coders/wbmp.c

/*
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%               Read/Write Wireless Bitmap (level 0) Image Format             %
%                                                                             %
%                              Software Design                                %
%                                John Cristy                                  %
%                               January 2000                                  %
%                                                                             %
%                                                                             %
%  Copyright 1999-2010 ImageMagick Studio LLC, a non-profit organization      %
%  dedicated to making software imaging solutions freely available.           %
%                                                                             %
%  You may not use this file except in compliance with the License.  You may  %
%  obtain a copy of the License at                                            %
%                                                                             %
%    http://www.imagemagick.org/script/license.php                            %
%                                                                             %
%  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.                                             %
%                                                                             %
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%
%
*/
/*
  Include declarations.
*/
#include "magick/studio.h"
#include "magick/blob.h"
#include "magick/blob-private.h"
#include "magick/cache.h"
#include "magick/color-private.h"
#include "magick/colormap.h"
#include "magick/colorspace.h"
#include "magick/exception.h"
#include "magick/exception-private.h"
#include "magick/image.h"
#include "magick/image-private.h"
#include "magick/list.h"
#include "magick/magick.h"
#include "magick/memory_.h"
#include "magick/monitor.h"
#include "magick/monitor-private.h"
#include "magick/quantum-private.h"
#include "magick/static.h"
#include "magick/string_.h"
#include "magick/module.h"

/*
  Forward declarations.
*/
static MagickBooleanType
  WriteWBMPImage(const ImageInfo *,Image *);

/*
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%   R e a d W B M P I m a g e                                                 %
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%  ReadWBMPImage() reads a WBMP (level 0) image file and returns it.  It
%  allocates the memory necessary for the new Image structure and returns a
%  pointer to the new image.
%
%  ReadWBMPImage was contributed by Milan Votava <votava@mageo.cz>.
%
%  The format of the ReadWBMPImage method is:
%
%      Image *ReadWBMPImage(const ImageInfo *image_info,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image_info: the image info.
%
%    o exception: return any errors or warnings in this structure.
%
*/

static MagickBooleanType WBMPReadInteger(Image *image,size_t *value)
{
  int
    byte;

  *value=0;
  do
  {
    byte=ReadBlobByte(image);
    if (byte == EOF)
      return(MagickFalse);
    *value<<=7;
    *value|=(unsigned int) (byte & 0x7f);
  } while (byte & 0x80);
  return(MagickTrue);
}

static Image *ReadWBMPImage(const ImageInfo *image_info,
  ExceptionInfo *exception)
{
  Image
    *image;

  int
    byte;

  ssize_t
    y;

  MagickBooleanType
    status;

  register IndexPacket
    *indexes;

  register ssize_t
    x;

  register PixelPacket
    *q;

  unsigned char
    bit;

  unsigned short
    header;

  /*
    Open image file.
  */
  assert(image_info != (const ImageInfo *) NULL);
  assert(image_info->signature == MagickSignature);
  if (image_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
      image_info->filename);
  assert(exception != (ExceptionInfo *) NULL);
  assert(exception->signature == MagickSignature);
  image=AcquireImage(image_info);
  status=OpenBlob(image_info,image,ReadBinaryBlobMode,exception);
  if (status == MagickFalse)
    {
      image=DestroyImageList(image);
      return((Image *) NULL);
    }
  if (ReadBlob(image,2,(unsigned char *) &header) == 0)
    ThrowReaderException(CorruptImageError,"ImproperImageHeader");
  if (header != 0)
    ThrowReaderException(CoderError,"OnlyLevelZerofilesSupported");
  /*
    Initialize image structure.
  */
  if (WBMPReadInteger(image,&image->columns) == MagickFalse)
    ThrowReaderException(CorruptImageError,"CorruptWBMPimage");
  if (WBMPReadInteger(image,&image->rows) == MagickFalse)
    ThrowReaderException(CorruptImageError,"CorruptWBMPimage");
  if ((image->columns == 0) || (image->rows == 0))
    ThrowReaderException(CorruptImageError,"ImproperImageHeader");
  if (DiscardBlobBytes(image,image->offset) == MagickFalse)
    ThrowFileException(exception,CorruptImageError,"UnexpectedEndOfFile",
      image->filename);
  if (AcquireImageColormap(image,2) == MagickFalse)
    ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
  if (image_info->ping != MagickFalse)
    {
      (void) CloseBlob(image);
      return(GetFirstImageInList(image));
    }
  /*
    Convert bi-level image to pixel packets.
  */
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    q=QueueAuthenticPixels(image,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      break;
    indexes=GetAuthenticIndexQueue(image);
    bit=0;
    byte=0;
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if (bit == 0)
        {
          byte=ReadBlobByte(image);
          if (byte == EOF)
            ThrowReaderException(CorruptImageError,"CorruptImage");
        }
      indexes[x]=(IndexPacket) ((byte & (0x01 << (7-bit))) ? 1 : 0);
      bit++;
      if (bit == 8)
        bit=0;
    }
    if (SyncAuthenticPixels(image,exception) == MagickFalse)
      break;
    status=SetImageProgress(image,LoadImageTag,(MagickOffsetType) y,
                image->rows);
    if (status == MagickFalse)
      break;
  }
  (void) SyncImage(image);
  if (EOFBlob(image) != MagickFalse)
    ThrowFileException(exception,CorruptImageError,"UnexpectedEndOfFile",
      image->filename);
  (void) CloseBlob(image);
  return(GetFirstImageInList(image));
}

