Function avifSampleTransformExpressionIsValid

src/sampletransform.c:13–39

// Convenience functions

avifBool avifSampleTransformExpressionIsValid(const avifSampleTransformExpression * tokens, uint32_t numInputImageItems)
{
    uint32_t stackSize = 0;
    for (uint32_t t = 0; t < tokens->count; ++t) {
        const avifSampleTransformToken * token = &tokens->tokens[t];
        AVIF_CHECK(token->type < AVIF_SAMPLE_TRANSFORM_RESERVED);
        if (token->type == AVIF_SAMPLE_TRANSFORM_INPUT_IMAGE_ITEM_INDEX) {
            // inputImageItemIndex is 1-based.
            AVIF_CHECK(token->inputImageItemIndex != 0);
            AVIF_CHECK(token->inputImageItemIndex <= numInputImageItems);
        }
        if (token->type < AVIF_SAMPLE_TRANSFORM_FIRST_UNARY_OPERATOR) {
            // Likely an operand.
            ++stackSize;
        } else if (token->type < AVIF_SAMPLE_TRANSFORM_FIRST_BINARY_OPERATOR) {
            // Likely a unary operator.
            AVIF_CHECK(stackSize >= 1);
            // Pop one and push one.
        } else {
            // Likely a binary operator.
            AVIF_CHECK(stackSize >= 2);
            --stackSize; // Pop two and push one.
        }
    }
    AVIF_CHECK(stackSize == 1);
    return AVIF_TRUE;
}

avifBool avifSampleTransformExpressionIsEquivalentTo(const avifSampleTransformExpression * a, const avifSampleTransformExpression * b)
{