Function get_blocks_count

Source/astcenc_entry.cpp:182–202

* @brief Get the total number of blocks in an image. * * This function also validates that the total size of the compressed image, * in bytes, would fit in a size_t. * * @param blocks_x Number of blocks in the X axis. * @param blocks_y Number of blocks in the Y axis. * @param blocks_z Number of blocks in the Z axis. * * @return The number of blocks in the image, or zero if total siz

 *         fit into a size_t.
 */
static size_t get_blocks_count(
	size_t blocks_x,
	size_t blocks_y,
	size_t blocks_z
) {
	bool overflow { false };

	// Compute block count
	size_t blocks_count = astc::mul_safe(blocks_x, blocks_y, overflow);
	blocks_count = astc::mul_safe(blocks_count, blocks_z, overflow);

	// Also compute byte count, but we only use overflow and not the result
	astc::mul_safe(blocks_count, 16, overflow);

	if (overflow)
	{
		return 0;
	}

	return blocks_count;
}

/**
 * @brief Validate CPU floating point meets assumptions made in the codec.