# include <unix.h>
#endif
-/* Maximum value for memLevel in deflateInit2 */
-#ifndef MAX_MEM_LEVEL
-# ifdef MAXSEG_64K
-# define MAX_MEM_LEVEL 8
-# else
-# define MAX_MEM_LEVEL 9
-# endif
-#endif
-
#ifndef FAR
# define FAR
#endif
# define MAX_WBITS 15 /* 32K LZ77 window */
#endif
-/* The memory requirements for deflate are (in bytes):
- 1 << (windowBits+2) + 1 << (memLevel+9)
- that is: 128K for windowBits=15 + 128K for memLevel = 8 (default values)
- plus a few kilobytes for small objects. For example, if you want to reduce
- the default memory requirements from 256K to 128K, compile with
- make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
- Of course this will generally degrade compression (there's no free lunch).
-
+/*
The memory requirements for inflate are (in bytes) 1 << windowBits
that is, 32K for windowBits=15 (default value) plus a few kilobytes
for small objects.
/* basic functions */
-extern int deflateInit OF((z_stream *strm, int level));
-/*
- Initializes the internal stream state for compression. The fields
- zalloc, zfree and opaque must be initialized before by the caller.
- If zalloc and zfree are set to Z_NULL, deflateInit updates them to
- use default allocation functions.
-
- The compression level must be Z_DEFAULT_COMPRESSION, or between 1 and 9:
- 1 gives best speed, 9 gives best compression. Z_DEFAULT_COMPRESSION requests
- a default compromise between speed and compression (currently equivalent
- to level 6).
-
- deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
- enough memory, Z_STREAM_ERROR if level is not a valid compression level.
- msg is set to null if there is no error message. deflateInit does not
- perform any compression: this will be done by deflate().
-*/
-
-
-extern int deflate OF((z_stream *strm, int flush));
-/*
- Performs one or both of the following actions:
-
- - Compress more input starting at next_in and update next_in and avail_in
- accordingly. If not all input can be processed (because there is not
- enough room in the output buffer), next_in and avail_in are updated and
- processing will resume at this point for the next call of deflate().
-
- - Provide more output starting at next_out and update next_out and avail_out
- 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.
-
- Before the call of deflate(), the application should ensure that at least
- one of the actions is possible, by providing more input and/or consuming
- more output, and updating avail_in or avail_out accordingly; avail_out
- 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
- (avail_out == 0), or after each call of deflate().
-
- If the parameter flush is set to Z_PARTIAL_FLUSH, the current compression
- block is terminated and flushed to the output buffer so that the
- decompressor can get all input data available so far. For method 9, a future
- variant on method 8, the current block will be flushed but not terminated.
- If flush is set to Z_FULL_FLUSH, the compression block is terminated, a
- special marker is output and the compression dictionary is discarded; this
- is useful to allow the decompressor to synchronize if one compressed block
- has been damaged (see inflateSync below). Flushing degrades compression and
- so should be used only when necessary. Using Z_FULL_FLUSH too often can
- seriously degrade the compression. If deflate returns with avail_out == 0,
- this function must be called again with the same value of the flush
- parameter and more output space (updated avail_out), until the flush is
- complete (deflate returns with non-zero avail_out).
-
- If the parameter flush is set to Z_PACKET_FLUSH, the compression
- block is terminated, and a zero-length stored block is output,
- omitting the length bytes (the effect of this is that the 3-bit type
- code 000 for a stored block is output, and the output is then
- byte-aligned). This is designed for use at the end of a PPP packet.
- In addition, if the current compression block contains all the data
- since the last Z_PACKET_FLUSH, it is never output as a stored block.
- If the current compression block output as a static or dynamic block
- would not be at least `minCompression' bytes smaller than the
- original data, then nothing is output for that block. (The type
- code for the zero-length stored block is still output, resulting in
- a single zero byte being output for the whole packet.)
- `MinCompression' is a parameter to deflateInit2, or 0 if deflateInit
- is used.
-
- If the parameter flush is set to Z_FINISH, all pending input is processed,
- all pending output is flushed and deflate returns with Z_STREAM_END if there
- was enough output space; if deflate returns with Z_OK, this function must be
- called again with Z_FINISH and more output space (updated avail_out) but no
- more input data, until it returns with Z_STREAM_END or an error. After
- deflate has returned Z_STREAM_END, the only possible operations on the
- stream are deflateReset or deflateEnd.
