Reorganize CLZWDecoder.
- Add a ctor and initialize more variables there, or initialize them in
the class declaration instead of in Decode().
- Take in the source data as a span instead of a raw pointer.
- Change |m_Early| to |m_nEarly| and avoid adding ints with bools.
- Fix nits and lint errors.
Change-Id: I1b95619c2e094796f9e7a9dfea07ad55cacbc1da
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/56412
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/core/fxcodec/flate/flatemodule.cpp b/core/fxcodec/flate/flatemodule.cpp
index 3604efb..0809c5b 100644
--- a/core/fxcodec/flate/flatemodule.cpp
+++ b/core/fxcodec/flate/flatemodule.cpp
@@ -108,73 +108,66 @@
class CLZWDecoder {
public:
- bool Decode(uint8_t* dest_buf,
- uint32_t* dest_size,
- const uint8_t* src_buf,
- uint32_t* src_size,
- bool early_change);
+ CLZWDecoder(pdfium::span<const uint8_t> src_span, bool early_change);
+
+ bool Decode(uint8_t* dest_buf, uint32_t* dest_size, uint32_t* src_size);
private:
void AddCode(uint32_t prefix_code, uint8_t append_char);
void DecodeString(uint32_t code);
- uint32_t m_InPos;
- uint32_t m_OutPos;
+ pdfium::span<const uint8_t> const m_spSrc;
+ uint32_t m_InPos = 0;
+ uint32_t m_OutPos = 0;
uint8_t* m_pOutput;
- const uint8_t* m_pInput;
- bool m_Early;
- uint32_t m_nCodes;
+ const uint8_t m_nEarly;
+ uint32_t m_nCodes = 0;
uint32_t m_StackLen;
- int m_CodeLen;
+ uint8_t m_CodeLen = 9;
uint32_t m_CodeArray[5021];
uint8_t m_DecodeStack[4000];
};
+CLZWDecoder::CLZWDecoder(pdfium::span<const uint8_t> src_span,
+ bool early_change)
+ : m_spSrc(src_span), m_nEarly(early_change ? 1 : 0) {}
+
void CLZWDecoder::AddCode(uint32_t prefix_code, uint8_t append_char) {
- if (m_nCodes + m_Early == 4094) {
+ if (m_nCodes + m_nEarly == 4094)
return;
- }
+
m_CodeArray[m_nCodes++] = (prefix_code << 16) | append_char;
- if (m_nCodes + m_Early == 512 - 258) {
+ if (m_nCodes + m_nEarly == 512 - 258)
m_CodeLen = 10;
- } else if (m_nCodes + m_Early == 1024 - 258) {
+ else if (m_nCodes + m_nEarly == 1024 - 258)
m_CodeLen = 11;
- } else if (m_nCodes + m_Early == 2048 - 258) {
+ else if (m_nCodes + m_nEarly == 2048 - 258)
m_CodeLen = 12;
- }
}
void CLZWDecoder::DecodeString(uint32_t code) {
while (1) {
int index = code - 258;
- if (index < 0 || index >= (int)m_nCodes) {
+ if (index < 0 || static_cast<uint32_t>(index) >= m_nCodes)
break;
- }
+
uint32_t data = m_CodeArray[index];
- if (m_StackLen >= sizeof(m_DecodeStack)) {
+ if (m_StackLen >= sizeof(m_DecodeStack))
return;
- }
- m_DecodeStack[m_StackLen++] = (uint8_t)data;
+
+ m_DecodeStack[m_StackLen++] = static_cast<uint8_t>(data);
code = data >> 16;
}
- if (m_StackLen >= sizeof(m_DecodeStack)) {
+ if (m_StackLen >= sizeof(m_DecodeStack))
return;
- }
- m_DecodeStack[m_StackLen++] = (uint8_t)code;
+
+ m_DecodeStack[m_StackLen++] = static_cast<uint8_t>(code);
}
bool CLZWDecoder::Decode(uint8_t* dest_buf,
uint32_t* dest_size,
- const uint8_t* src_buf,
- uint32_t* src_size,
- bool early_change) {
- m_CodeLen = 9;
- m_InPos = 0;
- m_OutPos = 0;
- m_pInput = src_buf;
+ uint32_t* src_size) {
m_pOutput = dest_buf;
- m_Early = early_change;
- m_nCodes = 0;
uint32_t old_code = 0xFFFFFFFF;
uint8_t last_char = 0;
while (1) {
@@ -182,19 +175,20 @@
break;
int byte_pos = m_InPos / 8;
- int bit_pos = m_InPos % 8, bit_left = m_CodeLen;
+ int bit_pos = m_InPos % 8;
+ uint8_t bit_left = m_CodeLen;
uint32_t code = 0;
if (bit_pos) {
bit_left -= 8 - bit_pos;
- code = (m_pInput[byte_pos++] & ((1 << (8 - bit_pos)) - 1)) << bit_left;
+ code = (m_spSrc[byte_pos++] & ((1 << (8 - bit_pos)) - 1)) << bit_left;
}
if (bit_left < 8) {
- code |= m_pInput[byte_pos] >> (8 - bit_left);
+ code |= m_spSrc[byte_pos] >> (8 - bit_left);
} else {
bit_left -= 8;
- code |= m_pInput[byte_pos++] << bit_left;
+ code |= m_spSrc[byte_pos++] << bit_left;
if (bit_left)
- code |= m_pInput[byte_pos] >> (8 - bit_left);
+ code |= m_spSrc[byte_pos] >> (8 - bit_left);
}
m_InPos += m_CodeLen;
@@ -795,20 +789,18 @@
PredictorType predictor_type = GetPredictor(predictor);
if (bLZW) {
- auto decoder = pdfium::MakeUnique<CLZWDecoder>();
+ auto decoder = pdfium::MakeUnique<CLZWDecoder>(src_span, bEarlyChange);
*dest_size = 0xFFFFFFFF;
offset = src_span.size();
- bool success = decoder->Decode(nullptr, dest_size, src_span.data(), &offset,
- bEarlyChange);
+ bool success = decoder->Decode(nullptr, dest_size, &offset);
if (!success || *dest_size == 0 || *dest_size + 1 < *dest_size)
return FX_INVALID_OFFSET;
- decoder = pdfium::MakeUnique<CLZWDecoder>();
+ decoder = pdfium::MakeUnique<CLZWDecoder>(src_span, bEarlyChange);
dest_buf->reset(FX_Alloc(uint8_t, *dest_size + 1));
uint8_t* dest_buf_ptr = dest_buf->get();
dest_buf_ptr[*dest_size] = '\0';
- decoder->Decode(dest_buf_ptr, dest_size, src_span.data(), &offset,
- bEarlyChange);
+ decoder->Decode(dest_buf_ptr, dest_size, &offset);
} else {
FlateUncompress(src_span, estimated_size, dest_buf, dest_size, &offset);
}
