ANTLRInputStream.h

/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

#pragma once

#include <string_view>

#include "CharStream.h"

namespace antlr4 {

  // Vacuum all input from a stream and then treat it
  // like a string. Can also pass in a string or char[] to use.
  // Input is expected to be encoded in UTF-8 and converted to UTF-32 internally.
  class ANTLR4CPP_PUBLIC ANTLRInputStream : public CharStream {
  protected:
    /// The data being scanned.
    // UTF-32
    std::u32string _data;

    /// 0..n-1 index into string of next char </summary>
    size_t p;

  public:
    /// What is name or source of this char stream?
    std::string name;

    ANTLRInputStream();

    ANTLRInputStream(std::string_view input);

    ANTLRInputStream(const char *data, size_t length);
    ANTLRInputStream(std::istream &stream);

    virtual void load(const std::string &input, bool lenient);
    virtual void load(const char *data, size_t length, bool lenient);
    virtual void load(std::istream &stream, bool lenient);

    virtual void load(const std::string &input) { load(input, false); }
    virtual void load(const char *data, size_t length) { load(data, length, false); }
    virtual void load(std::istream &stream) { load(stream, false); }

    /// Reset the stream so that it's in the same state it was
    /// when the object was created *except* the data array is not
    /// touched.
    virtual void reset();
    virtual void consume() override;
    virtual size_t LA(ssize_t i) override;
    virtual size_t LT(ssize_t i);

    /// <summary>
    /// Return the current input symbol index 0..n where n indicates the
    ///  last symbol has been read.  The index is the index of char to
    ///  be returned from LA(1).
    /// </summary>
    virtual size_t index() override;
    virtual size_t size() override;

    /// <summary>
    /// mark/release do nothing; we have entire buffer </summary>
    virtual ssize_t mark() override;
    virtual void release(ssize_t marker) override;

    /// <summary>
    /// consume() ahead until p==index; can't just set p=index as we must
    ///  update line and charPositionInLine. If we seek backwards, just set p
    /// </summary>
    virtual void seek(size_t index) override;