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/* A test program written to test robustness to decompression of

corrupted data. Usage is

unzcrash filename

and the program will read the specified file, compress it (in memory),

and then repeatedly decompress it, each time with a different bit of

the compressed data inverted, so as to test all possible one-bit errors.

This should not cause any invalid memory accesses. If it does,

I want to know about it!

PS. As you can see from the above description, the process is

incredibly slow. A file of size eg 5KB will cause it to run for

many hours.

*/

/* ------------------------------------------------------------------

This file is part of bzip2/libbzip2, a program and library for

lossless, block-sorting data compression.

bzip2/libbzip2 version 1.0.6 of 6 September 2010

Copyright (C) 1996-2010 Julian Seward <jseward@bzip.org>

Please read the WARNING, DISCLAIMER and PATENTS sections in the

README file.

This program is released under the terms of the license contained

in the file LICENSE.

------------------------------------------------------------------ */

#include <stdio.h>

#include <assert.h>

#include "bzlib.h"

#define M_BLOCK 1000000

typedef unsigned char uchar;

#define M_BLOCK_OUT (M_BLOCK + 1000000)

uchar inbuf[M_BLOCK];

uchar outbuf[M_BLOCK_OUT];

uchar zbuf[M_BLOCK + 600 + (M_BLOCK / 100)];

int nIn, nOut, nZ;

char *bzerrorstrings[] = {

"OK"

,"SEQUENCE_ERROR"

,"PARAM_ERROR"

,"MEM_ERROR"

,"DATA_ERROR"

,"DATA_ERROR_MAGIC"

,"IO_ERROR"

,"UNEXPECTED_EOF"

,"OUTBUFF_FULL"

,"???" /* for future */

,"???" /* for future */

,"???" /* for future */

,"???" /* for future */

,"???" /* for future */

,"???" /* for future */

};

void flip_bit ( int bit )

{

int byteno = bit / 8;

int bitno = bit % 8;

uchar mask = 1 << bitno;

//fprintf ( stderr, "(byte %d bit %d mask %d)",

// byteno, bitno, (int)mask );

zbuf[byteno] ^= mask;

}

int main ( int argc, char** argv )

{

FILE* f;

int r;

int bit;

int i;

if (argc != 2) {

fprintf ( stdout, "usage: unzcrash filename\n" );

return 0;

}

f = fopen ( argv[1], "r" );

if (!f) {

fprintf ( stderr, "unzcrash: can't open %s\n", argv[1] );

return 1;

}

nIn = fread ( inbuf, 1, M_BLOCK, f );

fprintf ( stderr, "%d bytes read\n", nIn );

nZ = M_BLOCK;

r = BZ2_bzBuffToBuffCompress (

zbuf, &nZ, inbuf, nIn, 9, 0, 30 );

assert (r == BZ_OK);

fprintf ( stderr, "%d after compression\n", nZ );

for (bit = 0; bit < nZ*8; bit++) {

fprintf ( stderr, "bit %d ", bit );

flip_bit ( bit );

nOut = M_BLOCK_OUT;

r = BZ2_bzBuffToBuffDecompress (

outbuf, &nOut, zbuf, nZ, 0, 0 );

fprintf ( stderr, " %d %s ", r, bzerrorstrings[-r] );

if (r != BZ_OK) {

fprintf ( stderr, "\n" );

} else {

if (nOut != nIn) {

fprintf(stderr, "nIn/nOut mismatch %d %d\n", nIn, nOut );

return 1;

} else {

for (i = 0; i < nOut; i++)

if (inbuf[i] != outbuf[i]) {

fprintf(stderr, "mismatch at %d\n", i );

return 1;

}

if (i == nOut) fprintf(stderr, "really ok!\n" );

}

}

flip_bit ( bit );

}

#if 0

assert (nOut == nIn);

for (i = 0; i < nOut; i++) {

if (inbuf[i] != outbuf[i]) {

fprintf ( stderr, "difference at %d !\n", i );

return 1;

}

}

#endif

fprintf ( stderr, "all ok\n" );

return 0;

}