TABLE OF CONTENTS z.library/Adler32 z.library/Adler32Combine z.library/Compress z.library/Compress2 z.library/CompressBound z.library/CRC32 z.library/CRC32Combine z.library/Deflate z.library/DeflateBound z.library/DeflateCopy z.library/DeflateEnd z.library/DeflateInit z.library/DeflateInit2 z.library/DeflateParams z.library/DeflatePrime z.library/DeflateReset z.library/DeflateSetDictionary z.library/DeflateSetHeader z.library/DeflateTune z.library/Inflate z.library/InflateBack z.library/InflateBackEnd z.library/InflateBackInit z.library/InflateCopy z.library/InflateEnd z.library/InflateGetHeader z.library/InflateInit z.library/InflateInit2 z.library/InflatePrime z.library/InflateReset z.library/InflateSetDictionary z.library/InflateSync z.library/Uncompress z.library/ZlibVersion z/main/InflateGetDictionary z.library/Adler32 z.library/Adler32 NAME Adler32 -- Update a running Adler-32 checksum SYNOPSIS uint32 Adler32(uint32 adler, const uint8 * buf, uint32 len); FUNCTION 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 CRC-32 but can be computed much faster. INPUTS adler - Initial or current Adler-32 checksum buf - Pointer to data or Z_NULL to get the initial checksum value. len - Length of data. RESULT Updated Adler-32 checksum. EXAMPLE uLong adler = adler32(0L, Z_NULL, 0); while (read_buffer(buffer, length) != EOF) { adler = adler32(adler, buffer, length); } if (adler != original_adler) error(); NOTES BUGS SEE ALSO Adler32Combine(), CRC32(), CRC32Combine() z.library/Adler32Combine z.library/Adler32Combine NAME Adler32Combine -- Combine two Adler-32 checksums into one SYNOPSIS uint32 Adler32Combine(uint32 adler1, uint32 adler2, int32 len2); FUNCTION 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. If len2 is negative, the result has no meaning or utility. INPUTS adler1 - First Adler-32 checksum. adler2 - Second Adler-32 checksum. len2 - Length of data for second Adler-32 checksum. RESULT Combined Adler-32 checksum. EXAMPLE NOTES BUGS SEE ALSO Adler32(), CRC32Combine(), CRC32() z.library/Compress z.library/Compress NAME Compress -- Compress from source to destination buffer. SYNOPSIS int32 Compress(APTR dest, uint32 * destLen, CONST_APTR source, uint32 sourceLen); FUNCTION 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. 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. INPUTS dest - Destination buffer. destLen - Length of destination buffer. source - Source buffer. sourceLen - Length of source buffer. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO CompressBound(), Compress2() z.library/Compress2 z.library/Compress2 NAME Compress2 -- Compress from source to destination buffer. (V53.2) SYNOPSIS int32 Compress2(APTR dest, uint32 * destLen, CONST_APTR source, uint32 sourceLen, int32 level); FUNCTION 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. INPUTS dest - Destination buffer. destLen - Length of destination buffer. source - Source buffer. sourceLen - Length of source buffer. level - Compression level. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO CompressBound(), Compress() z.library/CompressBound z.library/CompressBound NAME CompressBound -- Calculate the worst case length for compression (V53.4) SYNOPSIS uint32 CompressBound(uint32 sourceLen); FUNCTION 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. INPUTS sourceLen - Length of data to compress. RESULT The calculated worst case compressed size for the specified length of input data. EXAMPLE NOTES BUGS SEE ALSO Compress(), Compress2() z.library/CRC32 z.library/CRC32 NAME CRC32 -- Update a running CRC-32 checksum SYNOPSIS uint32 CRC32(uint32 crc, const uint8 * buf, uint32 len); FUNCTION Update a running CRC-32 with the bytes buf[0..len-1] and return the updated CRC-32. If buf is Z_NULL, this function returns the required initial value for the crc. Pre- and post-conditioning (one's complement) is performed within this function so it shouldn't be done by the application. INPUTS crc - Initial or current CRC-32 checksum. buf - Pointer to data or Z_NULL to get the initial checksum value. len - Length of data. RESULT Updated CRC-32 checksum. EXAMPLE uLong crc = crc32(0L, Z_NULL, 0); while (read_buffer(buffer, length) != EOF) { crc = crc32(crc, buffer, length); } if (crc != original_crc) error(); NOTES BUGS SEE ALSO CRC32Combine(), Adler32(), Adler32Combine() z.library/CRC32Combine z.library/CRC32Combine NAME CRC32Combine -- Combine two CRC-32 check values into one SYNOPSIS uint32 CRC32Combine(uint32 crc1, uint32 crc2, int32 len2); FUNCTION 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. INPUTS crc1 - First CRC-32 checksum. crc2 - Second CRC-32 checksum. len2 - Length of data for second CRC-32 checksum. RESULT Combined CRC-32 checksum. EXAMPLE NOTES BUGS SEE ALSO CRC32(), Adler32Combine(), Adler32() z.library/Deflate z.library/Deflate NAME Deflate -- Perform compression SYNOPSIS int32 Deflate(z_stream * strm, int32 flush); FUNCTION 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 accumulate 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. This completes the current deflate block and follows it with an empty stored block that is three bits plus filler bits to the next byte, followed by four bytes (00 00 ff ff). If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the