SkSLIndexExpression.h revision 9fd67a1f53809f5eff1210dd107241b450c48acc
1/* 2 * Copyright 2016 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8#ifndef SKSL_INDEX 9#define SKSL_INDEX 10 11#include "SkSLExpression.h" 12#include "SkSLUtil.h" 13 14namespace SkSL { 15 16/** 17 * Given a type, returns the type that will result from extracting an array value from it. 18 */ 19static const Type& index_type(const Type& type) { 20 if (type.kind() == Type::kMatrix_Kind) { 21 if (type.componentType() == *kFloat_Type) { 22 switch (type.columns()) { 23 case 2: return *kVec2_Type; 24 case 3: return *kVec3_Type; 25 case 4: return *kVec4_Type; 26 default: ASSERT(false); 27 } 28 } else { 29 ASSERT(type.componentType() == *kDouble_Type); 30 switch (type.columns()) { 31 case 2: return *kDVec2_Type; 32 case 3: return *kDVec3_Type; 33 case 4: return *kDVec4_Type; 34 default: ASSERT(false); 35 } 36 } 37 } 38 return type.componentType(); 39} 40 41/** 42 * An expression which extracts a value from an array or matrix, as in 'm[2]'. 43 */ 44struct IndexExpression : public Expression { 45 IndexExpression(std::unique_ptr<Expression> base, std::unique_ptr<Expression> index) 46 : INHERITED(base->fPosition, kIndex_Kind, index_type(base->fType)) 47 , fBase(std::move(base)) 48 , fIndex(std::move(index)) { 49 ASSERT(fIndex->fType == *kInt_Type); 50 } 51 52 std::string description() const override { 53 return fBase->description() + "[" + fIndex->description() + "]"; 54 } 55 56 const std::unique_ptr<Expression> fBase; 57 const std::unique_ptr<Expression> fIndex; 58 59 typedef Expression INHERITED; 60}; 61 62} // namespace 63 64#endif 65