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// Copyright 2014 Oleku Konko All rights reserved.
// Use of this source code is governed by a MIT
// license that can be found in the LICENSE file.
// This module is a Table Writer API for the Go Programming Language.
// The protocols were written in pure Go and works on windows and unix systems
package tablewriter
import (
"math"
"strings"
"github.com/mattn/go-runewidth"
)
var (
nl = "\n"
sp = " "
)
const defaultPenalty = 1e5
// Wrap wraps s into a paragraph of lines of length lim, with minimal
// raggedness.
func WrapString(s string, lim int) ([]string, int) {
words := strings.Split(strings.Replace(s, nl, sp, -1), sp)
var lines []string
max := 0
for _, v := range words {
max = runewidth.StringWidth(v)
if max > lim {
lim = max
}
}
for _, line := range WrapWords(words, 1, lim, defaultPenalty) {
lines = append(lines, strings.Join(line, sp))
}
return lines, lim
}
// WrapWords is the low-level line-breaking algorithm, useful if you need more
// control over the details of the text wrapping process. For most uses,
// WrapString will be sufficient and more convenient.
//
// WrapWords splits a list of words into lines with minimal "raggedness",
// treating each rune as one unit, accounting for spc units between adjacent
// words on each line, and attempting to limit lines to lim units. Raggedness
// is the total error over all lines, where error is the square of the
// difference of the length of the line and lim. Too-long lines (which only
// happen when a single word is longer than lim units) have pen penalty units
// added to the error.
func WrapWords(words []string, spc, lim, pen int) [][]string {
n := len(words)
length := make([][]int, n)
for i := 0; i < n; i++ {
length[i] = make([]int, n)
length[i][i] = runewidth.StringWidth(words[i])
for j := i + 1; j < n; j++ {
length[i][j] = length[i][j-1] + spc + runewidth.StringWidth(words[j])
}
}
nbrk := make([]int, n)
cost := make([]int, n)
for i := range cost {
cost[i] = math.MaxInt32
}
for i := n - 1; i >= 0; i-- {
if length[i][n-1] <= lim {
cost[i] = 0
nbrk[i] = n
} else {
for j := i + 1; j < n; j++ {
d := lim - length[i][j-1]
c := d*d + cost[j]
if length[i][j-1] > lim {
c += pen // too-long lines get a worse penalty
}
if c < cost[i] {
cost[i] = c
nbrk[i] = j
}
}
}
}
var lines [][]string
i := 0
for i < n {
lines = append(lines, words[i:nbrk[i]])
i = nbrk[i]
}
return lines
}
// getLines decomposes a multiline string into a slice of strings.
func getLines(s string) []string {
return strings.Split(s, nl)
}
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