output buffer, but the output is not aligned to a byte boundary. All of the input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. This completes the current deflate block and follows it with an empty fixed codes block that is 10 bits long. This assures that enough bytes are output in order for the decompressor to finish the block before the empty fixed code block. If flush is set to Z_BLOCK, a deflate block is completed and emitted, as for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to seven bits of the current block are held to be written as the next byte after the next deflate block is completed. In this case, the decompressor may not be provided enough bits at this point in order to complete decompression of the data provided so far to the compressor. It may need to wait for the next block to be emitted. This is for advanced applications that need to control the emission of deflate blocks. 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 value returned by deflateBound (see below). Then deflate is guaranteed to return Z_STREAM_END. If not enough output space is provided, deflate will not return Z_STREAM_END, and 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. INPUTS strm - Pointer to an initialized z_stream. flush - Wanted flushing behavior. Usually Z_NO_FLUSH is used. RESULT Z_OK or Z_STREAM_END for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateInit(), DeflateInit2(), DeflateEnd() z.library/DeflateBound z.library/DeflateBound NAME DeflateBound -- Calculate the worst case length for compression SYNOPSIS uint32 DeflateBound(z_stream * strm, uint32 sourceLen); FUNCTION deflateBound() returns an upper bound on the compressed size after deflation of sourceLen bytes. It must be called after deflate- Init() or deflateInit2(). This would be used to allocate an output buffer for deflation in a single pass, and so would be called before deflate(). If that first deflate() call is provided the sourceLen input bytes, an output buffer allocated to the size returned by deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed to return Z_STREAM_END. Note that it is possible for the compressed size to be larger than the value returned by deflateBound() if flush options other than Z_FINISH or Z_NO_FLUSH are used. INPUTS strm - Pointer to an initialized z_stream. sourceLen - Length of data to compress. RESULT The calculated worst case compressed size for the specified length of input data. EXAMPLE NOTES BUGS SEE ALSO DeflateInit(), DeflateInit2(), Deflate(), DeflateEnd() z.library/DeflateCopy z.library/DeflateCopy NAME DeflateCopy -- Duplicate a compression stream SYNOPSIS int32 DeflateCopy(z_stream * dest, z_stream * source); FUNCTION 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. INPUTS dest - Pointer to z_stream to store copy in. source - Pointer to z_stream to copy. RESULT Z_OK for success or error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateInit(), DeflateInit2(), Deflate(), DeflateEnd() z.library/DeflateEnd z.library/DeflateEnd NAME DeflateEnd -- Perform cleanup after compression SYNOPSIS int32 DeflateEnd(z_stream * strm); FUNCTION 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). INPUTS strm - Pointer to a z_stream to clean up after. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateInit(), DeflateInit2(), Deflate() z.library/DeflateInit z.library/DeflateInit NAME DeflateInit -- Initialize a z_stream for compression SYNOPSIS int32 DeflateInit(z_stream * strm, int32 level); FUNCTION 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(). INPUTS strm - Pointer to a z_stream to initialize. level - Compression level. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateInit2(), Deflate(), DeflateEnd() z.library/DeflateInit2 z.library/DeflateInit2 NAME DeflateInit2 -- Initialize a z_stream for compression SYNOPSIS int32 DeflateInit2(z_stream * strm, int32 level, int32 method, int32 windowBits, int32 memLevel, int32 strategy); FUNCTION 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_STRATEGY 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), or 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. deflateInit2 does not perform any compression: this will be done by deflate(). INPUTS strm - Pointer to a z_stream to initialize. level - Compression level. method - Should only be set to Z_DEFLATED for now. windowBits - Window size. memLevel - Determines how much memory is allocated for storing internal compression state data. strategy - Used to tune the compression algorithm. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateInit(), Deflate(), DeflateEnd() z.library/DeflateParams z.library/DeflateParams NAME DeflateParams -- Change the compression level and strategy SYNOPSIS int32 DeflateParams(z_stream * strm, int32 level, int32 strategy); FUNCTION 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. INPUTS strm - Pointer to z_stream. level - New compression level. strategy - New compression strategy. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateInit(), DeflateInit2(), Deflate(), DeflateEnd() z.library/DeflatePrime z.library/DeflatePrime NAME DeflatePrime -- Insert bits in the deflate output stream SYNOPSIS int32 DeflatePrime(z_stream * strm, int32 bits, int32 value); FUNCTION 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, Z_BUF_ERROR if there was not enough room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the source stream state was inconsistent. INPUTS strm - Pointer to an initialized z_stream. bits - Number of bits (must be <= 16). value - Bits to insert. