subread-overlay/app/src/main/kotlin/space/subread/overlay/Words.kt

app/src/main/kotlin/space/subread/overlay/Words.kt (1281 bytes)
1 package space.subread.overlay
2 
3 import android.icu.text.BreakIterator
4 
5 /** Finds the word under a finger. */
6 object Words {
7 
8     /**
9      * The range of the word of [text] that has the character at [offset]; null on a space or a
10      * punctuation mark.
11      *
12      * ICU cuts Japanese, Chinese and Thai with a dictionary, and other scripts at spaces and
13      * punctuation. The cut is a good first try, not a parse: the user can drag to make the
14      * selection longer.
15      */
16     fun at(text: CharSequence, offset: Int): IntRange? {
17         if (offset !in text.indices) return null
18         val words = BreakIterator.getWordInstance()
19         words.setText(text.toString())
20         val end = words.following(offset)
21         if (end == BreakIterator.DONE) return null
22         val isWord = words.ruleStatus != BreakIterator.WORD_NONE
23         val start = words.previous()
24         return if (isWord && start != BreakIterator.DONE) start until end else null
25     }
26 
27     /** The range from the word at [anchor] to the word at [offset], in the order of the text. */
28     fun between(text: CharSequence, anchor: IntRange, offset: Int): IntRange {
29         val other = at(text, offset) ?: return anchor
30         return minOf(anchor.first, other.first)..maxOf(anchor.last, other.last)
31     }
32 }