diff options
Diffstat (limited to 'util/text/text.go')
| -rw-r--r-- | util/text/text.go | 330 |
1 files changed, 0 insertions, 330 deletions
diff --git a/util/text/text.go b/util/text/text.go deleted file mode 100644 index 39584d5d..00000000 --- a/util/text/text.go +++ /dev/null @@ -1,330 +0,0 @@ -package text - -import ( - "github.com/mattn/go-runewidth" - "strings" - "unicode/utf8" -) - -// Force runewidth not to treat ambiguous runes as wide chars, so that things -// like unicode ellipsis/up/down/left/right glyphs can have correct runewidth -// and can be displayed correctly in terminals. -func init() { - runewidth.DefaultCondition.EastAsianWidth = false -} - -// Wrap a text for an exact line size -// Handle properly terminal color escape code -func Wrap(text string, lineWidth int) (string, int) { - return WrapLeftPadded(text, lineWidth, 0) -} - -// Wrap a text for an exact line size with a left padding -// Handle properly terminal color escape code -func WrapLeftPadded(text string, lineWidth int, leftPad int) (string, int) { - var lines []string - nbLine := 0 - pad := strings.Repeat(" ", leftPad) - - // tabs are formatted as 4 spaces - text = strings.Replace(text, "\t", " ", -1) - // NOTE: text is first segmented into lines so that softwrapLine can handle. - for _, line := range strings.Split(text, "\n") { - if line == "" || strings.TrimSpace(line) == "" { - lines = append(lines, "") - nbLine++ - } else { - wrapped := softwrapLine(line, lineWidth-leftPad) - firstLine := true - for _, seg := range strings.Split(wrapped, "\n") { - if firstLine { - lines = append(lines, pad+strings.TrimRight(seg, " ")) - firstLine = false - } else { - lines = append(lines, pad+strings.TrimSpace(seg)) - } - nbLine++ - } - } - } - return strings.Join(lines, "\n"), nbLine -} - -// Break a line into several lines so that each line consumes at most -// 'textWidth' cells. Lines break at groups of white spaces and multibyte -// chars. Nothing is removed from the original text so that it behaves like a -// softwrap. -// -// Required: The line shall not contain '\n' -// -// WRAPPING ALGORITHM: The line is broken into non-breakable chunks, then line -// breaks ("\n") are inserted between these groups so that the total length -// between breaks does not exceed the required width. Words that are longer than -// the textWidth are broken into pieces no longer than textWidth. -// -func softwrapLine(line string, textWidth int) string { - // NOTE: terminal escapes are stripped out of the line so the algorithm is - // simpler. Do not try to mix them in the wrapping algorithm, as it can get - // complicated quickly. - line1, termEscapes := extractTermEscapes(line) - - chunks := segmentLine(line1) - // Reverse the chunk array so we can use it as a stack. - for i, j := 0, len(chunks)-1; i < j; i, j = i+1, j-1 { - chunks[i], chunks[j] = chunks[j], chunks[i] - } - var line2 string = "" - var width int = 0 - for len(chunks) > 0 { - thisWord := chunks[len(chunks)-1] - wl := wordLen(thisWord) - if width+wl <= textWidth { - line2 += chunks[len(chunks)-1] - chunks = chunks[:len(chunks)-1] - width += wl - if width == textWidth && len(chunks) > 0 { - // NOTE: new line begins when current line is full and there are more - // chunks to come. - line2 += "\n" - width = 0 - } - } else if wl > textWidth { - // NOTE: By default, long words are splited to fill the remaining space. - // But if the long words is the first non-space word in the middle of the - // line, preceeding spaces shall not be counted in word spliting. - splitWidth := textWidth - width - if strings.HasSuffix(line2, "\n"+strings.Repeat(" ", width)) { - splitWidth += width - } - left, right := splitWord(chunks[len(chunks)-1], splitWidth) - chunks[len(chunks)-1] = right - line2 += left + "\n" - width = 0 - } else { - line2 += "\n" - width = 0 - } - } - - line3 := applyTermEscapes(line2, termEscapes) - return line3 -} - -// EscapeItem: Storage of terminal escapes in a line. 