Mercurial > octave-libtiff
view libinterp/corefcn/gzfstream.cc @ 31215:0fb5ca242d66
__tiff__.cc: added documentation to all internal functions
* libtinterp/corefcn/__tiff__.cc: Added documentation to all internal
functions to enable using help and print_usage.
author | magedrifaat <magedrifaat@gmail.com> |
---|---|
date | Wed, 07 Sep 2022 18:00:04 +0200 |
parents | 796f54d4ddbf |
children |
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//////////////////////////////////////////////////////////////////////// // // Copyright (C) 2005-2022 The Octave Project Developers // // See the file COPYRIGHT.md in the top-level directory of this // distribution or <https://octave.org/copyright/>. // // This file is part of Octave. // // Octave is free software: you can redistribute it and/or modify it // under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // Octave 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 General Public License for more details. // // You should have received a copy of the GNU General Public License // along with Octave; see the file COPYING. If not, see // <https://www.gnu.org/licenses/>. // //////////////////////////////////////////////////////////////////////// /* This file is adapted from the zlib 1.2.2 contrib/iostream3 code, written by Ludwig Schwardt <schwardt@sun.ac.za> original version by Kevin Ruland <kevin@rodin.wustl.edu> */ #if defined (HAVE_CONFIG_H) # include "config.h" #endif #include <iomanip> #include <istream> #include <ostream> #include "gzfstream.h" #if defined (HAVE_ZLIB) // For strcpy, strcat, strlen (mode strings). #include <cstring> // For BUFSIZ. #include <cstdio> // Internal buffer sizes (default and "unbuffered" versions) #define STASHED_CHARACTERS 16 #define BIGBUFSIZE (256 * 1024 + STASHED_CHARACTERS) #define SMALLBUFSIZE 1 // Default constructor gzfilebuf::gzfilebuf () : m_file(nullptr), m_io_mode(std::ios_base::openmode(0)), m_own_fd(false), m_buffer(nullptr), m_buffer_size(BIGBUFSIZE), m_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 (m_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 (m_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 nullptr; // Don't support simultaneous read/write access (yet) if ((mode & std::ios_base::in) && (mode & std::ios_base::out)) return nullptr; // 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 nullptr; // Attempt to open file if ((m_file = gzopen (name, char_mode)) == nullptr) return nullptr; // On success, allocate internal buffer and set flags this->enable_buffer (); m_io_mode = mode; m_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 nullptr; // Don't support simultaneous read/write access (yet) if ((mode & std::ios_base::in) && (mode & std::ios_base::out)) return nullptr; // 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 nullptr; // Attempt to attach to file if ((m_file = gzdopen (fd, char_mode)) == nullptr) return nullptr; // On success, allocate internal buffer and set flags this->enable_buffer (); m_io_mode = mode; m_own_fd = false; return this; } // Close gzipped file gzfilebuf * gzfilebuf::close () { // Fail immediately if no file is open if (! this->is_open ()) return nullptr; // Assume success gzfilebuf *retval = this; // Attempt to sync and close gzipped file if (this->sync () == -1) retval = nullptr; if (gzclose (m_file) < 0) retval = nullptr; // File is now gone anyway (postcondition [27.8.1.3.8]) m_file = nullptr; m_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 { // FIXME: do we need testb? // 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; 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 () || ! (m_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; } // Puts back a character to the stream in two cases. Firstly, when there // is no putback position available, and secondly when the character putback // differs from the one in the file. We can only support the first case // with gzipped files. gzfilebuf::int_type gzfilebuf::pbackfail (gzfilebuf::int_type c) { if (this->is_open ()) { if (gzseek (m_file, this->gptr () - this->egptr () - 1, SEEK_CUR) < 0) return traits_type::eof (); // Invalidates contents of the buffer enable_buffer (); // Attempt to fill internal buffer from gzipped file // (buffer must be guaranteed to exist...) int bytes_read = gzread (m_file, m_buffer, m_buffer_size); // Indicates error or EOF if (bytes_read <= 0) { // Reset get area this->setg (m_buffer, m_buffer, m_buffer); return traits_type::eof (); } // Make all bytes read from file available as get area this->setg (m_buffer, m_buffer, m_buffer + bytes_read); // If next character in get area differs from putback character // flag a failure gzfilebuf::int_type ret = traits_type::to_int_type (*(this->gptr ())); if (ret != c) return traits_type::eof (); else return ret; } else return traits_type::eof (); } // 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 () || ! (m_io_mode & std::ios_base::in)) return traits_type::eof (); // Copy the final characters to the front of the buffer int stash = 0; if (this->eback () && m_buffer && m_buffer_size > STASHED_CHARACTERS) { char_type *ptr1 = m_buffer; char_type *ptr2 = this->egptr () - STASHED_CHARACTERS + 1; if (ptr2 > this->eback ()) while (stash++ <= STASHED_CHARACTERS) *ptr1++ = *ptr2++; } // Attempt to fill internal buffer from gzipped file // (buffer must be guaranteed to exist...) int bytes_read = gzread (m_file, m_buffer + stash, m_buffer_size - stash); // Indicates