/*
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* Copyright 2010 The Android Open Source Project
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "SkMath.h"
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#include "SkScalar.h"
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SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[],
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const SkScalar values[], int length) {
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SkASSERT(length > 0);
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SkASSERT(keys != nullptr);
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SkASSERT(values != nullptr);
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#ifdef SK_DEBUG
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for (int i = 1; i < length; i++)
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SkASSERT(keys[i] >= keys[i-1]);
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#endif
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int right = 0;
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while (right < length && searchKey > keys[right])
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right++;
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// Could use sentinel values to eliminate conditionals, but since the
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// tables are taken as input, a simpler format is better.
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if (length == right)
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return values[length-1];
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if (0 == right)
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return values[0];
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// Otherwise, interpolate between right - 1 and right.
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SkScalar rightKey = keys[right];
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SkScalar leftKey = keys[right-1];
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SkScalar fract = (searchKey - leftKey) / (rightKey - leftKey);
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return SkScalarInterp(values[right-1], values[right], fract);
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}
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