49 lines
1.2 KiB
Go
49 lines
1.2 KiB
Go
package uncanny
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import (
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"errors"
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"fmt"
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"golang.org/x/text/encoding/charmap"
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)
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// encodeString encodes a Unicode string into a given charmap.
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// Unsupported characters are replaced by the default replacement symbol.
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// Mysteriously, this functionality is missing from x/text/encoding.
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// TODO Implement the custom NEC display encoding.
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func encodeString(s string) ([]byte) {
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ret := make([]byte, len(s))
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for i, c := range(s) {
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ret[i], _ = charmap.ISO8859_1.EncodeRune(c)
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}
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return ret
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}
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func (c *Can) DisplayWrite(line int, a []byte) error {
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var addr int
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switch line {
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case 0:
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addr = 0x80
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case 1:
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addr = 0xc0
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default:
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return errors.New("Invalid line")
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}
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// print in separate chunks, as one frame payload is limited to 7 bytes
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// the display has only 16 characters per line, so we truncate there
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for i := 0; i < len(a) && i < 16; i += 7 {
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err := c.bus.Publish(DisplayCommand{addr, a[i:i+7]}.Encode())
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if err != nil {
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return err
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}
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}
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return nil
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}
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func (c *Can) DisplayPrint(line int, a string) error {
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return c.DisplayWrite(line, encodeString(a))
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}
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func (c *Can) DisplayPrintf(line int, a string, args ...interface{}) error {
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s := fmt.Sprintf(a, args...)
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return c.DisplayPrint(line, s)
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}
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