root / ImageMagick / branches / ImageMagick-6.3.5 / magick / blob.c

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%                         BBBB   L       OOO   BBBB                           %
%                         B   B  L      O   O  B   B                          %
%                         BBBB   L      O   O  BBBB                           %
%                         B   B  L      O   O  B   B                          %
%                         BBBB   LLLLL   OOO   BBBB                           %
%                                                                             %
%                                                                             %
%                    ImageMagick Binary Large OBjectS Methods                 %
%                                                                             %
%                              Software Design                                %
%                                John Cristy                                  %
%                                 July 1999                                   %
%                                                                             %
%                                                                             %
%  Copyright 1999-2007 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 "magick/studio.h"
#include "magick/blob.h"
#include "magick/blob-private.h"
#include "magick/cache.h"
#include "magick/client.h"
#include "magick/constitute.h"
#include "magick/delegate.h"
#include "magick/exception.h"
#include "magick/exception-private.h"
#include "magick/image-private.h"
#include "magick/list.h"
#include "magick/log.h"
#include "magick/magick.h"
#include "magick/memory_.h"
#include "magick/resource_.h"
#include "magick/semaphore.h"
#include "magick/string_.h"
#include "magick/utility.h"
#if defined(HAVE_MMAP_FILEIO) && !defined(__WINDOWS__)
# include <sys/mman.h>
#endif
#if defined(HasZLIB)
#include "zlib.h"
#endif
#if defined(HasBZLIB)
#include "bzlib.h"
#endif

/*
  Define declarations.
*/
#if defined(HAVE_FSEEKO)
# define fseek  fseeko
# define ftell  ftello
#endif
#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
# define MAP_ANONYMOUS  MAP_ANON
#endif
#if !defined(MAP_FAILED)
#define MAP_FAILED  ((void *) -1)
#endif
#if !defined(MS_SYNC)
#define MS_SYNC  0x04
#endif

/*
  Typedef declarations.
*/
typedef enum
{
  UndefinedStream,
  FileStream,
  StandardStream,
  PipeStream,
  ZipStream,
  BZipStream,
  FifoStream,
  BlobStream
} StreamType;

struct _BlobInfo
{
  size_t
    length,
    extent,
    quantum;

  MagickBooleanType
    mapped,
    eof;

  MagickOffsetType
    offset;

  MagickSizeType
    size;

  MagickBooleanType
    exempt,
    status,
    temporary;

  StreamType
    type;

  FILE
    *file;

  StreamHandler
    stream;

  unsigned char
    *data;

  MagickBooleanType
    debug;

  SemaphoreInfo
    *semaphore;

  long
    reference_count;

  unsigned long
    signature;
};

/*
  Forward declarations.
*/
static int
  SyncBlob(Image *);

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
+   A t t a c h B l o b                                                       %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  AttachBlob() attaches a blob to the BlobInfo structure.
%
%  The format of the AttachBlob method is:
%
%      void AttachBlob(BlobInfo *blob_info,const void *blob,const size_t length)
%
%  A description of each parameter follows:
%
%    o blob_info: Specifies a pointer to a BlobInfo structure.
%
%    o blob: The address of a character stream in one of the image formats
%      understood by ImageMagick.
%
%    o length: This size_t integer reflects the length in bytes of the blob.
%
*/
MagickExport void AttachBlob(BlobInfo *blob_info,const void *blob,
  const size_t length)
{
  assert(blob_info != (BlobInfo *) NULL);
  if (blob_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
  blob_info->length=length;
  blob_info->extent=length;
  blob_info->quantum=(size_t) MagickMaxBufferSize;
  blob_info->offset=0;
  blob_info->type=BlobStream;
  blob_info->file=(FILE *) NULL;
  blob_info->data=(unsigned char *) blob;
  blob_info->mapped=MagickFalse;
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
+   B l o b T o F i l e                                                       %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  BlobToFile() writes a blob to a file.  It returns MagickFalse if an error
%  occurs otherwise MagickTrue.
%
%  The format of the BlobToFile method is:
%
%       MagickBooleanType BlobToFile(char *filename,const void *blob,
%        const size_t length,ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o filename: Write the blob to this file.
%
%    o blob: The address of a blob.
%
%    o length: This length in bytes of the blob.
%
%    o exception: Return any errors or warnings in this structure.
%
*/

static inline size_t MagickMin(const size_t x,const size_t y)
{
  if (x < y)
    return(x);
  return(y);
}

