func()

in encoding/traditionalchinese/big5.go [111:192]

• 72 lines of code
• 33 McCabe index (conditional complexity)

func (big5Encoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
	r, size := rune(0), 0
	for ; nSrc < len(src); nSrc += size {
		r = rune(src[nSrc])

		// Decode a 1-byte rune.
		if r < utf8.RuneSelf {
			size = 1
			if nDst >= len(dst) {
				err = transform.ErrShortDst
				break
			}
			dst[nDst] = uint8(r)
			nDst++
			continue

		} else {
			// Decode a multi-byte rune.
			r, size = utf8.DecodeRune(src[nSrc:])
			if size == 1 {
				// All valid runes of size 1 (those below utf8.RuneSelf) were
				// handled above. We have invalid UTF-8 or we haven't seen the
				// full character yet.
				if !atEOF && !utf8.FullRune(src[nSrc:]) {
					err = transform.ErrShortSrc
					break
				}
			}
		}

		if r >= utf8.RuneSelf {
			// func init checks that the switch covers all tables.
			switch {
			case encode0Low <= r && r < encode0High:
				if r = rune(encode0[r-encode0Low]); r != 0 {
					goto write2
				}
			case encode1Low <= r && r < encode1High:
				if r = rune(encode1[r-encode1Low]); r != 0 {
					goto write2
				}
			case encode2Low <= r && r < encode2High:
				if r = rune(encode2[r-encode2Low]); r != 0 {
					goto write2
				}
			case encode3Low <= r && r < encode3High:
				if r = rune(encode3[r-encode3Low]); r != 0 {
					goto write2
				}
			case encode4Low <= r && r < encode4High:
				if r = rune(encode4[r-encode4Low]); r != 0 {
					goto write2
				}
			case encode5Low <= r && r < encode5High:
				if r = rune(encode5[r-encode5Low]); r != 0 {
					goto write2
				}
			case encode6Low <= r && r < encode6High:
				if r = rune(encode6[r-encode6Low]); r != 0 {
					goto write2
				}
			case encode7Low <= r && r < encode7High:
				if r = rune(encode7[r-encode7Low]); r != 0 {
					goto write2
				}
			}
			err = internal.ErrASCIIReplacement
			break
		}

	write2:
		if nDst+2 > len(dst) {
			err = transform.ErrShortDst
			break
		}
		dst[nDst+0] = uint8(r >> 8)
		dst[nDst+1] = uint8(r)
		nDst += 2
		continue
	}
	return nDst, nSrc, err
}