void CCodec_RLScanlineDecoder::UpdateOperator(uint8_t used_bytes) {
if (used_bytes == 0) {
return;
}
if (m_Operator < 128) {
FXSYS_assert((FX_DWORD)m_Operator + 1 >= used_bytes);
if (used_bytes == m_Operator + 1) {
m_SrcOffset += used_bytes;
GetNextOperator();
return;
}
m_Operator -= used_bytes;
m_SrcOffset += used_bytes;
if (m_SrcOffset >= m_SrcSize) {
m_Operator = 128;
}
return;
}
uint8_t count = 257 - m_Operator;
FXSYS_assert((FX_DWORD)count >= used_bytes);
if (used_bytes == count) {
m_SrcOffset++;
GetNextOperator();
return;
}
count -= used_bytes;
m_Operator = 257 - count;
}
uint8_t* CCodec_RLScanlineDecoder::v_GetNextLine()
{
if (m_SrcOffset == 0) {
GetNextOperator();
} else {
if (m_bEOD) {
return NULL;
}
}
FXSYS_memset(m_pScanline, 0, m_Pitch);
FX_DWORD col_pos = 0;
FX_BOOL eol = FALSE;
while (m_SrcOffset < m_SrcSize && !eol) {
if (m_Operator < 128) {
FX_DWORD copy_len = m_Operator + 1;
if (col_pos + copy_len >= m_dwLineBytes) {
copy_len = m_dwLineBytes - col_pos;
eol = TRUE;
}
if (copy_len >= m_SrcSize - m_SrcOffset) {
copy_len = m_SrcSize - m_SrcOffset;
m_bEOD = TRUE;
}
FXSYS_memcpy(m_pScanline + col_pos, m_pSrcBuf + m_SrcOffset, copy_len);
col_pos += copy_len;
UpdateOperator((uint8_t)copy_len);
} else if (m_Operator > 128) {
int fill = 0;
if (m_SrcOffset - 1 < m_SrcSize - 1) {
fill = m_pSrcBuf[m_SrcOffset];
}
FX_DWORD duplicate_len = 257 - m_Operator;
if (col_pos + duplicate_len >= m_dwLineBytes) {
duplicate_len = m_dwLineBytes - col_pos;
eol = TRUE;
}
FXSYS_memset(m_pScanline + col_pos, fill, duplicate_len);
col_pos += duplicate_len;
UpdateOperator((uint8_t)duplicate_len);
} else {
m_bEOD = TRUE;
break;
}
}
return m_pScanline;
}
uint8_t* CCodec_RLScanlineDecoder::v_GetNextLine() {
if (m_SrcOffset == 0) {
GetNextOperator();
} else {
if (m_bEOD) {
return nullptr;
}
}
FXSYS_memset(m_pScanline, 0, m_Pitch);
uint32_t col_pos = 0;
bool eol = false;
while (m_SrcOffset < m_SrcSize && !eol) {
if (m_Operator < 128) {
uint32_t copy_len = m_Operator + 1;
if (col_pos + copy_len >= m_dwLineBytes) {
copy_len = m_dwLineBytes - col_pos;
eol = true;
}
if (copy_len >= m_SrcSize - m_SrcOffset) {
copy_len = m_SrcSize - m_SrcOffset;
m_bEOD = true;
}
FXSYS_memcpy(m_pScanline + col_pos, m_pSrcBuf + m_SrcOffset, copy_len);
col_pos += copy_len;
UpdateOperator((uint8_t)copy_len);
} else if (m_Operator > 128) {
int fill = 0;
if (m_SrcOffset - 1 < m_SrcSize - 1) {
fill = m_pSrcBuf[m_SrcOffset];
}
uint32_t duplicate_len = 257 - m_Operator;
if (col_pos + duplicate_len >= m_dwLineBytes) {
duplicate_len = m_dwLineBytes - col_pos;
eol = true;
}
FXSYS_memset(m_pScanline + col_pos, fill, duplicate_len);
col_pos += duplicate_len;
UpdateOperator((uint8_t)duplicate_len);
} else {
m_bEOD = true;
break;
}
}
return m_pScanline;
}