/*
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%   R e g i s t e r W B M P I m a g e                                         %
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%
%  RegisterWBMPImage() adds attributes for the WBMP image format to
%  the list of supported formats.  The attributes include the image format
%  tag, a method to read and/or write the format, whether the format
%  supports the saving of more than one frame to the same file or blob,
%  whether the format supports native in-memory I/O, and a brief
%  description of the format.
%
%  The format of the RegisterWBMPImage method is:
%
%      size_t RegisterWBMPImage(void)
%
*/
ModuleExport size_t RegisterWBMPImage(void)
{
  MagickInfo
    *entry;

  entry=SetMagickInfo("WBMP");
  entry->decoder=(DecodeImageHandler *) ReadWBMPImage;
  entry->encoder=(EncodeImageHandler *) WriteWBMPImage;
  entry->adjoin=MagickFalse;
  entry->description=ConstantString("Wireless Bitmap (level 0) image");
  entry->module=ConstantString("WBMP");
  (void) RegisterMagickInfo(entry);
  return(MagickImageCoderSignature);
}

/*
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%   U n r e g i s t e r W B M P I m a g e                                     %
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%
%  UnregisterWBMPImage() removes format registrations made by the
%  WBMP module from the list of supported formats.
%
%  The format of the UnregisterWBMPImage method is:
%
%      UnregisterWBMPImage(void)
%
*/
ModuleExport void UnregisterWBMPImage(void)
{
  (void) UnregisterMagickInfo("WBMP");
}

/*
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%   W r i t e W B M P I m a g e                                               %
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  WriteWBMPImage() writes an image to a file in the Wireless Bitmap
%  (level 0) image format.
%
%  WriteWBMPImage was contributed by Milan Votava <votava@mageo.cz>.
%
%  The format of the WriteWBMPImage method is:
%
%      MagickBooleanType WriteWBMPImage(const ImageInfo *image_info,
%        Image *image)
%
%  A description of each parameter follows.
%
%    o image_info: the image info.
%
%    o image:  The image.
%
%
*/

static void WBMPWriteInteger(Image *image,const size_t value)
{
  int
    bits,
    flag,
    n;

  register ssize_t
    i;

  unsigned char
    buffer[5],
    octet;

  n=1;
  bits=28;
  flag=MagickFalse;
  for (i=4; i >= 0; i--)
  {
    octet=(unsigned char) ((value >> bits) & 0x7f);
    if ((flag == 0) && (octet != 0))
      {
        flag=MagickTrue;
        n=i+1;
      }
    buffer[4-i]=octet | (i && (flag || octet))*(0x01 << 7);
    bits-=7;
  }
  (void) WriteBlob(image,(size_t) n,buffer+5-n);
}

static MagickBooleanType WriteWBMPImage(const ImageInfo *image_info,
  Image *image)
{
  ssize_t
    y;

  MagickBooleanType
    status;

  register const IndexPacket
    *indexes;

  register const PixelPacket
    *p;

  register ssize_t
    x;

  unsigned char
    bit,
    byte;

  /*
    Open output image file.
  */
  assert(image_info != (const ImageInfo *) NULL);
  assert(image_info->signature == MagickSignature);
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  status=OpenBlob(image_info,image,WriteBinaryBlobMode,&image->exception);
  if (status == MagickFalse)
    return(status);
  if (image->colorspace != RGBColorspace)
    (void) TransformImageColorspace(image,RGBColorspace);
  /*
    Convert image to a bi-level image.
  */
  (void) SetImageType(image,BilevelType);
  (void) WriteBlobMSBShort(image,0);
  WBMPWriteInteger(image,image->columns);
  WBMPWriteInteger(image,image->rows);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    p=GetVirtualPixels(image,0,y,image->columns,1,&image->exception);
    if (p == (const PixelPacket *) NULL)
      break;
    indexes=GetVirtualIndexQueue(image);
    bit=0;
    byte=0;
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if (PixelIntensity(p) >= ((MagickRealType) QuantumRange/2.0))
        byte|=0x1 << (7-bit);
      bit++;
      if (bit == 8)
        {
          (void) WriteBlobByte(image,byte);
          bit=0;
          byte=0;
        }
      p++;
    }
    if (bit != 0)
      (void) WriteBlobByte(image,byte);
    status=SetImageProgress(image,SaveImageTag,(MagickOffsetType) y,
                image->rows);
    if (status == MagickFalse)
      break;
  }
  (void) CloseBlob(image);
  return(MagickTrue);
}