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1 | /* blast.h -- interface for blast.c |
2 | Copyright (C) 2003 Mark Adler | |
3 | version 1.1, 16 Feb 2003 | |
4 | ||
5 | This software is provided 'as-is', without any express or implied | |
6 | warranty. In no event will the author be held liable for any damages | |
7 | arising from the use of this software. | |
8 | ||
9 | Permission is granted to anyone to use this software for any purpose, | |
10 | including commercial applications, and to alter it and redistribute it | |
11 | freely, subject to the following restrictions: | |
12 | ||
13 | 1. The origin of this software must not be misrepresented; you must not | |
14 | claim that you wrote the original software. If you use this software | |
15 | in a product, an acknowledgment in the product documentation would be | |
16 | appreciated but is not required. | |
17 | 2. Altered source versions must be plainly marked as such, and must not be | |
18 | misrepresented as being the original software. | |
19 | 3. This notice may not be removed or altered from any source distribution. | |
20 | ||
21 | Mark Adler madler@alumni.caltech.edu | |
22 | */ | |
23 | ||
24 | ||
25 | /* | |
26 | * blast() decompresses the PKWare Data Compression Library (DCL) compressed | |
27 | * format. It provides the same functionality as the explode() function in | |
28 | * that library. (Note: PKWare overused the "implode" verb, and the format | |
29 | * used by their library implode() function is completely different and | |
30 | * incompatible with the implode compression method supported by PKZIP.) | |
31 | */ | |
32 | ||
33 | ||
34 | typedef unsigned (*blast_in)(void *how, unsigned char **buf); | |
35 | typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len); | |
36 | /* Definitions for input/output functions passed to blast(). See below for | |
37 | * what the provided functions need to do. | |
38 | */ | |
39 | ||
40 | ||
41 | int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow); | |
42 | /* Decompress input to output using the provided infun() and outfun() calls. | |
43 | * On success, the return value of blast() is zero. If there is an error in | |
44 | * the source data, i.e. it is not in the proper format, then a negative value | |
45 | * is returned. If there is not enough input available or there is not enough | |
46 | * output space, then a positive error is returned. | |
47 | * | |
48 | * The input function is invoked: len = infun(how, &buf), where buf is set by | |
49 | * infun() to point to the input buffer, and infun() returns the number of | |
50 | * available bytes there. If infun() returns zero, then blast() returns with | |
51 | * an input error. (blast() only asks for input if it needs it.) inhow is for | |
52 | * use by the application to pass an input descriptor to infun(), if desired. | |
53 | * | |
54 | * The output function is invoked: err = outfun(how, buf, len), where the bytes | |
55 | * to be written are buf[0..len-1]. If err is not zero, then blast() returns | |
56 | * with an output error. outfun() is always called with len <= 4096. outhow | |
57 | * is for use by the application to pass an output descriptor to outfun(), if | |
58 | * desired. | |
59 | * | |
60 | * The return codes are: | |
61 | * | |
62 | * 2: ran out of input before completing decompression | |
63 | * 1: output error before completing decompression | |
64 | * 0: successful decompression | |
65 | * -1: literal flag not zero or one | |
66 | * -2: dictionary size not in 4..6 | |
67 | * -3: distance is too far back | |
68 | * | |
69 | * At the bottom of blast.c is an example program that uses blast() that can be | |
70 | * compiled to produce a command-line decompression filter by defining TEST. | |
71 | */ |