-
- Z_FINISH can be used immediately after deflateInit if all the compression
- is to be done in a single step. In this case, avail_out must be at least
- 0.1% larger than avail_in plus 12 bytes. If deflate does not return
- Z_STREAM_END, then it must be called again as described above.
-
- deflate() may update data_type if it can make a good guess about
- the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
- binary. This field is only for information purposes and does not affect
- the compression algorithm in any manner.
-
- deflate() returns Z_OK if some progress has been made (more input
- processed or more output produced), Z_STREAM_END if all input has been
- consumed and all output has been produced (only when flush is set to
- Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
- if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible.
-*/
-
-
-extern int deflateEnd OF((z_stream *strm));
-/*
- All dynamically allocated data structures for this stream are freed.
- This function discards any unprocessed input and does not flush any
- pending output.
-
- deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
- stream state was inconsistent. In the error case, msg may be set
- but then points to a static string (which must not be deallocated).
-*/
-
-
extern int inflateInit OF((z_stream *strm));
/*
Initializes the internal stream state for decompression. The fields
The following functions are needed only in some special applications.
*/
-extern int deflateInit2 OF((z_stream *strm,
- int level,
- int method,
- int windowBits,
- int memLevel,
- int strategy,
- int minCompression));
-/*
- This is another version of deflateInit with more compression options. The
- fields next_in, zalloc and zfree must be initialized before by the caller.
-
- The method parameter is the compression method. It must be 8 in this
- version of the library. (Method 9 will allow a 64K history buffer and
- partial block flushes.)
-
- 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 (the value 16 will be allowed for method 9). Larger
- values of this parameter result in better compression at the expense of
- memory usage. The default value is 15 if deflateInit is used instead.
-
- The memLevel parameter specifies how much memory should be allocated
- for the internal compression state. 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.
-
- The strategy parameter is used to tune the compression algorithm. Use
- the value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data
- produced by a filter (or predictor), or Z_HUFFMAN_ONLY 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 compress them better. The strategy
- parameter only affects the compression ratio but not the correctness of
- the compressed output even if it is not set appropriately.
-
- The minCompression parameter specifies the minimum reduction in size
- required for a compressed block to be output when Z_PACKET_FLUSH is
- used (see the description of deflate above).
-
- If next_in is not null, the library will use this buffer to hold also
- some history information; the buffer must either hold the entire input
- data, or have at least 1<<(windowBits+1) bytes and be writable. If next_in
- is null, the library will allocate its own history buffer (and leave next_in
- null). next_out need not be provided here but must be provided by the
- application for the next call of deflate().
-
- If the history buffer is provided by the application, next_in must
- must never be changed by the application since the compressor maintains
- information inside this buffer from call to call; the application
- must provide more input only by increasing avail_in. next_in is always
- reset by the library in this case.
-
- deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
- not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
- an invalid method). msg is set to null if there is no error message.
- deflateInit2 does not perform any compression: this will be done by
- deflate().
-*/
-
-extern int deflateCopy OF((z_stream *dest,
- z_stream *source));
-/*
- Sets the destination stream as a complete copy of the source stream. If
- the source stream is using an application-supplied history buffer, a new
- buffer is allocated for the destination stream. The compressed output
- buffer is always application-supplied. It's the responsibility of the
- application to provide the correct values of next_out and avail_out for the
- next call of deflate.
-
- This function is 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 deflateEnd. Note that deflateCopy duplicates the internal
- compression state which can be quite large, so this strategy is slow and
- can consume lots of memory.
-
- deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
- enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
- (such as zalloc being NULL). msg is left unchanged in both source and
- destination.
-*/
-
-extern int deflateReset OF((z_stream *strm));
-/*
- This function is equivalent to deflateEnd followed by deflateInit,
- but does not free and reallocate all the internal compression state.
- The stream will keep the same compression level and any other attributes
- that may have been set by deflateInit2.
-
- deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
- stream state was inconsistent (such as zalloc or state being NULL).
-*/
-
extern int inflateInit2 OF((z_stream *strm,
int windowBits));
/*
projects / ppp.git / blobdiff