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Diffstat (limited to 'kernel/include/linux/zlib.h')
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diff --git a/kernel/include/linux/zlib.h b/kernel/include/linux/zlib.h new file mode 100644 index 000000000..92dbbd3f6 --- /dev/null +++ b/kernel/include/linux/zlib.h @@ -0,0 +1,593 @@ +/* zlib.h -- interface of the 'zlib' general purpose compression library + + Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler + + 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. + + 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: + + 1. 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. + 2. Altered source versions must be plainly marked as such, and must not be + misrepresented as being the original software. + 3. This notice may not be removed or altered from any source distribution. + + Jean-loup Gailly Mark Adler + jloup@gzip.org madler@alumni.caltech.edu + + + The data format used by the zlib library is described by RFCs (Request for + Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt + (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). +*/ + +#ifndef _ZLIB_H +#define _ZLIB_H + +#include <linux/zconf.h> + +/* zlib deflate based on ZLIB_VERSION "1.1.3" */ +/* zlib inflate based on ZLIB_VERSION "1.2.3" */ + +/* + This is a modified version of zlib for use inside the Linux kernel. + The main changes are to perform all memory allocation in advance. + + Inflation Changes: + * Z_PACKET_FLUSH is added and used by ppp_deflate. Before returning + this checks there is no more input data available and the next data + is a STORED block. It also resets the mode to be read for the next + data, all as per PPP requirements. + * Addition of zlib_inflateIncomp which copies incompressible data into + the history window and adjusts the accoutning without calling + zlib_inflate itself to inflate the data. +*/ + +/* + 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. + + 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. + + The compressed data format used by default by the in-memory functions is + the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped + around a deflate stream, which is itself documented in RFC 1951. + + The library also supports reading and writing files in gzip (.gz) format + with an interface similar to that of stdio. + + The zlib format was designed to be compact and fast for use in memory + and on communications channels. The gzip format was designed for single- + file compression on file systems, has a larger header than zlib to maintain + directory information, and uses a different, slower check method than zlib. + + 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. +*/ + +struct internal_state; + +typedef struct z_stream_s { + const Byte *next_in; /* next input byte */ + uLong avail_in; /* number of bytes available at next_in */ + uLong total_in; /* total nb of input bytes read so far */ + + Byte *next_out; /* next output byte should be put there */ + uLong avail_out; /* remaining free space at next_out */ + uLong total_out; /* total nb of bytes output so far */ + + char *msg; /* last error message, NULL if no error */ + struct internal_state *state; /* not visible by applications */ + + void *workspace; /* memory allocated for this stream */ + + int data_type; /* best guess about the data type: ascii or binary */ + uLong adler; /* adler32 value of the uncompressed data */ + uLong reserved; /* reserved for future use */ +} z_stream; + +typedef z_stream *z_streamp; + +/* + The application must update next_in and avail_in when avail_in has + dropped to zero. It must update next_out and avail_out when avail_out + has dropped to zero. The application must initialize zalloc, zfree and + opaque before calling the init function. All other fields are set by the + compression library and must not be updated by the application. + + The opaque value provided by the application will be passed as the first + parameter for calls of zalloc and zfree. This can be useful for custom + memory management. The compression library attaches no meaning to the + opaque value. + + zalloc must return NULL if there is not enough memory for the object. + If zlib is used in a multi-threaded application, zalloc and zfree must be + thread safe. + + On 16-bit systems, the functions zalloc and zfree 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 zalloc 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). + + The fields total_in and total_out can be used for statistics or + progress reports. After compression, total_in 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). +*/ + + /* constants */ + +#define Z_NO_FLUSH 0 +#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ +#define Z_PACKET_FLUSH 2 +#define Z_SYNC_FLUSH 3 +#define Z_FULL_FLUSH 4 +#define Z_FINISH 5 +#define Z_BLOCK 6 /* Only for inflate at present */ +/* Allowed flush values; see deflate() and inflate() below for details */ + +#define Z_OK 0 +#define Z_STREAM_END 1 +#define Z_NEED_DICT 2 +#define Z_ERRNO (-1) +#define Z_STREAM_ERROR (-2) +#define Z_DATA_ERROR (-3) +#define Z_MEM_ERROR (-4) +#define Z_BUF_ERROR (-5) +#define Z_VERSION_ERROR (-6) +/* Return codes for the compression/decompression functions. Negative + * values are errors, positive values are used for special but normal events. + */ + +#define Z_NO_COMPRESSION 0 +#define Z_BEST_SPEED 1 +#define Z_BEST_COMPRESSION 9 +#define Z_DEFAULT_COMPRESSION (-1) +/* compression levels */ + +#define Z_FILTERED 1 +#define Z_HUFFMAN_ONLY 2 +#define Z_DEFAULT_STRATEGY 0 +/* compression strategy; see deflateInit2() below for details */ + +#define Z_BINARY 0 +#define Z_ASCII 1 +#define Z_UNKNOWN 2 +/* Possible values of the data_type field */ + +#define Z_DEFLATED 8 +/* The deflate compression method (the only one supported in this version) */ + + /* basic functions */ + +extern int zlib_deflate_workspacesize (int windowBits, int memLevel); +/* + Returns the number of bytes that needs to be allocated for a per- + stream workspace with the specified parameters. A pointer to this + number of bytes should be returned in stream->workspace before + you call zlib_deflateInit() or zlib_deflateInit2(). If you call + zlib_deflateInit(), specify windowBits = MAX_WBITS and memLevel = + MAX_MEM_LEVEL here. If you call zlib_deflateInit2(), the windowBits + and memLevel parameters passed to zlib_deflateInit2() must not + exceed those passed here. +*/ + +/* +extern int deflateInit (z_streamp 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 NULL, deflateInit updates them to + use default allocation functions. + + The compression level must be Z_DEFAULT_COMPRESSION, 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). + 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, + Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible + with the version assumed by the caller (ZLIB_VERSION). + 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 zlib_deflate (z_streamp strm, int flush); +/* + deflate 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. + + The detailed semantics are as follows. deflate 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 deflate returns Z_OK + and with zero avail_out, it must be called again after making room in the + output buffer because there might be more output pending. + + If the parameter flush is set to Z_SYNC_FLUSH, 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 + avail_in 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. + + If flush is set to Z_FULL_FLUSH, all output is flushed as with + Z_SYNC_FLUSH, and the compression state is reset so that decompression can + restart from this point if previous compressed data has been damaged or if + random access is desired. 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_FINISH, pending input is processed, + 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() sets strm->adler to the adler32 checksum of all input read + so far (that is, total_in bytes). + + 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 + (for example avail_in or avail_out was zero). +*/ + + +extern int zlib_deflateEnd (z_streamp 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, Z_DATA_ERROR if the stream was freed + prematurely (some input or output was discarded). In the error case, + msg may be set but then points to a static string (which must not be + deallocated). +*/ + + +extern int zlib_inflate_workspacesize (void); +/* + Returns the number of bytes that needs to be allocated for a per- + stream workspace. A pointer to this number of bytes should be + returned in stream->workspace before calling zlib_inflateInit(). +*/ + +/* +extern int zlib_inflateInit (z_streamp strm); + + Initializes the internal stream state for decompression. The fields + next_in, avail_in, and workspace must be initialized before by + the caller. If next_in is not NULL and avail_in is large enough (the exact + value depends on the compression method), inflateInit 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 + inflate. If zalloc and zfree are set to NULL, inflateInit updates them to + use default allocation functions. + + inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough + memory, Z_VERSION_ERROR if the zlib library version is incompatible with the + version assumed by the caller. msg is set to null if there is no error + message. inflateInit does not perform any decompression apart from reading + the zlib header if present: this will be done by inflate(). (So next_in and + avail_in may be modified, but next_out and avail_out are unchanged.) +*/ + + +extern int zlib_inflate (z_streamp strm, int flush); +/* + inflate decompresses 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. + + The detailed semantics are as follows. inflate performs one or both of the + following actions: + + - Decompress 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 is updated