MagickExport MagickBooleanType BlobToFile(char *filename,const void *blob,
  const size_t length,ExceptionInfo *exception)
{
  int
    file;

  register size_t
    i;

  ssize_t
    count;

  assert(filename != (const char *) NULL);
  (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",filename);
  assert(blob != (const void *) NULL);
  if (*filename == '\0')
    file=AcquireUniqueFileResource(filename);
  else
    file=open(filename,O_RDWR | O_CREAT | O_EXCL | O_BINARY,S_MODE);
  if (file == -1)
    {
      ThrowFileException(exception,BlobError,"UnableToWriteBlob",filename);
      return(MagickFalse);
    }
  for (i=0; i < length; i+=count)
  {
    count=(ssize_t) write(file,(const char *) blob+i,MagickMin(length-i,(size_t)
      SSIZE_MAX));
    if (count <= 0)
      {
        count=0;
        if (errno != EINTR)
          break;
      }
  }
  file=close(file)-1;
  if (i < length)
    {
      ThrowFileException(exception,BlobError,"UnableToWriteBlob",filename);
      return(MagickFalse);
    }
  return(MagickTrue);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   B l o b T o I m a g e                                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  BlobToImage() implements direct to memory image formats.  It returns the
%  blob as an image.
%
%  The format of the BlobToImage method is:
%
%      Image *BlobToImage(const ImageInfo *image_info,const void *blob,
%        const size_t length,ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image_info: The image info.
%
%    o blob: The address of a character stream in one of the image formats
%      understood by ImageMagick.
%
%    o length: This size_t integer reflects the length in bytes of the blob.
%
%    o exception: Return any errors or warnings in this structure.
%
*/
MagickExport Image *BlobToImage(const ImageInfo *image_info,const void *blob,
  const size_t length,ExceptionInfo *exception)
{
  const MagickInfo
    *magick_info;

  Image
    *image;

  ImageInfo
    *blob_info;

  MagickBooleanType
    status;

  assert(image_info != (ImageInfo *) NULL);
  assert(image_info->signature == MagickSignature);
  if (image_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
      image_info->filename);
  assert(exception != (ExceptionInfo *) NULL);
  if ((blob == (const void *) NULL) || (length == 0))
    {
      (void) ThrowMagickException(exception,GetMagickModule(),BlobError,
        "ZeroLengthBlobNotPermitted","`%s'",image_info->filename);
      return((Image *) NULL);
    }
  blob_info=CloneImageInfo(image_info);
  blob_info->blob=(void *) blob;
  blob_info->length=length;
  if (*blob_info->magick == '\0')
    (void) SetImageInfo(blob_info,MagickFalse,exception);
  magick_info=GetMagickInfo(blob_info->magick,exception);
  if (magick_info == (const MagickInfo *) NULL)
    {
      blob_info=DestroyImageInfo(blob_info);
      return((Image *) NULL);
    }
  if (GetMagickBlobSupport(magick_info) != MagickFalse)
    {
      /*
        Native blob support for this image format.
      */
      (void) CopyMagickString(blob_info->filename,image_info->filename,
        MaxTextExtent);
      (void) CopyMagickString(blob_info->magick,image_info->magick,
        MaxTextExtent);
      image=ReadImage(blob_info,exception);
      if (image != (Image *) NULL)
        (void) DetachBlob(image->blob);
      blob_info=DestroyImageInfo(blob_info);
      return(image);
    }
  /*
    Write blob to a temporary file on disk.
  */
  blob_info->blob=(void *) NULL;
  blob_info->length=0;
  *blob_info->filename='\0';
  status=BlobToFile(blob_info->filename,blob,length,exception);
  if (status == MagickFalse)
    {
      (void) RelinquishUniqueFileResource(blob_info->filename);
      blob_info=DestroyImageInfo(blob_info);
      return((Image *) NULL);
    }
  image=ReadImage(blob_info,exception);
  (void) RelinquishUniqueFileResource(blob_info->filename);
  blob_info=DestroyImageInfo(blob_info);
  return(image);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
+   C l o n e B l o b I n f o                                                 %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  CloneBlobInfo() makes a duplicate of the given blob info structure, or if
%  blob info is NULL, a new one.
%
%  The format of the CloneBlobInfo method is:
%
%      BlobInfo *CloneBlobInfo(const BlobInfo *blob_info)
%
%  A description of each parameter follows:
%
%    o blob_info: The blob info.
%
*/
MagickExport BlobInfo *CloneBlobInfo(const BlobInfo *blob_info)
{
  BlobInfo
    *clone_info;

