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diff --git a/zlib/old/zlib.html b/zlib/old/zlib.html deleted file mode 100644 index 8c1b190c3..000000000 --- a/zlib/old/zlib.html +++ /dev/null @@ -1,971 +0,0 @@ -<html> -<head> - <title> - zlib general purpose compression library version 1.1.4 - </title> -</head> -<body bgcolor="White" text="Black" vlink="Red" alink="Navy" link="Red"> -<!-- background="zlibbg.gif" --> - -<h1> zlib 1.1.4 Manual </h1> -<hr> -<a name="Contents"><h2>Contents</h2> -<ol type="I"> -<li> <a href="#Prologue">Prologue</a> -<li> <a href="#Introduction">Introduction</a> -<li> <a href="#Utility functions">Utility functions</a> -<li> <a href="#Basic functions">Basic functions</a> -<li> <a href="#Advanced functions">Advanced functions</a> -<li> <a href="#Constants">Constants</a> -<li> <a href="#struct z_stream_s">struct z_stream_s</a> -<li> <a href="#Checksum functions">Checksum functions</a> -<li> <a href="#Misc">Misc</a> -</ol> -<hr> -<a name="Prologue"><h2> Prologue </h2> - 'zlib' general purpose compression library version 1.1.4, March 11th, 2002 - <p> - Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler - <p> - This software is provided 'as-is', without any express or implied - warranty. In no event will the authors be held liable for any damages - arising from the use of this software. - <p> - Permission is granted to anyone to use this software for any purpose, - including commercial applications, and to alter it and redistribute it - freely, subject to the following restrictions: - <ol> - <li> The origin of this software must not be misrepresented ; you must not - claim that you wrote the original software. If you use this software - in a product, an acknowledgment in the product documentation would be - appreciated but is not required. - <li> Altered source versions must be plainly marked as such, and must not be - misrepresented as being the original software. - <li> This notice may not be removed or altered from any source distribution. - </ol> - - <dl> - <dt>Jean-loup Gailly - <dd><a href="mailto:jloup@gzip.org">jloup@gzip.org</a> - <dt>Mark Adler - <dd><a href="mailto:madler@alumni.caltech.edu">madler@alumni.caltech.edu</a> - </dl> - - The data format used by the zlib library is described by RFCs (Request for - Comments) 1950 to 1952 in the files - <a href="ftp://ds.internic.net/rfc/rfc1950.txt"> - ftp://ds.internic.net/rfc/rfc1950.txt </a> - (zlib format), - <a href="ftp://ds.internic.net/rfc/rfc1951.txt"> - rfc1951.txt </a> - (<a href="#deflate">deflate</a> format) and - <a href="ftp://ds.internic.net/rfc/rfc1952.txt"> - rfc1952.txt </a> - (gzip format). - <p> - This manual is converted from zlib.h by - <a href="mailto:piaip@csie.ntu.edu.tw"> piaip </a> - <p> - Visit <a href="http://ftp.cdrom.com/pub/infozip/zlib/"> - http://ftp.cdrom.com/pub/infozip/zlib/</a> - for the official zlib web page. - <p> - -<hr> -<a name="Introduction"><h2> Introduction </h2> - The 'zlib' compression library provides in-memory compression and - decompression functions, including integrity checks of the uncompressed - data. This version of the library supports only one compression method - (deflation) but other algorithms will be added later and will have the same - stream interface. - <p> - - Compression can be done in a single step if the buffers are large - enough (for example if an input file is mmap'ed), or can be done by - repeated calls of the compression function. In the latter case, the - application must provide more input and/or consume the output - (providing more output space) before each call. - <p> - - The library also supports reading and writing files in gzip (.gz) format - with an interface similar to that of stdio. - <p> - - The library does not install any signal handler. The decoder checks - the consistency of the compressed data, so the library should never - crash even in case of corrupted input. - <p> - -<hr> -<a name="Utility functions"><h2> Utility functions </h2> - The following utility functions are implemented on top of the - <a href="#Basic functions">basic stream-oriented functions</a>. - To simplify the interface, some - default options are assumed (compression level and memory usage, - standard memory allocation functions). The source code of these - utility functions can easily be modified if you need special options. -<h3> Function list </h3> -<ul> -<li> int <a href="#compress">compress</a> (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen); -<li> int <a href="#compress2">compress2</a> (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen, int level); -<li> int <a href="#uncompress">uncompress</a> (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen); -<li> typedef voidp gzFile; -<li> gzFile <a href="#gzopen">gzopen</a> (const char *path, const char *mode); -<li> gzFile <a href="#gzdopen">gzdopen</a> (int fd, const char *mode); -<li> int <a href="#gzsetparams">gzsetparams</a> (gzFile file, int level, int strategy); -<li> int <a href="#gzread">gzread</a> (gzFile file, voidp buf, unsigned len); -<li> int <a href="#gzwrite">gzwrite</a> (gzFile file, const voidp buf, unsigned len); -<li> int VA <a href="#gzprintf">gzprintf</a> (gzFile file, const char *format, ...); -<li> int <a href="#gzputs">gzputs</a> (gzFile file, const char *s); -<li> char * <a href="#gzgets">gzgets</a> (gzFile file, char *buf, int len); -<li> int <a href="#gzputc">gzputc</a> (gzFile file, int c); -<li> int <a href="#gzgetc">gzgetc</a> (gzFile file); -<li> int <a href="#gzflush">gzflush</a> (gzFile file, int flush); -<li> z_off_t <a href="#gzseek">gzseek</a> (gzFile file, z_off_t offset, int whence); -<li> z_off_t <a href="#gztell">gztell</a> (gzFile file); -<li> int <a href="#gzrewind">gzrewind</a> (gzFile file); -<li> int <a href="#gzeof">gzeof</a> (gzFile file); -<li> int <a href="#gzclose">gzclose</a> (gzFile file); -<li> const char * <a href="#gzerror">gzerror</a> (gzFile file, int *errnum); -</ul> -<h3> Function description </h3> -<dl> -<font color="Blue"><dt> int <a name="compress">compress</a> (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen);</font> -<dd> - 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.<p> - This function can be used to <a href="#compress">compress</a> a whole file at once if the - input file is mmap'ed.<p> - <a href="#compress">compress</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a> if there was not - enough memory, <a href="#Z_BUF_ERROR">Z_BUF_ERROR</a> if there was not enough room in the output - buffer.<p> - -<font color="Blue"><dt> int <a name="compress2">compress2</a> (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen, int level);</font> -<dd> - Compresses the source buffer into the destination buffer. The level - parameter has the same meaning as in <a href="#deflateInit">deflateInit</a>. 