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Safe guard against shifting empty register.

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This commit is contained in:
Bart Trzynadlowski 2017-09-23 15:40:20 +00:00
parent 98b0354dd6
commit c3eef706e8
1 changed files with 12 additions and 0 deletions

12
Src/Util/BitRegister.cpp
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@ -104,6 +104,9 @@ namespace Util
// preserve vector size // preserve vector size
void BitRegister::ShiftRight(size_t count) void BitRegister::ShiftRight(size_t count)
{ {
if (Empty())
return;
if (count < m_bits.size()) if (count < m_bits.size())
{ {
// Shift over bits to the right // Shift over bits to the right
@ -118,6 +121,9 @@ namespace Util
// preserve vector size // preserve vector size
void BitRegister::ShiftLeft(size_t count) void BitRegister::ShiftLeft(size_t count)
{ {
if (Empty())
return;
if (count < m_bits.size()) if (count < m_bits.size())
{ {
// Shift over bits to the left // Shift over bits to the left
@ -132,6 +138,9 @@ namespace Util
// preserve vector size // preserve vector size
uint8_t BitRegister::ShiftOutRight(uint8_t bit) uint8_t BitRegister::ShiftOutRight(uint8_t bit)
{ {
if (Empty())
return m_no_data;
uint8_t ejected = GetRightMost(); uint8_t ejected = GetRightMost();
ShiftRight(1); ShiftRight(1);
m_bits[0] = !!bit; m_bits[0] = !!bit;
@ -142,6 +151,9 @@ namespace Util
// preserve vector size // preserve vector size
uint8_t BitRegister::ShiftOutLeft(uint8_t bit) uint8_t BitRegister::ShiftOutLeft(uint8_t bit)
{ {
if (Empty())
return m_no_data;
uint8_t ejected = GetLeftMost(); uint8_t ejected = GetLeftMost();
ShiftLeft(1); ShiftLeft(1);
m_bits[m_bits.size() - 1] = !!bit; m_bits[m_bits.size() - 1] = !!bit;