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Improve contrib/blast to return unused bytes. Fix the test code

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to report the count of unused bytes at the end correctly.  Add the
ability to provide initial input to blast().
This commit is contained in:
Mark Adler 2013-08-24 01:53:31 -07:00
parent 89e335abb4
commit 799c87c0d8
2 changed files with 42 additions and 14 deletions
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42
contrib/blast/blast.c
View File

@ -1,7 +1,7 @@
/* blast.c
* Copyright (C) 2003, 2012 Mark Adler
* Copyright (C) 2003, 2012, 2013 Mark Adler
* For conditions of distribution and use, see copyright notice in blast.h
* version 1.2, 24 Oct 2012
* version 1.3, 24 Aug 2013
*
* blast.c decompresses data compressed by the PKWare Compression Library.
* This function provides functionality similar to the explode() function of
@ -24,8 +24,12 @@
* 1.1 16 Feb 2003 - Fixed distance check for > 4 GB uncompressed data
* 1.2 24 Oct 2012 - Add note about using binary mode in stdio
* - Fix comparisons of differently signed integers
* 1.3 24 Aug 2013 - Return unused input from blast()
* - Fix test code to correctly report unused input
* - Enable the provision of initial input to blast()
*/
#include <stddef.h> /* for NULL */
#include <setjmp.h> /* for setjmp(), longjmp(), and jmp_buf */
#include "blast.h" /* prototype for blast() */
@ -376,7 +380,8 @@ local int decomp(struct state *s)
}
/* See comments in blast.h */
int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow)
int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow,
unsigned *left, unsigned char **in)
{
struct state s; /* input/output state */
int err; /* return value */
@ -384,7 +389,12 @@ int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow)
/* initialize input state */
s.infun = infun;
s.inhow = inhow;
s.left = 0;
if (left != NULL && *left) {
s.left = *left;
s.in = *in;
}
else
s.left = 0;
s.bitbuf = 0;
s.bitcnt = 0;
@ -400,6 +410,12 @@ int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow)
else
err = decomp(&s); /* decompress */
/* return unused input */
if (left != NULL)
*left = s.left;
if (in != NULL)
*in = s.left ? s.in : NULL;
/* write any leftover output and update the error code if needed */
if (err != 1 && s.next && s.outfun(s.outhow, s.out, s.next) && err == 0)
err = 1;
@ -429,16 +445,20 @@ local int outf(void *how, unsigned char *buf, unsigned len)
/* Decompress a PKWare Compression Library stream from stdin to stdout */
int main(void)
{
int ret, n;
int ret;
unsigned left;
/* decompress to stdout */
ret = blast(inf, stdin, outf, stdout);
if (ret != 0) fprintf(stderr, "blast error: %d\n", ret);
left = 0;
ret = blast(inf, stdin, outf, stdout, &left, NULL);
if (ret != 0)
fprintf(stderr, "blast error: %d\n", ret);
/* see if there are any leftover bytes */
n = 0;
while (getchar() != EOF) n++;
if (n) fprintf(stderr, "blast warning: %d unused bytes of input\n", n);
/* count any leftover bytes */
while (getchar() != EOF)
left++;
if (left)
fprintf(stderr, "blast warning: %u unused bytes of input\n", left);
/* return blast() error code */
return ret;

14
contrib/blast/blast.h
View File

@ -1,6 +1,6 @@
/* blast.h -- interface for blast.c
Copyright (C) 2003, 2012 Mark Adler
version 1.2, 24 Oct 2012
Copyright (C) 2003, 2012, 2013 Mark Adler
version 1.3, 24 Aug 2013
This software is provided 'as-is', without any express or implied
warranty. In no event will the author be held liable for any damages
@ -42,7 +42,8 @@ typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len);
*/
int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow);
int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow,
unsigned *left, unsigned char **in);
/* Decompress input to output using the provided infun() and outfun() calls.
* On success, the return value of blast() is zero. If there is an error in
* the source data, i.e. it is not in the proper format, then a negative value
@ -55,12 +56,19 @@ int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow);
* an input error. (blast() only asks for input if it needs it.) inhow is for
* use by the application to pass an input descriptor to infun(), if desired.
*
* If left and in are not NULL and *left is not zero when blast() is called,
* then the *left bytes are *in are consumed for input before infun() is used.
*
* The output function is invoked: err = outfun(how, buf, len), where the bytes
* to be written are buf[0..len-1]. If err is not zero, then blast() returns
* with an output error. outfun() is always called with len <= 4096. outhow
* is for use by the application to pass an output descriptor to outfun(), if
* desired.
*
* If there is any unused input, *left is set to the number of bytes that were
* read and *in points to them. Otherwise *left is set to zero and *in is set
* to NULL. If left or in are NULL, then they are not set.
*
* The return codes are:
*
* 2: ran out of input before completing decompression