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateInit(), DeflateInit2(), Deflate(), DeflateEnd() z.library/DeflateReset z.library/DeflateReset NAME DeflateReset -- Reset compression stream SYNOPSIS int32 DeflateReset(z_stream * strm); FUNCTION 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). INPUTS strm - Pointer to a z_stream to reset. RESULT Z_OK for success or error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateInit(), DeflateInit2(), Deflate(), DeflateEnd() z.library/DeflateSetDictionary z.library/DeflateSetDictionary NAME DeflateSetDictionary -- Set initial dictionary for compression SYNOPSIS int32 DeflateSetDictionary(z_stream * strm, const uint8 * dictionary, uint32 dictLength); FUNCTION 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). without producing any compressed output. When using the zlib format, this function must be called immediately after deflateInit, deflateInit2 or deflateReset, and before any call of deflate. When doing raw deflate, this function must be called either before any call of deflate, or immediately after the completion of a deflate block, i.e. after all input has been consumed and all output has been delivered when using any of the flush options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. 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 not at a block boundary for raw deflate). deflateSetDictionary does not perform any compression: this will be done by deflate(). INPUTS strm - Pointer to an initialized z_stream. dictionary - Pointer to dictionary data. dictLength - Length of dictionary data. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateSetDictionary(), DeflateInit(), DeflateInit2(), Deflate(), DeflateEnd() z.library/DeflateSetHeader z.library/DeflateSetHeader NAME DeflateSetHeader -- Write gzip header into compression stream SYNOPSIS int32 DeflateSetHeader(z_stream * strm, gz_header * head); FUNCTION 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. INPUTS strm - Pointer to an initialized z_stream. head - Gzip header data to write into compression stream. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateGetHeader(), DeflateInit(), DeflateInit2(), Deflate(), DeflateEnd() z.library/DeflateTune z.library/DeflateTune NAME DeflateTune -- Fine tune deflate's internal compression parameters SYNOPSIS int32 DeflateTune(z_stream * strm, int32 good_length, int32 max_lazy, int32 nice_length, int32 max_chain); FUNCTION 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. INPUTS strm - Pointer to z_stream. good_length - See "deflate.c". max_lazy - See "deflate.c". nice_length - See "deflate.c". max_chain - See "deflate.c". RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateInit(), DeflateInit2(), Deflate(), DeflateEnd() z.library/Inflate z.library/Inflate NAME Inflate -- Perform decompression SYNOPSIS int32 Inflate(z_stream * strm, int32 flush); FUNCTION 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, Z_BLOCK, or Z_TREES. 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. data_type is set as noted here every time inflate() returns for all flush options, and so can be used to determine the amount of currently consumed input in bits. The Z_TREES option behaves as Z_BLOCK does, but it also returns when the end of each deflate block header is reached, before any actual data in that block is decoded. This allows the caller to determine the length of the deflate block header for later use in random access within a deflate block. 256 is added to the value of strm->data_type when inflate() returns immediately after reaching the end of the deflate block header. 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 of the uncompressed data for the operation to complete. (The size of the uncompressed data may have been saved by the compressor for this purpose.) The use of Z_FINISH is not required to perform an inflation in one step. However it may be used to inform inflate that a faster approach can be used for the single inflate() call. Z_FINISH also informs inflate to not maintain a sliding window if the stream completes, which reduces inflate's memory footprint. If the stream does not complete, either because not all of the stream is provided or not enough output space is provided, then a sliding window will be allocated and inflate() can be called again to continue the operation as if Z_NO_FLUSH had been used. 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 effects of the flush parameter in this implementation are on the return value of inflate() as noted below, when inflate() returns early when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of memory for a sliding window when Z_FINISH is used. If a preset dictionary is needed after this call (see inflateSetDictionary below), inflate sets strm->adler to the Adler-32 checksum of the dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise it sets strm->adler to the Adler-32 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, if requested when initializing with inflateInit2(). 