83 lines
1.6 KiB
Go
83 lines
1.6 KiB
Go
package clifmt
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import (
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"fmt"
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"io"
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"strconv"
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)
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type terminalColor uint32
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var colorMap = make(map[string]terminalColor)
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func init() {
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colorMap["red"] = 0xff0000
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colorMap["green"] = 0x00ff00
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colorMap["blue"] = 0x0000ff
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}
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// fromName returns the integer value of a color name
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// from the built-in color map ; it is case insensitive
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func fromName(s string) (terminalColor, error) {
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value, ok := colorMap[s]
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if !ok {
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return 0, fmt.Errorf("unknown color name '%'", s)
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}
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return value, nil
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}
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// fromHex returns the integer value associated with
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// an hexadecimal string (full-sized or short version)
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// the format is 'abc' or 'abcdef'
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func fromHex(s string) (terminalColor, error) {
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if len(s) != 3 && len(s) != 6 {
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return 0, fmt.Errorf("expect a size of 3 or 6 (remove the '#' prefix)")
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}
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// short version
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input := s
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if len(s) == 3 {
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input = fmt.Sprintf("%c%c%c%c%c%c", s[0], s[0], s[1], s[1], s[2], s[2])
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}
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n, err := strconv.ParseUint(input, 16, 32)
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if err != nil {
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return 0, err
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}
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return terminalColor(n), nil
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}
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// parseColor tries to parse a color string (can be a name or an hexa value)
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func parseColor(s string) (terminalColor, error) {
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// (0) ...
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if len(s) < 1 {
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return 0, io.ErrUnexpectedEOF
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}
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// (1) hexa
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if s[0] == '#' {
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return fromHex(s[1:])
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}
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// (2) name
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return fromName(s)
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}
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// Red component of the color
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func (c terminalColor) Red() uint8 {
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return uint8((c >> 16) & 0xff)
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}
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// Green component of the color
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func (c terminalColor) Green() uint8 {
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return uint8((c >> 8) & 0xff)
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}
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// Blue component of the color
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func (c terminalColor) Blue() uint8 {
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return uint8(c & 0xff)
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}
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