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. - <p> - - <a href="#compress2">compress2</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a> if there was not enough - memory, <a href="#Z_BUF_ERROR">Z_BUF_ERROR</a> if there was not enough room in the output buffer, - <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the level parameter is invalid. - <p> - -<font color="Blue"><dt> int <a name="uncompress">uncompress</a> (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen);</font> -<dd> - 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. <p> - This function can be used to decompress a whole file at once if the - input file is mmap'ed. - <p> - - <a href="#uncompress">uncompress</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a> if there was not - enough memory, <a href="#Z_BUF_ERROR">Z_BUF_ERROR</a> if there was not enough room in the output - buffer, or <a href="#Z_DATA_ERROR">Z_DATA_ERROR</a> if the input data was corrupted. - <p> - -<dt> typedef voidp gzFile; -<dd> <p> - -<font color="Blue"><dt> gzFile <a name="gzopen">gzopen</a> (const char *path, const char *mode);</font> -<dd> - 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") or a strategy: 'f' for filtered data as in "wb6f", 'h' for - Huffman only compression as in "wb1h". (See the description - of <a href="#deflateInit2">deflateInit2</a> for more information about the strategy parameter.) - <p> - - <a href="#gzopen">gzopen</a> can be used to read a file which is not in gzip format ; in this - case <a href="#gzread">gzread</a> will directly read from the file without decompression. - <p> - - <a href="#gzopen">gzopen</a> returns NULL if the file could not be opened or if there was - insufficient memory to allocate the (de)compression <a href="#state">state</a> ; errno - can be checked to distinguish the two cases (if errno is zero, the - zlib error is <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a>). - <p> - -<font color="Blue"><dt> gzFile <a name="gzdopen">gzdopen</a> (int fd, const char *mode);</font> -<dd> - <a href="#gzdopen">gzdopen</a>() 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 <a href="#gzopen">gzopen</a>. - <p> - The next call of <a href="#gzclose">gzclose</a> 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 <a href="#gzdopen">gzdopen</a>(dup(fd), mode). - <p> - <a href="#gzdopen">gzdopen</a> returns NULL if there was insufficient memory to allocate - the (de)compression <a href="#state">state</a>. - <p> - -<font color="Blue"><dt> int <a name="gzsetparams">gzsetparams</a> (gzFile file, int level, int strategy);</font> -<dd> - Dynamically update the compression level or strategy. See the description - of <a href="#deflateInit2">deflateInit2</a> for the meaning of these parameters. - <p> - <a href="#gzsetparams">gzsetparams</a> returns <a href="#Z_OK">Z_OK</a> if success, or <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the file was not - opened for writing. - <p> - -<font color="Blue"><dt> int <a name="gzread">gzread</a> (gzFile file, voidp buf, unsigned len);</font> -<dd> - Reads the given number of uncompressed bytes from the compressed file. - If the input file was not in gzip format, <a href="#gzread">gzread</a> copies the given number - of bytes into the buffer. - <p> - <a href="#gzread">gzread</a> returns the number of uncompressed bytes actually read (0 for - end of file, -1 for error). - <p> - -<font color="Blue"><dt> int <a name="gzwrite">gzwrite</a> (gzFile file, const voidp buf, unsigned len);</font> -<dd> - Writes the given number of uncompressed bytes into the compressed file. - <a href="#gzwrite">gzwrite</a> returns the number of uncompressed bytes actually written - (0 in case of error). - <p> - -<font color="Blue"><dt> int VA <a name="gzprintf">gzprintf</a> (gzFile file, const char *format, ...);</font> -<dd> - Converts, formats, and writes the args to the compressed file under - control of the format string, as in fprintf. <a href="#gzprintf">gzprintf</a> returns the number of - uncompressed bytes actually written (0 in case of error). - <p> - -<font color="Blue"><dt> int <a name="gzputs">gzputs</a> (gzFile file, const char *s);</font> -<dd> - Writes the given null-terminated string to the compressed file, excluding - the terminating null character. - <p> - <a href="#gzputs">gzputs</a> returns the number of characters written, or -1 in case of error. - <p> - -<font color="Blue"><dt> char * <a name="gzgets">gzgets</a> (gzFile file, char *buf, int len);</font> -<dd> - Reads bytes from the compressed file until len-1 characters are read, or - a newline character is read and transferred to buf, or an end-of-file - condition is encountered. The string is then terminated with a null - character. - <p> - <a href="#gzgets">gzgets</a> returns buf, or <a href="#Z_NULL">Z_NULL</a> in case of error. - <p> - -<font color="Blue"><dt> int <a name="gzputc">gzputc</a> (gzFile file, int c);</font> -<dd> - Writes c, converted to an unsigned char, into the compressed file. - <a href="#gzputc">gzputc</a> returns the value that was written, or -1 in case of error. - <p> - -<font color="Blue"><dt> int <a name="gzgetc">gzgetc</a> (gzFile file);</font> -<dd> - Reads one byte from the compressed file. <a href="#gzgetc">gzgetc</a> returns this byte - or -1 in case of end of file or error. - <p> - -<font color="Blue"><dt> int <a name="gzflush">gzflush</a> (gzFile file, int flush);</font> -<dd> - Flushes all pending output into the compressed file. The parameter - flush is as in the <a href="#deflate">deflate</a>() function. The return value is the zlib - error number (see function <a href="#gzerror">gzerror</a> below). <a href="#gzflush">gzflush</a> returns <a href="#Z_OK">Z_OK</a> if - the flush parameter is <a href="#Z_FINISH">Z_FINISH</a> and all output could be flushed. - <p> - <a href="#gzflush">gzflush</a> should be called only when strictly necessary because it can - degrade compression. - <p> - -<font color="Blue"><dt> z_off_t <a name="gzseek">gzseek</a> (gzFile file, z_off_t offset, int whence);</font> -<dd> - Sets the starting position for the next <a href="#gzread">gzread</a> or <a href="#gzwrite">gzwrite</a> on the - given compressed file. The offset represents a number of bytes in the - uncompressed data stream. The whence parameter is defined as in lseek(2); - the value SEEK_END is not supported. - <p> - If the file is opened for reading, this function is emulated but can be - extremely slow. If the file is opened for writing, only forward seeks are - supported ; <a href="#gzseek">gzseek</a> then compresses a sequence of zeroes up to the new - starting position. - <p> - <a href="#gzseek">gzseek</a> returns the resulting offset location as measured in bytes from - the beginning of the uncompressed stream, or -1 in case of error, in - particular if the file is opened for writing and the new starting position - would be before the current position. - <p> - -<font color="Blue"><dt> int <a name="gzrewind">gzrewind</a> (gzFile file);</font> -<dd> - Rewinds the given file. This function is supported only for reading. - <p> - <a