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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /zlib/contrib/iostream3/zfstream.cc | |
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Diffstat (limited to 'zlib/contrib/iostream3/zfstream.cc')
-rw-r--r-- | zlib/contrib/iostream3/zfstream.cc | 479 |
1 files changed, 479 insertions, 0 deletions
diff --git a/zlib/contrib/iostream3/zfstream.cc b/zlib/contrib/iostream3/zfstream.cc new file mode 100644 index 000000000..94eb93344 --- /dev/null +++ b/zlib/contrib/iostream3/zfstream.cc @@ -0,0 +1,479 @@ +/* + * 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); +} |