diff options
Diffstat (limited to 'cpp/src/sfntly/data/font_data.cc')
-rw-r--r-- | cpp/src/sfntly/data/font_data.cc | 44 |
1 files changed, 27 insertions, 17 deletions
diff --git a/cpp/src/sfntly/data/font_data.cc b/cpp/src/sfntly/data/font_data.cc index d2b95ea..95bee3e 100644 --- a/cpp/src/sfntly/data/font_data.cc +++ b/cpp/src/sfntly/data/font_data.cc @@ -14,11 +14,13 @@ * limitations under the License. */ -#include <limits.h> +#include "sfntly/data/font_data.h" + #include <algorithm> #include <functional> +#include <limits> -#include "sfntly/data/font_data.h" +#include "sfntly/port/logging.h" namespace sfntly { @@ -26,21 +28,29 @@ int32_t FontData::Size() const { return std::min<int32_t>(array_->Size() - bound_offset_, bound_length_); } -bool FontData::Bound(int32_t offset, int32_t length) { - if (offset + length > Size() || offset < 0 || length < 0) - return false; - - bound_offset_ += offset; +void FontData::Bound(int32_t offset, int32_t length) { + // Inputs should not be negative. + CHECK(offset >= 0); + CHECK(length >= 0); + + // Check to make sure |bound_offset_| will not overflow. + CHECK(bound_offset_ <= std::numeric_limits<int32_t>::max() - offset); + const int32_t new_offset = bound_offset_ + offset; + + if (length == GROWABLE_SIZE) { + // When |length| has the special value of GROWABLE_SIZE, it means the size + // should not have any artificial limits, thus it is just the underlying + // |array_|'s size. Just make sure |new_offset| is still within bounds. + CHECK(new_offset <= array_->Size()); + } else { + // When |length| has any other value, |new_offset| + |length| points to the + // end of the array. Make sure that is within bounds, but use subtraction to + // avoid an integer overflow. + CHECK(new_offset <= array_->Size() - length); + } + + bound_offset_ = new_offset; bound_length_ = length; - return true; -} - -bool FontData::Bound(int32_t offset) { -if (offset > Size() || offset < 0) - return false; - - bound_offset_ += offset; - return true; } int32_t FontData::Length() const { @@ -60,7 +70,7 @@ FontData::FontData(FontData* data, int32_t offset) { Init(data->array_); Bound(data->bound_offset_ + offset, (data->bound_length_ == GROWABLE_SIZE) - ? GROWABLE_SIZE : data->bound_length_ - offset); + ? GROWABLE_SIZE : data->bound_length_ - offset); } FontData::~FontData() {} |