href="#gzrewind">gzrewind</a>(file) is equivalent to (int)<a href="#gzseek">gzseek</a>(file, 0L, SEEK_SET) - <p> - -<font color="Blue"><dt> z_off_t <a name="gztell">gztell</a> (gzFile file);</font> -<dd> - Returns the starting position for the next <a href="#gzread">gzread</a> or <a href="#gzwrite">gzwrite</a> on the - given compressed file. This position represents a number of bytes in the - uncompressed data stream. - <p> - - <a href="#gztell">gztell</a>(file) is equivalent to <a href="#gzseek">gzseek</a>(file, 0L, SEEK_CUR) - <p> - -<font color="Blue"><dt> int <a name="gzeof">gzeof</a> (gzFile file);</font> -<dd> - Returns 1 when EOF has previously been detected reading the given - input stream, otherwise zero. - <p> - -<font color="Blue"><dt> int <a name="gzclose">gzclose</a> (gzFile file);</font> -<dd> - Flushes all pending output if necessary, closes the compressed file - and deallocates all the (de)compression <a href="#state">state</a>. The return value is the zlib - error number (see function <a href="#gzerror">gzerror</a> below). - <p> - -<font color="Blue"><dt> const char * <a name="gzerror">gzerror</a> (gzFile file, int *errnum);</font> -<dd> - 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 <a href="#Z_ERRNO">Z_ERRNO</a> and the application may consult errno - to get the exact error code. - <p> -</dl> -<hr> -<a name="Basic functions"><h2> Basic functions </h2> -<h3> Function list </h3> -<ul> -<li> const char * <a href="#zlibVersion">zlibVersion</a> (void); -<li> int <a href="#deflateInit">deflateInit</a> (<a href="#z_streamp">z_streamp</a> strm, int level); -<li> int <a href="#deflate">deflate</a> (<a href="#z_streamp">z_streamp</a> strm, int flush); -<li> int <a href="#deflateEnd">deflateEnd</a> (<a href="#z_streamp">z_streamp</a> strm); -<li> int <a href="#inflateInit">inflateInit</a> (<a href="#z_streamp">z_streamp</a> strm); -<li> int <a href="#inflate">inflate</a> (<a href="#z_streamp">z_streamp</a> strm, int flush); -<li> int <a href="#inflateEnd">inflateEnd</a> (<a href="#z_streamp">z_streamp</a> strm); -</ul> - -<h3> Function description </h3> -<dl> -<font color="Blue"><dt> const char * <a name="zlibVersion">zlibVersion</a> (void);</font> -<dd> The application can compare <a href="#zlibVersion">zlibVersion</a> and ZLIB_VERSION for consistency. - If the first character differs, the library code actually used is - not compatible with the zlib.h header file used by the application. - This check is automatically made by <a href="#deflateInit">deflateInit</a> and <a href="#inflateInit">inflateInit</a>. - <p> - -<font color="Blue"><dt> int <a name="deflateInit">deflateInit</a> (<a href="#z_streamp">z_streamp</a> strm, int level);</font> -<dd> - Initializes the internal stream <a href="#state">state</a> for compression. The fields - <a href="#zalloc">zalloc</a>, <a href="#zfree">zfree</a> and <a href="#opaque">opaque</a> must be initialized before by the caller. - If <a href="#zalloc">zalloc</a> and <a href="#zfree">zfree</a> are set to <a href="#Z_NULL">Z_NULL</a>, <a href="#deflateInit">deflateInit</a> updates them to - use default allocation functions. - <p> - - The compression level must be <a href="#Z_DEFAULT_COMPRESSION">Z_DEFAULT_COMPRESSION</a>, or between 0 and 9: - 1 gives best speed, 9 gives best compression, 0 gives no compression at - all (the input data is simply copied a block at a time). - <p> - - <a href="#Z_DEFAULT_COMPRESSION">Z_DEFAULT_COMPRESSION</a> requests a default compromise between speed and - compression (currently equivalent to level 6). - <p> - - <a href="#deflateInit">deflateInit</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a> if there was not - enough memory, <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if level is not a valid compression level, - <a href="#Z_VERSION_ERROR">Z_VERSION_ERROR</a> if the zlib library version (<a href="#zlib_version">zlib_version</a>) is incompatible - with the version assumed by the caller (ZLIB_VERSION). - <a href="#msg">msg</a> is set to null if there is no error message. <a href="#deflateInit">deflateInit</a> does not - perform any compression: this will be done by <a href="#deflate">deflate</a>(). - <p> - -<font color="Blue"><dt> int <a name="deflate">deflate</a> (<a href="#z_streamp">z_streamp</a> strm, int flush);</font> -<dd> - <a href="#deflate">deflate</a> compresses as much data as possible, and stops when the input - buffer becomes empty or the output buffer becomes full. It may introduce some - output latency (reading input without producing any output) except when - forced to flush.<p> - - The detailed semantics are as follows. <a href="#deflate">deflate</a> performs one or both of the - following actions: - - <ul> - <li> Compress more input starting at <a href="#next_in">next_in</a> and update <a href="#next_in">next_in</a> and <a href="#avail_in">avail_in</a> - accordingly. If not all input can be processed (because there is not - enough room in the output buffer), <a href="#next_in">next_in</a> and <a href="#avail_in">avail_in</a> are updated and - processing will resume at this point for the next call of <a href="#deflate">deflate</a>(). - - <li> - Provide more output starting at <a href="#next_out">next_out</a> and update <a href="#next_out">next_out</a> and <a href="#avail_out">avail_out</a> - accordingly. This action is forced if the parameter flush is non zero. - Forcing flush frequently degrades the compression ratio, so this parameter - should be set only when necessary (in interactive applications). - Some output may be provided even if flush is not set. - </ul> <p> - - Before the call of <a href="#deflate">deflate</a>(), the application should ensure that at least - one of the actions is possible, by providing more input and/or consuming - more output, and updating <a href="#avail_in">avail_in</a> or <a href="#avail_out">avail_out</a> accordingly ; <a href="#avail_out">avail_out</a> - should never be zero before the call. The application can consume the - compressed output when it wants, for example when the output buffer is full - (<a href="#avail_out">avail_out</a> == 0), or after each call of <a href="#deflate">deflate</a>(). If <a href="#deflate">deflate</a> returns <a href="#Z_OK">Z_OK</a> - and with zero <a href="#avail_out">avail_out</a>, it must be called again after making room in the - output buffer because there might be more output pending. - <p> - - If the parameter flush is set to <a href="#Z_SYNC_FLUSH">Z_SYNC_FLUSH</a>, all pending output is - flushed to the output buffer and the output is aligned on a byte boundary, so - that the decompressor can get all input data available so far. (In particular - <a href="#avail_in">avail_in</a> is zero after the call if enough output space has been provided - before the call.) Flushing may degrade compression for some compression - algorithms and so it should be used only when necessary. - <p> - - If flush is set to <a href="#Z_FULL_FLUSH">Z_FULL_FLUSH</a>, all