func printCharInfoTables()

in unicode/norm/maketables.go [575:710]
125 lines of code
39 McCabe index (conditional complexity)

func printCharInfoTables(w io.Writer) int {
	mkstr := func(r rune, f *FormInfo) (int, string) {
		d := f.expandedDecomp
		s := string([]rune(d))
		if max := 1 << 6; len(s) >= max {
			const msg = "%U: too many bytes in decomposition: %d >= %d"
			log.Fatalf(msg, r, len(s), max)
		}
		head := uint8(len(s))
		if f.quickCheck[MComposed] != QCYes {
			head |= 0x40
		}
		if f.combinesForward {
			head |= 0x80
		}
		s = string([]byte{head}) + s

		lccc := ccc(d[0])
		tccc := ccc(d[len(d)-1])
		cc := ccc(r)
		if cc != 0 && lccc == 0 && tccc == 0 {
			log.Fatalf("%U: trailing and leading ccc are 0 for non-zero ccc %d", r, cc)
		}
		if tccc < lccc && lccc != 0 {
			const msg = "%U: lccc (%d) must be <= tcc (%d)"
			log.Fatalf(msg, r, lccc, tccc)
		}
		index := normalDecomp
		nTrail := chars[r].nTrailingNonStarters
		nLead := chars[r].nLeadingNonStarters
		if tccc > 0 || lccc > 0 || nTrail > 0 {
			tccc <<= 2
			tccc |= nTrail
			s += string([]byte{tccc})
			index = endMulti
			for _, r := range d[1:] {
				if ccc(r) == 0 {
					index = firstCCC
				}
			}
			if lccc > 0 || nLead > 0 {
				s += string([]byte{lccc})
				if index == firstCCC {
					log.Fatalf("%U: multi-segment decomposition not supported for decompositions with leading CCC != 0", r)
				}
				index = firstLeadingCCC
			}
			if cc != lccc {
				if cc != 0 {
					log.Fatalf("%U: for lccc != ccc, expected ccc to be 0; was %d", r, cc)
				}
				index = firstCCCZeroExcept
			}
		} else if len(d) > 1 {
			index = firstMulti
		}
		return index, s
	}

	decompSet := makeDecompSet()
	const nLeadStr = "\x00\x01" // 0-byte length and tccc with nTrail.
	decompSet.insert(firstStarterWithNLead, nLeadStr)

	// Store the uniqued decompositions in a byte buffer,
	// preceded by their byte length.
	for _, c := range chars {
		for _, f := range c.forms {
			if len(f.expandedDecomp) == 0 {
				continue
			}
			if f.combinesBackward {
				log.Fatalf("%U: combinesBackward and decompose", c.codePoint)
			}
			index, s := mkstr(c.codePoint, &f)
			decompSet.insert(index, s)
		}
	}

	decompositions := bytes.NewBuffer(make([]byte, 0, 10000))
	size := 0
	positionMap := make(map[string]uint16)
	decompositions.WriteString("\000")
	fmt.Fprintln(w, "const (")
	for i, m := range decompSet {
		sa := []string{}
		for s := range m {
			sa = append(sa, s)
		}
		sort.Strings(sa)
		for _, s := range sa {
			p := decompositions.Len()
			decompositions.WriteString(s)
			positionMap[s] = uint16(p)
		}
		if cname[i] != "" {
			fmt.Fprintf(w, "%s = 0x%X\n", cname[i], decompositions.Len())
		}
	}
	fmt.Fprintln(w, "maxDecomp = 0x8000")
	fmt.Fprintln(w, ")")
	b := decompositions.Bytes()
	printBytes(w, b, "decomps")
	size += len(b)

	varnames := []string{"nfc", "nfkc"}
	for i := 0; i < FNumberOfFormTypes; i++ {
		trie := triegen.NewTrie(varnames[i])

		for r, c := range chars {
			f := c.forms[i]
			d := f.expandedDecomp
			if len(d) != 0 {
				_, key := mkstr(c.codePoint, &f)
				trie.Insert(rune(r), uint64(positionMap[key]))
				if c.ccc != ccc(d[0]) {
					// We assume the lead ccc of a decomposition !=0 in this case.
					if ccc(d[0]) == 0 {
						log.Fatalf("Expected leading CCC to be non-zero; ccc is %d", c.ccc)
					}
				}
			} else if c.nLeadingNonStarters > 0 && len(f.expandedDecomp) == 0 && c.ccc == 0 && !f.combinesBackward {
				// Handle cases where it can't be detected that the nLead should be equal
				// to nTrail.
				trie.Insert(c.codePoint, uint64(positionMap[nLeadStr]))
			} else if v := makeEntry(&f, &c)<<8 | uint16(c.ccc); v != 0 {
				trie.Insert(c.codePoint, uint64(0x8000|v))
			}
		}
		sz, err := trie.Gen(w, triegen.Compact(&normCompacter{name: varnames[i]}))
		if err != nil {
			log.Fatal(err)
		}
		size += sz
	}
	return size
}