this->gptr() && (this->gptr() < this->egptr()))
return std::streamsize(this->egptr() - this->gptr());
else
return 0;
}
// Fill get area from gzipped file
gzfilebuf::int_type
gzfilebuf::underflow()
{
// If something is left in the get area by chance, return it
// (this shouldn't normally happen, as underflow is only supposed
// to be called when gptr >= egptr, but it serves as error check)
if (this->gptr() && (this->gptr() < this->egptr()))
return traits_type::to_int_type(*(this->gptr()));
// If the file hasn't been opened for reading, produce error
if (!this->is_open() || !(io_mode & std::ios_base::in))
return traits_type::eof();
// Attempt to fill internal buffer from gzipped file
// (buffer must be guaranteed to exist...)
int bytes_read = gzread(file, buffer, buffer_size);
// Indicates error or EOF
if (bytes_read <= 0)
{
// Reset get area
this->setg(buffer, buffer, buffer);
return traits_type::eof();
}
// Make all bytes read from file available as get area
this->setg(buffer, buffer, buffer + bytes_read);
// Return next character in get area
return traits_type::to_int_type(*(this->gptr()));
}
// Write put area to gzipped file
gzfilebuf::int_type
gzfilebuf::overflow(int_type c)
{
// Determine whether put area is in use
if (this->pbase())
{
// Double-check pointer range
if (this->pptr() > this->epptr() || this->pptr() < this->pbase())
return traits_type::eof();
// Add extra character to buffer if not EOF
if (!traits_type::eq_int_type(c, traits_type::eof()))
{
*(this->pptr()) = traits_type::to_char_type(c);
this->pbump(1);
}
// Number of characters to write to file
int bytes_to_write = this->pptr() - this->pbase();
// Overflow doesn't fail if nothing is to be written
if (bytes_to_write > 0)
{
// If the file hasn't been opened for writing, produce error
if (!this->is_open() || !(io_mode & std::ios_base::out))
return traits_type::eof();
// If gzipped file won't accept all bytes written to it, fail
if (gzwrite(file, this->pbase(), bytes_to_write) != bytes_to_write)
return traits_type::eof();
// Reset next pointer to point to pbase on success
this->pbump(-bytes_to_write);
}
}
// Write extra character to file if not EOF
else if (!traits_type::eq_int_type(c, traits_type::eof()))
{
// If the file hasn't been opened for writing, produce error
if (!this->is_open() || !(io_mode & std::ios_base::out))
return traits_type::eof();
// Impromptu char buffer (allows "unbuffered" output)
char_type last_char = traits_type::to_char_type(c);
// If gzipped file won't accept this character, fail
if (gzwrite(file, &last_char, 1) != 1)
return traits_type::eof();
}
// If you got here, you have succeeded (even if c was EOF)
// The return value should therefore be non-EOF
if (traits_type::eq_int_type(c, traits_type::eof()))
return traits_type::not_eof(c);
else
return c;
}
// Assign new buffer
std::streambuf*
gzfilebuf::setbuf(char_type* p,
std::streamsize n)
{
// First make sure stuff is sync'ed, for safety
if (this->sync() == -1)
return NULL;
// If buffering is turned off on purpose via setbuf(0,0), still allocate one...
// "Unbuffered" only really refers to put [27.8.1.4.10], while get needs at
// least a buffer of size 1 (very inefficient though, therefore make it bigger?)
// This follows from [27.5.2.4.3]/12 (gptr needs to point at something, it seems)
if (!p || !n)
{
// Replace existing buffer (if any) with small internal buffer
this->disable_buffer();
buffer = NULL;
buffer_size = 0;
own_buffer = true;
this->enable_buffer();
}
else
{
// Replace existing buffer (if any) with external buffer
this->disable_buffer();
buffer = p;
buffer_size = n;
own_buffer = false;
this->enable_buffer();
}
return this;
}
// Write put area to gzipped file (i.e. ensures that put area is empty)
int
gzfilebuf::sync()
{
return traits_type::eq_int_type(this->overflow(), traits_type::eof()) ? -1 : 0;
}
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
// Allocate internal buffer
void
gzfilebuf::enable_buffer()
{
// If internal buffer required, allocate one
if (own_buffer && !buffer)
{
// Check for buffered vs. "unbuffered"
if (buffer_size > 0)
{
// Allocate internal buffer
buffer = new char_type[buffer_size];
// Get area starts empty and will be expanded by underflow as need arises
this->setg(buffer, buffer, buffer);
// Setup entire internal buffer as put area.