output is flushed as with - <a href="#Z_SYNC_FLUSH">Z_SYNC_FLUSH</a>, and the compression <a href="#state">state</a> is reset so that decompression can - restart from this point if previous compressed data has been damaged or if - random access is desired. Using <a href="#Z_FULL_FLUSH">Z_FULL_FLUSH</a> too often can seriously degrade - the compression. - <p> - - If <a href="#deflate">deflate</a> returns with <a href="#avail_out">avail_out</a> == 0, this function must be called again - with the same value of the flush parameter and more output space (updated - <a href="#avail_out">avail_out</a>), until the flush is complete (<a href="#deflate">deflate</a> returns with non-zero - <a href="#avail_out">avail_out</a>). - <p> - - If the parameter flush is set to <a href="#Z_FINISH">Z_FINISH</a>, pending input is processed, - pending output is flushed and <a href="#deflate">deflate</a> returns with <a href="#Z_STREAM_END">Z_STREAM_END</a> if there - was enough output space ; if <a href="#deflate">deflate</a> returns with <a href="#Z_OK">Z_OK</a>, this function must be - called again with <a href="#Z_FINISH">Z_FINISH</a> and more output space (updated <a href="#avail_out">avail_out</a>) but no - more input data, until it returns with <a href="#Z_STREAM_END">Z_STREAM_END</a> or an error. After - <a href="#deflate">deflate</a> has returned <a href="#Z_STREAM_END">Z_STREAM_END</a>, the only possible operations on the - stream are <a href="#deflateReset">deflateReset</a> or <a href="#deflateEnd">deflateEnd</a>. - <p> - - <a href="#Z_FINISH">Z_FINISH</a> can be used immediately after <a href="#deflateInit">deflateInit</a> if all the compression - is to be done in a single step. In this case, <a href="#avail_out">avail_out</a> must be at least - 0.1% larger than <a href="#avail_in">avail_in</a> plus 12 bytes. If <a href="#deflate">deflate</a> does not return - <a href="#Z_STREAM_END">Z_STREAM_END</a>, then it must be called again as described above. - <p> - - <a href="#deflate">deflate</a>() sets strm-> <a href="#adler">adler</a> to the <a href="#adler32">adler32</a> checksum of all input read - so far (that is, <a href="#total_in">total_in</a> bytes). - <p> - - <a href="#deflate">deflate</a>() may update <a href="#data_type">data_type</a> if it can make a good guess about - the input data type (<a href="#Z_ASCII">Z_ASCII</a> or <a href="#Z_BINARY">Z_BINARY</a>). In doubt, the data is considered - binary. This field is only for information purposes and does not affect - the compression algorithm in any manner. - <p> - - <a href="#deflate">deflate</a>() returns <a href="#Z_OK">Z_OK</a> if some progress has been made (more input - processed or more output produced), <a href="#Z_STREAM_END">Z_STREAM_END</a> if all input has been - consumed and all output has been produced (only when flush is set to - <a href="#Z_FINISH">Z_FINISH</a>), <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the stream <a href="#state">state</a> was inconsistent (for example - if <a href="#next_in">next_in</a> or <a href="#next_out">next_out</a> was NULL), <a href="#Z_BUF_ERROR">Z_BUF_ERROR</a> if no progress is possible - (for example <a href="#avail_in">avail_in</a> or <a href="#avail_out">avail_out</a> was zero). - <p> - -<font color="Blue"><dt> int <a name="deflateEnd">deflateEnd</a> (<a href="#z_streamp">z_streamp</a> strm);</font> -<dd> - All dynamically allocated data structures for this stream are freed. - This function discards any unprocessed input and does not flush any - pending output. - <p> - - <a href="#deflateEnd">deflateEnd</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the - stream <a href="#state">state</a> was inconsistent, <a href="#Z_DATA_ERROR">Z_DATA_ERROR</a> if the stream was freed - prematurely (some input or output was discarded). In the error case, - <a href="#msg">msg</a> may be set but then points to a static string (which must not be - deallocated). - <p> - -<font color="Blue"><dt> int <a name="inflateInit">inflateInit</a> (<a href="#z_streamp">z_streamp</a> strm);</font> -<dd> - Initializes the internal stream <a href="#state">state</a> for decompression. The fields - <a href="#next_in">next_in</a>, <a href="#avail_in">avail_in</a>, <a href="#zalloc">zalloc</a>, <a href="#zfree">zfree</a> and <a href="#opaque">opaque</a> must be initialized before by - the caller. If <a href="#next_in">next_in</a> is not <a href="#Z_NULL">Z_NULL</a> and <a href="#avail_in">avail_in</a> is large enough (the exact - value depends on the compression method), <a href="#inflateInit">inflateInit</a> determines the - compression method from the zlib header and allocates all data structures - accordingly ; otherwise the allocation will be deferred to the first call of - <a href="#inflate">inflate</a>. If <a href="#zalloc">zalloc</a> and <a href="#zfree">zfree</a> are set to <a href="#Z_NULL">Z_NULL</a>, <a href="#inflateInit">inflateInit</a> updates them to - use default allocation functions. - <p> - - <a href="#inflateInit">inflateInit</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a> if there was not enough - memory, <a href="#Z_VERSION_ERROR">Z_VERSION_ERROR</a> if the zlib library version is incompatible with the - version assumed by the caller. <a href="#msg">msg</a> is set to null if there is no error - message. <a href="#inflateInit">inflateInit</a> does not perform any decompression apart from reading - the zlib header if present: this will be done by <a href="#inflate">inflate</a>(). (So <a href="#next_in">next_in</a> and - <a href="#avail_in">avail_in</a> may be modified, but <a href="#next_out">next_out</a> and <a href="#avail_out">avail_out</a> are unchanged.) - <p> - -<font color="Blue"><dt> int <a name="inflate">inflate</a> (<a href="#z_streamp">z_streamp</a> strm, int flush);</font> -<dd> - <a href="#inflate">inflate</a> decompresses as much data as possible, and stops when the input - buffer becomes empty or the output buffer becomes full. It may some - introduce some output latency (reading input without producing any output) - except when forced to flush. - <p> - - The detailed semantics are as follows. <a href="#inflate">inflate</a> performs one or both of the - following actions: - - <ul> - <li> Decompress more input starting at <a href="#next_in">next_in</a> and update <a href="#next_in">next_in</a> and <a href="#avail_in">avail_in</a> - accordingly. If not all input can be processed (because there is not - enough room in the output buffer), <a href="#next_in">next_in</a> is updated and processing - will resume at this point for the next call of <a href="#inflate">inflate</a>(). - - <li> Provide more output starting at <a href="#next_out">next_out</a> and update <a href="#next_out">next_out</a> and - <a href="#avail_out">avail_out</a> accordingly. <a href="#inflate">inflate</a>() provides as much output as possible, - until there is no more input data or no more space in the output buffer - (see below about the