granicus.if.org Git - imagemagick/blob - coders/stegano.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   6 %              SSSSS  TTTTT  EEEEE   GGGG   AAA   N   N   OOO                 %
   7 %              SS       T    E      G      A   A  NN  N  O   O                %
   8 %               SSS     T    EEE    G  GG  AAAAA  N N N  O   O                %
   9 %                 SS    T    E      G   G  A   A  N  NN  O   O                %
  10 %              SSSSS    T    EEEEE   GGG   A   A  N   N   OOO                 %
  11 %                                                                             %
  12 %                                                                             %
  13 %                       Write A Steganographic Image.                         %
  14 %                                                                             %
  15 %                              Software Design                                %
  16 %                                   Cristy                                    %
  17 %                                 July 1992                                   %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2015 ImageMagick Studio LLC, a non-profit organization      %
  21 %  dedicated to making software imaging solutions freely available.           %
  22 %                                                                             %
  23 %  You may not use this file except in compliance with the License.  You may  %
  24 %  obtain a copy of the License at                                            %
  25 %                                                                             %
  26 %    http://www.imagemagick.org/script/license.php                            %
  27 %                                                                             %
  28 %  Unless required by applicable law or agreed to in writing, software        %
  29 %  distributed under the License is distributed on an "AS IS" BASIS,          %
  30 %  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
  31 %  See the License for the specific language governing permissions and        %
  32 %  limitations under the License.                                             %
  33 %                                                                             %
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35 %
  36 %
  37 */
  38 \f
  39 /*
  40   Include declarations.
  41 */
  42 #include "MagickCore/studio.h"
  43 #include "MagickCore/blob.h"
  44 #include "MagickCore/blob-private.h"
  45 #include "MagickCore/cache.h"
  46 #include "MagickCore/colormap.h"
  47 #include "MagickCore/constitute.h"
  48 #include "MagickCore/exception.h"
  49 #include "MagickCore/exception-private.h"
  50 #include "MagickCore/image.h"
  51 #include "MagickCore/image-private.h"
  52 #include "MagickCore/list.h"
  53 #include "MagickCore/magick.h"
  54 #include "MagickCore/memory_.h"
  55 #include "MagickCore/monitor.h"
  56 #include "MagickCore/monitor-private.h"
  57 #include "MagickCore/pixel-accessor.h"
  58 #include "MagickCore/quantum-private.h"
  59 #include "MagickCore/static.h"
  60 #include "MagickCore/string_.h"
  61 #include "MagickCore/module.h"
  62 \f
  63 /*
  64 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  65 %                                                                             %
  66 %                                                                             %
  67 %                                                                             %
  68 %   R e a d S T E G A N O I m a g e                                           %
  69 %                                                                             %
  70 %                                                                             %
  71 %                                                                             %
  72 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  73 %
  74 %  ReadSTEGANOImage() reads a steganographic image hidden within another
  75 %  image type.  It allocates the memory necessary for the new Image structure
  76 %  and returns a pointer to the new image.
  77 %
  78 %  The format of the ReadSTEGANOImage method is:
  79 %
  80 %      Image *ReadSTEGANOImage(const ImageInfo *image_info,
  81 %        ExceptionInfo *exception)
  82 %
  83 %  A description of each parameter follows:
  84 %
  85 %    o image_info: the image info.
  86 %
  87 %    o exception: return any errors or warnings in this structure.
  88 %
  89 */
  90 static Image *ReadSTEGANOImage(const ImageInfo *image_info,
  91   ExceptionInfo *exception)
  92 {
  93 #define GetBit(alpha,i) MagickMin((((size_t) (alpha) >> (size_t) \
  94   (i)) & 0x01),16)
  95 #define SetBit(i,set) SetPixelIndex(image,((set) != 0 ? \
  96   (size_t) GetPixelIndex(image,q) | (one << (size_t) (i)) : \
  97   (size_t) GetPixelIndex(image,q) & ~(one << (size_t) (i))),q)
  98
  99   Image
 100     *image,
 101     *watermark;
 102
 103   ImageInfo
 104     *read_info;
 105
 106   int
 107     c;
 108
 109   MagickBooleanType
 110     status;
 111
 112   PixelInfo
 113     pixel;
 114
 115   register Quantum
 116     *q;
 117
 118   register ssize_t
 119     x;
 120
 121   size_t
 122     depth,
 123     one;
 124
 125   ssize_t
 126     i,
 127     j,
 128     k,
 129     y;
