This is to catch the '4 MB text without a single line break'.

For very long lines, find suitable break points at roughly 1K intervals and save them in the line array, too.

Find the line ends and store them in an array.

I wondered about the same thing for my own editor project. Even so, in VB.NET running on a fast machine, this can handle about 20 MB/second. This only wraps at spaces, and if you want to wrap a string that already contains line breaks, you need to split it at the line breaks, send each piece to this function and then reassemble the string. The index (with the same width as the original call). Trim trailing spaces from the portion before the index,Īnd leading spaces from the portion after the index.Īnd the result of calling WordWrap on the trimmed portion after Split the trimmed string into two pieces at the index. If there are no spaces, use the width as the index. If the trimmed string's length is <= the width,įind the index of the last space in the trimmed string, starting at width Trim the input string of leading and trailing spaces. Starting from that, I made more and more complex tests and ended up with a recursive solution that (at least for my purposes) quite efficiently handles the task. Clearly, the simplest thing that works is to return the input string untouched. I started with the test that wrapping the string 'Hello, world!' at 80 width should return 'Hello, World!'.

I used a TDD approach almost as strict as the one from the Go example. I had occasion to write a word wrap function recently, and I want to share what I came up with. It's also fairly culturally specific, as I don't know much about the word-wrapping rules of other cultures. It does split up words if they are too long for a line. It does make sure that dashes stick to the word before it (so you don't end up with stack -overflow) though it doesn't favour moving small hyphenated words to a newline rather than splitting them. It's fairly primitive - it splits on spaces, tabs and dashes. Dashes and the likes should stick to the word occuring before it. String word = str.Substring(startIndex, index - startIndex) Ĭhar nextChar = str.Substring(index, 1) Int index = str.IndexOfAny(splitChars, startIndex) Private static string Explode(string str, char splitChars) Remove leading whitespace from the word so the new line starts flush to the left. StrBuilder.Append(word.Substring(0, width - 1) + '-') If the current word is too long to fit on a line even on it's own then Avoids situation where wrapped whitespace causes emptylines in text. Only move down to a new line if we have text on the current line. StringBuilder strBuilder = new StringBuilder() Private static string WordWrap(string str, int width) It should be fairly easy to translate into other languages (except perhaps for IndexOfAny). Here is a word-wrap algorithm I've written in C#.

Xojo break