43 lines
829 B
Go
43 lines
829 B
Go
package encoding
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import (
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"bytes"
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"fmt"
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)
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type GSM7Coder struct{}
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func (c *GSM7Coder) Encode(s string, buf *bytes.Buffer) error {
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// utf8 := *(*[]byte)(unsafe.Pointer(&s))
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utf8 := []byte(s)
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var offset byte = 1
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var bitshift byte = 1
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for index, septet := range utf8 {
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if septet > 0b01111111 {
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return fmt.Errorf("invalid character at index %d", index)
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}
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bindex := byte(index)
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if bindex == 0 {
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continue
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}
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mask := byte(255 >> (8 - bitshift))
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masked := (mask & septet) << (8 - bitshift)
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utf8[bindex-offset] |= masked
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utf8[bindex] >>= bitshift
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buf.WriteByte(utf8[bindex-offset])
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bitshift++
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if bitshift == 8 {
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offset++
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bitshift = 1
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}
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}
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return nil
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}
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func (c *GSM7Coder) Decode(buf *bytes.Buffer) (string, error) {
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return buf.String(), nil
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}
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