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| -rw-r--r-- | plugins/Utils.pas/zlib.pp | 1258 |
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diff --git a/plugins/Utils.pas/zlib.pp b/plugins/Utils.pas/zlib.pp new file mode 100644 index 0000000000..d7346cb624 --- /dev/null +++ b/plugins/Utils.pas/zlib.pp @@ -0,0 +1,1258 @@ +{$ifndef NO_SMART_LINK} +{$smartlink on} +{$endif} +unit zlib; + +interface + +{ Needed for array of const } +{$mode objfpc} +{ for linux for linking with libc } +{$ifdef unix} + {$linklib c} +{$endif} + +{$packrecords c} + +uses + ctypes; + +const +{$ifdef netware} {zlib.nlm comes with netware6} + libz='zlib'; +{$else} + {$ifdef windows} + libz='zlib'; + {$else windows} + libz='z'; + {$endif windows} +{$endif} + +{$ifndef windows} +{$linklib libz} +{$endif windows} + +(* + 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 using the functions that start + with "gz". The gzip format is different from the zlib format. gzip is a + gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. + + This library can optionally read and write gzip streams in memory as well. + + 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. +*) + +const + ZLIB_VERSION = '1.2.3'; + ZLIB_VERNUM = $1230; + +type + uInt = cuint; + + puIntf = ^uIntf; + uIntf = uInt; + + uLong = culong; + + puLongf = ^uLongf; + uLongf = uLong; + + pBytef = ^Bytef; + Bytef = cchar; + + alloc_func = function(opaque: pointer; items: uInt; size: uInt): pointer; cdecl; + TAllocfunc = alloc_func; + + free_func = procedure(opaque: pointer; items: uInt; size: uInt); cdecl; + TFreeFunc = free_func; + + internal_statep = ^internal_state; + internal_state = record end; + TInternalState = internal_state; + PInternalState = internal_statep; + + z_off_t = coff_t; + + z_streamp = ^z_stream; + z_stream = record + next_in : pBytef; // next input byte + avail_in : uInt; // number of bytes available at next_in + total_in : uLong; // total nb of input bytes read so far + + next_out : pBytef; // next output byte should be put there + avail_out : uInt; // remaining free space at next_out + total_out : uLong; // total nb of bytes output so far + + msg : pBytef; // last error message, NULL if no error + state : internal_statep; // not visible by applications + + zalloc : alloc_func; // used to allocate the internal state + zfree : free_func; // used to free the internal state + opaque : pointer; // private data object passed to zalloc and zfree + + data_type : cint; // best guess about the data type: binary or text + adler : uLong; // adler32 value of the uncompressed data + reserved : uLong; // reserved for future use + end; + TZStreamRec = z_stream; + TZStream = z_stream; + PZStream = z_streamp; + +(* + gzip header information passed to and from zlib routines. See RFC 1952 + for more details on the meanings of these fields. +*) + + gz_headerp = ^gz_header; + gz_header = record + text : cint; // true if compressed data believed to be text + time : uLong; // modification time + xflags : cint; // extra flags (not used when writing a gzip file) + os : cint; // operating system + extra : pBytef; // pointer to extra field or Z_NULL if none + extra_len : uInt; // extra field length (valid if extra != Z_NULL) + extra_max : uInt; // space at extra (only when reading header) + name : pBytef; // pointer to zero-terminated file name or Z_NULL + name_max : uInt; // space at name (only when reading header) + comment : Bytef; // pointer to zero-terminated comment or Z_NULL + comm_max : uInt; // space at comment (only when reading header) + hcrc : cint; // true if there was or will be a header crc + done : cint; // true when done reading gzip header (not used when writing a gzip file) + end; + +(* + 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 Z_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). +*) + +const + Z_NO_FLUSH = 0; + Z_PARTIAL_FLUSH = 1; // will be removed, use Z_SYNC_FLUSH instead + Z_SYNC_FLUSH = 2; + Z_FULL_FLUSH = 3; + Z_FINISH = 4; + Z_BLOCK = 5; +(* Allowed flush values; see deflate() and inflate() below for details *) + + Z_OK = 0; + Z_STREAM_END = 1; + Z_NEED_DICT = 2; + Z_ERRNO = (-1); + Z_STREAM_ERROR = (-2); + Z_DATA_ERROR = (-3); + Z_MEM_ERROR = (-4); + Z_BUF_ERROR = (-5); + Z_VERSION_ERROR = (-6); +(* Return codes for the compression/decompression functions. Negative + * values are errors, positive values are used for special but normal events. + *) + + Z_NO_COMPRESSION = 0; + Z_BEST_SPEED = 1; + Z_BEST_COMPRESSION = 9; + Z_DEFAULT_COMPRESSION = -(1); +(* compression levels *) + + Z_FILTERED = 1; + Z_HUFFMAN_ONLY = 2; + Z_RLE = 3; + Z_FIXED = 4; + Z_DEFAULT_STRATEGY = 0; +(* compression strategy; see deflateInit2() below for details *) + + Z_BINARY = 0; + Z_TEXT = 1; + Z_ASCII = Z_TEXT; // for compatibility with 1.2.2 and earlier + Z_UNKNOWN = 2; +(* Possible values of the data_type field (though see inflate()) *) + + Z_DEFLATED = 8; +(* The