All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.google.common.css.compiler.ast.StringCharStream Maven / Gradle / Ivy

Go to download

Closure Stylesheets is an extension to CSS that adds variables, functions, conditionals, and mixins to standard CSS. The tool also supports minification, linting, RTL flipping, and CSS class renaming.

The newest version!
/*
 * Copyright 2009 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.css.compiler.ast;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.Lists;
import com.google.common.primitives.Ints;

import java.io.IOException;
import java.util.List;

/**
 * Efficient {@code String} based {@link CharStream} implementation.
 *
 * @author [email protected] (Damian Gajda)
 */
public class StringCharStream implements CharStream {

  private static final IOException END_OF_STREAM = new IOException();

  /** The input string. */
  private final String input;
  private final int length;
  private int charPos;
  private int line;
  private int column;
  private char lastChar;

  private int tokenStart;
  private int beginLine;
  private int beginColumn;

  private int tabSize = 1;
  private boolean trackLineColumn;

  /**
   * This array (working as a map: lineNumber -> characterIndex) helps to
   * compute token locations efficiently. First element is not used as line
   * numbers are 1 based.
   */
  private int[] lineToCharIndex;

  /**
   * Creates a character stream for a given string.
   *
   * @param inputString input string for this stream
   */
  public StringCharStream(String inputString) {
    input = inputString;
    length = input.length();

    lastChar = '\u0000';
    charPos = -1;
    column = 0;
    line = 1;

    tokenStart = charPos;
    beginLine = line;
    beginColumn = column;

    initCharIndex(input);
  }

  private void initCharIndex(String source) {
    List lineToCharIndexList = Lists.newArrayList();
    int charIndex = -1;
    lineToCharIndexList.add(charIndex);
    do {
      charIndex++;
      lineToCharIndexList.add(charIndex);
      charIndex = source.indexOf('\n', charIndex);
    } while (charIndex >= 0);
    lineToCharIndex = Ints.toArray(lineToCharIndexList);
  }

  /**
   * Returns an absolute character location for given line and column location.
   *
   * @param lineNumber line number (1 based)
   * @param indexInLine column number (1 based)
   * @return 0 based absolute character index in the input string
   */
  public int convertToCharacterIndex(int lineNumber, int indexInLine) {
    return lineToCharIndex[lineNumber] + indexInLine - 1;
  }

  /**
   * @return index of last read character
   */
  public int getCharIndex() {
    return charPos;
  }

  /**
   * @return index of the first character of a token
   */
  @VisibleForTesting
  int getTokenStart() {
    return tokenStart;
  }

  /** {@inheritDoc} */
  @Override
  public char readChar() throws IOException {
    if (charPos + 1 == length) {
      throw END_OF_STREAM;
    }

    if (lastChar == '\n') {
      line++;
      column = 0;
    }
    if (lastChar == '\t') {
      column += (tabSize - (column % tabSize));
    } else {
      column++;
    }
    lastChar = input.charAt(++charPos);
    return lastChar;
  }

  /** {@inheritDoc} */
  @Deprecated
  @Override
  public int getColumn() {
    return getEndColumn();
  }

  /** {@inheritDoc} */
  @Deprecated
  @Override
  public int getLine() {
    return getEndLine();
  }

  /** {@inheritDoc} */
  @Override
  public int getEndColumn() {
    return column;
  }

  /** {@inheritDoc} */
  @Override
  public int getEndLine() {
    return line;
  }

  /** {@inheritDoc} */
  @Override
  public int getBeginColumn() {
    return beginColumn;
  }

  /** {@inheritDoc} */
  @Override
  public int getBeginLine() {
    return beginLine;
  }

  /** {@inheritDoc} */
  @Override
  public void backup(int amount) {
    charPos -= amount;
    while (line > 1 && lineToCharIndex[line] > charPos) {
      line--;
    }
    column = charPos - lineToCharIndex[line] + 1;
    lastChar = charPos < 0 ? '\u0000' : input.charAt(charPos);
  }

  /** {@inheritDoc} */
  @Override
  public char BeginToken() throws IOException {
    readChar();
    tokenStart = charPos;
    beginLine = line;
    beginColumn = column;
    return lastChar;
  }

  /** {@inheritDoc} */
  @Override
  public String GetImage() {
    return input.substring(tokenStart, charPos + 1);
  }

  /** {@inheritDoc} */
  @Override
  public char[] GetSuffix(int len) {
    int end = charPos + 1;
    int start = end - len;
    char[] chars = new char[end - start];
    input.getChars(start, end, chars, 0);
    return chars;
  }

  /** {@inheritDoc} */
  @Override
  public void Done() {
    // Does nothing since no resources need to be freed.
  }

  @Override
  public void setTabSize(int tabSize) {
    throw new UnsupportedOperationException("setTabSize() is not supported.");
  }

  @Override
  public int getTabSize() {
    return tabSize;
  }

  @Override
  public boolean getTrackLineColumn() {
    return trackLineColumn;
  }

  @Override
  public void setTrackLineColumn(boolean trackLineColumn) {
    this.trackLineColumn = trackLineColumn;
  }
}




© 2015 - 2024 Weber Informatics LLC | Privacy Policy