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Adds a further sanity check.

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This commit is contained in:
Thomas Harte 2020-09-15 17:04:04 -04:00
parent 2fd5cc056c
commit b831b31382
1 changed files with 6 additions and 1 deletions
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7
Outputs/ScanTargets/BufferingScanTarget.cpp
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@ -58,13 +58,18 @@ uint8_t *BufferingScanTarget::begin_data(size_t required_length, size_t required
end_x = aligned_start_x + uint16_t(1 + required_length); end_x = aligned_start_x + uint16_t(1 + required_length);
} }
// Check whether that steps over the read pointer. // Check whether that steps over the read pointer; if so then the final address will be closer
// to the write pointer than the old.
const auto end_address = TextureAddress(end_x, output_y); const auto end_address = TextureAddress(end_x, output_y);
const auto read_pointers = read_pointers_.load(std::memory_order::memory_order_relaxed); const auto read_pointers = read_pointers_.load(std::memory_order::memory_order_relaxed);
const auto end_distance = TextureSub(end_address, read_pointers.write_area); const auto end_distance = TextureSub(end_address, read_pointers.write_area);
const auto previous_distance = TextureSub(write_pointers_.write_area, read_pointers.write_area); const auto previous_distance = TextureSub(write_pointers_.write_area, read_pointers.write_area);
// Perform a quick sanity check.
assert(end_distance >= 0);
assert(previous_distance >= 0);
// If allocating this would somehow make the write pointer back away from the read pointer, // If allocating this would somehow make the write pointer back away from the read pointer,
// there must not be enough space left. // there must not be enough space left.
if(end_distance < previous_distance) { if(end_distance < previous_distance) {