flush parameter). - </ul> <p> - - Before the call of <a href="#inflate">inflate</a>(), the application should ensure that at least - one of the actions is possible, by providing more input and/or consuming - more output, and updating the next_* and avail_* values accordingly. - The application can consume the uncompressed output when it wants, for - example when the output buffer is full (<a href="#avail_out">avail_out</a> == 0), or after each - call of <a href="#inflate">inflate</a>(). If <a href="#inflate">inflate</a> returns <a href="#Z_OK">Z_OK</a> and with zero <a href="#avail_out">avail_out</a>, it - must be called again after making room in the output buffer because there - might be more output pending. - <p> - - If the parameter flush is set to <a href="#Z_SYNC_FLUSH">Z_SYNC_FLUSH</a>, <a href="#inflate">inflate</a> flushes as much - output as possible to the output buffer. The flushing behavior of <a href="#inflate">inflate</a> is - not specified for values of the flush parameter other than <a href="#Z_SYNC_FLUSH">Z_SYNC_FLUSH</a> - and <a href="#Z_FINISH">Z_FINISH</a>, but the current implementation actually flushes as much output - as possible anyway. - <p> - - <a href="#inflate">inflate</a>() should normally be called until it returns <a href="#Z_STREAM_END">Z_STREAM_END</a> or an - error. However if all decompression is to be performed in a single step - (a single call of <a href="#inflate">inflate</a>), the parameter flush should be set to - <a href="#Z_FINISH">Z_FINISH</a>. In this case all pending input is processed and all pending - output is flushed ; <a href="#avail_out">avail_out</a> must be large enough to hold all the - uncompressed data. (The size of the uncompressed data may have been saved - by the compressor for this purpose.) The next operation on this stream must - be <a href="#inflateEnd">inflateEnd</a> to deallocate the decompression <a href="#state">state</a>. The use of <a href="#Z_FINISH">Z_FINISH</a> - is never required, but can be used to inform <a href="#inflate">inflate</a> that a faster routine - may be used for the single <a href="#inflate">inflate</a>() call. - <p> - - If a preset dictionary is needed at this point (see <a href="#inflateSetDictionary">inflateSetDictionary</a> - below), <a href="#inflate">inflate</a> sets strm-<a href="#adler">adler</a> to the <a href="#adler32">adler32</a> checksum of the - dictionary chosen by the compressor and returns <a href="#Z_NEED_DICT">Z_NEED_DICT</a> ; otherwise - it sets strm-> <a href="#adler">adler</a> to the <a href="#adler32">adler32</a> checksum of all output produced - so far (that is, <a href="#total_out">total_out</a> bytes) and returns <a href="#Z_OK">Z_OK</a>, <a href="#Z_STREAM_END">Z_STREAM_END</a> or - an error code as described below. At the end of the stream, <a href="#inflate">inflate</a>() - checks that its computed <a href="#adler32">adler32</a> checksum is equal to that saved by the - compressor and returns <a href="#Z_STREAM_END">Z_STREAM_END</a> only if the checksum is correct. - <p> - - <a href="#inflate">inflate</a>() returns <a href="#Z_OK">Z_OK</a> if some progress has been made (more input processed - or more output produced), <a href="#Z_STREAM_END">Z_STREAM_END</a> if the end of the compressed data has - been reached and all uncompressed output has been produced, <a href="#Z_NEED_DICT">Z_NEED_DICT</a> if a - preset dictionary is needed at this point, <a href="#Z_DATA_ERROR">Z_DATA_ERROR</a> if the input data was - corrupted (input stream not conforming to the zlib format or incorrect - <a href="#adler32">adler32</a> checksum), <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the stream structure was inconsistent - (for example if <a href="#next_in">next_in</a> or <a href="#next_out">next_out</a> was NULL), <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a> if there was not - enough memory, <a href="#Z_BUF_ERROR">Z_BUF_ERROR</a> if no progress is possible or if there was not - enough room in the output buffer when <a href="#Z_FINISH">Z_FINISH</a> is used. In the <a href="#Z_DATA_ERROR">Z_DATA_ERROR</a> - case, the application may then call <a href="#inflateSync">inflateSync</a> to look for a good - compression block. - <p> - -<font color="Blue"><dt> int <a name="inflateEnd">inflateEnd</a> (<a href="#z_streamp">z_streamp</a> strm);</font> -<dd> - All dynamically allocated data structures for this stream are freed. - This function discards any unprocessed input and does not flush any - pending output. - <p> - - <a href="#inflateEnd">inflateEnd</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the stream <a href="#state">state</a> - was inconsistent. In the error case, <a href="#msg">msg</a> may be set but then points to a - static string (which must not be deallocated). -</dl> -<hr> -<a name="Advanced functions"><h2> Advanced functions </h2> - The following functions are needed only in some special applications. -<h3> Function list </h3> -<ul> -<li> int <a href="#deflateInit2">deflateInit2</a> (<a href="#z_streamp">z_streamp</a> strm, -<li> int <a href="#deflateSetDictionary">deflateSetDictionary</a> (<a href="#z_streamp">z_streamp</a> strm, const Bytef *dictionary, uInt dictLength); -<li> int <a href="#deflateCopy">deflateCopy</a> (<a href="#z_streamp">z_streamp</a> dest, <a href="#z_streamp">z_streamp</a> source); -<li> int <a href="#deflateReset">deflateReset</a> (<a href="#z_streamp">z_streamp</a> strm); -<li> int <a href="#deflateParams">deflateParams</a> (<a href="#z_streamp">z_streamp</a> strm, int level, int strategy); -<li> int <a href="#inflateInit2">inflateInit2</a> (<a href="#z_streamp">z_streamp</a> strm, int windowBits); -<li> int <a href="#inflateSetDictionary">inflateSetDictionary</a> (<a href="#z_streamp">z_streamp</a> strm, const Bytef *dictionary, uInt dictLength); -<li> int <a href="#inflateSync">inflateSync</a> (<a href="#z_streamp">z_streamp</a> strm); -<li> int <a href="#inflateReset">inflateReset</a> (<a href="#z_streamp">z_streamp</a> strm); - -</ul> -<h3> Function description </h3> -<dl> -<font color="Blue"><dt> int <a name="deflateInit2">deflateInit2</a> (<a href="#z_streamp">z_streamp</a> strm, int level, int method, int windowBits, int memLevel, int strategy);</font> - -<dd> This is another version of <a href="#deflateInit">deflateInit</a> with more compression options. The - fields <a href="#next_in">next_in</a>, <a href="#zalloc">zalloc</a>, <a href="#zfree">zfree</a> and <a href="#opaque">opaque</a> must be initialized before by - the caller.<p> - - The method parameter is the compression method. It must be <a href="#Z_DEFLATED">Z_DEFLATED</a> in - this version of the library.<p> - - The windowBits parameter is the base two logarithm of the window size - (the size of the history buffer). It should be in the range 8..15 for this - version of the library. Larger values of this parameter result in better - compression at the expense of memory usage. The default value is 15 if - <a href="#deflateInit">deflateInit</a> is used instead.