/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%                         GGGG  RRRR    AAA   Y   Y                           %
%                        G      R   R  A   A   Y Y                            %
%                        G  GG  RRRR   AAAAA    Y                             %
%                        G   G  R R    A   A    Y                             %
%                         GGG   R  R   A   A    Y                             %
%                                                                             %
%                                                                             %
%                    Read/Write RAW Gray Image Format                         %
%                                                                             %
%                              Software Design                                %
%                                   Cristy                                    %
%                                 July 1992                                   %
%                                                                             %
%                                                                             %
%  Copyright 1999-2016 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.                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
*/

/*
  Include declarations.
*/
#include "MagickCore/studio.h"
#include "MagickCore/attribute.h"
#include "MagickCore/blob.h"
#include "MagickCore/blob-private.h"
#include "MagickCore/cache.h"
#include "MagickCore/colorspace.h"
#include "MagickCore/colorspace-private.h"
#include "MagickCore/constitute.h"
#include "MagickCore/exception.h"
#include "MagickCore/exception-private.h"
#include "MagickCore/image.h"
#include "MagickCore/image-private.h"
#include "MagickCore/list.h"
#include "MagickCore/magick.h"
#include "MagickCore/memory_.h"
#include "MagickCore/monitor.h"
#include "MagickCore/monitor-private.h"
#include "MagickCore/pixel.h"
#include "MagickCore/pixel-accessor.h"
#include "MagickCore/quantum-private.h"
#include "MagickCore/static.h"
#include "MagickCore/statistic.h"
#include "MagickCore/string_.h"
#include "MagickCore/module.h"

/*
  Forward declarations.
*/
static MagickBooleanType
  WriteGRAYImage(const ImageInfo *,Image *,ExceptionInfo *);

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   R e a d G R A Y I m a g e                                                 %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  ReadGRAYImage() reads an image of raw grayscale samples and returns
%  it.  It allocates the memory necessary for the new Image structure and
%  returns a pointer to the new image.
%
%  The format of the ReadGRAYImage method is:
%
%      Image *ReadGRAYImage(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 Image *ReadGRAYImage(const ImageInfo *image_info,
  ExceptionInfo *exception)
{
  const unsigned char
    *pixels;

  Image
    *canvas_image,
    *image;

  MagickBooleanType
    status;

  MagickOffsetType
    scene;

  QuantumInfo
    *quantum_info;

  QuantumType
    quantum_type;

  size_t
    length;

  ssize_t
    count,
    y;

  /*
    Open image file.
  */
  assert(image_info != (const ImageInfo *) NULL);
  assert(image_info->signature == MagickCoreSignature);
  if (image_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
      image_info->filename);
  assert(exception != (ExceptionInfo *) NULL);
  assert(exception->signature == MagickCoreSignature);
  image=AcquireImage(image_info,exception);
  if ((image->columns == 0) || (image->rows == 0))
    ThrowReaderException(OptionError,"MustSpecifyImageSize");
  status=OpenBlob(image_info,image,ReadBinaryBlobMode,exception);
  if (status == MagickFalse)
    {
      image=DestroyImageList(image);
      return((Image *) NULL);
    }
  if (DiscardBlobBytes(image,(size_t) image->offset) == MagickFalse)
    ThrowFileException(exception,CorruptImageError,"UnexpectedEndOfFile",
      image->filename);
  /*
    Create virtual canvas to support cropping (i.e. image.gray[100x100+10+20]).
  */
  SetImageColorspace(image,GRAYColorspace,exception);
  canvas_image=CloneImage(image,image->extract_info.width,1,MagickFalse,
    exception);
  (void) SetImageVirtualPixelMethod(canvas_image,BlackVirtualPixelMethod,
    exception);
  quantum_type=GrayQuantum;
  quantum_info=AcquireQuantumInfo(image_info,canvas_image);
  if (quantum_info == (QuantumInfo *) NULL)
    ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
  pixels=(const unsigned char *) NULL;
  if (image_info->number_scenes != 0)
    while (image->scene < image_info->scene)
    {
      /*
        Skip to next image.
      */
      image->scene++;
      length=GetQuantumExtent(canvas_image,quantum_info,quantum_type);
      for (y=0; y < (ssize_t) image->rows; y++)
      {
        pixels=(const unsigned char *) ReadBlobStream(image,length,
          GetQuantumPixels(quantum_info),&count);
        if (count != (ssize_t) length)
          break;
      }
    }
  scene=0;
  count=0;
  length=0;
  do
  {
    /*
      Read pixels to virtual canvas image then push to image.
    */
    if ((image_info->ping != MagickFalse) && (image_info->number_scenes != 0))
      if (image->scene >= (image_info->scene+image_info->number_scenes-1))
        break;
    status=SetImageExtent(image,image->columns,image->rows,exception);
    if (status == MagickFalse)
      return(DestroyImageList(image));
    SetImageColorspace(image,GRAYColorspace,exception);
    if (scene == 0)
      {
        length=GetQuantumExtent(canvas_image,quantum_info,quantum_type);
        pixels=(const unsigned char *) ReadBlobStream(image,length,
          GetQuantumPixels(quantum_info),&count);
      }
    for (y=0; y < (ssize_t) image->extract_info.height; y++)
    {
      register const Quantum
        *magick_restrict p;

