Split input and output parameters for PNG_Predictor()
Change the in-out parameters to out-parameters. Pass in a separate span
for the input instead.
Change-Id: Ie17d6c2ea9cf018255fbd4b6da1f0e218c788397
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/119270
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Thomas Sepez <tsepez@google.com>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/core/fxcodec/flate/flatemodule.cpp b/core/fxcodec/flate/flatemodule.cpp
index 2d848f0..c909aaf 100644
--- a/core/fxcodec/flate/flatemodule.cpp
+++ b/core/fxcodec/flate/flatemodule.cpp
@@ -386,8 +386,9 @@
bool PNG_Predictor(int Colors,
int BitsPerComponent,
int Columns,
- std::unique_ptr<uint8_t, FxFreeDeleter>* data_buf,
- uint32_t* data_size) {
+ pdfium::span<const uint8_t> src_span,
+ std::unique_ptr<uint8_t, FxFreeDeleter>* result_buf,
+ uint32_t* result_size) {
const uint32_t row_size =
fxge::CalculatePitch8(BitsPerComponent, Colors, Columns).value_or(0);
if (row_size == 0) {
@@ -399,37 +400,37 @@
// Avoid divide by 0.
return false;
}
- const uint32_t row_count = (*data_size + row_size) / src_row_size;
+ const size_t row_count = (src_span.size() + row_size) / src_row_size;
if (row_count == 0) {
return false;
}
- const uint32_t last_row_size = *data_size % src_row_size;
+ const uint32_t last_row_size = src_span.size() % src_row_size;
std::unique_ptr<uint8_t, FxFreeDeleter> dest_buf(
FX_Alloc2D(uint8_t, row_size, row_count));
- uint32_t byte_cnt = 0;
- const uint8_t* pSrcData = data_buf->get();
+ size_t byte_count = 0;
+ const uint8_t* pSrcData = src_span.data();
uint8_t* pDestData = dest_buf.get();
const uint8_t* pPrevDestData = nullptr;
- for (uint32_t row = 0; row < row_count; row++) {
+ for (size_t row = 0; row < row_count; row++) {
uint8_t tag = pSrcData[0];
- byte_cnt++;
+ byte_count++;
if (tag == 0) {
uint32_t move_size = row_size;
- if ((row + 1) * (move_size + 1) > *data_size) {
+ if ((row + 1) * (move_size + 1) > src_span.size()) {
move_size = last_row_size - 1;
}
FXSYS_memcpy(pDestData, pSrcData + 1, move_size);
pSrcData += move_size + 1;
pPrevDestData = pDestData;
pDestData += move_size;
- byte_cnt += move_size;
+ byte_count += move_size;
continue;
}
const uint32_t BytesPerPixel = (Colors * BitsPerComponent + 7) / 8;
- for (uint32_t byte = 0; byte < row_size && byte_cnt < *data_size;
- ++byte, ++byte_cnt) {
+ for (uint32_t byte = 0; byte < row_size && byte_count < src_span.size();
+ ++byte, ++byte_count) {
uint8_t raw_byte = pSrcData[byte + 1];
switch (tag) {
case 1: {
@@ -485,9 +486,10 @@
pPrevDestData = pDestData;
pDestData += row_size;
}
- *data_buf = std::move(dest_buf);
- *data_size = row_size * row_count -
- (last_row_size > 0 ? (src_row_size - last_row_size) : 0);
+ *result_buf = std::move(dest_buf);
+ size_t dest_size = row_size * row_count -
+ (last_row_size > 0 ? (src_row_size - last_row_size) : 0);
+ *result_size = pdfium::checked_cast<uint32_t>(dest_size);
return true;
}
@@ -876,10 +878,15 @@
return {std::move(dest_buf), dest_size, bytes_consumed};
}
case PredictorType::kPng: {
- bool ret = PNG_Predictor(Colors, BitsPerComponent, Columns, &dest_buf,
- &dest_size);
- return {std::move(dest_buf), dest_size,
- ret ? bytes_consumed : FX_INVALID_OFFSET};
+ std::unique_ptr<uint8_t, FxFreeDeleter> result_buf;
+ uint32_t result_size = 0;
+ bool ret = PNG_Predictor(Colors, BitsPerComponent, Columns,
+ pdfium::make_span(dest_buf.get(), dest_size),
+ &result_buf, &result_size);
+ if (!ret) {
+ return {std::move(dest_buf), dest_size, FX_INVALID_OFFSET};
+ }
+ return {std::move(result_buf), result_size, bytes_consumed};
}
case PredictorType::kFlate: {
bool ret = TIFF_Predictor(Colors, BitsPerComponent, Columns,
