javax.imageio.stream.ImageInputStream#length ( )源码实例Demo

下面列出了javax.imageio.stream.ImageInputStream#length ( ) 实例代码,或者点击链接到github查看源代码,也可以在右侧发表评论。

源代码1 项目: webp-imageio   文件: WebPImageReaderSpi.java
@Override
public boolean canDecodeInput( Object source ) throws IOException {
  if ( !( source instanceof ImageInputStream ) ) {
    return false;
  }

  ImageInputStream stream = ( ImageInputStream ) source;
  byte[] b = new byte[ 4 ];
  ByteOrder oldByteOrder = stream.getByteOrder();
  stream.mark();
  stream.setByteOrder( ByteOrder.LITTLE_ENDIAN );

  try {
    stream.readFully( b );
    if ( !Arrays.equals( b, RIFF ) ) {
      return false;
    }
    long chunkLength = stream.readUnsignedInt();
    long streamLength = stream.length();
    if ( streamLength != -1 && streamLength != chunkLength + 8 ) {
      return false;
    }
    stream.readFully( b );
    if ( !Arrays.equals( b, WEBP ) ) {
      return false;
    }

    stream.readFully( b );
    if ( !Arrays.equals( b, VP8_ ) && !Arrays.equals( b, VP8X ) ) {
      return false;
    }
  } finally {
    stream.setByteOrder( oldByteOrder );
    stream.reset();
  }

  return true;
}
 
源代码2 项目: j-webp   文件: WebPReader.java
private void readData() throws IOException {
  if ( fData != null ) {
    return;
  }

  ImageInputStream input = ( ImageInputStream ) getInput();
  long length = input.length();
  if ( length > Integer.MAX_VALUE ) {
    throw new IOException( "Cannot read image of size " + length );
  }

  if ( input.getStreamPosition() != 0L ) {
    if ( isSeekForwardOnly() ) {
      throw new IOException();
    }
    else {
      input.seek( 0 );
    }
  }

  byte[] data;
  if ( length > 0 ) {
    data = new byte[ ( int ) length ];
    input.readFully( data );
  }
  else {
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    byte[] buffer = new byte[ 4096 ];
    int bytesRead;
    while ( ( bytesRead = input.read( buffer ) ) != -1 ) {
      out.write( buffer, 0, bytesRead );
    }
    out.close();
    data = out.toByteArray();
  }
  fData = data;
}
 
源代码3 项目: j-webp   文件: WebPImageReaderSpi.java
@Override
public boolean canDecodeInput( Object source ) throws IOException {
  if ( !( source instanceof ImageInputStream ) ) {
    return false;
  }

  ImageInputStream stream = ( ImageInputStream ) source;
  byte[] b = new byte[ 4 ];
  ByteOrder oldByteOrder = stream.getByteOrder();
  stream.mark();
  stream.setByteOrder( ByteOrder.LITTLE_ENDIAN );

  try {
    stream.readFully( b );
    if ( !Arrays.equals( b, RIFF ) ) {
      return false;
    }
    long chunkLength = stream.readUnsignedInt();
    long streamLength = stream.length();
    if ( streamLength != -1 && streamLength != chunkLength + 8 ) {
      return false;
    }
    stream.readFully( b );
    if ( !Arrays.equals( b, WEBP ) ) {
      return false;
    }

    stream.readFully( b );
    if ( !Arrays.equals( b, VP8_ ) && !Arrays.equals( b, VP8L ) && !Arrays.equals( b, VP8X ) ) {
      return false;
    }
  } finally {
    stream.setByteOrder( oldByteOrder );
    stream.reset();
  }

  return true;
}
 
源代码4 项目: webp-imageio   文件: WebPReader.java
private void readData() throws IOException {
  if ( fData != null ) {
    return;
  }

  ImageInputStream input = ( ImageInputStream ) getInput();
  long length = input.length();
  if ( length > Integer.MAX_VALUE ) {
    throw new IOException( "Cannot read image of size " + length );
  }

  if ( input.getStreamPosition() != 0L ) {
    if ( isSeekForwardOnly() ) {
      throw new IOException();
    }
    else {
      input.seek( 0 );
    }
  }

  byte[] data;
  if ( length > 0 ) {
    data = new byte[ ( int ) length ];
    input.readFully( data );
  }
  else {
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    byte[] buffer = new byte[ 4096 ];
    int bytesRead;
    while ( ( bytesRead = input.read( buffer ) ) != -1 ) {
      out.write( buffer, 0, bytesRead );
    }
    out.close();
    data = out.toByteArray();
  }
  fData = data;
}
 
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码6 项目: dragonwell8_jdk   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码7 项目: TencentKona-8   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码8 项目: jdk8u60   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码9 项目: JDKSourceCode1.8   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码10 项目: openjdk-jdk8u   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码11 项目: openjdk-jdk8u-backup   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码12 项目: Bytecoder   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码13 项目: openjdk-jdk9   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码14 项目: jdk8u-jdk   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码15 项目: hottub   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码16 项目: openjdk-8-source   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码17 项目: openjdk-8   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码18 项目: jdk8u_jdk   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码19 项目: jdk8u-jdk   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}
 
源代码20 项目: jdk8u-dev-jdk   文件: WBMPImageReaderSpi.java
public boolean canDecodeInput(Object source) throws IOException {
    if (!(source instanceof ImageInputStream)) {
        return false;
    }

    ImageInputStream stream = (ImageInputStream)source;

    stream.mark();
    try {
        int type = stream.readByte();   // TypeField
        int fixHeaderField = stream.readByte();
        // check WBMP "header"
        if (type != 0 || fixHeaderField != 0) {
            // while WBMP reader does not support ext WBMP headers
            return false;
        }

        int width = ReaderUtil.readMultiByteInteger(stream);
        int height = ReaderUtil.readMultiByteInteger(stream);
        // check image dimension
        if (width <= 0 || height <= 0) {
            return false;
        }

        long dataLength = stream.length();
        if (dataLength == -1) {
            // We can't verify that amount of data in the stream
            // corresponds to image dimension because we do not know
            // the length of the data stream.
            // Assuming that wbmp image are used for mobile devices,
            // let's introduce an upper limit for image dimension.
            // In case if exact amount of raster data is unknown,
            // let's reject images with dimension above the limit.
            return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
        }

        dataLength -= stream.getStreamPosition();

        long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

        return (dataLength == scanSize * height);
    } finally {
        stream.reset();
    }
}