and processing + will resume at this point for the next call of inflate(). + + - Provide more output starting at next_out and update next_out and avail_out + accordingly. inflate() 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). + + Before the call of inflate(), 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 (avail_out == 0), or after each + call of inflate(). If inflate returns Z_OK and with zero avail_out, it + must be called again after making room in the output buffer because there + might be more output pending. + + The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, + Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much + output as possible to the output buffer. Z_BLOCK requests that inflate() stop + if and when it gets to the next deflate block boundary. When decoding the + zlib or gzip format, this will cause inflate() to return immediately after + the header and before the first block. When doing a raw inflate, inflate() + will go ahead and process the first block, and will return when it gets to + the end of that block, or when it runs out of data. + + The Z_BLOCK option assists in appending to or combining deflate streams. + Also to assist in this, on return inflate() will set strm->data_type to the + number of unused bits in the last byte taken from strm->next_in, plus 64 + if inflate() is currently decoding the last block in the deflate stream, + plus 128 if inflate() returned immediately after decoding an end-of-block + code or decoding the complete header up to just before the first byte of the + deflate stream. The end-of-block will not be indicated until all of the + uncompressed data from that block has been written to strm->next_out. The + number of unused bits may in general be greater than seven, except when + bit 7 of data_type is set, in which case the number of unused bits will be + less than eight. + + inflate() should normally be called until it returns Z_STREAM_END or an + error. However if all decompression is to be performed in a single step + (a single call of inflate), the parameter flush should be set to + Z_FINISH. In this case all pending input is processed and all pending + output is flushed; avail_out 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 inflateEnd to deallocate the decompression state. The use of Z_FINISH + is never required, but can be used to inform inflate that a faster approach + may be used for the single inflate() call. + + In this implementation, inflate() always flushes as much output as + possible to the output buffer, and always uses the faster approach on the + first call. So the only effect of the flush parameter in this implementation + is on the return value of inflate(), as noted below, or when it returns early + because Z_BLOCK is used. + + If a preset dictionary is needed after this call (see inflateSetDictionary + below), inflate sets strm->adler to the adler32 checksum of the dictionary + chosen by the compressor and returns Z_NEED_DICT; otherwise it sets + strm->adler to the adler32 checksum of all output produced so far (that is, + total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described + below. At the end of the stream, inflate() checks that its computed adler32 + checksum is equal to that saved by the compressor and returns Z_STREAM_END + only if the checksum is correct. + + inflate() will decompress and check either zlib-wrapped or gzip-wrapped + deflate data. The header type is detected automatically. Any information + contained in the gzip header is not retained, so applications that need that + information should instead use raw inflate, see inflateInit2() below, or + inflateBack() and perform their own processing of the gzip header and + trailer. + + inflate() returns Z_OK if some progress has been made (more input processed + or more output produced), Z_STREAM_END if the end of the compressed data has + been reached and all uncompressed output has been produced, Z_NEED_DICT if a + preset dictionary is needed at this point, Z_DATA_ERROR if the input data was + corrupted (input stream not conforming to the zlib format or incorrect check + value), Z_STREAM_ERROR if the stream structure was inconsistent (for example + if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, + Z_BUF_ERROR if no progress is possible or if there was not enough room in the + output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and + inflate() can be called again with more input and more output space to + continue decompressing. If Z_DATA_ERROR is returned, the application may then + call inflateSync() to look for a good compression block if a partial recovery + of the data is desired. +*/ + + +extern int zlib_inflateEnd (z_streamp strm); +/* + All dynamically allocated data structures for this stream are freed. + This function discards any unprocessed input and does not flush any + pending output. + + inflateEnd 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). +*/ + + /* Advanced functions */ + +/* + The following functions are needed only in some special applications. +*/ + +/* +extern int deflateInit2 (z_streamp strm, + int level, + int method, + int windowBits, + int memLevel, + int strategy); + + This is another version of deflateInit with more compression options. The + fields next_in, zalloc, zfree and opaque must be initialized before by + the caller. + + The method parameter is the compression method. It must be Z_DEFLATED in + this version of the library. + + 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 + 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 effect of Z_FILTERED is to force more + Huffman coding and less string matching; it is somewhat intermediate + between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects + the compression ratio but not the correctness of the compressed output even + if it is not set appropriately. + + 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 zlib_deflateReset (z_streamp 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). +*/ + +static inline unsigned long deflateBound(unsigned long s) +{ + return s + ((s + 7) >> 3) + ((s + 63) >> 6) + 11; +} + +/* +extern int inflateInit2 (z_streamp strm, int windowBits); + + This is another version of inflateInit with an extra parameter. The + fields next_in, avail_in, zalloc, zfree and opaque must be initialized + before by the caller. + + 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 inflateInit is used + instead. windowBits must be greater than or equal to the windowBits value + provided to deflateInit2() while compressing, or it must be equal to 15 if + deflateInit2() was not used. If a compressed stream with a larger window + size is given as input, inflate() will return with the error code + Z_DATA_ERROR instead of trying to allocate a larger window. + + windowBits can also be -8..-15 for raw inflate. In this case, -windowBits + determines the window size. inflate() will then process raw deflate data, + not looking for a zlib or gzip header, not generating a check value, and not + looking for any check values for comparison at the end of the stream. This + is for use with other formats that use the deflate compressed data format + such as zip. Those formats provide their own check values. If a custom + format is developed using the raw deflate format for compressed data, it is + recommended that a check value such as an adler32 or a crc32 be applied to + the uncompressed data as is done in the zlib, gzip, and zip formats. For + most applications, the zlib format should be used as is. Note that comments + above on the use in deflateInit2() applies to the magnitude of windowBits. + + windowBits can also be greater than 15 for optional gzip decoding. Add + 32 to windowBits to enable zlib and gzip decoding with automatic header + detection, or add 16 to decode only the gzip format (the zlib format will + return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is + a crc32 instead of an adler32. + + inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough + memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg + is set to null if there is no error message. inflateInit2 does not perform + any decompression apart from reading the zlib header if present: this will + be done by inflate(). (So next_in and avail_in may be modified, but next_out + and avail_out are unchanged.) +*/ + +extern int zlib_inflateReset (z_streamp strm); +/* + This function is equivalent to inflateEnd followed by inflateInit, + but does not free and reallocate all the internal decompression state. + The stream will keep attributes that may have been set by inflateInit2. + + inflateReset 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 zlib_inflateIncomp (z_stream *strm); +/* + This function adds the data at next_in (avail_in bytes) to the output + history without performing any output. There must be no pending output, + and the decompressor must be expecting to see the start of a block. + Calling this function is equivalent to decompressing a stored block + containing the data at next_in (except that the data is not output). +*/ + +#define zlib_deflateInit(strm, level) \ + zlib_deflateInit2((strm), (level), Z_DEFLATED, MAX_WBITS, \ + DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY) +#define zlib_inflateInit(strm) \ + zlib_inflateInit2((strm), DEF_WBITS) + +extern int zlib_deflateInit2(z_streamp strm, int level, int method, + int windowBits, int memLevel, + int strategy); +extern int zlib_inflateInit2(z_streamp strm, int windowBits); + +#if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL) + struct internal_state {int dummy;}; /* hack for buggy compilers */ +#endif + +/* Utility function: initialize zlib, unpack binary blob, clean up zlib, + * return len or negative error code. */ +extern int zlib_inflate_blob(void *dst, unsigned dst_sz, const void *src, unsigned src_sz); + +#endif /* _ZLIB_H */ |