116dce513Schristos /* blast.h -- interface for blast.c 2ede78133Schristos Copyright (C) 2003, 2012, 2013 Mark Adler 3ede78133Schristos version 1.3, 24 Aug 2013 416dce513Schristos 516dce513Schristos This software is provided 'as-is', without any express or implied 616dce513Schristos warranty. In no event will the author be held liable for any damages 716dce513Schristos arising from the use of this software. 816dce513Schristos 916dce513Schristos Permission is granted to anyone to use this software for any purpose, 1016dce513Schristos including commercial applications, and to alter it and redistribute it 1116dce513Schristos freely, subject to the following restrictions: 1216dce513Schristos 1316dce513Schristos 1. The origin of this software must not be misrepresented; you must not 1416dce513Schristos claim that you wrote the original software. If you use this software 1516dce513Schristos in a product, an acknowledgment in the product documentation would be 1616dce513Schristos appreciated but is not required. 1716dce513Schristos 2. Altered source versions must be plainly marked as such, and must not be 1816dce513Schristos misrepresented as being the original software. 1916dce513Schristos 3. This notice may not be removed or altered from any source distribution. 2016dce513Schristos 2116dce513Schristos Mark Adler madler@alumni.caltech.edu 2216dce513Schristos */ 2316dce513Schristos 2416dce513Schristos 2516dce513Schristos /* 2616dce513Schristos * blast() decompresses the PKWare Data Compression Library (DCL) compressed 2716dce513Schristos * format. It provides the same functionality as the explode() function in 2816dce513Schristos * that library. (Note: PKWare overused the "implode" verb, and the format 2916dce513Schristos * used by their library implode() function is completely different and 3016dce513Schristos * incompatible with the implode compression method supported by PKZIP.) 3116dce513Schristos * 3216dce513Schristos * The binary mode for stdio functions should be used to assure that the 3316dce513Schristos * compressed data is not corrupted when read or written. For example: 3416dce513Schristos * fopen(..., "rb") and fopen(..., "wb"). 3516dce513Schristos */ 3616dce513Schristos 3716dce513Schristos 3816dce513Schristos typedef unsigned (*blast_in)(void *how, unsigned char **buf); 3916dce513Schristos typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len); 4016dce513Schristos /* Definitions for input/output functions passed to blast(). See below for 4116dce513Schristos * what the provided functions need to do. 4216dce513Schristos */ 4316dce513Schristos 4416dce513Schristos 45ede78133Schristos int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow, 46ede78133Schristos unsigned *left, unsigned char **in); 4716dce513Schristos /* Decompress input to output using the provided infun() and outfun() calls. 4816dce513Schristos * On success, the return value of blast() is zero. If there is an error in 4916dce513Schristos * the source data, i.e. it is not in the proper format, then a negative value 5016dce513Schristos * is returned. If there is not enough input available or there is not enough 5116dce513Schristos * output space, then a positive error is returned. 5216dce513Schristos * 5316dce513Schristos * The input function is invoked: len = infun(how, &buf), where buf is set by 5416dce513Schristos * infun() to point to the input buffer, and infun() returns the number of 5516dce513Schristos * available bytes there. If infun() returns zero, then blast() returns with 5616dce513Schristos * an input error. (blast() only asks for input if it needs it.) inhow is for 5716dce513Schristos * use by the application to pass an input descriptor to infun(), if desired. 5816dce513Schristos * 59ede78133Schristos * If left and in are not NULL and *left is not zero when blast() is called, 60*e992f068Schristos * then the *left bytes at *in are consumed for input before infun() is used. 61ede78133Schristos * 6216dce513Schristos * The output function is invoked: err = outfun(how, buf, len), where the bytes 6316dce513Schristos * to be written are buf[0..len-1]. If err is not zero, then blast() returns 6416dce513Schristos * with an output error. outfun() is always called with len <= 4096. outhow 6516dce513Schristos * is for use by the application to pass an output descriptor to outfun(), if 6616dce513Schristos * desired. 6716dce513Schristos * 68ede78133Schristos * If there is any unused input, *left is set to the number of bytes that were 69ede78133Schristos * read and *in points to them. Otherwise *left is set to zero and *in is set 70ede78133Schristos * to NULL. If left or in are NULL, then they are not set. 71ede78133Schristos * 7216dce513Schristos * The return codes are: 7316dce513Schristos * 7416dce513Schristos * 2: ran out of input before completing decompression 7516dce513Schristos * 1: output error before completing decompression 7616dce513Schristos * 0: successful decompression 7716dce513Schristos * -1: literal flag not zero or one 7816dce513Schristos * -2: dictionary size not in 4..6 7916dce513Schristos * -3: distance is too far back 8016dce513Schristos * 8116dce513Schristos * At the bottom of blast.c is an example program that uses blast() that can be 8216dce513Schristos * compiled to produce a command-line decompression filter by defining TEST. 8316dce513Schristos */ 84