'item' is the actural -// escape command, and 'pos' is the index in the rune array where the 'item' -// shall be inserted back. For example, the escape item in "F\x1b33mox" is -// {"\x1b33m", 1}. -type escapeItem struct { - item string - pos int -} - -// Extract terminal escapes out of a line, returns a new line without terminal -// escapes and a slice of escape items. The terminal escapes can be inserted -// back into the new line at rune index 'item.pos' to recover the original line. -// -// Required: The line shall not contain "\n" -// -func extractTermEscapes(line string) (string, []escapeItem) { - var termEscapes []escapeItem - var line1 string - - pos := 0 - item := "" - occupiedRuneCount := 0 - inEscape := false - for i, r := range []rune(line) { - if r == '\x1b' { - pos = i - item = string(r) - inEscape = true - continue - } - if inEscape { - item += string(r) - if r == 'm' { - termEscapes = append(termEscapes, escapeItem{item, pos - occupiedRuneCount}) - occupiedRuneCount += utf8.RuneCountInString(item) - inEscape = false - } - continue - } - line1 += string(r) - } - - return line1, termEscapes -} - -// Apply the extracted terminal escapes to the edited line. The only edit -// allowed is to insert "\n" like that in softwrapLine. Callers shall ensure -// this since this function is not able to check it. -func applyTermEscapes(line string, escapes []escapeItem) string { - if len(escapes) == 0 { - return line - } - - var out string = "" - - currPos := 0 - currItem := 0 - for _, r := range line { - if currItem < len(escapes) && currPos == escapes[currItem].pos { - // NOTE: We avoid terminal escapes at the end of a line by move them one - // pass the end of line, so that algorithms who trim right spaces are - // happy. But algorithms who trim left spaces are still unhappy. - if r == '\n' { - out += "\n" + escapes[currItem].item - } else { - out += escapes[currItem].item + string(r) - currPos++ - } - currItem++ - } else { - if r != '\n' { - currPos++ - } - out += string(r) - } - } - - // Don't forget the trailing escape, if any. - if currItem == len(escapes)-1 && currPos == escapes[currItem].pos { - out += escapes[currItem].item - } - - return out -} - -// Segment a line into chunks, where each chunk consists of chars with the same -// type and is not breakable. -func segmentLine(s string) []string { - var chunks []string - - var word string - wordType := none - flushWord := func() { - chunks = append(chunks, word) - word = "" - wordType = none - } - - for _, r := range s { - // A WIDE_CHAR itself constitutes a chunk. - thisType := runeType(r) - if thisType == wideChar { - if wordType != none { - flushWord() - } - chunks = append(chunks, string(r)) - continue - } - // Other type of chunks starts with a char of that type, and ends with a - // char with different type or end of string. - if thisType != wordType { - if wordType != none { - flushWord() - } - word = string(r) - wordType = thisType - } else { - word += string(r) - } - } - if word != "" { - flushWord() - } - - return chunks -} - -// Rune categories -// -// These categories are so defined that each category forms a non-breakable -// chunk. It IS NOT the same as unicode code point categories. -// -const ( - none int = iota - wideChar - invisible - shortUnicode - space - visibleAscii -) - -// Determine the category of a rune. -func runeType(r rune) int { - rw := runewidth.RuneWidth(r) - if rw > 1 { - return wideChar - } else if rw == 0 { - return invisible - } else if r > 127 { - return shortUnicode - } else if r == ' ' { - return space - } else { - return visibleAscii - } -} - -// wordLen return the length of a word, while ignoring the terminal escape -// sequences -func wordLen(word string) int { - length := 0 - escape := false - - for _, char := range word { - if char == '\x1b' { - escape = true - } - if !escape { - length += runewidth.RuneWidth(rune(char)) - } - if char == 'm' { - escape = false - } - } - - return length -} - -// splitWord split a word at the given length, while ignoring the terminal escape sequences -func splitWord(word string, length int) (string, string) { - runes := []rune(word) - var result []rune - added := 0 - escape := false - - if length == 0 { - return "", word - } - - for _, r := range runes { - if r == '\x1b' { - escape = true - } - - width := runewidth.RuneWidth(r) - if width+added > length { - // wide character made the length overflow - break - } - - result = append(result, r) - - if !escape { - added += width - if added >= length { - break - } - } - - if r == 'm' { - escape = false - } - } - - leftover := runes[len(result):] - - return string(result), string(leftover) -} |