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 "SkSLContext.h"
12 #include "SkSLExpression.h"
13 #include "SkSLUtil.h"
14
15 namespace SkSL {
16
17 /**
18 * Given a type, returns the type that will result from extracting an array value from it.
19 */
index_type(const Context & context,const Type & type)20 static const Type& index_type(const Context& context, const Type& type) {
21 if (type.kind() == Type::kMatrix_Kind) {
22 if (type.componentType() == *context.fFloat_Type) {
23 switch (type.rows()) {
24 case 2: return *context.fVec2_Type;
25 case 3: return *context.fVec3_Type;
26 case 4: return *context.fVec4_Type;
27 default: ASSERT(false);
28 }
29 } else {
30 ASSERT(type.componentType() == *context.fDouble_Type);
31 switch (type.rows()) {
32 case 2: return *context.fDVec2_Type;
33 case 3: return *context.fDVec3_Type;
34 case 4: return *context.fDVec4_Type;
35 default: ASSERT(false);
36 }
37 }
38 }
39 return type.componentType();
40 }
41
42 /**
43 * An expression which extracts a value from an array or matrix, as in 'm[2]'.
44 */
45 struct IndexExpression : public Expression {
IndexExpressionIndexExpression46 IndexExpression(const Context& context, std::unique_ptr<Expression> base,
47 std::unique_ptr<Expression> index)
48 : INHERITED(base->fPosition, kIndex_Kind, index_type(context, base->fType))
49 , fBase(std::move(base))
50 , fIndex(std::move(index)) {
51 ASSERT(fIndex->fType == *context.fInt_Type || fIndex->fType == *context.fUInt_Type);
52 }
53
descriptionIndexExpression54 SkString description() const override {
55 return fBase->description() + "[" + fIndex->description() + "]";
56 }
57
58 std::unique_ptr<Expression> fBase;
59 std::unique_ptr<Expression> fIndex;
60
61 typedef Expression INHERITED;
62 };
63
64 } // namespace
65
66 #endif
67