Rewrite lexer to comply with CQL spec

[cql-java-moved-to-github.git] / src / main / java / org / z3950 / zing / cql / CQLLexerSimple.java

diff --git a/src/main/java/org/z3950/zing/cql/CQLLexerSimple.java b/src/main/java/org/z3950/zing/cql/CQLLexerSimple.java
new file mode 100644 (file)
index 0000000..80931cc
--- /dev/null
+++ b/src/main/java/org/z3950/zing/cql/CQLLexerSimple.java
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 1995-2014, Index Datassss
+ * All rights reserved.
+ * See the file LICENSE for details.
+ */
+package org.z3950.zing.cql;
+
+/**
+ *
+ * @author jakub
+ */
+public class CQLLexerSimple implements CQLLexer {
+  private String qs;
+  private int qi;
+  private int ql;
+  private int what = TT_NOTHING;
+  private String val;
+  private String lval;
+  private StringBuilder buf = new StringBuilder();
+
+  public CQLLexerSimple(String cql, boolean debug) {
+    qs = cql;
+    ql = cql.length();
+  }
+
+  @Override
+  public void move() {
+    //eat whitespace
+    while (qi < ql && strchr(" \t\r\n", qs.charAt(qi)))
+      qi++;
+    //eof
+    if (qi == ql) {
+      what = TT_EOF;
+      return;
+    }
+    //current char
+    char c = qs.charAt(qi);
+    //separators
+    if (strchr("()/", c)) {
+      what = c;
+      qi++;
+    //comparitor
+    } else if (strchr("<>=", c)) {
+      what = c;
+      qi++;
+      //two-char comparitor
+      if (qi < ql) {
+        char d = qs.charAt(qi);
+        String comp = String.valueOf((char) c) + String.valueOf((char) d);
+        if (comp.equals("==")) {
+          what = TT_EQEQ;
+          qi++;
+        }
+        else if (comp.equals("<=")) {
+          what = TT_LE;
+          qi++;
+        }
+        else if (comp.equals(">=")) {
+          what = TT_GE;
+          qi++;
+        }
+        else if (comp.equals("<>")) {
+          what = TT_NE;
+          qi++;
+        }
+      }
+    //quoted string
+    } else if (strchr("\"", c)) { //no single-quotes
+      what = '"';
+      //remember quote char
+      char mark = c;
+      qi++;
+      boolean escaped = false;
+      buf.setLength(0); //reset buffer
+      while (qi < ql) {
+        if (!escaped && qs.charAt(qi) == mark) //terminator
+          break;
+        if (escaped && strchr("*?^\\", qs.charAt(qi))) //no escaping for d-quote
+          buf.append("\\");
+        if (!escaped && qs.charAt(qi) == '\\') { //escape-char
+          escaped = true;
+          qi++;
+          continue;
+        }
+        escaped = false; //reset escape
+        buf.append(qs.charAt(qi));
+        qi++;
+      }
+      val = buf.toString();
+      lval = val.toLowerCase();
+      if (qi < ql)
+        qi++;
+      else //unterminated
+        what = TT_EOF; //notify error
+      //unquoted string
+    } else {
+      what = TT_WORD;
+      buf.setLength(0); //reset buffer
+      while (qi < ql
+        && !strchr("()/<>= \t\r\n", qs.charAt(qi))) {
+        buf.append(qs.charAt(qi));
+        qi++;
+      }
+      val = buf.toString();
+      lval = val.toLowerCase();
+      if (lval.equals("or")) what = TT_OR;
+      else if (lval.equals("and")) what = TT_AND;
+      else if (lval.equals("not")) what = TT_NOT;
+      else if (lval.equals("prox")) what = TT_PROX;
+      else if (lval.equals("sortby")) what = TT_SORTBY;
+    }
+  }
+
+  private boolean strchr(String s, char ch) {
+    return s.indexOf(ch) >= 0;
+  }
+
+  @Override
+  public String value() {
+    return val;
+  }
+
+  @Override
+  public int what() {
+    return what;
+  }
+
+  @Override
+  public String render() {
+    return render(what, true);
+  }
+
+  @Override
+  public String render(int token, boolean quoteChars) {
+    switch (token) {
+      case TT_EOF:
+        return "EOF";
+      case TT_WORD:
+        return "word: " + val;
+      case '"':
+        return "string: \"" + val + "\"";
+      case TT_LE:
+        return "<=";
+      case TT_GE:
+        return ">=";
+      case TT_NE:
+        return "<>";
+      case TT_EQEQ:
+        return "==";
+      case TT_AND:
+        return "and";
+      case TT_NOT:
+        return "not";
+      case TT_OR:
+        return "or";
+      case TT_PROX:
+        return "prox";
+      case TT_SORTBY:
+        return "sortby";
+      default:
+        //a single character, such as '(' or '/' or relation
+        String res = String.valueOf((char) token);
+        if (quoteChars)
+          res = "'" + res + "'";
+        return res;
+    }
+  }
+
+  @Override
+  public int pos() {
+    return qi;
+  }
+}