deflate compression method (the only one supported in this version) *) + + Z_NULL = 0; +(* for initializing zalloc, zfree, opaque *) + +function zlibVersion:pchar; cdecl; external libz name 'zlibVersion'; +(* + The application can compare zlibVersion 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 deflateInit and inflateInit. +*) + +function deflateInit_(var strm: z_stream; level: cint; version: pchar; stream_size: cint): cint; cdecl; external libz name 'deflateInit_'; +function deflateInit(var strm: z_stream; level: cint): cint; +(* + 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 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(). +*) + +function deflate(var strm: z_stream; flush: cint): cint; cdecl; external libz name 'deflate'; +(* + 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. + + Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to + decide how much data to accumualte before producing output, in order to + maximize compression. + + 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 + 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). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that + avail_out is greater than six to avoid repeated flush markers due to + avail_out == 0 on return. + + 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 + the value returned by deflateBound (see below). 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 strm->data_type if it can make a good guess about + the input data type (Z_BINARY or Z_TEXT). 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). Note that Z_BUF_ERROR is not + fatal, and deflate() can be called again with more input and more output + space to continue compressing. +*) + +function deflateEnd(var strm: z_stream): cint; cdecl; external libz name 'deflateEnd'; +(* + 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). +*) + +function inflateInit_(var strm: z_stream; version: pchar; stream_size: cint): cint; cdecl; external libz name 'inflateInit_'; +function inflateInit(var strm: z_stream): cint; +(* + Initializes the internal stream state for decompression. The fields + next_in, avail_in, zalloc, zfree and opaque must be initialized before by + the caller. If next_in is not Z_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 Z_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.) +*) + +function inflate(var strm: z_stream; flush: cint): cint; cdecl; external libz name 'inflate'; +(* + 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. +*) + +function inflateEnd(var strm: z_stream): cint; cdecl; external libz name 'inflateEnd'; +(* + 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). +*) + +function deflateInit2_(var strm: z_stream; level, method, windowBits, memLevel, strategy: cint; version: pchar; stream_size: cint): cint; cdecl; external libz name 'deflateInit2_'; +function deflateInit2(var strm: z_stream; level, method, windowBits, memLevel, strategy: cint): longint; +(* + 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. + + windowBits can also be -8..-15 for raw deflate. In this case, -windowBits + determines the window size. deflate() will then generate raw deflate data + with no zlib header or trailer, and will not compute an adler32 check value. + + windowBits can also be greater than 15 for optional gzip encoding. Add + 16 to windowBits to write a simple gzip header and trailer around the + compressed data instead of a zlib wrapper. The gzip header will have no + file name, no extra data, no comment, no modification time (set to zero), + no header crc, and the operating system will be set to 255 (unknown). If a + gzip stream is being written, strm->adler is a crc32 instead of an adler32. + + 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), Z_HUFFMAN_ONLY to force Huffman encoding only (no + string match), or Z_RLE to limit match distances to one (run-length + encoding). 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. Z_RLE is designed to be almost as fast as + Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy + parameter only affects the compression ratio but not the correctness of the + compressed output even if it is not set appropriately. Z_FIXED prevents the + use of dynamic Huffman codes, allowing for a simpler decoder for special + applications. + + 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(). +*) + +function deflateSetDictionary(var strm: z_stream; dictionary: pbytef; dictLength: uInt): cint; cdecl; external libz name 'deflateSetDictionary'; +(* + Initializes the compression dictionary from the given byte sequence + without producing any compressed output. This function must be called + immediately after deflateInit, deflateInit2 or deflateReset, before any + call of deflate. The compressor and decompressor must use exactly the same + dictionary (see inflateSetDictionary). + + 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. + + Depending on the size of the