/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.mvel2.asm.signature;

/**
 * A type signature parser to make a signature visitor visit an existing
 * signature.
 *
 * @author Thomas Hallgren
 * @author Eric Bruneton
 */
public class SignatureReader {

  /**
   * The signature to be read.
   */
  private final String signature;

  /**
   * Constructs a {@link SignatureReader} for the given signature.
   *
   * @param signature A <i>ClassSignature</i>, <i>MethodTypeSignature</i>,
   *                  or <i>FieldTypeSignature</i>.
   */
  public SignatureReader(final String signature) {
    this.signature = signature;
  }

  /**
   * Makes the given visitor visit the signature of this
   * {@link SignatureReader}. This signature is the one specified in the
   * constructor (see {@link #SignatureReader(String) SignatureReader}). This
   * method is intended to be called on a {@link SignatureReader} that was
   * created using a <i>ClassSignature</i> (such as the
   * <code>signature</code> parameter of the
   * {@link org.objectweb.asm.ClassVisitor#visit ClassVisitor.visit} method)
   * or a <i>MethodTypeSignature</i> (such as the <code>signature</code>
   * parameter of the
   * {@link org.objectweb.asm.ClassVisitor#visitMethod ClassVisitor.visitMethod}
   * method).
   *
   * @param v the visitor that must visit this signature.
   */
  public void accept(final SignatureVisitor v) {
    String signature = this.signature;
    int len = signature.length();
    int pos;
    char c;

    if (signature.charAt(0) == '<') {
      pos = 2;
      do {
        int end = signature.indexOf(':', pos);
        v.visitFormalTypeParameter(signature.substring(pos - 1, end));
        pos = end + 1;

        c = signature.charAt(pos);
        if (c == 'L' || c == '[' || c == 'T') {
          pos = parseType(signature, pos, v.visitClassBound());
        }

        for (; ; ) {
          if ((c = signature.charAt(pos++)) == ':') {
            pos = parseType(signature, pos, v.visitInterfaceBound());
          }
          else {
            break;
          }
        }
      } while (c != '>');
    }
    else {
      pos = 0;
    }

    if (signature.charAt(pos) == '(') {
      pos = pos + 1;
      while (signature.charAt(pos) != ')') {
        pos = parseType(signature, pos, v.visitParameterType());
      }
      pos = parseType(signature, pos + 1, v.visitReturnType());
      while (pos < len) {
        pos = parseType(signature, pos + 1, v.visitExceptionType());
      }
    }
    else {
      pos = parseType(signature, pos, v.visitSuperclass());
      while (pos < len) {
        pos = parseType(signature, pos, v.visitInterface());
      }
    }
  }

  /**
   * Makes the given visitor visit the signature of this
   * {@link SignatureReader}. This signature is the one specified in the
   * constructor (see {@link #SignatureReader(String) SignatureReader}). This
   * method is intended to be called on a {@link SignatureReader} that was
   * created using a <i>FieldTypeSignature</i>, such as the
   * <code>signature</code> parameter of the
   * {@link org.objectweb.asm.ClassVisitor#visitField
   * ClassVisitor.visitField} or {@link
   * org.objectweb.asm.MethodVisitor#visitLocalVariable
   * MethodVisitor.visitLocalVariable} methods.
   *
   * @param v the visitor that must visit this signature.
   */
  public void acceptType(final SignatureVisitor v) {
    parseType(this.signature, 0, v);
  }

  /**
   * Parses a field type signature and makes the given visitor visit it.
   *
   * @param signature a string containing the signature that must be parsed.
   * @param pos       index of the first character of the signature to parsed.
   * @param v         the visitor that must visit this signature.
   * @return the index of the first character after the parsed signature.
   */
  private static int parseType(
      final String signature,
      int pos,
      final SignatureVisitor v) {
    char c;
    int start, end;
    boolean visited, inner;
    String name;

    switch (c = signature.charAt(pos++)) {
      case 'Z':
      case 'C':
      case 'B':
      case 'S':
      case 'I':
      case 'F':
      case 'J':
      case 'D':
      case 'V':
        v.visitBaseType(c);
        return pos;

      case '[':
        return parseType(signature, pos, v.visitArrayType());

      case 'T':
        end = signature.indexOf(';', pos);
        v.visitTypeVariable(signature.substring(pos, end));
        return end + 1;

      default: // case 'L':
        start = pos;
        visited = false;
        inner = false;
        for (; ; ) {
          switch (c = signature.charAt(pos++)) {
            case '.':
            case ';':
              if (!visited) {
                name = signature.substring(start, pos - 1);
                if (inner) {
                  v.visitInnerClassType(name);
                }
                else {
                  v.visitClassType(name);
                }
              }
              if (c == ';') {
                v.visitEnd();
                return pos;
              }
              start = pos;
              visited = false;
              inner = true;
              break;

            case '<':
              name = signature.substring(start, pos - 1);
              if (inner) {
                v.visitInnerClassType(name);
              }
              else {
                v.visitClassType(name);
              }
              visited = true;
              top:
              for (; ; ) {
                switch (c = signature.charAt(pos)) {
                  case '>':
                    break top;
                  case '*':
                    ++pos;
                    v.visitTypeArgument();
                    break;
                  case '+':
                  case '-':
                    pos = parseType(signature,
                        pos + 1,
                        v.visitTypeArgument(c));
                    break;
                  default:
                    pos = parseType(signature,
                        pos,
                        v.visitTypeArgument('='));
                    break;
                }
              }
          }
        }
    }
  }
}