      register ssize_t
        x;

      register Quantum
        *magick_restrict q;

      if (count != (ssize_t) length)
        {
          ThrowFileException(exception,CorruptImageError,
            "UnexpectedEndOfFile",image->filename);
          break;
        }
      q=GetAuthenticPixels(canvas_image,0,0,canvas_image->columns,1,exception);
      if (q == (Quantum *) NULL)
        break;
      length=ImportQuantumPixels(canvas_image,(CacheView *) NULL,quantum_info,
        quantum_type,pixels,exception);
      if (SyncAuthenticPixels(canvas_image,exception) == MagickFalse)
        break;
      if (((y-image->extract_info.y) >= 0) && 
          ((y-image->extract_info.y) < (ssize_t) image->rows))
        {
          p=GetVirtualPixels(canvas_image,canvas_image->extract_info.x,0,
            image->columns,1,exception);
          q=QueueAuthenticPixels(image,0,y-image->extract_info.y,image->columns,
            1,exception);
          if ((p == (const Quantum *) NULL) ||
              (q == (Quantum *) NULL))
            break;
          for (x=0; x < (ssize_t) image->columns; x++)
          {
            SetPixelGray(image,GetPixelGray(canvas_image,p),q);
            p+=GetPixelChannels(canvas_image);
            q+=GetPixelChannels(image);
          }
          if (SyncAuthenticPixels(image,exception) == MagickFalse)
            break;
        }
      if (image->previous == (Image *) NULL)
        {
          status=SetImageProgress(image,LoadImageTag,(MagickOffsetType) y,
            image->rows);
          if (status == MagickFalse)
            break;
        }
      pixels=(const unsigned char *) ReadBlobStream(image,length,
        GetQuantumPixels(quantum_info),&count);
    }
    SetQuantumImageType(image,quantum_type);
    /*
      Proceed to next image.
    */
    if (image_info->number_scenes != 0)
      if (image->scene >= (image_info->scene+image_info->number_scenes-1))
        break;
    if (count == (ssize_t) length)
      {
        /*
          Allocate next image structure.
        */
        AcquireNextImage(image_info,image,exception);
        if (GetNextImageInList(image) == (Image *) NULL)
          {
            image=DestroyImageList(image);
            return((Image *) NULL);
          }
        image=SyncNextImageInList(image);
        status=SetImageProgress(image,LoadImagesTag,TellBlob(image),
          GetBlobSize(image));
        if (status == MagickFalse)
          break;
      }
    scene++;
  } while (count == (ssize_t) length);
  quantum_info=DestroyQuantumInfo(quantum_info);
  canvas_image=DestroyImage(canvas_image);
  (void) CloseBlob(image);
  return(GetFirstImageInList(image));
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   R e g i s t e r G R A Y I m a g e                                         %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  RegisterGRAYImage() adds attributes for the GRAY 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 RegisterGRAYImage method is:
%
%      size_t RegisterGRAYImage(void)
%
*/
ModuleExport size_t RegisterGRAYImage(void)
{
  MagickInfo
    *entry;

