133 lines
3.8 KiB
Ragel
133 lines
3.8 KiB
Ragel
package textseg
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import (
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"errors"
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"unicode/utf8"
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)
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// Generated from grapheme_clusters.rl. DO NOT EDIT
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%%{
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# (except you are actually in grapheme_clusters.rl here, so edit away!)
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machine graphclust;
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write data;
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}%%
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var Error = errors.New("invalid UTF8 text")
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// ScanGraphemeClusters is a split function for bufio.Scanner that splits
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// on grapheme cluster boundaries.
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func ScanGraphemeClusters(data []byte, atEOF bool) (int, []byte, error) {
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if len(data) == 0 {
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return 0, nil, nil
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}
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// Ragel state
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cs := 0 // Current State
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p := 0 // "Pointer" into data
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pe := len(data) // End-of-data "pointer"
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ts := 0
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te := 0
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act := 0
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eof := pe
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// Make Go compiler happy
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_ = ts
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_ = te
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_ = act
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_ = eof
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startPos := 0
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endPos := 0
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%%{
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include GraphemeCluster "grapheme_clusters_table.rl";
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action start {
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startPos = p
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}
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action end {
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endPos = p
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}
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action emit {
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return endPos+1, data[startPos:endPos+1], nil
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}
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ZWJGlue = ZWJ (Glue_After_Zwj | E_Base_GAZ Extend* E_Modifier?)?;
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AnyExtender = Extend | ZWJGlue | SpacingMark;
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Extension = AnyExtender*;
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ReplacementChar = (0xEF 0xBF 0xBD);
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CRLFSeq = CR LF;
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ControlSeq = Control | ReplacementChar;
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HangulSeq = (
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L+ (((LV? V+ | LVT) T*)?|LV?) |
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LV V* T* |
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V+ T* |
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LVT T* |
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T+
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) Extension;
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EmojiSeq = (E_Base | E_Base_GAZ) Extend* E_Modifier? Extension;
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ZWJSeq = ZWJGlue Extension;
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EmojiFlagSeq = Regional_Indicator Regional_Indicator? Extension;
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UTF8Cont = 0x80 .. 0xBF;
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AnyUTF8 = (
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0x00..0x7F |
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0xC0..0xDF . UTF8Cont |
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0xE0..0xEF . UTF8Cont . UTF8Cont |
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0xF0..0xF7 . UTF8Cont . UTF8Cont . UTF8Cont
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);
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# OtherSeq is any character that isn't at the start of one of the extended sequences above, followed by extension
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OtherSeq = (AnyUTF8 - (CR|LF|Control|ReplacementChar|L|LV|V|LVT|T|E_Base|E_Base_GAZ|ZWJ|Regional_Indicator|Prepend)) Extension;
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# PrependSeq is prepend followed by any of the other patterns above, except control characters which explicitly break
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PrependSeq = Prepend+ (HangulSeq|EmojiSeq|ZWJSeq|EmojiFlagSeq|OtherSeq)?;
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CRLFTok = CRLFSeq >start @end;
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ControlTok = ControlSeq >start @end;
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HangulTok = HangulSeq >start @end;
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EmojiTok = EmojiSeq >start @end;
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ZWJTok = ZWJSeq >start @end;
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EmojiFlagTok = EmojiFlagSeq >start @end;
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OtherTok = OtherSeq >start @end;
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PrependTok = PrependSeq >start @end;
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main := |*
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CRLFTok => emit;
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ControlTok => emit;
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HangulTok => emit;
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EmojiTok => emit;
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ZWJTok => emit;
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EmojiFlagTok => emit;
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PrependTok => emit;
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OtherTok => emit;
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# any single valid UTF-8 character would also be valid per spec,
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# but we'll handle that separately after the loop so we can deal
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# with requesting more bytes if we're not at EOF.
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*|;
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write init;
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write exec;
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}%%
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// If we fall out here then we were unable to complete a sequence.
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// If we weren't able to complete a sequence then either we've
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// reached the end of a partial buffer (so there's more data to come)
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// or we have an isolated symbol that would normally be part of a
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// grapheme cluster but has appeared in isolation here.
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if !atEOF {
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// Request more
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return 0, nil, nil
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}
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// Just take the first UTF-8 sequence and return that.
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_, seqLen := utf8.DecodeRune(data)
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return seqLen, data[:seqLen], nil
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}
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