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xbzrle.c: Avoid undefined behaviour with signed arithmetic
Use unsigned types for doing bitwise arithmetic in the xzbrle calculations, to avoid undefined behaviour: xbzrle.c:99:49: runtime error: left shift of 72340172838076673 by 7 places cannot be represented in type 'long' Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
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xbzrle.c
8
xbzrle.c
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@ -28,7 +28,7 @@ int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
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{
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{
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uint32_t zrun_len = 0, nzrun_len = 0;
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uint32_t zrun_len = 0, nzrun_len = 0;
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int d = 0, i = 0;
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int d = 0, i = 0;
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long res, xor;
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long res;
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uint8_t *nzrun_start = NULL;
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uint8_t *nzrun_start = NULL;
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g_assert(!(((uintptr_t)old_buf | (uintptr_t)new_buf | slen) %
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g_assert(!(((uintptr_t)old_buf | (uintptr_t)new_buf | slen) %
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@ -93,9 +93,11 @@ int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
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/* word at a time for speed, use of 32-bit long okay */
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/* word at a time for speed, use of 32-bit long okay */
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if (!res) {
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if (!res) {
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/* truncation to 32-bit long okay */
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/* truncation to 32-bit long okay */
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long mask = (long)0x0101010101010101ULL;
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unsigned long mask = (unsigned long)0x0101010101010101ULL;
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while (i < slen) {
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while (i < slen) {
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xor = *(long *)(old_buf + i) ^ *(long *)(new_buf + i);
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unsigned long xor;
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xor = *(unsigned long *)(old_buf + i)
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^ *(unsigned long *)(new_buf + i);
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if ((xor - mask) & ~xor & (mask << 7)) {
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if ((xor - mask) & ~xor & (mask << 7)) {
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/* found the end of an nzrun within the current long */
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/* found the end of an nzrun within the current long */
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while (old_buf[i] != new_buf[i]) {
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while (old_buf[i] != new_buf[i]) {
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