  clone_info=(BlobInfo *) AcquireMagickMemory(sizeof(*clone_info));
  if (clone_info == (BlobInfo *) NULL)
    ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
  GetBlobInfo(clone_info);
  if (blob_info == (BlobInfo *) NULL)
    return(clone_info);
  clone_info->length=blob_info->length;
  clone_info->extent=blob_info->extent;
  clone_info->quantum=blob_info->quantum;
  clone_info->mapped=blob_info->mapped;
  clone_info->eof=blob_info->eof;
  clone_info->offset=blob_info->offset;
  clone_info->size=blob_info->size;
  clone_info->exempt=blob_info->exempt;
  clone_info->status=blob_info->status;
  clone_info->temporary=blob_info->temporary;
  clone_info->type=blob_info->type;
  clone_info->file=blob_info->file;
  clone_info->stream=blob_info->stream;
  clone_info->data=blob_info->data;
  clone_info->debug=IsEventLogging();
  clone_info->reference_count=1;
  clone_info->semaphore=(SemaphoreInfo *) NULL;
  return(clone_info);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
+   C l o s e B l o b                                                         %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  CloseBlob() closes a stream associated with the image.
%
%  The format of the CloseBlob method is:
%
%      void CloseBlob(Image *image)
%
%  A description of each parameter follows:
%
%    o image: The image.
%
*/
MagickExport void CloseBlob(Image *image)
{
  int
    status;

  /*
    Close image file.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  assert(image->blob != (BlobInfo *) NULL);
  if (image->blob->type == UndefinedStream)
    return;
  (void) SyncBlob(image);
  image->blob->size=GetBlobSize(image);
  image->blob->eof=MagickFalse;
  if (image->blob->exempt != MagickFalse)
    return;
  status=0;
  switch (image->blob->type)
  {
    case UndefinedStream:
      break;
    case FileStream:
    case StandardStream:
    case PipeStream:
    {
      status=ferror(image->blob->file);
      break;
    }
    case ZipStream:
    {
#if defined(HasZLIB)
      (void) gzerror(image->blob->file,&status);
#endif
      break;
    }
    case BZipStream:
    {
#if defined(HasBZLIB)
      (void) BZ2_bzerror((BZFILE *) image->blob->file,&status);
#endif
      break;
    }
    case FifoStream:
    case BlobStream:
      break;
  }
  image->blob->status=status < 0 ? MagickTrue : MagickFalse;
  switch (image->blob->type)
  {
    case UndefinedStream:
      break;
    case FileStream:
    case StandardStream:
    {
      status=fclose(image->blob->file);
      break;
    }
    case PipeStream:
    {
#if defined(HAVE_POPEN)
      status=pclose(image->blob->file);
#endif
      break;
    }
    case ZipStream:
    {
#if defined(HasZLIB)
      status=gzclose(image->blob->file);
#endif
      break;
    }
    case BZipStream:
    {
#if defined(HasBZLIB)
      BZ2_bzclose((BZFILE *) image->blob->file);
#endif
      break;
    }
    case FifoStream:
    case BlobStream:
      break;
  }
  (void) DetachBlob(image->blob);
  image->blob->status=status < 0  ? MagickTrue : MagickFalse;
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
+   D e s t r o y B l o b                                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  DestroyBlob() deallocates memory associated with a blob.
%
%  The format of the DestroyBlob method is:
%
%      void DestroyBlob(Image *image)
%
%  A description of each parameter follows:
%
%    o image: The image.
%
*/
MagickExport void DestroyBlob(Image *image)
{
  MagickBooleanType
    destroy;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  destroy=MagickFalse;
  AcquireSemaphoreInfo(&image->blob->semaphore);
  image->blob->reference_count--;
  if (image->blob->reference_count == 0)
    destroy=MagickTrue;
  RelinquishSemaphoreInfo(image->blob->semaphore);
  if (destroy == MagickFalse)
    return;
  CloseBlob(image);
  if (image->blob->mapped != MagickFalse)
    (void) UnmapBlob(image->blob->data,image->blob->length);
  if (image->blob->semaphore != (SemaphoreInfo *) NULL)
    image->blob->semaphore=DestroySemaphoreInfo(image->blob->semaphore);
  image->blob->signature=(~MagickSignature);
  image->blob=(BlobInfo *) RelinquishMagickMemory(image->blob);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
+   D e t a c h B l o b                                                       %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  DetachBlob() detaches a blob from the BlobInfo structure.
%
%  The format of the DetachBlob method is:
%
%      unsigned char *DetachBlob(BlobInfo *blob_info)
%
%  A description of each parameter follows:
%
%    o blob_info: Specifies a pointer to a BlobInfo structure.
%
*/
MagickExport unsigned char *DetachBlob(BlobInfo *blob_info)
{
  unsigned char
    *data;

