mirror of https://bitbucket.org/ausocean/av.git
98 lines
2.0 KiB
Go
98 lines
2.0 KiB
Go
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/*
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DESCRIPTION
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helpers.go provides general helper utilities.
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AUTHORS
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Saxon Nelson-Milton <saxon@ausocean.org>, The Australian Ocean Laboratory (AusOcean)
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LICENSE
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rtp.go is Copyright (C) 2018 the Australian Ocean Lab (AusOcean)
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It is free software: you can redistribute it and/or modify them
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under the terms of the GNU General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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It is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with revid in gpl.txt. If not, see [GNU licenses](http://www.gnu.org/licenses).
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*/
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package h264dec
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import (
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"errors"
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"math"
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)
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// binToSlice is a helper function to convert a string of binary into a
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// corresponding byte slice, e.g. "0100 0001 1000 1100" => {0x41,0x8c}.
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// Spaces in the string are ignored.
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func binToSlice(s string) ([]byte, error) {
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var (
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a byte = 0x80
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cur byte
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bytes []byte
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)
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for i, c := range s {
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switch c {
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case ' ':
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continue
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case '1':
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cur |= a
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case '0':
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default:
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return nil, errors.New("invalid binary string")
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}
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a >>= 1
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if a == 0 || i == (len(s)-1) {
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bytes = append(bytes, cur)
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cur = 0
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a = 0x80
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}
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}
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return bytes, nil
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}
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// binToInt converts a binary string provided as a string and returns as an int.
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// White spaces are ignored.
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func binToInt(s string) (int, error) {
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var sum int
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var nSpace int
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for i := len(s) - 1; i >= 0; i-- {
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if s[i] == ' ' {
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nSpace++
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continue
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}
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sum += int(math.Pow(2, float64(len(s)-1-i-nSpace))) * int(s[i]-'0')
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}
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return sum, nil
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}
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func maxi(a, b int) int {
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if a > b {
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return a
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}
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return b
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}
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func mini(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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func absi(a int) int {
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if a < 0 {
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return -a
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}
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return a
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}
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