1 | /* blast.h -- interface for blast.c |
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2 | Copyright (C) 2003 Mark Adler |
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3 | version 1.1, 16 Feb 2003 |
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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 | |
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33 | |
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34 | typedef unsigned (*blast_in)(void *how, unsigned char **buf); |
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35 | typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len); |
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36 | /* Definitions for input/output functions passed to blast(). See below for |
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37 | * what the provided functions need to do. |
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38 | */ |
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39 | |
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40 | |
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41 | int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow); |
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42 | /* Decompress input to output using the provided infun() and outfun() calls. |
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43 | * On success, the return value of blast() is zero. If there is an error in |
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44 | * the source data, i.e. it is not in the proper format, then a negative value |
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45 | * is returned. If there is not enough input available or there is not enough |
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46 | * output space, then a positive error is returned. |
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47 | * |
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48 | * The input function is invoked: len = infun(how, &buf), where buf is set by |
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49 | * infun() to point to the input buffer, and infun() returns the number of |
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50 | * available bytes there. If infun() returns zero, then blast() returns with |
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51 | * an input error. (blast() only asks for input if it needs it.) inhow is for |
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52 | * use by the application to pass an input descriptor to infun(), if desired. |
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53 | * |
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54 | * The output function is invoked: err = outfun(how, buf, len), where the bytes |
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55 | * to be written are buf[0..len-1]. If err is not zero, then blast() returns |
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56 | * with an output error. outfun() is always called with len <= 4096. outhow |
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57 | * is for use by the application to pass an output descriptor to outfun(), if |
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58 | * desired. |
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59 | * |
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60 | * The return codes are: |
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61 | * |
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62 | * 2: ran out of input before completing decompression |
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63 | * 1: output error before completing decompression |
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64 | * 0: successful decompression |
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65 | * -1: literal flag not zero or one |
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66 | * -2: dictionary size not in 4..6 |
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67 | * -3: distance is too far back |
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68 | * |
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69 | * At the bottom of blast.c is an example program that uses blast() that can be |
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70 | * compiled to produce a command-line decompression filter by defining TEST. |
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71 | */ |
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