<p> - - The memLevel parameter specifies how much memory should be allocated - for the internal compression <a href="#state">state</a>. memLevel=1 uses minimum memory but - is slow and reduces compression ratio ; memLevel=9 uses maximum memory - for optimal speed. The default value is 8. See zconf.h for total memory - usage as a function of windowBits and memLevel.<p> - - The strategy parameter is used to tune the compression algorithm. Use the - value <a href="#Z_DEFAULT_STRATEGY">Z_DEFAULT_STRATEGY</a> for normal data, <a href="#Z_FILTERED">Z_FILTERED</a> for data produced by a - filter (or predictor), or <a href="#Z_HUFFMAN_ONLY">Z_HUFFMAN_ONLY</a> to force Huffman encoding only (no - string match). Filtered data consists mostly of small values with a - somewhat random distribution. In this case, the compression algorithm is - tuned to <a href="#compress">compress</a> them better. The effect of <a href="#Z_FILTERED">Z_FILTERED</a> is to force more - Huffman coding and less string matching ; it is somewhat intermediate - between Z_DEFAULT and <a href="#Z_HUFFMAN_ONLY">Z_HUFFMAN_ONLY</a>. The strategy parameter only affects - the compression ratio but not the correctness of the compressed output even - if it is not set appropriately.<p> - - <a href="#deflateInit2">deflateInit2</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a> if there was not enough - memory, <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if a parameter is invalid (such as an invalid - method). <a href="#msg">msg</a> is set to null if there is no error message. <a href="#deflateInit2">deflateInit2</a> does - not perform any compression: this will be done by <a href="#deflate">deflate</a>().<p> - -<font color="Blue"><dt> int <a name="deflateSetDictionary">deflateSetDictionary</a> (<a href="#z_streamp">z_streamp</a> strm, const Bytef *dictionary, uInt dictLength);</font> -<dd> - Initializes the compression dictionary from the given byte sequence - without producing any compressed output. This function must be called - immediately after <a href="#deflateInit">deflateInit</a>, <a href="#deflateInit2">deflateInit2</a> or <a href="#deflateReset">deflateReset</a>, before any - call of <a href="#deflate">deflate</a>. The compressor and decompressor must use exactly the same - dictionary (see <a href="#inflateSetDictionary">inflateSetDictionary</a>).<p> - - The dictionary should consist of strings (byte sequences) that are likely - to be encountered later in the data to be compressed, with the most commonly - used strings preferably put towards the end of the dictionary. Using a - dictionary is most useful when the data to be compressed is short and can be - predicted with good accuracy ; the data can then be compressed better than - with the default empty dictionary.<p> - - Depending on the size of the compression data structures selected by - <a href="#deflateInit">deflateInit</a> or <a href="#deflateInit2">deflateInit2</a>, a part of the dictionary may in effect be - discarded, for example if the dictionary is larger than the window size in - <a href="#deflate">deflate</a> or deflate2. Thus the strings most likely to be useful should be - put at the end of the dictionary, not at the front.<p> - - Upon return of this function, strm-> <a href="#adler">adler</a> is set to the Adler32 value - of the dictionary ; the decompressor may later use this value to determine - which dictionary has been used by the compressor. (The Adler32 value - applies to the whole dictionary even if only a subset of the dictionary is - actually used by the compressor.)<p> - - <a href="#deflateSetDictionary">deflateSetDictionary</a> returns <a href="#Z_OK">Z_OK</a> if success, or <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if a - parameter is invalid (such as NULL dictionary) or the stream <a href="#state">state</a> is - inconsistent (for example if <a href="#deflate">deflate</a> has already been called for this stream - or if the compression method is bsort). <a href="#deflateSetDictionary">deflateSetDictionary</a> does not - perform any compression: this will be done by <a href="#deflate">deflate</a>().<p> - -<font color="Blue"><dt> int <a name="deflateCopy">deflateCopy</a> (<a href="#z_streamp">z_streamp</a> dest, <a href="#z_streamp">z_streamp</a> source);</font> -<dd> - Sets the destination stream as a complete copy of the source stream.<p> - - This function can be useful when several compression strategies will be - tried, for example when there are several ways of pre-processing the input - data with a filter. The streams that will be discarded should then be freed - by calling <a href="#deflateEnd">deflateEnd</a>. Note that <a href="#deflateCopy">deflateCopy</a> duplicates the internal - compression <a href="#state">state</a> which can be quite large, so this strategy is slow and - can consume lots of memory.<p> - - <a href="#deflateCopy">deflateCopy</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a> if there was not - enough memory, <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the source stream <a href="#state">state</a> was inconsistent - (such as <a href="#zalloc">zalloc</a> being NULL). <a href="#msg">msg</a> is left unchanged in both source and - destination.<p> - -<font color="Blue"><dt> int <a name="deflateReset">deflateReset</a> (<a href="#z_streamp">z_streamp</a> strm);</font> -<dd> This function is equivalent to <a href="#deflateEnd">deflateEnd</a> followed by <a href="#deflateInit">deflateInit</a>, - but does not free and reallocate all the internal compression <a href="#state">state</a>. - The stream will keep the same compression level and any other attributes - that may have been set by <a href="#deflateInit2">deflateInit2</a>.<p> - - <a href="#deflateReset">deflateReset</a> returns <a href="#Z_OK">Z_OK</a> if success, or <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the source - stream <a href="#state">state</a> was inconsistent (such as <a href="#zalloc">zalloc</a> or <a href="#state">state</a> being NULL).<p> - -<font color="Blue"><dt> int <a name="deflateParams">deflateParams</a> (<a href="#z_streamp">z_streamp</a> strm, int level, int strategy);</font> -<dd> - Dynamically update the compression level and compression strategy. The - interpretation of level and strategy is as in <a href="#deflateInit2">deflateInit2</a>. This can be - used to switch between compression and straight copy of the input data, or - to switch to a different kind of input data requiring a different - strategy. If the compression level is changed, the input available so far - is compressed with the old level (and may be flushed); the new level will - take effect only at the next call of <a href="#deflate">deflate</a>().<p> - - Before the call of <a href="#deflateParams">deflateParams</a>, the stream <a href="#state">state</a> must be set as for - a call of <a href="#deflate">deflate</a>(), since the currently available input may have to - be compressed and flushed. In particular, strm-> <a href="#avail_out">avail_out</a> must be - non-zero.