| 1 | /* blast.h -- interface for blast.c
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| 2 | Copyright (C) 2003, 2012 Mark Adler
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| 3 | version 1.2, 24 Oct 2012
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| 4 |
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| 5 | This software is provided 'as-is', without any express or implied
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| 6 | warranty. In no event will the author be held liable for any damages
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| 7 | arising from the use of this software.
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| 8 |
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| 9 | Permission is granted to anyone to use this software for any purpose,
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| 10 | including commercial applications, and to alter it and redistribute it
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| 11 | freely, subject to the following restrictions:
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| 12 |
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| 13 | 1. The origin of this software must not be misrepresented; you must not
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| 14 | claim that you wrote the original software. If you use this software
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| 15 | in a product, an acknowledgment in the product documentation would be
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| 16 | appreciated but is not required.
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| 17 | 2. Altered source versions must be plainly marked as such, and must not be
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| 18 | misrepresented as being the original software.
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| 19 | 3. This notice may not be removed or altered from any source distribution.
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| 20 |
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| 21 | Mark Adler madler@alumni.caltech.edu
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| 22 | */
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| 23 |
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| 24 |
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| 25 | /*
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| 26 | * blast() decompresses the PKWare Data Compression Library (DCL) compressed
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| 27 | * format. It provides the same functionality as the explode() function in
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| 28 | * that library. (Note: PKWare overused the "implode" verb, and the format
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| 29 | * used by their library implode() function is completely different and
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| 30 | * incompatible with the implode compression method supported by PKZIP.)
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| 31 | *
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| 32 | * The binary mode for stdio functions should be used to assure that the
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| 33 | * compressed data is not corrupted when read or written. For example:
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| 34 | * fopen(..., "rb") and fopen(..., "wb").
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| 35 | */
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| 36 |
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| 37 |
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| 38 | typedef unsigned (*blast_in)(void *how, unsigned char **buf);
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| 39 | typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len);
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| 40 | /* Definitions for input/output functions passed to blast(). See below for
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| 41 | * what the provided functions need to do.
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| 42 | */
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| 43 |
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| 44 |
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| 45 | int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow);
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| 46 | /* Decompress input to output using the provided infun() and outfun() calls.
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| 47 | * On success, the return value of blast() is zero. If there is an error in
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| 48 | * the source data, i.e. it is not in the proper format, then a negative value
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| 49 | * is returned. If there is not enough input available or there is not enough
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| 50 | * output space, then a positive error is returned.
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| 51 | *
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| 52 | * The input function is invoked: len = infun(how, &buf), where buf is set by
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| 53 | * infun() to point to the input buffer, and infun() returns the number of
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| 54 | * available bytes there. If infun() returns zero, then blast() returns with
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| 55 | * an input error. (blast() only asks for input if it needs it.) inhow is for
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| 56 | * use by the application to pass an input descriptor to infun(), if desired.
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| 57 | *
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| 58 | * The output function is invoked: err = outfun(how, buf, len), where the bytes
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| 59 | * to be written are buf[0..len-1]. If err is not zero, then blast() returns
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| 60 | * with an output error. outfun() is always called with len <= 4096. outhow
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| 61 | * is for use by the application to pass an output descriptor to outfun(), if
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| 62 | * desired.
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| 63 | *
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| 64 | * The return codes are:
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| 65 | *
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| 66 | * 2: ran out of input before completing decompression
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| 67 | * 1: output error before completing decompression
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| 68 | * 0: successful decompression
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| 69 | * -1: literal flag not zero or one
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| 70 | * -2: dictionary size not in 4..6
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| 71 | * -3: distance is too far back
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| 72 | *
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| 73 | * At the bottom of blast.c is an example program that uses blast() that can be
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| 74 | * compiled to produce a command-line decompression filter by defining TEST.
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| 75 | */
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