error or EOF if (bytes_read <= 0) { // Reset get area this->setg (m_buffer, m_buffer, m_buffer); return traits_type::eof (); } // Make all bytes read from file plus the stash available as get area this->setg (m_buffer, m_buffer + stash, m_buffer + bytes_read + stash); // 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 () || ! (m_io_mode & std::ios_base::out)) return traits_type::eof (); // If gzipped file won't accept all bytes written to it, fail if (gzwrite (m_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 () || ! (m_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 (m_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 nullptr; // 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 (); m_buffer = nullptr; m_buffer_size = 0; m_own_buffer = true; this->enable_buffer (); } else { // Replace existing buffer (if any) with external buffer this->disable_buffer (); m_buffer = p; m_buffer_size = n; m_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 (m_own_buffer && ! m_buffer) { // Check for buffered vs. "unbuffered" if (m_buffer_size > 0) { // Allocate internal buffer m_buffer = new char_type [m_buffer_size]; // Get area starts empty and will be expanded by underflow as needed this->setg (m_buffer, m_buffer, m_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 (m_buffer, m_buffer + m_buffer_size - 1); } else { // Even in "unbuffered" case, (small?) get buffer is still required m_buffer_size = SMALLBUFSIZE; m_buffer = new char_type [m_buffer_size]; this->setg (m_buffer, m_buffer, m_buffer); // "Unbuffered" means no put buffer this->setp (nullptr, nullptr); } } else { // If buffer already allocated, reset buffer pointers just to make sure no // stale chars are lying around this->setg (m_buffer, m_buffer, m_buffer); this->setp (m_buffer, m_buffer + m_buffer_size - 1); } } // Destroy internal buffer void gzfilebuf::disable_buffer () { // If internal buffer exists, deallocate it if (m_own_buffer && m_buffer) { // Preserve unbuffered status by zeroing size if (! this->pbase ()) m_buffer_size = 0; delete [] m_buffer; m_buffer = nullptr; this->setg (nullptr, nullptr, nullptr); this->setp (nullptr, nullptr); } else { // Reset buffer pointers to initial state if external buffer exists this->setg (m_buffer, m_buffer, m_buffer); if (m_buffer) this->setp (m_buffer, m_buffer + m_buffer_size - 1); else this->setp (nullptr, nullptr); } } /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ // Seek functions gzfilebuf::pos_type gzfilebuf::seekoff (off_type off, std::ios_base::seekdir way, std::ios_base::openmode) { pos_type ret = pos_type (off_type (-1)); if (this->is_open ()) { off_type computed_off = off; if ((m_io_mode & std::ios_base::in) && way == std::ios_base::cur) computed_off += this->gptr () - this->egptr (); // Handle tellg/tellp as a special case up front, no need to seek // or invalidate get/put buffers if (off == 0 && way == std::ios_base::cur) return pos_type (gztell (m_file) + computed_off); if (way == std::ios_base::beg) ret = pos_type (gzseek (m_file, computed_off, SEEK_SET)); else if (way == std::ios_base::cur) ret = pos_type (gzseek (m_file, computed_off, SEEK_CUR)); else // Can't seek from end of a gzipped file, so this will give -1 ret = pos_type (gzseek (m_file, computed_off, SEEK_END)); if (m_io_mode & std::ios_base::in) // Invalidates contents of the buffer enable_buffer (); else // flush contents of buffer to file overflow (); } return ret; } gzfilebuf::pos_type gzfilebuf::seekpos (pos_type sp, std::ios_base::openmode) { pos_type ret = pos_type (off_type (-1)); if (this->is_open ()) { ret = pos_type (gzseek (m_file, sp, SEEK_SET)); if (m_io_mode & std::ios_base::in) // Invalidates contents of the buffer enable_buffer (); else // flush contents of buffer to file overflow (); } return ret; } // Default constructor initializes stream buffer gzifstream::gzifstream () : std::istream (nullptr), m_sb () { this->init (&m_sb); } // Initialize stream buffer and open file gzifstream::gzifstream (const char *name, std::ios_base::openmode mode) : std::istream (nullptr), m_sb () { this->init (&m_sb); this->open (name, mode); } // Initialize stream buffer and attach to file gzifstream::gzifstream (int fd, std::ios_base::openmode mode) : std::istream (nullptr), m_sb () { this->init (&m_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 (! m_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 (! m_sb.attach (fd, mode | std::ios_base::in)) this->setstate (std::ios_base::failbit); else this->clear (); } // Close file void gzifstream::close () { if (! m_sb.close ()) this->setstate (std::ios_base::failbit); } // Default constructor initializes stream buffer gzofstream::gzofstream () : std::ostream (nullptr), m_sb () { this->init (&m_sb); } // Initialize stream buffer and open file gzofstream::gzofstream (const char *name, std::ios_base::openmode mode) : std::ostream (nullptr), m_sb () { this->init (&m_sb); this->open (name, mode); } // Initialize stream buffer and attach to file gzofstream::gzofstream (int fd, std::ios_base::openmode mode) : std::ostream (nullptr), m_sb () { this->init (&m_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 (! m_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 (! m_sb.attach (fd, mode | std::ios_base::out)) this->setstate (std::ios_base::failbit); else this->clear (); } // Close file void gzofstream::close () { if (! m_sb.close ()) this->setstate (std::ios_base::failbit); } #endif