Add method to dump FSM to dot

src/smack/smack.rs

@@ -1,4 +1,5 @@
 use std::mem;
+use std::convert::TryFrom;
 
 use crate::smack::smack_constants::*;
 use crate::smack::smack_pattern::SmackPattern;
@@ -344,6 +345,50 @@ impl Smack {
         }
         (idx - px_start, row)
     }
+    fn show(&self) {
+        println!("digraph D {{");
+        for row in 0..self.m_state_count {
+            for i in 1..self.symbol_count {
+                let s = self.symbol_to_char[i];
+                let from = {
+                    if row == BASE_STATE {
+                        String::from("BASE")
+                    } else if row == UNANCHORED_STATE {
+                        String::from("UNANCHORED")
+                    } else if row >= self.m_match_limit {
+                        format!("\"{}\"", std::str::from_utf8(&self.m_pattern_list[self.m_match[row].m_ids[0]].pattern).unwrap())
+                    } else {
+                        format!("{}", row).into()
+                    }
+                };
+                let to = {
+                    let dst = self.goto(row, s);
+                    if dst == BASE_STATE {
+                        String::from("BASE")
+                    } else if dst == UNANCHORED_STATE {
+                        String::from("UNANCHORED")
+                    } else if dst >= self.m_match_limit {
+                        format!("\"{}\"", std::str::from_utf8(&self.m_pattern_list[self.m_match[dst].m_ids[0]].pattern).unwrap())
+                    } else {
+                        format!("{}", dst).into()
+                    }
+                };
+                let c = {
+                    if s == CHAR_ANCHOR_START {
+                        String::from("^")
+                    } else if s == CHAR_ANCHOR_END {
+                        String::from("$")
+                    } else if s == b'*'.into() {
+                        String::from("ANY")
+                    } else {
+                        format!("{}", u8::try_from(s).unwrap() as char)
+                    }
+                };
+                println!("  {} -> {} [label=\"{}\"]", from, to, c);
+            }
+        }
+        println!("}}");
+    }
     fn inner_match_shift7(&self, px: Vec<u8>, length: usize, state: usize) -> (usize, usize) {
         let px_start = 0;
         let px_end = length;