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. When processing gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output producted so far. The CRC-32 is checked against the gzip 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. INPUTS strm - Pointer to an initialized z_stream. flush - Wanted flushing behavior. RESULT Z_OK or Z_STREAM_END for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateInit(), InflateInit2(), InflateEnd() z.library/InflateBack z.library/InflateBack NAME InflateBack -- Perform compression using callbacks SYNOPSIS int32 InflateBack(z_stream * strm, in_func in, void * in_desc, out_func out, void * out_desc); FUNCTION inflateBack() does a raw inflate with a single call using a call- back interface for input and output. This is potentially 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. inflate() can be faster on modern CPUs when used with large buffers. inflateBack() 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_in 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. INPUTS strm - Pointer to an initialized z_stream. in - Input callback function. in_desc - Opaque data pointer that will be passed as the first argument to the in() function above. out - Output callback function. out_desc - Opaque data pointer that will be passed as the first argument to the out() function above. RESULT Z_STREAM_END for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateBackInit(), InflateBackEnd() z.library/InflateBackEnd z.library/InflateBackEnd NAME InflateBackEnd -- Perform cleanup after decompression using callbacks SYNOPSIS int32 InflateBackEnd(z_stream * strm); FUNCTION All memory allocated by inflateBackInit() is freed. inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream state was inconsistent. INPUTS strm - Pointer to a z_stream to clean up after. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateBackInit(), InflateBack() z.library/InflateBackInit z.library/InflateBackInit NAME InflateBackInit -- Initialize a z_stream for decompression using callbacks SYNOPSIS int32 InflateBackInit(z_stream * strm, int32 windowBits, uint8 * window); FUNCTION 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 parameters 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. INPUTS strm - Pointer to a z_stream to initialize. windowBits - Window size. window - Window buffer. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateBack(), InflateBackEnd() z.library/InflateCopy z.library/InflateCopy NAME InflateCopy -- Duplicate a decompression stream SYNOPSIS int32 InflateCopy(z_stream * dest, z_stream * source); FUNCTION 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. INPUTS dest - Pointer to z_stream to store copy in. source - Pointer to z_stream to copy. RESULT Z_OK for success or error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateInit(), InflateInit2(), Inflate(), InflateEnd() z.library/InflateEnd z.library/InflateEnd NAME InflateEnd -- Perform cleanup after decompression SYNOPSIS int32 InflateEnd(z_stream * strm); FUNCTION 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). INPUTS strm - Pointer to a z_stream to clean up after. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateInit(), InflateInit2(), Inflate() z.library/InflateGetHeader z.library/InflateGetHeader NAME InflateGetHeader -- Read gzip header from decompression stream SYNOPSIS int32 InflateGetHeader(z_stream * strm, gz_header * head); FUNCTION 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. INPUTS strm - Pointer to an initialized z_stream. head - Gzip header data will be read into here. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO DeflateSetHeader(), InflateInit(), InflateInit2(), Inflate(), InflateEnd() z.library/InflateInit z.library/InflateInit NAME InflateInit -- Initialize a z_stream for decompression SYNOPSIS int32 InflateInit(z_stream * strm); FUNCTION 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, or Z_STREAM_ERROR if the parameters are invalid, such as a null pointer to the structure. msg is set to null if there is no error message. inflateInit does not perform any decompression apart from possibly reading the zlib header if present: actual decompression will be done by inflate(). (So next_in and avail_in may be modified, but next_out and avail_out are unused and unchanged.) The current implementation of inflateInit() does not process any header information -- that is deferred until inflate() is called. INPUTS strm - Pointer to a z_stream to initialize. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateInit2(), Inflate(), InflateEnd() z.library/InflateInit2 z.library/InflateInit2 NAME InflateInit2 -- Initialize a z_stream for decompression SYNOPSIS int32 InflateInit2(z_stream * strm, int32 windowBits); FUNCTION 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 zero to request that inflate use the window size in the zlib header of the compressed stream. 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_VERSION_ERROR if the zlib library version is incompatible with the version assumed by the caller, Z_STREAM_ERROR if a parameters are invalid, such as a null pointer to the structure. 