compression data structures selected by + deflateInit or deflateInit2, a part of the dictionary may in effect be + discarded, for example if the dictionary is larger than the window size in + deflate or deflate2. Thus the strings most likely to be useful should be + put at the end of the dictionary, not at the front. In addition, the + current implementation of deflate will use at most the window size minus + 262 bytes of the provided dictionary. + + Upon return of this function, strm->adler 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.) If a raw deflate was requested, then the + adler32 value is not computed and strm->adler is not set. + + deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a + parameter is invalid (such as NULL dictionary) or the stream state is + inconsistent (for example if deflate has already been called for this stream + or if the compression method is bsort). deflateSetDictionary does not + perform any compression: this will be done by deflate(). +*) + +function deflateCopy(var dest, source: z_stream): cint; cdecl; external libz name 'deflateCopy'; +(* + Sets the destination stream as a complete copy of the source stream. + + 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 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. +*) + +function deflateReset(var strm: z_stream): cint; cdecl; external libz name 'deflateReset'; +(* + 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). +*) + +function deflateParams(var strm: z_stream; level: cint; strategy: cint): cint; cdecl; external libz name 'deflateParams'; +(* + Dynamically update the compression level and compression strategy. The + interpretation of level and strategy is as in deflateInit2. 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 deflate(). + + Before the call of deflateParams, the stream state must be set as for + a call of deflate(), since the currently available input may have to + be compressed and flushed. In particular, strm->avail_out must be non-zero. + + deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source + stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR + if strm->avail_out was zero. +*) + +function deflateTune(var strm: z_stream; good_length, max_lazy, nice_length, max_chain: cint): cint; cdecl; external libz name 'deflateTune'; +(* + Fine tune deflate's internal compression parameters. This should only be + used by someone who understands the algorithm used by zlib's deflate for + searching for the best matching string, and even then only by the most + fanatic optimizer trying to squeeze out the last compressed bit for their + specific input data. Read the deflate.c source code for the meaning of the + max_lazy, good_length, nice_length, and max_chain parameters. + + deflateTune() can be called after deflateInit() or deflateInit2(), and + returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. +*) + +function deflateBound(var strm: z_stream; sourceLen: uLong): uLong; cdecl; external libz name 'deflateBound'; +(* + deflateBound() returns an upper bound on the compressed size after + deflation of sourceLen bytes. It must be called after deflateInit() + or deflateInit2(). This would be used to allocate an output buffer + for deflation in a single pass, and so would be called before deflate(). +*) + +function deflatePrime(var strm: z_stream; bits, value: cint): cint; cdecl; external libz name 'deflatePrime'; +(* + deflatePrime() inserts bits in the deflate output stream. The intent + is that this function is used to start off the deflate output with the + bits leftover from a previous deflate stream when appending to it. As such, + this function can only be used for raw deflate, and must be used before the + first deflate() call after a deflateInit2() or deflateReset(). bits must be + less than or equal to 16, and that many of the least significant bits of + value will be inserted in the output. + + deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source + stream state was inconsistent. +*) + +function deflateSetHeader(var strm: z_stream; var head: gz_header): cint; cdecl; external libz name 'deflateSetHeader'; +(* + deflateSetHeader() provides gzip header information for when a gzip + stream is requested by deflateInit2(). deflateSetHeader() may be called + after deflateInit2() or deflateReset() and before the first call of + deflate(). The text, time, os, extra field, name, and comment information + in the provided gz_header structure are written to the gzip header (xflag is + ignored -- the extra flags are set according to the compression level). The + caller must assure that, if not Z_NULL, name and comment are terminated with + a zero byte, and that if extra is not Z_NULL, that extra_len bytes are + available there. If hcrc is true, a gzip header crc is included. Note that + the current versions of the command-line version of gzip (up through version + 1.3.x) do not support header