mirror of https://github.com/cc65/cc65.git
176 lines
6.9 KiB
C
176 lines
6.9 KiB
C
/*****************************************************************************/
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/* */
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/* zlib.h */
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/* */
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/* Decompression routines for the 'deflate' format */
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/* */
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/* */
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/* */
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/* (C) 2000-2015 Piotr Fusik <fox@scene.pl> */
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/* */
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/* This file is based on the zlib.h from 'zlib' general purpose compression */
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/* library, version 1.1.3, (C) 1995-1998 Jean-loup Gailly and Mark Adler. */
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/* */
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/* Jean-loup Gailly Mark Adler */
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/* jloup@gzip.org madler@alumni.caltech.edu */
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/* */
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/* This software is provided 'as-is', without any expressed or implied */
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/* warranty. In no event will the authors be held liable for any damages */
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/* arising from the use of this software. */
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/* */
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/* Permission is granted to anyone to use this software for any purpose, */
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/* including commercial applications, and to alter it and redistribute it */
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/* freely, subject to the following restrictions: */
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/* */
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/* 1. The origin of this software must not be misrepresented; you must not */
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/* claim that you wrote the original software. If you use this software */
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/* in a product, an acknowledgment in the product documentation would be */
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/* appreciated but is not required. */
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/* 2. Altered source versions must be plainly marked as such, and must not */
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/* be misrepresented as being the original software. */
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/* 3. This notice may not be removed or altered from any source */
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/* distribution. */
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/* */
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/*****************************************************************************/
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#ifndef _ZLIB_H
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#define _ZLIB_H
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#define Z_OK 0
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#define Z_DATA_ERROR (-3)
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/* Return codes for uncompress() */
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#define Z_DEFLATED 8
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/* The deflate compression method (the only one supported) */
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#define Z_NULL 0
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unsigned __fastcall__ inflatemem (unsigned char* dest,
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const unsigned char* source);
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/*
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Decompresses the source buffer into the destination buffer.
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Returns the size of the uncompressed data (number of bytes written starting
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from dest).
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This function expects data in the DEFLATE format, described in RFC
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(Request for Comments) 1951 in the file
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ftp://ds.internic.net/rfc/rfc1951.txt.
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This function does not exist in the original zlib. Its implementation
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using original zlib might be following:
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unsigned inflatemem (char* dest, const char* source)
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{
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z_stream stream;
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stream.next_in = (Bytef*) source;
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stream.avail_in = 65535;
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stream.next_out = dest;
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stream.avail_out = 65535;
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stream.zalloc = (alloc_func) 0;
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stream.zfree = (free_func) 0;
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inflateInit2(&stream, -MAX_WBITS);
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inflate(&stream, Z_FINISH);
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inflateEnd(&stream);
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return stream.total_out;
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}
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*/
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int __fastcall__ uncompress (unsigned char* dest, unsigned* destLen,
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const unsigned char* source, unsigned sourceLen);
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/*
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Original zlib description:
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Decompresses the source buffer into the destination buffer. sourceLen is
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the byte length of the source buffer. Upon entry, destLen is the total
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size of the destination buffer, which must be large enough to hold the
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entire uncompressed data. (The size of the uncompressed data must have
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been saved previously by the compressor and transmitted to the decompressor
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by some mechanism outside the scope of this compression library.)
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Upon exit, destLen is the actual size of the compressed buffer.
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This function can be used to decompress a whole file at once if the
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input file is mmap'ed.
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uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
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enough memory, Z_BUF_ERROR if there was not enough room in the output
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buffer, or Z_DATA_ERROR if the input data was corrupted.
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Implementation notes:
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This function expects data in the ZLIB format, described in RFC 1950
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in the file ftp://ds.internic.net/rfc/rfc1950.txt. The ZLIB format is
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essentially the DEFLATE format plus a very small header and Adler-32
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checksum.
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Z_MEM_ERROR and Z_BUF_ERROR are never returned in this implementation.
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*/
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unsigned long __fastcall__ adler32 (unsigned long adler,
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const unsigned char* buf,
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unsigned len);
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/*
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Original zlib description:
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Update a running Adler-32 checksum with the bytes buf[0..len-1] and
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return the updated checksum. If buf is NULL, this function returns
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the required initial value for the checksum.
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An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
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much faster. Usage example:
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unsigned long adler = adler32(0L, Z_NULL, 0);
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while (read_buffer(buffer, length) != EOF) {
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adler = adler32(adler, buffer, length);
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}
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if (adler != original_adler) error();
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Implementation notes:
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This function isn't actually much faster than crc32(), but it is smaller
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and does not use any lookup tables.
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*/
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unsigned long __fastcall__ crc32 (unsigned long crc,
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const unsigned char* buf,
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unsigned len);
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/*
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Original zlib description:
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Update a running crc with the bytes buf[0..len-1] and return the updated
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crc. If buf is NULL, this function returns the required initial value
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for the crc. Pre- and post-conditioning (one's complement) is performed
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within this function so it shouldn't be done by the application.
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Usage example:
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unsigned long crc = crc32(0L, Z_NULL, 0);
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while (read_buffer(buffer, length) != EOF) {
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crc = crc32(crc, buffer, length);
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}
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if (crc != original_crc) error();
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Implementation notes:
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This function uses statically allocated 1 KB lookup table. The table is
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initialised before it is used for the first time (that is, if buffer is
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NULL or length is zero, then the lookup table isn't initialised).
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*/
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/* end of zlib.h */
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#endif
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