60 lines
1.7 KiB
Go
60 lines
1.7 KiB
Go
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// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package fixed implements fixed-point integer types.
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package fixed // import "golang.org/x/image/math/fixed"
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import (
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"fmt"
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)
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// TODO: implement fmt.Formatter for %f and %g.
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// Int26_6 is a signed 26.6 fixed-point number.
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//
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// The integer part ranges from -33554432 to 33554431, inclusive. The
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// fractional part has 6 bits of precision.
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//
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// For example, the number one-and-a-quarter is Int26_6(1<<6 + 1<<4).
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type Int26_6 int32
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// String returns a human-readable representation of a 26.6 fixed-point number.
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//
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// For example, the number one-and-a-quarter becomes "1:16".
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func (x Int26_6) String() string {
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const shift, mask = 6, 1<<6 - 1
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if x >= 0 {
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return fmt.Sprintf("%d:%02d", int32(x>>shift), int32(x&mask))
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}
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x = -x
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if x >= 0 {
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return fmt.Sprintf("-%d:%02d", int32(x>>shift), int32(x&mask))
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}
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return "-33554432:00" // The minimum value is -(1<<25).
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}
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// Int52_12 is a signed 52.12 fixed-point number.
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//
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// The integer part ranges from -2251799813685248 to 2251799813685247,
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// inclusive. The fractional part has 12 bits of precision.
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//
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// For example, the number one-and-a-quarter is Int52_12(1<<12 + 1<<10).
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type Int52_12 int64
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// String returns a human-readable representation of a 52.12 fixed-point
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// number.
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//
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// For example, the number one-and-a-quarter becomes "1:1024".
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func (x Int52_12) String() string {
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const shift, mask = 12, 1<<12 - 1
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if x >= 0 {
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return fmt.Sprintf("%d:%04d", int64(x>>shift), int64(x&mask))
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}
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x = -x
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if x >= 0 {
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return fmt.Sprintf("-%d:%04d", int64(x>>shift), int64(x&mask))
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}
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return "-2251799813685248:0000" // The minimum value is -(1<<51).
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}
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