mirror of
https://codeberg.org/forgejo/forgejo.git
synced 2024-12-27 01:44:10 -05:00
87 lines
2.2 KiB
Go
87 lines
2.2 KiB
Go
|
package text
|
||
|
|
|
||
|
|
import (
|
||
|
|
"bytes"
|
||
|
|
"math"
|
||
|
|
)
|
||
|
|
|
||
|
|
var (
|
||
|
|
nl = []byte{'\n'}
|
||
|
|
sp = []byte{' '}
|
||
|
|
)
|
||
|
|
|
||
|
|
const defaultPenalty = 1e5
|
||
|
|
|
||
|
|
// Wrap wraps s into a paragraph of lines of length lim, with minimal
|
||
|
|
// raggedness.
|
||
|
|
func Wrap(s string, lim int) string {
|
||
|
|
return string(WrapBytes([]byte(s), lim))
|
||
|
|
}
|
||
|
|
|
||
|
|
// WrapBytes wraps b into a paragraph of lines of length lim, with minimal
|
||
|
|
// raggedness.
|
||
|
|
func WrapBytes(b []byte, lim int) []byte {
|
||
|
|
words := bytes.Split(bytes.Replace(bytes.TrimSpace(b), nl, sp, -1), sp)
|
||
|
|
var lines [][]byte
|
||
|
|
for _, line := range WrapWords(words, 1, lim, defaultPenalty) {
|
||
|
|
lines = append(lines, bytes.Join(line, sp))
|
||
|
|
}
|
||
|
|
return bytes.Join(lines, nl)
|
||
|
|
}
|
||
|
|
|
||
|
|
// 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, either
|
||
|
|
// Wrap or WrapBytes will be sufficient and more convenient.
|
||
|
|
//
|
||
|
|
// WrapWords splits a list of words into lines with minimal "raggedness",
|
||
|
|
// treating each byte 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 [][]byte, spc, lim, pen int) [][][]byte {
|
||
|
|
n := len(words)
|
||
|
|
|
||
|
|
length := make([][]int, n)
|
||
|
|
for i := 0; i < n; i++ {
|
||
|
|
length[i] = make([]int, n)
|
||
|
|
length[i][i] = len(words[i])
|
||
|
|
for j := i + 1; j < n; j++ {
|
||
|
|
length[i][j] = length[i][j-1] + spc + len(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 || i == n-1 {
|
||
|
|
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 [][][]byte
|
||
|
|
i := 0
|
||
|
|
for i < n {
|
||
|
|
lines = append(lines, words[i:nbrk[i]])
|
||
|
|
i = nbrk[i]
|
||
|
|
}
|
||
|
|
return lines
|
||
|
|
}
|