// The one-past-end pointer actually points to the last element of the buffer,
// so that overflow(c) can safely add the extra character c to the sequence.
// These pointers remain in place for the duration of the buffer
this->setp(buffer, buffer + buffer_size - 1);
}
else
{
// Even in "unbuffered" case, (small?) get buffer is still required
buffer_size = SMALLBUFSIZE;
buffer = new char_type[buffer_size];
this->setg(buffer, buffer, buffer);
// "Unbuffered" means no put buffer
this->setp(0, 0);
}
}
else
{
// If buffer already allocated, reset buffer pointers just to make sure no
// stale chars are lying around
this->setg(buffer, buffer, buffer);
this->setp(buffer, buffer + buffer_size - 1);
}
}
// Destroy internal buffer
void
gzfilebuf::disable_buffer()
{
// If internal buffer exists, deallocate it
if (own_buffer && buffer)
{
// Preserve unbuffered status by zeroing size
if (!this->pbase())
buffer_size = 0;
delete[] buffer;
buffer = NULL;
this->setg(0, 0, 0);
this->setp(0, 0);
}
else
{
// Reset buffer pointers to initial state if external buffer exists
this->setg(buffer, buffer, buffer);
if (buffer)
this->setp(buffer, buffer + buffer_size - 1);
else
this->setp(0, 0);
}
}
/*****************************************************************************/
// Default constructor initializes stream buffer
gzifstream::gzifstream()
: std::istream(NULL), sb()
{ this->init(&sb); }
// Initialize stream buffer and open file
gzifstream::gzifstream(const char* name,
std::ios_base::openmode mode)
: std::istream(NULL), sb()
{
this->init(&sb);
this->open(name, mode);
}
// Initialize stream buffer and attach to file
gzifstream::gzifstream(int fd,
std::ios_base::openmode mode)
: std::istream(NULL), sb()
{
this->init(&sb);
this->attach(fd, mode);
}
// Open file and go into fail() state if unsuccessful
void
gzifstream::open(const char* name,
std::ios_base::openmode mode)
{
if (!sb.open(name, mode | std::ios_base::in))
this->setstate(std::ios_base::failbit);
else
this->clear();
}
// Attach to file and go into fail() state if unsuccessful
void
gzifstream::attach(int fd,
std::ios_base::openmode mode)
{
if (!sb.attach(fd, mode | std::ios_base::in))
this->setstate(std::ios_base::failbit);
else
this->clear();
}
// Close file
void
gzifstream::close()
{
if (!sb.close())
this->setstate(std::ios_base::failbit);
}
/*****************************************************************************/
// Default constructor initializes stream buffer
gzofstream::gzofstream()
: std::ostream(NULL), sb()
{ this->init(&sb); }
// Initialize stream buffer and open file
gzofstream::gzofstream(const char* name,
std::ios_base::openmode mode)
: std::ostream(NULL), sb()
{
this->init(&sb);
this->open(name, mode);
}
// Initialize stream buffer and attach to file
gzofstream::gzofstream(int fd,
std::ios_base::openmode mode)
: std::ostream(NULL), sb()
{
this->init(&sb);
this->attach(fd, mode);
}
// Open file and go into fail() state if unsuccessful
void
gzofstream::open(const char* name,
std::ios_base::openmode mode)
{
if (!sb.open(name, mode | std::ios_base::out))
this->setstate(std::ios_base::failbit);
else
this->clear();
}
// Attach to file and go into fail() state if unsuccessful
void
gzofstream::attach(int fd,
std::ios_base::openmode mode)
{
if (!sb.attach(fd, mode | std::ios_base::out))
this->setstate(std::ios_base::failbit);
else
this->clear();
}
// Close file
void
gzofstream::close()
{
if (!sb.close())
this->setstate(std::ios_base::failbit);
}