crc's, and will report that it is a "multi-part + gzip file" and give up. + + If deflateSetHeader is not used, the default gzip header has text false, + the time set to zero, and os set to 255, with no extra, name, or comment + fields. The gzip header is returned to the default state by deflateReset(). + + deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source + stream state was inconsistent. +*) + +function inflateInit2_(var strm: z_stream; windowBits: cint; version:pchar; stream_size: cint): cint; cdecl; external libz name 'inflateInit2_'; +function inflateInit2(var strm: z_stream; windowBits: cint): cint; +(* + 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.) +*) + +function inflateSetDictionary(var strm: z_stream; dictionary: pbytef; dictLength: uInt): cint; cdecl; external libz name 'inflateSetDictionary'; +(* + Initializes the decompression dictionary from the given uncompressed byte + sequence. This function must be called immediately after a call of inflate, + if that call returned Z_NEED_DICT. The dictionary chosen by the compressor + can be determined from the adler32 value returned by that call of inflate. + The compressor and decompressor must use exactly the same dictionary (see + deflateSetDictionary). For raw inflate, this function can be called + immediately after inflateInit2() or inflateReset() and before any call of + inflate() to set the dictionary. The application must insure that the + dictionary that was used for compression is provided. + + inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a + parameter is invalid (such as NULL dictionary) or the stream state is + inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the + expected one (incorrect adler32 value). inflateSetDictionary does not + perform any decompression: this will be done by subsequent calls of + inflate(). +*) + +function inflateSync(var strm: z_stream): cint; cdecl; external libz name 'inflateSync'; +(* + Skips invalid compressed data until a full flush point (see above the + description of deflate with Z_FULL_FLUSH) can be found, or until all + available input is skipped. No output is provided. + + inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR + if no more input was provided, Z_DATA_ERROR if no flush point has been found, + or Z_STREAM_ERROR if the stream structure was inconsistent. In the success + case, the application may save the current current value of total_in which + indicates where valid compressed data was found. In the error case, the + application may repeatedly call inflateSync, providing more input each time, + until success or end of the input data. +*) + +function inflateCopy(var dest, source: z_stream): cint; cdecl; external libz name 'inflateCopy'; +(* + Sets the destination stream as a complete copy of the source stream. + + This function can be useful when randomly accessing a large stream. The + first pass through the stream can periodically record the inflate state, + allowing restarting inflate at those points when randomly accessing the + stream. + + inflateCopy 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. +*) + +function inflateReset(var strm: z_stream): cint; cdecl; external libz name 'inflateReset'; +(* + 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). +*) + +function inflatePrime(var strm: z_stream; bits, value: cint): cint; cdecl; external libz name 'inflateReset'; +(* + This function inserts bits in the inflate input stream. The intent is + that this function is used to start inflating at a bit position in the + middle of a byte. The provided bits will be used before any bytes are used + from next_in. This function should only be used with raw inflate, and + should be used before the first inflate() call after inflateInit2() or + inflateReset(). bits must be less than or equal to 16, and that many of the + least significant bits of value will be inserted in the input. + + inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source + stream state was inconsistent. +*) + +function inflateGetHeader(var strm: z_stream; var head: gz_header): cint; cdecl; external libz name 'inflateGetHeader'; +(* + inflateGetHeader() requests that gzip header information be stored in the + provided gz_header structure. inflateGetHeader() may be called after + inflateInit2() or inflateReset(), and before the first call of inflate(). + As inflate() processes the gzip stream, head->done is zero until the header + is completed, at which time head->done is set to one. If a zlib stream is + being decoded, then head->done is set to -1 to indicate that there will be + no gzip header information forthcoming. Note that Z_BLOCK can be used to + force inflate() to return immediately after header processing is complete + and before any actual data is decompressed. + + The text, time, xflags, and os fields are filled in with the gzip header + contents. hcrc is set to true if there is a header CRC. (The