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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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