  entry=AcquireMagickInfo("GRAY","GRAY","Raw gray samples");
  entry->decoder=(DecodeImageHandler *) ReadGRAYImage;
  entry->encoder=(EncodeImageHandler *) WriteGRAYImage;
  entry->flags|=CoderRawSupportFlag;
  entry->flags|=CoderEndianSupportFlag;
  (void) RegisterMagickInfo(entry);
  return(MagickImageCoderSignature);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   U n r e g i s t e r G R A Y I m a g e                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  UnregisterGRAYImage() removes format registrations made by the
%  GRAY module from the list of supported formats.
%
%  The format of the UnregisterGRAYImage method is:
%
%      UnregisterGRAYImage(void)
%
*/
ModuleExport void UnregisterGRAYImage(void)
{
  (void) UnregisterMagickInfo("GRAY");
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   W r i t e G R A Y I m a g e                                               %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  WriteGRAYImage() writes an image to a file as gray scale intensity
%  values.
%
%  The format of the WriteGRAYImage method is:
%
%      MagickBooleanType WriteGRAYImage(const ImageInfo *image_info,
%        Image *image,ExceptionInfo *exception)
%
%  A description of each parameter follows.
%
%    o image_info: the image info.
%
%    o image:  The image.
%
%    o exception: return any errors or warnings in this structure.
%
*/
static MagickBooleanType WriteGRAYImage(const ImageInfo *image_info,
  Image *image,ExceptionInfo *exception)
{
  MagickBooleanType
    status;

  MagickOffsetType
    scene;

  QuantumInfo
    *quantum_info;

  QuantumType
    quantum_type;

  size_t
    length;

  ssize_t
    count,
    y;

  unsigned char
    *pixels;

  /*
    Open output image file.
  */
  assert(image_info != (const ImageInfo *) NULL);
  assert(image_info->signature == MagickCoreSignature);
  assert(image != (Image *) NULL);
  assert(image->signature == MagickCoreSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  assert(exception != (ExceptionInfo *) NULL);
  assert(exception->signature == MagickCoreSignature);
  status=OpenBlob(image_info,image,WriteBinaryBlobMode,exception);
  if (status == MagickFalse)
    return(status);
  scene=0;
  do
  {
    /*
      Write grayscale pixels.
    */
    (void) TransformImageColorspace(image,sRGBColorspace,exception);
    quantum_type=GrayQuantum;
    quantum_info=AcquireQuantumInfo(image_info,image);
    if (quantum_info == (QuantumInfo *) NULL)
      ThrowWriterException(ResourceLimitError,"MemoryAllocationFailed");
    pixels=(unsigned char *) GetQuantumPixels(quantum_info);
    for (y=0; y < (ssize_t) image->rows; y++)
    {
      register const Quantum
        *magick_restrict p;

      p=GetVirtualPixels(image,0,y,image->columns,1,exception);
      if (p == (const Quantum *) NULL)
        break;
      length=ExportQuantumPixels(image,(CacheView *) NULL,quantum_info,
        quantum_type,pixels,exception);
      count=WriteBlob(image,length,pixels);
      if (count != (ssize_t) length)
        break;
      if (image->previous == (Image *) NULL)
        {
          status=SetImageProgress(image,SaveImageTag,(MagickOffsetType) y,
            image->rows);
          if (status == MagickFalse)
            break;
        }
    }
    quantum_info=DestroyQuantumInfo(quantum_info);
    if (GetNextImageInList(image) == (Image *) NULL)
      break;
    image=SyncNextImageInList(image);
    status=SetImageProgress(image,SaveImagesTag,scene++,
      GetImageListLength(image));
    if (status == MagickFalse)
      break;
  } while (image_info->adjoin != MagickFalse);
  (void) CloseBlob(image);
  return(MagickTrue);
}