forkjo/modules/mahonia/shiftjis.go
2014-09-07 19:58:01 -04:00

88 lines
1.4 KiB
Go

package mahonia
// Converters for the Shift-JIS encoding.
import (
"unicode/utf8"
)
func init() {
RegisterCharset(&Charset{
Name: "Shift_JIS",
Aliases: []string{"MS_Kanji", "csShiftJIS", "SJIS", "ibm-943", "windows-31j", "cp932", "windows-932"},
NewDecoder: func() Decoder {
return decodeSJIS
},
NewEncoder: func() Encoder {
shiftJISOnce.Do(reverseShiftJISTable)
return encodeSJIS
},
})
}
func decodeSJIS(p []byte) (c rune, size int, status Status) {
if len(p) == 0 {
return 0, 0, NO_ROOM
}
b := p[0]
if b < 0x80 {
return rune(b), 1, SUCCESS
}
if 0xa1 <= b && b <= 0xdf {
return rune(b) + (0xff61 - 0xa1), 1, SUCCESS
}
if b == 0x80 || b == 0xa0 {
return utf8.RuneError, 1, INVALID_CHAR
}
if len(p) < 2 {
return 0, 0, NO_ROOM
}
jis := int(b)<<8 + int(p[1])
c = rune(shiftJISToUnicode[jis])
if c == 0 {
return utf8.RuneError, 2, INVALID_CHAR
}
return c, 2, SUCCESS
}
func encodeSJIS(p []byte, c rune) (size int, status Status) {
if len(p) == 0 {
return 0, NO_ROOM
}
if c < 0x80 {
p[0] = byte(c)
return 1, SUCCESS
}
if 0xff61 <= c && c <= 0xff9f {
// half-width katakana
p[0] = byte(c - (0xff61 - 0xa1))
return 1, SUCCESS
}
if len(p) < 2 {
return 0, NO_ROOM
}
if c > 0xffff {
p[0] = '?'
return 1, INVALID_CHAR
}
jis := unicodeToShiftJIS[c]
if jis == 0 {
p[0] = '?'
return 1, INVALID_CHAR
}
p[0] = byte(jis >> 8)
p[1] = byte(jis)
return 2, SUCCESS
}