84 lines
3.8 KiB
C
84 lines
3.8 KiB
C
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/* blast.h -- interface for blast.c
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Copyright (C) 2003, 2012, 2013 Mark Adler
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version 1.3, 24 Aug 2013
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the author be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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Mark Adler madler@alumni.caltech.edu
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*/
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/*
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* blast() decompresses the PKWare Data Compression Library (DCL) compressed
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* format. It provides the same functionality as the explode() function in
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* that library. (Note: PKWare overused the "implode" verb, and the format
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* used by their library implode() function is completely different and
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* incompatible with the implode compression method supported by PKZIP.)
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*
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* The binary mode for stdio functions should be used to assure that the
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* compressed data is not corrupted when read or written. For example:
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* fopen(..., "rb") and fopen(..., "wb").
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*/
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typedef unsigned (*blast_in)(void *how, unsigned char **buf);
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typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len);
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/* Definitions for input/output functions passed to blast(). See below for
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* what the provided functions need to do.
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*/
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int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow,
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unsigned *left, unsigned char **in);
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/* Decompress input to output using the provided infun() and outfun() calls.
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* On success, the return value of blast() is zero. If there is an error in
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* the source data, i.e. it is not in the proper format, then a negative value
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* is returned. If there is not enough input available or there is not enough
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* output space, then a positive error is returned.
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*
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* The input function is invoked: len = infun(how, &buf), where buf is set by
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* infun() to point to the input buffer, and infun() returns the number of
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* available bytes there. If infun() returns zero, then blast() returns with
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* an input error. (blast() only asks for input if it needs it.) inhow is for
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* use by the application to pass an input descriptor to infun(), if desired.
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*
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* If left and in are not NULL and *left is not zero when blast() is called,
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* then the *left bytes are *in are consumed for input before infun() is used.
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*
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* The output function is invoked: err = outfun(how, buf, len), where the bytes
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* to be written are buf[0..len-1]. If err is not zero, then blast() returns
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* with an output error. outfun() is always called with len <= 4096. outhow
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* is for use by the application to pass an output descriptor to outfun(), if
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* desired.
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*
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* If there is any unused input, *left is set to the number of bytes that were
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* read and *in points to them. Otherwise *left is set to zero and *in is set
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* to NULL. If left or in are NULL, then they are not set.
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*
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* The return codes are:
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*
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* 2: ran out of input before completing decompression
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* 1: output error before completing decompression
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* 0: successful decompression
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* -1: literal flag not zero or one
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* -2: dictionary size not in 4..6
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* -3: distance is too far back
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*
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* At the bottom of blast.c is an example program that uses blast() that can be
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* compiled to produce a command-line decompression filter by defining TEST.
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*/
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