header CRC + was valid if done is set to one.) If extra is not Z_NULL, then extra_max + contains the maximum number of bytes to write to extra. Once done is true, + extra_len contains the actual extra field length, and extra contains the + extra field, or that field truncated if extra_max is less than extra_len. + If name is not Z_NULL, then up to name_max characters are written there, + terminated with a zero unless the length is greater than name_max. If + comment is not Z_NULL, then up to comm_max characters are written there, + terminated with a zero unless the length is greater than comm_max. When + any of extra, name, or comment are not Z_NULL and the respective field is + not present in the header, then that field is set to Z_NULL to signal its + absence. This allows the use of deflateSetHeader() with the returned + structure to duplicate the header. However if those fields are set to + allocated memory, then the application will need to save those pointers + elsewhere so that they can be eventually freed. + + If inflateGetHeader is not used, then the header information is simply + discarded. The header is always checked for validity, including the header + CRC if present. inflateReset() will reset the process to discard the header + information. The application would need to call inflateGetHeader() again to + retrieve the header from the next gzip stream. + + inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source + stream state was inconsistent. +*) + +function inflateBackInit_(var strm: z_stream; windowBits: cint; window: pointer; version: pchar; stream_size: cint): cint; cdecl; external libz name 'inflateBackInit_'; +function inflateBackInit(var strm: z_stream; windowBits: cint; window: pointer): cint; +(* + Initialize the internal stream state for decompression using inflateBack() + calls. The fields zalloc, zfree and opaque in strm must be initialized + before the call. If zalloc and zfree are Z_NULL, then the default library- + derived memory allocation routines are used. windowBits is the base two + logarithm of the window size, in the range 8..15. window is a caller + supplied buffer of that size. Except for special applications where it is + assured that deflate was used with small window sizes, windowBits must be 15 + and a 32K byte window must be supplied to be able to decompress general + deflate streams. + + See inflateBack() for the usage of these routines. + + inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of + the paramaters are invalid, Z_MEM_ERROR if the internal state could not + be allocated, or Z_VERSION_ERROR if the version of the library does not + match the version of the header file. +*) + +type + in_func = function(in_desc: pointer; var c: pcuchar): cuint; cdecl; + out_func = function(out_desc: pointer; c: pcuchar; i: cuint): cint; cdecl; +//typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); +//typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); + +function inflateBack(var strm: z_stream; inf: in_func; in_desc: pointer; outf: out_func; out_desc: pointer): cint; cdecl; external libz name 'inflateBack'; +(* + inflateBack() does a raw inflate with a single call using a call-back + interface for input and output. This is more efficient than inflate() for + file i/o applications in that it avoids copying between the output and the + sliding window by simply making the window itself the output buffer. This + function trusts the application to not change the output buffer passed by + the output function, at least until inflateBack() returns. + + inflateBackInit() must be called first to allocate the internal state + and to initialize the state with the user-provided window buffer. + inflateBack() may then be used multiple times to inflate a complete, raw + deflate stream with each call. inflateBackEnd() is then called to free + the allocated state. + + A raw deflate stream is one with no zlib or gzip header or trailer. + This routine would normally be used in a utility that reads zip or gzip + files and writes out uncompressed files. The utility would decode the + header and process the trailer on its own, hence this routine expects + only the raw deflate stream to decompress. This is different from the + normal behavior of inflate(), which expects either a zlib or gzip header and + trailer around the deflate stream. + + inflateBack() uses two subroutines supplied by the caller that are then + called by inflateBack() for input and output. inflateBack() calls those + routines until it reads a complete deflate stream and writes out all of the + uncompressed data, or until it encounters an error. The function's + parameters and return types are defined above in the in_func and out_func + typedefs. inflateBack() will call in(in_desc, &buf) which should return the + number of bytes of provided input, and a pointer to that input in buf. If + there is no input available, in() must return