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) (((size_t) (alpha) >> (size_t) (i)) & 0x01)
  94 #define SetBit(i,set) SetPixelIndex(image,((set) != 0 ? \
  95   (size_t) GetPixelIndex(image,q) | (one << (size_t) (i)) : \
  96   (size_t) GetPixelIndex(image,q) & ~(one << (size_t) (i))),q)
  97
  98   Image
  99     *image,
 100     *watermark;
 101
 102   ImageInfo
 103     *read_info;
 104
 105   int
 106     c;
 107
 108   MagickBooleanType
 109     status;
 110
 111   PixelInfo
 112     pixel;
 113
 114   register Quantum
 115     *q;
 116
 117   register ssize_t
 118     x;
 119
 120   size_t
 121     depth,
 122     one;
 123
 124   ssize_t
 125     i,
 126     j,
 127     k,
 128     y;
 129
 130   /*
 131     Initialize Image structure.
 132   */
 133   assert(image_info != (const ImageInfo *) NULL);
 134   assert(image_info->signature == MagickSignature);
 135   if (image_info->debug != MagickFalse)
 136     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
 137       image_info->filename);
 138   assert(exception != (ExceptionInfo *) NULL);
 139   assert(exception->signature == MagickSignature);
 140   one=1;
 141   image=AcquireImage(image_info,exception);
 142   if ((image->columns == 0) || (image->rows == 0))
 143     ThrowReaderException(OptionError,"MustSpecifyImageSize");
 144   read_info=CloneImageInfo(image_info);
 145   SetImageInfoBlob(read_info,(void *) NULL,0);
 146   *read_info->magick='\0';
 147   watermark=ReadImage(read_info,exception);
 148   read_info=DestroyImageInfo(read_info);
 149   if (watermark == (Image *) NULL)
 150     return((Image *) NULL);
 151   watermark->depth=MAGICKCORE_QUANTUM_DEPTH;
 152   if (AcquireImageColormap(image,MaxColormapSize,exception) == MagickFalse)
 153     ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
 154   if (image_info->ping != MagickFalse)
 155     {
 156       (void) CloseBlob(image);
 157       return(GetFirstImageInList(image));
 158     }
 159   status=SetImageExtent(image,image->columns,image->rows,exception);
 160   if (status == MagickFalse)
 161     return(DestroyImageList(image));
 162   /*
 163     Get hidden watermark from low-order bits of image.
 164   */
 165   c=0;
 166   i=0;
 167   j=0;
 168   i=(ssize_t) (watermark->depth-1);
 169   depth=watermark->depth;
 170   for (k=image->offset; (i >= 0) && (j < (ssize_t) depth); i--)
 171   {
 172     for (y=0; (y < (ssize_t) image->rows) && (j < (ssize_t) depth); y++)
 173     {
 174       x=0;
 175       for ( ; (x < (ssize_t) image->columns) && (j < (ssize_t) depth); x++)
 176       {
 177         if ((k/(ssize_t) watermark->columns) >= (ssize_t) watermark->rows)
 178           break;
 179         (void) GetOneVirtualPixelInfo(watermark,UndefinedVirtualPixelMethod,
 180           k % (ssize_t) watermark->columns,k/(ssize_t) watermark->columns,
 181           &pixel,exception);
 182         q=GetAuthenticPixels(image,x,y,1,1,exception);
 183         if (q == (Quantum *) NULL)
 184           break;
 185         switch (c)
 186         {
 187           case 0:
 188           {
 189             SetBit(i,GetBit(pixel.red,j));
 190             break;
 191           }
 192           case 1:
 193           {
 194             SetBit(i,GetBit(pixel.green,j));
 195             break;
 196           }
 197           case 2:
 198           {
 199             SetBit(i,GetBit(pixel.blue,j));
 200             break;
 201           }
 202         }
 203         if (SyncAuthenticPixels(image,exception) == MagickFalse)
 204           break;
 205         c++;
 206         if (c == 3)
 207           c=0;
 208         k++;
 209         if (k == (ssize_t) (watermark->columns*watermark->columns))
 210           k=0;
 211         if (k == image->offset)
 212           j++;
 213       }
 214     }
 215     status=SetImageProgress(image,LoadImagesTag,(MagickOffsetType) i,depth);
 216     if (status == MagickFalse)
 217       break;
 218   }
 219   watermark=DestroyImage(watermark);
 220   (void) SyncImage(image,exception);
 221   return(GetFirstImageInList(image));
 222 }
 223 \f
 224 /*
 225 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 226 %                                                                             %
 227 %                                                                             %
 228 %                                                                             %
 229 %   R e g i s t e r S T E G A N O I m a g e                                   %
 230 %                                                                             %
 231 %                                                                             %
 232 %                                                                             %
 233 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 234 %
 235 %  RegisterSTEGANOImage() adds attributes for the STEGANO image format to
 236 %  the list of supported formats.  The attributes include the image format
 237 %  tag, a method to read and/or write the format, whether the format
 238 %  supports the saving of more than one frame to the same file or blob,
 239 %  whether the format supports native in-memory I/O, and a brief
 240 %  description of the format.
 241 %
 242 %  The format of the RegisterSTEGANOImage method is:
 243 %
 244 %      size_t RegisterSTEGANOImage(void)
 245 %
 246 */
 247 ModuleExport size_t RegisterSTEGANOImage(void)
 248 {
 249   MagickInfo
 250     *entry;
 251
 252   entry=AcquireMagickInfo("STEGANO","STEGANO","Steganographic image");
 253   entry->decoder=(DecodeImageHandler *) ReadSTEGANOImage;
 254   entry->format_type=ImplicitFormatType;
 255   (void) RegisterMagickInfo(entry);
 256   return(MagickImageCoderSignature);
 257 }
 258 \f
 259 /*
 260 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 261 %                                                                             %
 262 %                                                                             %
 263 %                                                                             %
 264 %   U n r e g i s t e r S T E G A N O I m a g e                               %
 265 %                                                                             %
 266 %                                                                             %
 267 %                                                                             %
 268 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 269 %
 270 %  UnregisterSTEGANOImage() removes format registrations made by the
 271 %  STEGANO module from the list of supported formats.
 272 %
 273 %  The format of the UnregisterSTEGANOImage method is:
 274 %
 275 %      UnregisterSTEGANOImage(void)
 276 %
 277 */
 278 ModuleExport void UnregisterSTEGANOImage(void)
 279 {
 280   (void) UnregisterMagickInfo("STEGANO");
 281 }