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-rw-r--r--ext/iostream3/zfstream.cc479
1 files changed, 479 insertions, 0 deletions
diff --git a/ext/iostream3/zfstream.cc b/ext/iostream3/zfstream.cc
new file mode 100644
index 000000000..94eb93344
--- /dev/null
+++ b/ext/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);
+}
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