+ /* utility functions */
+
+/*
+ The following utility functions are implemented on top of the
+ basic stream-oriented functions. To simplify the interface, some
+ default options are assumed (compression level, window size,
+ standard memory allocation functions). The source code of these
+ utility functions can easily be modified if you need special options.
+*/
+
+extern int EXPORT compress OF((Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen));
+/*
+ Compresses the source buffer into the destination buffer. sourceLen is
+ the byte length of the source buffer. Upon entry, destLen is the total
+ size of the destination buffer, which must be at least 0.1% larger than
+ sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
+ compressed buffer.
+ This function can be used to compress a whole file at once if the
+ input file is mmap'ed.
+ compress returns Z_OK if success, Z_MEM_ERROR if there was not
+ enough memory, Z_BUF_ERROR if there was not enough room in the output
+ buffer.
+*/
+
+extern int EXPORT uncompress OF((Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen));
+/*
+ Decompresses the source buffer into the destination buffer. sourceLen is
+ the byte length of the source buffer. Upon entry, destLen is the total
+ size of the destination buffer, which must be large enough to hold the
+ entire uncompressed data. (The size of the uncompressed data must have
+ been saved previously by the compressor and transmitted to the decompressor
+ by some mechanism outside the scope of this compression library.)
+ Upon exit, destLen is the actual size of the compressed buffer.
+ This function can be used to decompress a whole file at once if the
+ input file is mmap'ed.
+
+ uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
+ enough memory, Z_BUF_ERROR if there was not enough room in the output
+ buffer, or Z_DATA_ERROR if the input data was corrupted.
+*/
+
+
+typedef voidp gzFile;
+
+extern gzFile EXPORT gzopen OF((const char *path, const char *mode));
+/*
+ Opens a gzip (.gz) file for reading or writing. The mode parameter
+ is as in fopen ("rb" or "wb") but can also include a compression level
+ ("wb9"). gzopen can be used to read a file which is not in gzip format;
+ in this case gzread will directly read from the file without decompression.
+ gzopen returns NULL if the file could not be opened or if there was
+ insufficient memory to allocate the (de)compression state; errno
+ can be checked to distinguish the two cases (if errno is zero, the
+ zlib error is Z_MEM_ERROR).
+*/
+
+extern gzFile EXPORT gzdopen OF((int fd, const char *mode));
+/*
+ gzdopen() associates a gzFile with the file descriptor fd. File
+ descriptors are obtained from calls like open, dup, creat, pipe or
+ fileno (in the file has been previously opened with fopen).
+ The mode parameter is as in gzopen.
+ The next call of gzclose on the returned gzFile will also close the
+ file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
+ descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
+ gzdopen returns NULL if there was insufficient memory to allocate
+ the (de)compression state.
+*/
+
+extern int EXPORT gzread OF((gzFile file, voidp buf, unsigned len));
+/*
+ Reads the given number of uncompressed bytes from the compressed file.
+ If the input file was not in gzip format, gzread copies the given number
+ of bytes into the buffer.
+ gzread returns the number of uncompressed bytes actually read (0 for
+ end of file, -1 for error). */
+
+extern int EXPORT gzwrite OF((gzFile file, const voidp buf, unsigned len));
+/*
+ Writes the given number of uncompressed bytes into the compressed file.
+ gzwrite returns the number of uncompressed bytes actually written
+ (0 in case of error).
+*/
+
+extern int EXPORT gzflush OF((gzFile file, int flush));
+/*
+ Flushes all pending output into the compressed file. The parameter
+ flush is as in the deflate() function. The return value is the zlib
+ error number (see function gzerror below). gzflush returns Z_OK if
+ the flush parameter is Z_FINISH and all output could be flushed.
+ gzflush should be called only when strictly necessary because it can
+ degrade compression.
+*/
+
+extern int EXPORT gzclose OF((gzFile file));
+/*
+ Flushes all pending output if necessary, closes the compressed file
+ and deallocates all the (de)compression state. The return value is the zlib
+ error number (see function gzerror below).
+*/
+
+extern const char * EXPORT gzerror OF((gzFile file, int *errnum));
+/*
+ Returns the error message for the last error which occurred on the
+ given compressed file. errnum is set to zlib error number. If an
+ error occurred in the file system and not in the compression library,
+ errnum is set to Z_ERRNO and the application may consult errno
+ to get the exact error code.
+*/
+