zero--buf is ignored in that + case--and inflateBack() will return a buffer error. inflateBack() will call + out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() + should return zero on success, or non-zero on failure. If out() returns + non-zero, inflateBack() will return with an error. Neither in() nor out() + are permitted to change the contents of the window provided to + inflateBackInit(), which is also the buffer that out() uses to write from. + The length written by out() will be at most the window size. Any non-zero + amount of input may be provided by in(). + + For convenience, inflateBack() can be provided input on the first call by + setting strm->next_in and strm->avail_in. If that input is exhausted, then + in() will be called. Therefore strm->next_in must be initialized before + calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called + immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in + must also be initialized, and then if strm->avail_in is not zero, input will + initially be taken from strm->next_in[0 .. strm->avail_in - 1]. + + The in_desc and out_desc parameters of inflateBack() is passed as the + first parameter of in() and out() respectively when they are called. These + descriptors can be optionally used to pass any information that the caller- + supplied in() and out() functions need to do their job. + + On return, inflateBack() will set strm->next_in and strm->avail_in to + pass back any unused input that was provided by the last in() call. The + return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR + if in() or out() returned an error, Z_DATA_ERROR if there was a format + error in the deflate stream (in which case strm->msg is set to indicate the + nature of the error), or Z_STREAM_ERROR if the stream was not properly + initialized. In the case of Z_BUF_ERROR, an input or output error can be + distinguished using strm->next_in which will be Z_NULL only if in() returned + an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to + out() returning non-zero. (in() will always be called before out(), so + strm->next_in is assured to be defined if out() returns non-zero.) Note + that inflateBack() cannot return Z_OK. +*) + + +function inflateBackEnd(var strm: z_stream): cint; cdecl; external libz name 'inflateBackEnd'; +(* + All memory allocated by inflateBackInit() is freed. + + inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream + state was inconsistent. +*) + + +function compress(dest: pbytef; destLen: puLongf; source: pbytef; sourceLen: uLong): cint; cdecl; external libz name 'compress'; +(* + 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 the value returned + by compressBound(sourceLen). Upon exit, destLen is the actual size of the + compressed buffer. + This function can be used to compress a whole file at once if the + input file is mmap'ed. + compress returns Z_OK if success, Z_MEM_ERROR if there was not + enough memory, Z_BUF_ERROR if there was not enough room in the output + buffer. +*) + +function compress2(dest: pbytef; destLen: puLongf; source: pbytef; sourceLen: uLong; level: cint): cint; cdecl; external libz name 'compress2'; +(* + Compresses the source buffer into the destination buffer. The level + parameter has the same meaning as in deflateInit. 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 the value returned by + compressBound(sourceLen). Upon exit, destLen is the actual size of the + compressed buffer. + + compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough + memory, Z_BUF_ERROR if there was not enough room in the output buffer, + Z_STREAM_ERROR if the level parameter is invalid. +*) + +function compressBound(sourceLen: uLong): uLong; cdecl; external libz name 'compressBound'; +(* + compressBound() returns an upper bound on the compressed size after + compress() or compress2() on sourceLen bytes. It would be used before + a compress() or compress2() call to allocate the destination buffer. +*) + +function uncompress(dest: pbytef; destLen: puLongf; source: pbytef; sourceLen: uLong):cint; cdecl; external libz name 'uncompress'; +(* + Decompresses the source buffer into the destination buffer. sourceLen is + the byte length of the source buffer. Upon entry, destLen is the total + size of the destination buffer, which must be large enough to hold the + entire uncompressed data. (The size of the uncompressed data must have + been saved previously by the compressor and transmitted to the decompressor + by some mechanism outside the scope of this compression library.) + Upon exit, destLen is the actual size of the compressed buffer. + This function can be used to decompress a whole file at once if the + input file is mmap'ed. + + uncompress returns Z_OK if success, Z_MEM_ERROR if there was not + enough memory, Z_BUF_ERROR if there was not enough room in the output + buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. +*) + +type + gzFile = pointer; + +function gzopen(path: pchar; mode: pchar): gzFile; cdecl; external libz name 'gzopen'; +(* + 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", or 'R' for run-length encoding + as in "wb1R". (See the description of deflateInit2 for more information + about the strategy parameter.) + + gzopen can be used to read a file which is not in gzip format; in this + case gzread will directly read from the file without decompression. + + gzopen returns NULL if the file could not be opened or if there was + insufficient memory to allocate the (de)compression state; errno + can be checked to distinguish the two cases (if errno is zero, the + zlib error is Z_MEM_ERROR). +*) + +function gzdopen(fd: cint; mode:pchar):gzFile; cdecl; external libz name 'gzdopen'; +(* + gzdopen() associates a gzFile with the file descriptor fd. File + descriptors are obtained from calls like open, dup, creat, pipe or + fileno (in the file has been previously opened with fopen). + The mode parameter is as in gzopen. + The next call of gzclose on the returned gzFile will also close the + file descriptor fd, just like fclose(fdopen(fd), mode) closes the file + descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). + gzdopen returns NULL if there was insufficient memory to allocate + the (de)compression state. +*) + +function gzsetparams(thefile:gzFile; level: cint; strategy: cint): cint; cdecl; external libz name 'gzsetparams'; +(* + Dynamically update the compression level or strategy. See the description + of deflateInit2 for the meaning of these parameters. + gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not + opened for writing. +*) + +function gzread(thefile:gzFile; buf:pointer; len:cardinal): cint; cdecl; external libz name 'gzread'; +(* + Reads the given number of uncompressed bytes from the compressed file. + If the input file was not in gzip format, gzread copies the given number + of bytes into the buffer. + gzread returns the number of uncompressed bytes actually read (0 for + end of file, -1 for error). +*) + +function gzwrite(thefile:gzFile; buf:pointer; len:cardinal): cint; cdecl; external libz name 'gzwrite'; +(* + Writes the given number of uncompressed bytes into the compressed file. + gzwrite returns the number of uncompressed bytes actually written + (0 in case of error). +*) + +function gzprintf(thefile:gzFile; format:pbytef; args:array of const): cint; cdecl; external libz name 'gzprintf'; +(* + Converts, formats, and writes the args to the compressed file under + control of the format string, as in fprintf. gzprintf returns the number of + uncompressed bytes actually written (0 in case of error). The number of + uncompressed bytes written is limited to 4095. The caller should assure that + this limit is not exceeded. If it is exceeded, then gzprintf() will return + return an error (0) with nothing written. In this case, there may also be a + buffer overflow with unpredictable consequences, which is possible only if + zlib was compiled with the insecure functions sprintf() or vsprintf() + because the secure snprintf() or vsnprintf() functions were not available. +*) + +function gzputs(thefile:gzFile; s:pbytef): cint; cdecl; external libz name 'gzputs'; +(* + Writes the given null-terminated string to the compressed file, excluding + the terminating null character. + gzputs returns the number of characters written, or -1 in case of error. +*) + +function gzgets(thefile:gzFile; buf:pbytef; len: cint):pbytef; cdecl; external libz name 'gzgets'; +(* + 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. + gzgets returns buf, or Z_NULL in case of error. +*) + +function gzputc(thefile:gzFile; c:char):char; cdecl; external libz name 'gzputc'; +(* + Writes c, converted to an unsigned char, into the compressed file. + gzputc returns the value that was written, or -1 in case of error. +*) + +function gzgetc(thefile:gzFile):char; cdecl; external libz name 'gzgetc'; +(* + Reads one byte from the compressed file. gzgetc returns this byte + or -1 in case of end of file or error. +*) + +function gzflush(thefile:gzFile; flush: cint): cint; cdecl; external libz name 'gzflush'; +(* + Push one character back onto the stream to be read again later. + Only one character of push-back is allowed. gzungetc() returns the + character pushed, or -1 on failure. gzungetc() will fail if a + character has been pushed but not read yet, or if c is -1. The pushed + character will be discarded if the stream is repositioned with gzseek() + or gzrewind(). +*) + +function gzseek(thefile:gzFile; offset:z_off_t; whence: cint):z_off_t; cdecl; external libz name 'gzseek'; +(* + Sets the starting position for the next gzread or gzwrite 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. + 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; gzseek then compresses a sequence of zeroes up to the new + starting position. + + gzseek 