zlib 1.2.0.2v1.2.0.2

5 files changed, 1047 insertions, 0 deletions

diff --git a/contrib/iostream3/README b/contrib/iostream3/README
new file mode 100644
index 0000000..6f73d58
--- /dev/null
+++ b/contrib/iostream3/README
@@ -0,0 +1,35 @@
+These classes provide a C++ stream interface to the zlib library. It allows you
+to do things like:
+
+  gzofstream outf("blah.gz");
+  outf << "These go into the gzip file " << 123 << endl;
+  
+It does this by deriving a specialized stream buffer for gzipped files, which is
+the way Stroustrup would have done it. :-> 
+
+The gzifstream and gzofstream classes were originally written by Kevin Ruland
+and made available in the zlib contrib/iostream directory. The older version still
+compiles under gcc 2.xx, but not under gcc 3.xx, which sparked the development of 
+this version.
+
+The new classes are as standard-compliant as possible, closely following the 
+approach of the standard library's fstream classes. It compiles under gcc versions 
+3.2 and 3.3, but not under gcc 2.xx. This is mainly due to changes in the standard 
+library naming scheme. The new version of gzifstream/gzofstream/gzfilebuf differs 
+from the previous one in the following respects:
+- added showmanyc
+- added setbuf, with support for unbuffered output via setbuf(0,0)
+- a few bug fixes of stream behavior
+- gzipped output file opened with default compression level instead of maximum level
+- setcompressionlevel()/strategy() members replaced by single setcompression()
+
+The code is provided "as is", with the permission to use, copy, modify, distribute 
+and sell it for any purpose without fee.
+
+Ludwig Schwardt
+<schwardt@sun.ac.za>
+
+DSP Lab
+Electrical & Electronic Engineering Department
+University of Stellenbosch
+South Africa
diff --git a/contrib/iostream3/TODO b/contrib/iostream3/TODO
new file mode 100644
index 0000000..4578326
--- /dev/null
+++ b/contrib/iostream3/TODO
@@ -0,0 +1,17 @@
+Possible upgrades to gzfilebuf:
+
+- The ability to do putback (e.g. putbackfail)
+
+- The ability to seek (zlib supports this, but could be slow/tricky)
+
+- Simultaneous read/write access (does it make sense?)
+
+- Support for ios_base::ate open mode
+
+- Locale support?
+
+- Check public interface to see which calls give problems
+  (due to dependence on library internals)
+
+- Override operator<<(ostream&, gzfilebuf*) to allow direct copying 
+  of stream buffer to stream ( i.e. os << is.rdbuf(); )
diff --git a/contrib/iostream3/test.cc b/contrib/iostream3/test.cc
new file mode 100644
index 0000000..9ffa8be
--- /dev/null
+++ b/contrib/iostream3/test.cc
@@ -0,0 +1,50 @@
+/*
+ * Test program for gzifstream and gzofstream
+ * 
+ * by Ludwig Schwardt <schwardt@sun.ac.za>
+ * original version by Kevin Ruland <kevin@rodin.wustl.edu>
+ */
+
+#include "zfstream.h"
+#include <iostream>      // for cout
+
+int main() {
+
+  gzofstream outf;
+  gzifstream inf;
+  char buf[80];
+  
+  outf.open("test1.txt.gz");
+  outf << "The quick brown fox sidestepped the lazy canine\n" 
+       << 1.3 << "\nPlan " << 9 << std::endl;
+  outf.close();
+  std::cout << "Wrote the following message to 'test1.txt.gz' (check with zcat or zless):\n"
+            << "The quick brown fox sidestepped the lazy canine\n"
+            << 1.3 << "\nPlan " << 9 << std::endl;
+  
+  std::cout << "\nReading 'test1.txt.gz' (buffered) produces:\n";
+  inf.open("test1.txt.gz");
+  while (inf.getline(buf,80,'\n')) {
+    std::cout << buf << "\t(" << inf.rdbuf()->in_avail() << " chars left in buffer)\n";
+  }
+  inf.close();
+
+  outf.rdbuf()->pubsetbuf(0,0);
+  outf.open("test2.txt.gz");
+  outf << setcompression(Z_NO_COMPRESSION)
+       << "The quick brown fox sidestepped the lazy canine\n"
+       << 1.3 << "\nPlan " << 9 << std::endl;
+  outf.close();
+  std::cout << "\nWrote the same message to 'test2.txt.gz' in uncompressed form";
+
+  std::cout << "\nReading 'test2.txt.gz' (unbuffered) produces:\n";
+  inf.rdbuf()->pubsetbuf(0,0);
+  inf.open("test2.txt.gz");
+  while (inf.getline(buf,80,'\n')) {
+    std::cout << buf << "\t(" << inf.rdbuf()->in_avail() << " chars left in buffer)\n";
+  }
+  inf.close();
+
+  return 0;
+
+}
diff --git a/contrib/iostream3/zfstream.cc b/contrib/iostream3/zfstream.cc
new file mode 100644
index 0000000..24d15fa
--- /dev/null
+++ b/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);
+}
diff --git a/contrib/iostream3/zfstream.h b/contrib/iostream3/zfstream.h
new file mode 100644
index 0000000..ad76e8b
--- /dev/null
+++ b/contrib/iostream3/zfstream.h
@@ -0,0 +1,466 @@
+/*
+ * 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