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: actual decompression be done by inflate(). (So next_in and avail_in may be modified, but next_out and avail_out are unused and unchanged.) The current implementation of inflateInit2() does not process any header information -- that is deferred until inflate() is called. INPUTS strm - Pointer to a z_stream to initialize. windowBits - Window size. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateInit(), Inflate(), InflateEnd() z.library/InflatePrime z.library/InflatePrime NAME InflatePrime -- Insert bits in the inflate input stream SYNOPSIS int32 InflatePrime(z_stream * strm, int32 bits, int32 value); FUNCTION 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. If bits is negative, then the input stream bit buffer is emptied. Then inflatePrime() can be called again to put bits in the buffer. This is used to clear out bits leftover after feeding inflate a block description prior to feeding inflate codes. inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source stream state was inconsistent. INPUTS strm - Pointer to an initialized z_stream. bits - Number of bits (must be <= 16). value - Bits to insert. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateInit(), InflateInit2(), Inflate(), InflateEnd() z.library/InflateReset z.library/InflateReset NAME InflateReset -- Reset decompression stream SYNOPSIS int32 InflateReset(z_stream * strm); FUNCTION 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). INPUTS strm - Pointer to a z_stream to reset. RESULT Z_OK for success or error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateInit(), InflateInit2(), Inflate(), InflateEnd() z.library/InflateSetDictionary z.library/InflateSetDictionary NAME InflateSetDictionary -- Set initial dictionary for decompression SYNOPSIS int32 InflateSetDictionary(z_stream * strm, const uint8 * dictionary, uint32 dictLength); FUNCTION 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 at any time to set the dictionary. If the provided dictionary is smaller than the window and there is already data in the window, then the provided dictionary will amend what's there. 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). inflateSet- Dictionary does not perform any decompression: this will be done by subsequent calls of inflate(). INPUTS strm - Pointer to an initialized z_stream. dictionary - Pointer to dictionary data. dictLength - Length of dictionary data. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateInit(), InflateInit2(), Inflate(), InflateEnd() z.library/InflateSync z.library/InflateSync NAME InflateSync -- Search for a possible full flush point SYNOPSIS int32 InflateSync(z_stream * strm); FUNCTION Skips invalid compressed data until a possible full flush point (see above for the description of deflate with Z_FULL_FLUSH) can be found, or until all available input is skipped. No output is provided. inflateSync searches for a 00 00 FF FF pattern in the compressed data. All full flush points have this pattern, but not all occurrences of this pattern are full flush points. inflateSync returns Z_OK if a possible 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. INPUTS strm - Pointer to an initialized z_stream. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO InflateInit(), InflateInit2(), Inflate(), InflateEnd() z.library/Uncompress z.library/Uncompress NAME Uncompress -- Decompress from source to destination buffer SYNOPSIS int32 Uncompress(APTR dest, uint32 * destLen, CONST_APTR source, uint32 sourceLen); FUNCTION 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. 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. In the case where there is not enough room, uncompress() will fill the output buffer with the uncompressed data up to that point. INPUTS dest - Destination buffer. destLen - Length of destination buffer. source - Source buffer. sourceLen - Length of source buffer. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO z.library/ZlibVersion z.library/ZlibVersion NAME ZlibVersion -- Get the zlib version as a string SYNOPSIS CONST_STRPTR ZlibVersion(void); FUNCTION 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. INPUTS RESULT Version string in the form "x.y.z" where x is the version number and y and z are the major and minor revisons. EXAMPLE NOTES BUGS SEE ALSO z/main/InflateGetDictionary z/main/InflateGetDictionary NAME InflateGetDictionary -- Request current state of dictionary (V53.4) SYNOPSIS int32 InflateGetDictionary(z_stream * strm, uint8 * dictionary, uint32 * dictLength); FUNCTION Returns the sliding dictionary being maintained by inflate. dictLength is set to the number of bytes in the dictionary, and that many bytes are copied to dictionary. dictionary must have enough space, where 32768 bytes is always enough. If inflateGet- Dictionary() is called with dictionary equal to Z_NULL, then only the dictionary length is returned, and nothing is copied. Similary, if dictLength is Z_NULL, then it is not set. inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the stream state is inconsistent. INPUTS strm - Pointer to an initialized z_stream. dictionary - Buffer to store the dictionary data in. dictLength - Length of buffer and the read dictionary length is stored here. RESULT Z_OK for success or an error code for failure. EXAMPLE NOTES BUGS SEE ALSO