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. +*) + +function gzrewind(thefile:gzFile): cint; cdecl; external libz name 'gzrewind'; +(* + Rewinds the given file. This function is supported only for reading. + + gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) +*) + +function gztell(thefile:gzFile):z_off_t; cdecl; external libz name 'gztell'; +(* + Returns the starting position for the next gzread or gzwrite on the + given compressed file. This position represents a number of bytes in the + uncompressed data stream. + + gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) +*) + +function gzeof(thefile:gzFile):longbool; cdecl; external libz name 'gzeof'; +(* + Returns 1 when EOF has previously been detected reading the given + input stream, otherwise zero. +*) + +function gzclose(thefile:gzFile): cint; cdecl; external libz name 'gzclose'; +(* + Flushes all pending output if necessary, closes the compressed file + and deallocates all the (de)compression state. The return value is the zlib + error number (see function gzerror below). +*) + +function gzerror(thefile:gzFile; var errnum: cint):pbytef; cdecl; external libz name 'gzerror'; +(* + Returns the error message for the last error which occurred on the + given compressed file. errnum is set to zlib error number. If an + error occurred in the file system and not in the compression library, + errnum is set to Z_ERRNO and the application may consult errno + to get the exact error code. +*) + +procedure gzclearerr(thefile: gzFile); cdecl; external libz name 'gzclearerr'; +(* + Clears the error and end-of-file flags for file. This is analogous to the + clearerr() function in stdio. This is useful for continuing to read a gzip + file that is being written concurrently. +*) + +function adler32(adler: uLong; buf: pbytef; len: uInt): uLong; cdecl; external libz name 'adler32'; +(* + 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. + An Adler-32 checksum is almost as reliable as a CRC32 but can be computed + much faster. Usage example: + + uLong adler = adler32(0L, Z_NULL, 0); + + while (read_buffer(buffer, length) != EOF) { + adler = adler32(adler, buffer, length); + } + if (adler != original_adler) error(); +*) + +function adler32_combine(adler1, adler2: uLong; len2: z_off_t): uLong; cdecl; external libz name 'adler32_combine'; +(* + Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 + and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for + each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of + seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. +*) + +function crc32(crc: uLong; buf: pbytef; len: uInt): uLong; cdecl; external libz name 'crc32'; +(* + Update a running CRC-32 with the bytes buf[0..len-1] and return the + updated CRC-32. If buf is NULL, this function returns the required initial + value for the 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: + + uLong crc = crc32(0L, Z_NULL, 0); + + while (read_buffer(buffer, length) != EOF) { + crc = crc32(crc, buffer, length); + } + if (crc != original_crc) error(); +*) + +function crc32_combine(crc1, crc2: uLong; len2: z_off_t): uLong; cdecl; external libz name 'crc32_combine'; +(* + Combine two CRC-32 check values into one. For two sequences of bytes, + seq1 and seq2 with lengths len1 and len2, CRC-32 check values were + calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 + check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and + len2. +*) + + +function zError(err: cint): pchar; cdecl; external libz name 'zError'; +function inflateSyncPoint(var z: z_stream): cint; cdecl; external libz name 'inflateSyncPoint'; +function get_crc_table: pointer; cdecl; external libz name 'get_crc_table'; + +function zlibAllocMem(AppData: Pointer; Items, Size: UInt): Pointer; cdecl; +procedure zlibFreeMem(AppData, Block: Pointer); cdecl; + +implementation + +function deflateInit(var strm: z_stream; level: cint): cint; +begin + Result := deflateInit_(strm, level, ZLIB_VERSION, sizeof(z_stream)); +end; + +function inflateInit(var strm: z_stream): cint; +begin + Result := inflateInit_(strm, ZLIB_VERSION, sizeof(z_stream)); +end; + +function deflateInit2(var strm: z_stream; level, method, windowBits, memLevel, strategy: cint): cint; +begin + Result := deflateInit2_(strm, level, method, windowBits, memLevel, strategy, ZLIB_VERSION, sizeof(z_stream)); +end; + +function inflateInit2(var strm: z_stream; windowBits: cint): cint; +begin + Result := inflateInit2_(strm, windowBits, ZLIB_VERSION, sizeof(z_stream)); +end; + +function inflateBackInit(var strm: z_stream; windowBits: cint; window: pointer): cint; +begin + Result := inflateBackInit_(strm, windowBits, window, ZLIB_VERSION, sizeof(z_stream)); +end; + +function zlibAllocMem(AppData: Pointer; Items, Size: UInt): Pointer; cdecl; + + begin + Result := AllocMem(Items * Size); + end; + +procedure zlibFreeMem(AppData, Block: Pointer); cdecl; + + begin + FreeMem(Block); + end; + + +end. |