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 "src/sksl/SkSLContext.h"
12#include "src/sksl/SkSLUtil.h"
13#include "src/sksl/ir/SkSLExpression.h"
14
15namespace SkSL {
16
17/**
18 * Given a type, returns the type that will result from extracting an array value from it.
19 */
20static 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.fFloat2_Type;
25 case 3: return *context.fFloat3_Type;
26 case 4: return *context.fFloat4_Type;
27 default: SkASSERT(false);
28 }
29 } else if (type.componentType() == *context.fHalf_Type) {
30 switch (type.rows()) {
31 case 2: return *context.fHalf2_Type;
32 case 3: return *context.fHalf3_Type;
33 case 4: return *context.fHalf4_Type;
34 default: SkASSERT(false);
35 }
36 } else {
37 SkASSERT(type.componentType() == *context.fDouble_Type);
38 switch (type.rows()) {
39 case 2: return *context.fDouble2_Type;
40 case 3: return *context.fDouble3_Type;
41 case 4: return *context.fDouble4_Type;
42 default: SkASSERT(false);
43 }
44 }
45 }
46 return type.componentType();
47}
48
49/**
50 * An expression which extracts a value from an array or matrix, as in 'm[2]'.
51 */
52struct IndexExpression : public Expression {
53 IndexExpression(const Context& context, std::unique_ptr<Expression> base,
54 std::unique_ptr<Expression> index)
55 : INHERITED(base->fOffset, kIndex_Kind, index_type(context, base->fType))
56 , fBase(std::move(base))
57 , fIndex(std::move(index)) {
58 SkASSERT(fIndex->fType == *context.fInt_Type || fIndex->fType == *context.fUInt_Type);
59 }
60
61 bool hasProperty(Property property) const override {
62 return fBase->hasProperty(property) || fIndex->hasProperty(property);
63 }
64
65 std::unique_ptr<Expression> clone() const override {
66 return std::unique_ptr<Expression>(new IndexExpression(fBase->clone(), fIndex->clone(),
67 &fType));
68 }
69
70#ifdef SK_DEBUG
71 String description() const override {
72 return fBase->description() + "[" + fIndex->description() + "]";
73 }
74#endif
75
76 std::unique_ptr<Expression> fBase;
77 std::unique_ptr<Expression> fIndex;
78
79 typedef Expression INHERITED;
80
81private:
82 IndexExpression(std::unique_ptr<Expression> base, std::unique_ptr<Expression> index,
83 const Type* type)
84 : INHERITED(base->fOffset, kIndex_Kind, *type)
85 , fBase(std::move(base))
86 , fIndex(std::move(index)) {}
87};
88
89} // namespace
90
91#endif
92