content: /*
   * Copyright 2014-2025 Real Logic Limited.
   *
   * 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
   *
   * https://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 org.agrona;
  
  /**
   * View over a {@link DirectBuffer} which contains an ASCII string for a given range.
   */
  public class AsciiSequenceView implements CharSequence
  {
      private DirectBuffer buffer;
      private int offset;
      private int length;
  
      /**
       * Default constructor.
       */
      public AsciiSequenceView()
      {
      }
  
      /**
       * Construct a view over a {@link DirectBuffer} from an offset for a given length.
       *
       * @param buffer containing the ASCII sequence.
       * @param offset at which the ASCII sequence begins.
       * @param length of the ASCII sequence in bytes.
       */
      public AsciiSequenceView(final DirectBuffer buffer, final int offset, final int length)
      {
          this.buffer = buffer;
          this.offset = offset;
          this.length = length;
      }
  
      /**
       * {@inheritDoc}
       */
      public int length()
      {
          return length;
      }
  
      /**
       * Gets the underlying buffer which this is a view over.
       *
       * @return the underlying buffer which this is a view over.
       */
      public DirectBuffer buffer()
      {
          return buffer;
      }
  
      /**
       * Gets the offset into the underlying buffer.
       *
       * @return the offset into the underlying buffer.
       */
      public int offset()
      {
          return offset;
      }
  
      /**
       * {@inheritDoc}
       */
      public char charAt(final int index)
      {
          if (index < 0 || index >= length)
          {
              throw new StringIndexOutOfBoundsException("index=" + index + " length=" + length);
          }
  
          return (char)buffer.getByte(offset + index);
      }
  
      /**
       * {@inheritDoc}
       */
      public AsciiSequenceView subSequence(final int start, final int end)
      {
          if (start < 0)
          {
              throw new StringIndexOutOfBoundsException("start=" + start);
          }
  
          if (end > length)
          {
              throw new StringIndexOutOfBoundsException("end=" + end + " length=" + length);
          }
  
          if (end - start < 0)
          {
              throw new StringIndexOutOfBoundsException("start=" + start + " end=" + end);
          }
  
          return new AsciiSequenceView(buffer, offset + start, end - start);
      }
  
      /**
       * Wrap a range of an existing buffer containing an ASCII sequence.
       *
       * @param buffer containing the ASCII sequence.
       * @param offset at which the ASCII sequence begins.
       * @param length of the ASCII sequence in bytes.
       * @return this for a fluent API.
       */
      public AsciiSequenceView wrap(final DirectBuffer buffer, final int offset, final int length)
      {
          this.buffer = buffer;
          this.offset = offset;
          this.length = length;
  
          return this;
      }
  
      /**
       * Reset the view to null.
       */
      public void reset()
      {
          this.buffer = null;
          this.offset = 0;
          this.length = 0;
      }
  
      /**
       * Copy the bytes from a view into a provided buffer.
       *
       * @param dstBuffer into which the bytes will be copied.
       * @param dstOffset offset in the destination buffer to begin the copy.
       * @return the number of bytes copied.
       */
      public int getBytes(final MutableDirectBuffer dstBuffer, final int dstOffset)
      {
          if (null == buffer || length <= 0)
          {
              return 0;
          }
  
          dstBuffer.putBytes(dstOffset, buffer, offset, length);
  
          return length;
      }
  
      /**
       * {@inheritDoc}
       */
      public String toString()
      {
          if (null == buffer || length <= 0)
          {
              return "";
          }
  
          return buffer.getStringWithoutLengthAscii(offset, length);
      }
  }
  