mirror of
https://github.com/tjboldt/ProDOS-Utilities.git
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68 lines
1.7 KiB
Go
68 lines
1.7 KiB
Go
// Copyright Terence J. Boldt (c)2021-2022
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// Use of this source code is governed by an MIT
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// license that can be found in the LICENSE file.
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// This file provides conversion to and from ProDOS time format
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package prodos
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import (
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"time"
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)
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// DateTimeToProDOS converts Time to ProDOS date time
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// 49041 ($BF91) 49040 ($BF90)
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//
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// 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
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// +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
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// DATE: | year | month | day |
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// +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
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//
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// 49043 ($BF93) 49042 ($BF92)
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//
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// 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
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// +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
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// TIME: | hour | | minute |
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// +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
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func DateTimeToProDOS(dateTime time.Time) []byte {
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year := dateTime.Year() % 100
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month := dateTime.Month()
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day := dateTime.Day()
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hour := dateTime.Hour()
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minute := dateTime.Minute()
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buffer := make([]byte, 4)
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buffer[0] = ((byte(month) & 15) << 5) + byte(day)
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buffer[1] = (byte(year) << 1) + (byte(month) >> 3)
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buffer[2] = byte(minute)
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buffer[3] = byte(hour)
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return buffer
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}
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// DateTimeFromProDOS converts Time from ProDOS date time
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func DateTimeFromProDOS(buffer []byte) time.Time {
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if buffer[0] == 0 &&
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buffer[1] == 0 &&
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buffer[2] == 0 &&
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buffer[3] == 0 {
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return time.Time{}
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}
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twoDigitYear := buffer[1] >> 1
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var year int
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if twoDigitYear < 76 {
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year = 2000 + int(twoDigitYear)
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} else {
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year = 1900 + int(twoDigitYear)
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}
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month := int(buffer[0]>>5 + (buffer[1]&1)<<3)
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day := int(buffer[0] & 31)
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hour := int(buffer[3])
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minute := int(buffer[2])
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parsedTime := time.Date(year, time.Month(month), day, hour, minute, 0, 0, time.Local)
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return parsedTime
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}
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