00001 /* blast.h -- interface for blast.c 00002 Copyright (C) 2003 Mark Adler 00003 version 1.1, 16 Feb 2003 00004 00005 This software is provided 'as-is', without any express or implied 00006 warranty. In no event will the author be held liable for any damages 00007 arising from the use of this software. 00008 00009 Permission is granted to anyone to use this software for any purpose, 00010 including commercial applications, and to alter it and redistribute it 00011 freely, subject to the following restrictions: 00012 00013 1. The origin of this software must not be misrepresented; you must not 00014 claim that you wrote the original software. If you use this software 00015 in a product, an acknowledgment in the product documentation would be 00016 appreciated but is not required. 00017 2. Altered source versions must be plainly marked as such, and must not be 00018 misrepresented as being the original software. 00019 3. This notice may not be removed or altered from any source distribution. 00020 00021 Mark Adler madler@alumni.caltech.edu 00022 */ 00023 00024 00025 /* 00026 * blast() decompresses the PKWare Data Compression Library (DCL) compressed 00027 * format. It provides the same functionality as the explode() function in 00028 * that library. (Note: PKWare overused the "implode" verb, and the format 00029 * used by their library implode() function is completely different and 00030 * incompatible with the implode compression method supported by PKZIP.) 00031 */ 00032 00033 00034 typedef unsigned (*blast_in)(void *how, unsigned char **buf); 00035 typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len); 00036 /* Definitions for input/output functions passed to blast(). See below for 00037 * what the provided functions need to do. 00038 */ 00039 00040 00041 int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow); 00042 /* Decompress input to output using the provided infun() and outfun() calls. 00043 * On success, the return value of blast() is zero. If there is an error in 00044 * the source data, i.e. it is not in the proper format, then a negative value 00045 * is returned. If there is not enough input available or there is not enough 00046 * output space, then a positive error is returned. 00047 * 00048 * The input function is invoked: len = infun(how, &buf), where buf is set by 00049 * infun() to point to the input buffer, and infun() returns the number of 00050 * available bytes there. If infun() returns zero, then blast() returns with 00051 * an input error. (blast() only asks for input if it needs it.) inhow is for 00052 * use by the application to pass an input descriptor to infun(), if desired. 00053 * 00054 * The output function is invoked: err = outfun(how, buf, len), where the bytes 00055 * to be written are buf[0..len-1]. If err is not zero, then blast() returns 00056 * with an output error. outfun() is always called with len <= 4096. outhow 00057 * is for use by the application to pass an output descriptor to outfun(), if 00058 * desired. 00059 * 00060 * The return codes are: 00061 * 00062 * 2: ran out of input before completing decompression 00063 * 1: output error before completing decompression 00064 * 0: successful decompression 00065 * -1: literal flag not zero or one 00066 * -2: dictionary size not in 4..6 00067 * -3: distance is too far back 00068 * 00069 * At the bottom of blast.c is an example program that uses blast() that can be 00070 * compiled to produce a command-line decompression filter by defining TEST. 00071 */