 130
 131   /*
 132     Initialize Image structure.
 133   */
 134   assert(image_info != (const ImageInfo *) NULL);
 135   assert(image_info->signature == MagickSignature);
 136   if (image_info->debug != MagickFalse)
 137     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
 138       image_info->filename);
 139   assert(exception != (ExceptionInfo *) NULL);
 140   assert(exception->signature == MagickSignature);
 141   one=1;
 142   image=AcquireImage(image_info,exception);
 143   if ((image->columns == 0) || (image->rows == 0))
 144     ThrowReaderException(OptionError,"MustSpecifyImageSize");
 145   read_info=CloneImageInfo(image_info);
 146   SetImageInfoBlob(read_info,(void *) NULL,0);
 147   *read_info->magick='\0';
 148   watermark=ReadImage(read_info,exception);
 149   read_info=DestroyImageInfo(read_info);
 150   if (watermark == (Image *) NULL)
 151     return((Image *) NULL);
 152   watermark->depth=MAGICKCORE_QUANTUM_DEPTH;
 153   if (AcquireImageColormap(image,MaxColormapSize,exception) == MagickFalse)
 154     ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
 155   if (image_info->ping != MagickFalse)
 156     {
 157       (void) CloseBlob(image);
 158       return(GetFirstImageInList(image));
 159     }
 160   status=SetImageExtent(image,image->columns,image->rows,exception);
 161   if (status == MagickFalse)
 162     return(DestroyImageList(image));
 163   /*
 164     Get hidden watermark from low-order bits of image.
 165   */
 166   c=0;
 167   i=0;
 168   j=0;
 169   i=(ssize_t) (watermark->depth-1);
 170   depth=watermark->depth;
 171   for (k=image->offset; (i >= 0) && (j < (ssize_t) depth); i--)
 172   {
 173     for (y=0; (y < (ssize_t) image->rows) && (j < (ssize_t) depth); y++)
 174     {
 175       x=0;
 176       for ( ; (x < (ssize_t) image->columns) && (j < (ssize_t) depth); x++)
 177       {
 178         if ((k/(ssize_t) watermark->columns) >= (ssize_t) watermark->rows)
 179           break;
 180         (void) GetOneVirtualPixelInfo(watermark,UndefinedVirtualPixelMethod,
 181           k % (ssize_t) watermark->columns,k/(ssize_t) watermark->columns,
 182           &pixel,exception);
 183         q=GetAuthenticPixels(image,x,y,1,1,exception);
 184         if (q == (Quantum *) NULL)
 185           break;
 186         switch (c)
 187         {
 188           case 0:
 189           {
 190             SetBit(i,GetBit(pixel.red,j));
 191             break;
 192           }
 193           case 1:
 194           {
 195             SetBit(i,GetBit(pixel.green,j));
 196             break;
 197           }
 198           case 2:
 199           {
 200             SetBit(i,GetBit(pixel.blue,j));
 201             break;
 202           }
 203         }
 204         if (SyncAuthenticPixels(image,exception) == MagickFalse)
 205           break;
 206         c++;
 207         if (c == 3)
 208           c=0;
 209         k++;
 210         if (k == (ssize_t) (watermark->columns*watermark->columns))
 211           k=0;
 212         if (k == image->offset)
 213           j++;
 214       }
 215     }
 216     status=SetImageProgress(image,LoadImagesTag,(MagickOffsetType) i,depth);
 217     if (status == MagickFalse)
 218       break;
 219   }
 220   watermark=DestroyImage(watermark);
 221   (void) SyncImage(image,exception);
 222   return(GetFirstImageInList(image));
 223 }
 224 \f
 225 /*
 226 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 227 %                                                                             %
 228 %                                                                             %
 229 %                                                                             %
 230 %   R e g i s t e r S T E G A N O I m a g e                                   %
 231 %                                                                             %
 232 %                                                                             %
 233 %                                                                             %
 234 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 235 %
 236 %  RegisterSTEGANOImage() adds attributes for the STEGANO image format to
 237 %  the list of supported formats.  The attributes include the image format
 238 %  tag, a method to read and/or write the format, whether the format
 239 %  supports the saving of more than one frame to the same file or blob,
 240 %  whether the format supports native in-memory I/O, and a brief
 241 %  description of the format.
 242 %
 243 %  The format of the RegisterSTEGANOImage method is:
 244 %
 245 %      size_t RegisterSTEGANOImage(void)
 246 %
 247 */
 248 ModuleExport size_t RegisterSTEGANOImage(void)
 249 {
 250   MagickInfo
 251     *entry;
 252
 253   entry=SetMagickInfo("STEGANO");
 254   entry->decoder=(DecodeImageHandler *) ReadSTEGANOImage;
 255   entry->format_type=ImplicitFormatType;
 256   entry->description=ConstantString("Steganographic image");
 257   entry->module=ConstantString("STEGANO");
 258   (void) RegisterMagickInfo(entry);
 259   return(MagickImageCoderSignature);
 260 }
 261 \f
 262 /*
 263 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 264 %                                                                             %
 265 %                                                                             %
 266 %                                                                             %
 267 %   U n r e g i s t e r S T E G A N O I m a g e                               %
 268 %                                                                             %
 269 %                                                                             %
 270 %                                                                             %
 271 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 272 %
 273 %  UnregisterSTEGANOImage() removes format registrations made by the
 274 %  STEGANO module from the list of supported formats.
 275 %
 276 %  The format of the UnregisterSTEGANOImage method is:
 277 %
 278 %      UnregisterSTEGANOImage(void)
 279 %
 280 */
 281 ModuleExport void UnregisterSTEGANOImage(void)
 282 {
 283   (void) UnregisterMagickInfo("STEGANO");
 284 }