88 lines
2.1 KiB
Go
88 lines
2.1 KiB
Go
package mahonia
|
|
|
|
import (
|
|
"sync"
|
|
"unicode/utf8"
|
|
)
|
|
|
|
// A kutenTable holds the data for a double-byte character set, arranged by ku
|
|
// (区, zone) and ten (点, position). These can be converted to various actual
|
|
// encoding schemes.
|
|
type kutenTable struct {
|
|
// Data[ku][ten] is the unicode value for the character at that zone and
|
|
// position.
|
|
Data [94][94]uint16
|
|
|
|
// FromUnicode holds the ku and ten for each Unicode code point.
|
|
// It is not available until Reverse() has been called.
|
|
FromUnicode [][2]byte
|
|
|
|
// once is used to synchronize the generation of FromUnicode.
|
|
once sync.Once
|
|
}
|
|
|
|
// Reverse generates FromUnicode.
|
|
func (t *kutenTable) Reverse() {
|
|
t.once.Do(func() {
|
|
t.FromUnicode = make([][2]byte, 65536)
|
|
for ku := range t.Data {
|
|
for ten, unicode := range t.Data[ku] {
|
|
t.FromUnicode[unicode] = [2]byte{byte(ku), byte(ten)}
|
|
}
|
|
}
|
|
})
|
|
}
|
|
|
|
// DecodeLow decodes a character from an encoding that does not have the high
|
|
// bit set.
|
|
func (t *kutenTable) DecodeLow(p []byte) (c rune, size int, status Status) {
|
|
if len(p) < 2 {
|
|
return 0, 0, NO_ROOM
|
|
}
|
|
ku := p[0] - 0x21
|
|
ten := p[1] - 0x21
|
|
if ku > 93 || ten > 93 {
|
|
return utf8.RuneError, 1, INVALID_CHAR
|
|
}
|
|
u := t.Data[ku][ten]
|
|
if u == 0 {
|
|
return utf8.RuneError, 1, INVALID_CHAR
|
|
}
|
|
return rune(u), 2, SUCCESS
|
|
}
|
|
|
|
// DecodeHigh decodes a character from an encoding that has the high bit set.
|
|
func (t *kutenTable) DecodeHigh(p []byte) (c rune, size int, status Status) {
|
|
if len(p) < 2 {
|
|
return 0, 0, NO_ROOM
|
|
}
|
|
ku := p[0] - 0xa1
|
|
ten := p[1] - 0xa1
|
|
if ku > 93 || ten > 93 {
|
|
return utf8.RuneError, 1, INVALID_CHAR
|
|
}
|
|
u := t.Data[ku][ten]
|
|
if u == 0 {
|
|
return utf8.RuneError, 1, INVALID_CHAR
|
|
}
|
|
return rune(u), 2, SUCCESS
|
|
}
|
|
|
|
// EncodeHigh encodes a character in an encoding that has the high bit set.
|
|
func (t *kutenTable) EncodeHigh(p []byte, c rune) (size int, status Status) {
|
|
if len(p) < 2 {
|
|
return 0, NO_ROOM
|
|
}
|
|
if c > 0xffff {
|
|
p[0] = '?'
|
|
return 1, INVALID_CHAR
|
|
}
|
|
kuten := t.FromUnicode[c]
|
|
if kuten == [2]byte{0, 0} && c != rune(t.Data[0][0]) {
|
|
p[0] = '?'
|
|
return 1, INVALID_CHAR
|
|
}
|
|
p[0] = kuten[0] + 0xa1
|
|
p[1] = kuten[1] + 0xa1
|
|
return 2, SUCCESS
|
|
}
|