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Implement upx_zlib_test_overlap() following upx_lzma_test_overlap()

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This commit is contained in:
John Reiser 2007-04-25 20:19:40 -07:00
parent 72dfc743fd
commit 1a90a1daa8
1 changed files with 21 additions and 5 deletions
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26
src/compress_zlib.cpp
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@ -191,6 +191,15 @@ done:
// test_overlap
**************************************************************************/
// from <ucl/ucl.h>:
// test an overlapping in-place decompression within a buffer:
// - try a virtual decompression from &buf[src_off] -> &buf[0]
// - no data is actually written
// - only the bytes at buf[src_off..src_off+src_len-1] will get accessed
//
// 2007-04-25 However, I do not see any "virtual decompress" function in zlib
// that avoids writing the result. Therefore, do an actual decompress.
int upx_zlib_test_overlap ( const upx_bytep buf, unsigned src_off,
unsigned src_len, unsigned* dst_len,
int method,
@ -198,17 +207,24 @@ int upx_zlib_test_overlap ( const upx_bytep buf, unsigned src_off,
{
assert(method == M_DEFLATE);
// FIXME - implement this
// Note that Packer::verifyOverlappingDecompression() will
// verify the final result in any case.
UNUSED(buf);
unsigned overlap_overhead = src_off + src_len - *dst_len;
//printf("upx_zlib_test_overlap: %d\n", overlap_overhead);
if ((int)overlap_overhead >= 256)
return UPX_E_OK;
UNUSED(cresult);
upx_bytep const dst = (upx_bytep)malloc(src_off + src_len);
if (dst) {
upx_bytep const src = &dst[src_off];
// High ends of src and dst are equal (including overlap_overhead.)
memcpy(src, &buf[src_off], src_len);
int const rv = upx_zlib_decompress(src, src_len, dst, &dlen,
method, cresult);
free(dst);
if (UPX_E_OK==rv) {
return UPX_E_OK;
}
}
return UPX_E_ERROR;
}