1aaf4ece6Schristos /* blast.h -- interface for blast.c 2c3423655Schristos Copyright (C) 2003, 2012, 2013 Mark Adler 3c3423655Schristos version 1.3, 24 Aug 2013 4aaf4ece6Schristos 5aaf4ece6Schristos This software is provided 'as-is', without any express or implied 6aaf4ece6Schristos warranty. In no event will the author be held liable for any damages 7aaf4ece6Schristos arising from the use of this software. 8aaf4ece6Schristos 9aaf4ece6Schristos Permission is granted to anyone to use this software for any purpose, 10aaf4ece6Schristos including commercial applications, and to alter it and redistribute it 11aaf4ece6Schristos freely, subject to the following restrictions: 12aaf4ece6Schristos 13aaf4ece6Schristos 1. The origin of this software must not be misrepresented; you must not 14aaf4ece6Schristos claim that you wrote the original software. If you use this software 15aaf4ece6Schristos in a product, an acknowledgment in the product documentation would be 16aaf4ece6Schristos appreciated but is not required. 17aaf4ece6Schristos 2. Altered source versions must be plainly marked as such, and must not be 18aaf4ece6Schristos misrepresented as being the original software. 19aaf4ece6Schristos 3. This notice may not be removed or altered from any source distribution. 20aaf4ece6Schristos 21aaf4ece6Schristos Mark Adler madler@alumni.caltech.edu 22aaf4ece6Schristos */ 23aaf4ece6Schristos 24aaf4ece6Schristos 25aaf4ece6Schristos /* 26aaf4ece6Schristos * blast() decompresses the PKWare Data Compression Library (DCL) compressed 27aaf4ece6Schristos * format. It provides the same functionality as the explode() function in 28aaf4ece6Schristos * that library. (Note: PKWare overused the "implode" verb, and the format 29aaf4ece6Schristos * used by their library implode() function is completely different and 30aaf4ece6Schristos * incompatible with the implode compression method supported by PKZIP.) 31c3423655Schristos * 32c3423655Schristos * The binary mode for stdio functions should be used to assure that the 33c3423655Schristos * compressed data is not corrupted when read or written. For example: 34c3423655Schristos * fopen(..., "rb") and fopen(..., "wb"). 35aaf4ece6Schristos */ 36aaf4ece6Schristos 37aaf4ece6Schristos 38aaf4ece6Schristos typedef unsigned (*blast_in)(void *how, unsigned char **buf); 39aaf4ece6Schristos typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len); 40aaf4ece6Schristos /* Definitions for input/output functions passed to blast(). See below for 41aaf4ece6Schristos * what the provided functions need to do. 42aaf4ece6Schristos */ 43aaf4ece6Schristos 44aaf4ece6Schristos 45c3423655Schristos int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow, 46c3423655Schristos unsigned *left, unsigned char **in); 47aaf4ece6Schristos /* Decompress input to output using the provided infun() and outfun() calls. 48aaf4ece6Schristos * On success, the return value of blast() is zero. If there is an error in 49aaf4ece6Schristos * the source data, i.e. it is not in the proper format, then a negative value 50aaf4ece6Schristos * is returned. If there is not enough input available or there is not enough 51aaf4ece6Schristos * output space, then a positive error is returned. 52aaf4ece6Schristos * 53aaf4ece6Schristos * The input function is invoked: len = infun(how, &buf), where buf is set by 54aaf4ece6Schristos * infun() to point to the input buffer, and infun() returns the number of 55aaf4ece6Schristos * available bytes there. If infun() returns zero, then blast() returns with 56aaf4ece6Schristos * an input error. (blast() only asks for input if it needs it.) inhow is for 57aaf4ece6Schristos * use by the application to pass an input descriptor to infun(), if desired. 58aaf4ece6Schristos * 59c3423655Schristos * If left and in are not NULL and *left is not zero when blast() is called, 60*ec47cc4bSchristos * then the *left bytes at *in are consumed for input before infun() is used. 61c3423655Schristos * 62aaf4ece6Schristos * The output function is invoked: err = outfun(how, buf, len), where the bytes 63aaf4ece6Schristos * to be written are buf[0..len-1]. If err is not zero, then blast() returns 64aaf4ece6Schristos * with an output error. outfun() is always called with len <= 4096. outhow 65aaf4ece6Schristos * is for use by the application to pass an output descriptor to outfun(), if 66aaf4ece6Schristos * desired. 67aaf4ece6Schristos * 68c3423655Schristos * If there is any unused input, *left is set to the number of bytes that were 69c3423655Schristos * read and *in points to them. Otherwise *left is set to zero and *in is set 70c3423655Schristos * to NULL. If left or in are NULL, then they are not set. 71c3423655Schristos * 72aaf4ece6Schristos * The return codes are: 73aaf4ece6Schristos * 74aaf4ece6Schristos * 2: ran out of input before completing decompression 75aaf4ece6Schristos * 1: output error before completing decompression 76aaf4ece6Schristos * 0: successful decompression 77aaf4ece6Schristos * -1: literal flag not zero or one 78aaf4ece6Schristos * -2: dictionary size not in 4..6 79aaf4ece6Schristos * -3: distance is too far back 80aaf4ece6Schristos * 81aaf4ece6Schristos * At the bottom of blast.c is an example program that uses blast() that can be 82aaf4ece6Schristos * compiled to produce a command-line decompression filter by defining TEST. 83aaf4ece6Schristos */ 84