<p> - - <a href="#deflateParams">deflateParams</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the source - stream <a href="#state">state</a> was inconsistent or if a parameter was invalid, <a href="#Z_BUF_ERROR">Z_BUF_ERROR</a> - if strm->avail_out was zero.<p> - -<font color="Blue"><dt> int <a name="inflateInit2">inflateInit2</a> (<a href="#z_streamp">z_streamp</a> strm, int windowBits);</font> - -<dd> This is another version of <a href="#inflateInit">inflateInit</a> with an extra parameter. The - fields <a href="#next_in">next_in</a>, <a href="#avail_in">avail_in</a>, <a href="#zalloc">zalloc</a>, <a href="#zfree">zfree</a> and <a href="#opaque">opaque</a> must be initialized - before by the caller.<p> - - The windowBits parameter is the base two logarithm of the maximum window - size (the size of the history buffer). It should be in the range 8..15 for - this version of the library. The default value is 15 if <a href="#inflateInit">inflateInit</a> is used - instead. If a compressed stream with a larger window size is given as - input, <a href="#inflate">inflate</a>() will return with the error code <a href="#Z_DATA_ERROR">Z_DATA_ERROR</a> instead of - trying to allocate a larger window.<p> - - <a href="#inflateInit2">inflateInit2</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_MEM_ERROR">Z_MEM_ERROR</a> if there was not enough - memory, <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if a parameter is invalid (such as a negative - memLevel). <a href="#msg">msg</a> is set to null if there is no error message. <a href="#inflateInit2">inflateInit2</a> - does not perform any decompression apart from reading the zlib header if - present: this will be done by <a href="#inflate">inflate</a>(). (So <a href="#next_in">next_in</a> and <a href="#avail_in">avail_in</a> may be - modified, but <a href="#next_out">next_out</a> and <a href="#avail_out">avail_out</a> are unchanged.)<p> - -<font color="Blue"><dt> int <a name="inflateSetDictionary">inflateSetDictionary</a> (<a href="#z_streamp">z_streamp</a> strm, const Bytef *dictionary, uInt dictLength);</font> -<dd> - Initializes the decompression dictionary from the given uncompressed byte - sequence. This function must be called immediately after a call of <a href="#inflate">inflate</a> - if this call returned <a href="#Z_NEED_DICT">Z_NEED_DICT</a>. The dictionary chosen by the compressor - can be determined from the Adler32 value returned by this call of - <a href="#inflate">inflate</a>. The compressor and decompressor must use exactly the same - dictionary (see <a href="#deflateSetDictionary">deflateSetDictionary</a>).<p> - - <a href="#inflateSetDictionary">inflateSetDictionary</a> returns <a href="#Z_OK">Z_OK</a> if success, <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if a - parameter is invalid (such as NULL dictionary) or the stream <a href="#state">state</a> is - inconsistent, <a href="#Z_DATA_ERROR">Z_DATA_ERROR</a> if the given dictionary doesn't match the - expected one (incorrect Adler32 value). <a href="#inflateSetDictionary">inflateSetDictionary</a> does not - perform any decompression: this will be done by subsequent calls of - <a href="#inflate">inflate</a>().<p> - -<font color="Blue"><dt> int <a name="inflateSync">inflateSync</a> (<a href="#z_streamp">z_streamp</a> strm);</font> - -<dd> Skips invalid compressed data until a full flush point (see above the - description of <a href="#deflate">deflate</a> with <a href="#Z_FULL_FLUSH">Z_FULL_FLUSH</a>) can be found, or until all - available input is skipped. No output is provided.<p> - - <a href="#inflateSync">inflateSync</a> returns <a href="#Z_OK">Z_OK</a> if a full flush point has been found, <a href="#Z_BUF_ERROR">Z_BUF_ERROR</a> - if no more input was provided, <a href="#Z_DATA_ERROR">Z_DATA_ERROR</a> if no flush point has been found, - or <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the stream structure was inconsistent. In the success - case, the application may save the current current value of <a href="#total_in">total_in</a> which - indicates where valid compressed data was found. In the error case, the - application may repeatedly call <a href="#inflateSync">inflateSync</a>, providing more input each time, - until success or end of the input data.<p> - -<font color="Blue"><dt> int <a name="inflateReset">inflateReset</a> (<a href="#z_streamp">z_streamp</a> strm);</font> -<dd> - This function is equivalent to <a href="#inflateEnd">inflateEnd</a> followed by <a href="#inflateInit">inflateInit</a>, - but does not free and reallocate all the internal decompression <a href="#state">state</a>. - The stream will keep attributes that may have been set by <a href="#inflateInit2">inflateInit2</a>. - <p> - - <a href="#inflateReset">inflateReset</a> returns <a href="#Z_OK">Z_OK</a> if success, or <a href="#Z_STREAM_ERROR">Z_STREAM_ERROR</a> if the source - stream <a href="#state">state</a> was inconsistent (such as <a href="#zalloc">zalloc</a> or <a href="#state">state</a> being NULL). - <p> -</dl> - -<hr> -<a name="Checksum functions"><h2> Checksum functions </h2> - These functions are not related to compression but are exported - anyway because they might be useful in applications using the - compression library. -<h3> Function list </h3> -<ul> -<li> uLong <a href="#adler32">adler32</a> (uLong <a href="#adler">adler</a>, const Bytef *buf, uInt len); -<li> uLong <a href="#crc32">crc32</a> (uLong crc, const Bytef *buf, uInt len); -</ul> -<h3> Function description </h3> -<dl> -<font color="Blue"><dt> uLong <a name="adler32">adler32</a> (uLong <a href="#adler">adler</a>, const Bytef *buf, uInt len);</font> -<dd> - Update a running Adler-32 checksum with the bytes buf[0..len-1] and - return the updated checksum. If buf is NULL, this function returns - the required initial value for the checksum. - <p> - An Adler-32 checksum is almost as reliable as a CRC32 but can be computed - much faster. Usage example: - <pre> - - uLong <a href="#adler">adler</a> = <a href="#adler32">adler32</a>(0L, <a href="#Z_NULL">Z_NULL</a>, 0); - - while (read_buffer(buffer, length) != EOF) { - <a href="#adler">adler</a> = <a href="#adler32">adler32</a>(<a href="#adler">adler</a>, buffer, length); - } - if (<a href="#adler">adler</a> != original_adler) error(); - </pre> - -<font color="Blue"><dt> uLong <a name="crc32">crc32</a> (uLong crc, const Bytef *buf, uInt len);</font> -<dd> - Update a running crc with the bytes buf[0..len-1] and return the updated - crc. If buf is NULL, this function returns the required initial value - for the crc. Pre- and post-conditioning (one's complement) is performed - within this function so it shouldn't be done by the application. - Usage example: - <pre> - - uLong crc = <a href="#crc32">crc32</a>(0L, <a href="#Z_NULL">Z_NULL</a>, 