Allow for escaping the delimiter

Author: leaty

csv-core/src/reader.rs

@@ -428,14 +428,15 @@ enum NfaState {
     InQuotedField = 3,
     InEscapedQuote = 4,
     InDoubleEscapedQuote = 5,
-    InComment = 6,
+    InEscapeSequence = 6,
+    InComment = 7,
     // All states below are "final field" states.
     // Namely, they indicate that a field has been parsed.
-    EndFieldDelim = 7,
+    EndFieldDelim = 8,
     // All states below are "final record" states.
     // Namely, they indicate that a record has been parsed.
-    EndRecord = 8,
-    CRLF = 9,
+    EndRecord = 9,
+    CRLF = 10,
 }
 
 /// A list of NFA states that have an explicit representation in the DFA.
@@ -970,7 +971,7 @@ impl Reader {
         match state {
             End | StartRecord | EndRecord | InComment | CRLF => End,
             StartField | EndFieldDelim | EndFieldTerm | InField
-            | InQuotedField | InEscapedQuote | InDoubleEscapedQuote
+            | InQuotedField | InEscapedQuote | InDoubleEscapedQuote | InEscapeSequence
             | InRecordTerm => EndRecord,
         }
     }
@@ -1018,6 +1019,8 @@ impl Reader {
                     (EndFieldDelim, NfaInputAction::Discard)
                 } else if self.term.equals(c) {
                     (EndFieldTerm, NfaInputAction::Epsilon)
+                } else if !self.quoting && self.escape == Some(c) {
+                    (InEscapeSequence, NfaInputAction::Discard)
                 } else {
                     (InField, NfaInputAction::CopyToOutput)
                 }
@@ -1043,6 +1046,9 @@ impl Reader {
                     (InField, NfaInputAction::CopyToOutput)
                 }
             }
+            InEscapeSequence => {
+                (InField, NfaInputAction::CopyToOutput)
+            },
             InComment => {
                 if b'\n' == c {
                     (StartRecord, NfaInputAction::Discard)