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1 | /* blast.h -- interface for blast.c |
2 | Copyright (C) 2003, 2012, 2013 Mark Adler |
3 | version 1.3, 24 Aug 2013 |
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 | * The binary mode for stdio functions should be used to assure that the |
33 | * compressed data is not corrupted when read or written. For example: |
34 | * fopen(..., "rb") and fopen(..., "wb"). |
35 | */ |
36 | |
37 | |
38 | typedef unsigned (*blast_in)(void *how, unsigned char **buf); |
39 | typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len); |
40 | /* Definitions for input/output functions passed to blast(). See below for |
41 | * what the provided functions need to do. |
42 | */ |
43 | |
44 | |
45 | int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow, |
46 | unsigned *left, unsigned char **in); |
47 | /* Decompress input to output using the provided infun() and outfun() calls. |
48 | * On success, the return value of blast() is zero. If there is an error in |
49 | * the source data, i.e. it is not in the proper format, then a negative value |
50 | * is returned. If there is not enough input available or there is not enough |
51 | * output space, then a positive error is returned. |
52 | * |
53 | * The input function is invoked: len = infun(how, &buf), where buf is set by |
54 | * infun() to point to the input buffer, and infun() returns the number of |
55 | * available bytes there. If infun() returns zero, then blast() returns with |
56 | * an input error. (blast() only asks for input if it needs it.) inhow is for |
57 | * use by the application to pass an input descriptor to infun(), if desired. |
58 | * |
59 | * If left and in are not NULL and *left is not zero when blast() is called, |
60 | * then the *left bytes at *in are consumed for input before infun() is used. |
61 | * |
62 | * The output function is invoked: err = outfun(how, buf, len), where the bytes |
63 | * to be written are buf[0..len-1]. If err is not zero, then blast() returns |
64 | * with an output error. outfun() is always called with len <= 4096. outhow |
65 | * is for use by the application to pass an output descriptor to outfun(), if |
66 | * desired. |
67 | * |
68 | * If there is any unused input, *left is set to the number of bytes that were |
69 | * read and *in points to them. Otherwise *left is set to zero and *in is set |
70 | * to NULL. If left or in are NULL, then they are not set. |
71 | * |
72 | * The return codes are: |
73 | * |
74 | * 2: ran out of input before completing decompression |
75 | * 1: output error before completing decompression |
76 | * 0: successful decompression |
77 | * -1: literal flag not zero or one |
78 | * -2: dictionary size not in 4..6 |
79 | * -3: distance is too far back |
80 | * |
81 | * At the bottom of blast.c is an example program that uses blast() that can be |
82 | * compiled to produce a command-line decompression filter by defining TEST. |
83 | */ |