SkSafeRange.h

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/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#ifndef SkSafeRange_DEFINED
#define SkSafeRange_DEFINED
 
#include "include/core/SkTypes.h"
 
#include <cstdint>
 
// SkSafeRange always check that a series of operations are in-range.
// This check is sticky, so that if any one operation fails, the object will remember that and
// return false from ok().
 
class SkSafeRange {
public:
    explicit operator bool() const { return fOK; }
 
    bool ok() const { return fOK; }
 
    // checks 0 <= value <= max.
    // On success, returns value
    // On failure, returns 0 and sets ok() to false
    template <typename T> T checkLE(uint64_t value, T max) {
        SkASSERT(static_cast<int64_t>(max) >= 0);
        if (value > static_cast<uint64_t>(max)) {
            fOK = false;
            value = 0;
        }
        return static_cast<T>(value);
    }
 
    int checkGE(int value, int min) {
        if (value < min) {
            fOK = false;
            value = min;
        }
        return value;
    }
 
private:
    bool fOK = true;
};
 
#endif