3
0
mirror of https://github.com/ergochat/ergo.git synced 2024-12-23 03:02:48 +01:00
ergo/irc/utils/text.go
2019-11-09 20:31:39 -05:00

127 lines
3.1 KiB
Go

// Copyright (c) 2017 Daniel Oaks <daniel@danieloaks.net>
// released under the MIT license
package utils
import "bytes"
import "time"
// WordWrap wraps the given text into a series of lines that don't exceed lineWidth characters.
func WordWrap(text string, lineWidth int) []string {
var lines []string
var cacheLine, cacheWord bytes.Buffer
for _, char := range text {
if char == '\r' {
continue
} else if char == '\n' {
cacheLine.Write(cacheWord.Bytes())
lines = append(lines, cacheLine.String())
cacheWord.Reset()
cacheLine.Reset()
} else if (char == ' ' || char == '-') && cacheLine.Len()+cacheWord.Len()+1 < lineWidth {
// natural word boundary
cacheLine.Write(cacheWord.Bytes())
cacheLine.WriteRune(char)
cacheWord.Reset()
} else if lineWidth <= cacheLine.Len()+cacheWord.Len()+1 {
// time to wrap to next line
if cacheLine.Len() < (lineWidth / 2) {
// this word takes up more than half a line... just split in the middle of the word
cacheLine.Write(cacheWord.Bytes())
cacheLine.WriteRune(char)
cacheWord.Reset()
} else {
cacheWord.WriteRune(char)
}
lines = append(lines, cacheLine.String())
cacheLine.Reset()
} else {
// normal character
cacheWord.WriteRune(char)
}
}
if 0 < cacheWord.Len() {
cacheLine.Write(cacheWord.Bytes())
}
if 0 < cacheLine.Len() {
lines = append(lines, cacheLine.String())
}
return lines
}
type MessagePair struct {
Message string
Msgid string
}
// SplitMessage represents a message that's been split for sending.
type SplitMessage struct {
MessagePair
Wrapped []MessagePair // if this is nil, `Message` didn't need wrapping and can be sent to anyone
Time time.Time
}
const defaultLineWidth = 400
func MakeSplitMessage(original string, origIs512 bool) (result SplitMessage) {
result.Message = original
result.Msgid = GenerateSecretToken()
result.Time = time.Now().UTC()
if !origIs512 && defaultLineWidth < len(original) {
wrapped := WordWrap(original, defaultLineWidth)
result.Wrapped = make([]MessagePair, len(wrapped))
for i, wrappedMessage := range wrapped {
result.Wrapped[i] = MessagePair{
Message: wrappedMessage,
Msgid: GenerateSecretToken(),
}
}
}
return
}
// TokenLineBuilder is a helper for building IRC lines composed of delimited tokens,
// with a maximum line length.
type TokenLineBuilder struct {
lineLen int
delim string
buf bytes.Buffer
result []string
}
func (t *TokenLineBuilder) Initialize(lineLen int, delim string) {
t.lineLen = lineLen
t.delim = delim
}
// Add adds a token to the line, creating a new line if necessary.
func (t *TokenLineBuilder) Add(token string) {
tokenLen := len(token)
if t.buf.Len() != 0 {
tokenLen += len(t.delim)
}
if t.lineLen < t.buf.Len()+tokenLen {
t.result = append(t.result, t.buf.String())
t.buf.Reset()
}
if t.buf.Len() != 0 {
t.buf.WriteString(t.delim)
}
t.buf.WriteString(token)
}
// Lines terminates the line-building and returns all the lines.
func (t *TokenLineBuilder) Lines() (result []string) {
result = t.result
t.result = nil
if t.buf.Len() != 0 {
result = append(result, t.buf.String())
t.buf.Reset()
}
return
}