0); - - while (read_buffer(buffer, length) != EOF) { - crc = <a href="#crc32">crc32</a>(crc, buffer, length); - } - if (crc != original_crc) error(); - </pre> -</dl> -<hr> -<a name="struct z_stream_s"><h2> struct z_stream_s </h2> -<font color="Blue"> -<a name="z_stream_s"> -<pre> -typedef struct z_stream_s { - Bytef *<a name="next_in">next_in</a>; /* next input byte */ - uInt <a name="avail_in">avail_in</a>; /* number of bytes available at <a href="#next_in">next_in</a> */ - uLong <a name="total_in">total_in</a>; /* total nb of input bytes read so far */ - - Bytef *<a name="next_out">next_out</a>; /* next output byte should be put there */ - uInt <a name="avail_out">avail_out</a>; /* remaining free space at <a href="#next_out">next_out</a> */ - uLong <a name="total_out">total_out</a>; /* total nb of bytes output so far */ - - char *<a name="msg">msg</a>; /* last error message, NULL if no error */ - struct internal_state FAR *<a name="state">state</a>; /* not visible by applications */ - - alloc_func <a name="zalloc">zalloc</a>; /* used to allocate the internal <a href="#state">state</a> */ - free_func <a name="zfree">zfree</a>; /* used to free the internal <a href="#state">state</a> */ - voidpf <a name="opaque">opaque</a>; /* private data object passed to <a href="#zalloc">zalloc</a> and <a href="#zfree">zfree</a> */ - - int <a name="data_type">data_type</a>; /* best guess about the data type: ascii or binary */ - uLong <a name="adler">adler</a>; /* <a href="#adler32">adler32</a> value of the uncompressed data */ - uLong <a name="reserved">reserved</a>; /* <a href="#reserved">reserved</a> for future use */ -} <a href="#z_stream_s">z_stream</a> ; - -typedef <a href="#z_stream_s">z_stream</a> FAR * <a name="z_streamp">z_streamp</a>; ÿ -</pre> -</font> - The application must update <a href="#next_in">next_in</a> and <a href="#avail_in">avail_in</a> when <a href="#avail_in">avail_in</a> has - dropped to zero. It must update <a href="#next_out">next_out</a> and <a href="#avail_out">avail_out</a> when <a href="#avail_out">avail_out</a> - has dropped to zero. The application must initialize <a href="#zalloc">zalloc</a>, <a href="#zfree">zfree</a> and - <a href="#opaque">opaque</a> before calling the init function. All other fields are set by the - compression library and must not be updated by the application. <p> - - The <a href="#opaque">opaque</a> value provided by the application will be passed as the first - parameter for calls of <a href="#zalloc">zalloc</a> and <a href="#zfree">zfree</a>. This can be useful for custom - memory management. The compression library attaches no meaning to the - <a href="#opaque">opaque</a> value. <p> - - <a href="#zalloc">zalloc</a> must return <a href="#Z_NULL">Z_NULL</a> if there is not enough memory for the object. - If zlib is used in a multi-threaded application, <a href="#zalloc">zalloc</a> and <a href="#zfree">zfree</a> must be - thread safe. <p> - - On 16-bit systems, the functions <a href="#zalloc">zalloc</a> and <a href="#zfree">zfree</a> must be able to allocate - exactly 65536 bytes, but will not be required to allocate more than this - if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, - pointers returned by <a href="#zalloc">zalloc</a> for objects of exactly 65536 bytes *must* - have their offset normalized to zero. The default allocation function - provided by this library ensures this (see zutil.c). To reduce memory - requirements and avoid any allocation of 64K objects, at the expense of - compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). - <p> - - The fields <a href="#total_in">total_in</a> and <a href="#total_out">total_out</a> can be used for statistics or - progress reports. After compression, <a href="#total_in">total_in</a> holds the total size of - the uncompressed data and may be saved for use in the decompressor - (particularly if the decompressor wants to decompress everything in - a single step). <p> - -<hr> -<a name="Constants"><h2> Constants </h2> -<font color="Blue"> -<pre> -#define <a name="Z_NO_FLUSH">Z_NO_FLUSH</a> 0 -#define <a name="Z_PARTIAL_FLUSH">Z_PARTIAL_FLUSH</a> 1 - /* will be removed, use <a href="#Z_SYNC_FLUSH">Z_SYNC_FLUSH</a> instead */ -#define <a name="Z_SYNC_FLUSH">Z_SYNC_FLUSH</a> 2 -#define <a name="Z_FULL_FLUSH">Z_FULL_FLUSH</a> 3 -#define <a name="Z_FINISH">Z_FINISH</a> 4 -/* Allowed flush values ; see <a href="#deflate">deflate</a>() below for details */ - -#define <a name="Z_OK">Z_OK</a> 0 -#define <a name="Z_STREAM_END">Z_STREAM_END</a> 1 -#define <a name="Z_NEED_DICT">Z_NEED_DICT</a> 2 -#define <a name="Z_ERRNO">Z_ERRNO</a> (-1) -#define <a name="Z_STREAM_ERROR">Z_STREAM_ERROR</a> (-2) -#define <a name="Z_DATA_ERROR">Z_DATA_ERROR</a> (-3) -#define <a name="Z_MEM_ERROR">Z_MEM_ERROR</a> (-4) -#define <a name="Z_BUF_ERROR">Z_BUF_ERROR</a> (-5) -#define <a name="Z_VERSION_ERROR">Z_VERSION_ERROR</a> (-6) -/* Return codes for the compression/decompression functions. Negative - * values are errors, positive values are used for special but normal events. - */ - -#define <a name="Z_NO_COMPRESSION">Z_NO_COMPRESSION</a> 0 -#define <a name="Z_BEST_SPEED">Z_BEST_SPEED</a> 1 -#define <a name="Z_BEST_COMPRESSION">Z_BEST_COMPRESSION</a> 9 -#define <a name="Z_DEFAULT_COMPRESSION">Z_DEFAULT_COMPRESSION</a> (-1) -/* compression levels */ - -#define <a name="Z_FILTERED">Z_FILTERED</a> 1 -#define <a name="Z_HUFFMAN_ONLY">Z_HUFFMAN_ONLY</a> 2 -#define <a name="Z_DEFAULT_STRATEGY">Z_DEFAULT_STRATEGY</a> 0 -/* compression strategy ; see <a href="#deflateInit2">deflateInit2</a>() below for details */ - -#define <a name="Z_BINARY">Z_BINARY</a> 0 -#define <a name="Z_ASCII">Z_ASCII</a> 1 -#define <a name="Z_UNKNOWN">Z_UNKNOWN</a> 2 -/* Possible values of the <a href="#data_type">data_type</a> field */ - -#define <a name="Z_DEFLATED">Z_DEFLATED</a> 8 -/* The <a href="#deflate">deflate</a> compression method (the only one supported in this version) */ - -#define <a name="Z_NULL">Z_NULL</a> 0 /* for initializing <a href="#zalloc">zalloc</a>, <a href="#zfree">zfree</a>, <a href="#opaque">opaque</a> */ - -#define <a name="zlib_version">zlib_version</a> <a href="#zlibVersion">zlibVersion</a>() -/* for compatibility with versions less than 1.0.2 */ -</pre> -</font> - -<hr> -<a name="Misc"><h2> Misc </h2> - <a href="#deflateInit">deflateInit</a> and <a href="#inflateInit">inflateInit</a> are macros to allow checking the zlib version - and the compiler's view of <a href="#z_stream_s">z_stream</a>. - <p> - Other functions: - <dl> - <font color="Blue"><dt> const char * <a name="zError">zError</a> (int err);</font> - <font color="Blue"><dt> int <a name="inflateSyncPoint">inflateSyncPoint</a> (<a href="#z_streamp">z_streamp</a> z);</font> - <font color="Blue"><dt> const uLongf * <a name="get_crc_table">get_crc_table</a> (void);</font> - </dl> - <hr> - <font size="-1"> - Last update: Wed Oct 13 20:42:34 1999<br> - piapi@csie.ntu.edu.tw - </font> - -</body> -</html> |