  assert(blob_info != (BlobInfo *) NULL);
  if (blob_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
  if (blob_info->mapped != MagickFalse)
    (void) UnmapBlob(blob_info->data,blob_info->length);
  blob_info->mapped=MagickFalse;
  blob_info->length=0;
  blob_info->offset=0;
  blob_info->eof=MagickFalse;
  blob_info->exempt=MagickFalse;
  blob_info->type=UndefinedStream;
  blob_info->file=(FILE *) NULL;
  data=blob_info->data;
  blob_info->data=(unsigned char *) NULL;
  blob_info->stream=(StreamHandler) NULL;
  return(data);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
+  E O F B l o b                                                              %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  EOFBlob() returns a non-zero value when EOF has been detected reading from
%  a blob or file.
%
%  The format of the EOFBlob method is:
%
%      int EOFBlob(const Image *image)
%
%  A description of each parameter follows:
%
%    o image: The image.
%
*/
MagickExport int EOFBlob(const Image *image)
{
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
  assert(image->blob != (BlobInfo *) NULL);
  assert(image->blob->type != UndefinedStream);
  switch (image->blob->type)
  {
    case UndefinedStream:
      break;
    case FileStream:
    case StandardStream:
    case PipeStream:
    {
      image->blob->eof=feof(image->blob->file) != 0 ? MagickTrue : MagickFalse;
      break;
    }
    case ZipStream:
    {
      image->blob->eof=MagickFalse;
      break;
    }
    case BZipStream:
    {
#if defined(HasBZLIB)
      int
        status;

      status=0;
      (void) BZ2_bzerror((BZFILE *) image->blob->file,&status);
      image->blob->eof=status == BZ_UNEXPECTED_EOF ? MagickTrue : MagickFalse;
#endif
      break;
    }
    case FifoStream:
    {
      image->blob->eof=MagickFalse;
      break;
    }
    case BlobStream:
      break;
  }
  return((int) image->blob->eof);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
+   F i l e T o B l o b                                                       %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  FileToBlob() returns the contents of a file as a blob.  It returns the
%  file as a blob and its length.  If an error occurs, NULL is returned.
%
%  The format of the FileToBlob method is:
%
%      unsigned char *FileToBlob(const char *filename,const size_t extent,
%        size_t *length,ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o blob:  FileToBlob() returns the contents of a file as a blob.  If
%      an error occurs NULL is returned.
%
%    o filename: The filename.
%
%    o extent:  The maximum length of the blob.
%
%    o length: On return, this reflects the actual length of the blob.
%
%    o exception: Return any errors or warnings in this structure.
%
*/
MagickExport unsigned char *FileToBlob(const char *filename,const size_t extent,
  size_t *length,ExceptionInfo *exception)
{
  int
    file;

  MagickOffsetType
    offset;

  register size_t
    i;

  ssize_t
    count;

  unsigned char
    *blob;

  void
    *map;

  assert(filename != (const char *) NULL);
  (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",filename);
  assert(exception != (ExceptionInfo *) NULL);
  *length=0;
  file=fileno(stdin);
  if (LocaleCompare(filename,"-") != 0)
    file=open(filename,O_RDONLY | O_BINARY);
  if (file == -1)
    {
      ThrowFileException(exception,BlobError,"UnableToOpenFile",filename);
      return((unsigned char *) NULL);
    }
  offset=(MagickOffsetType) MagickSeek(file,0,SEEK_END);
  count=0;
  if ((offset < 0) || (offset != (MagickOffsetType) ((ssize_t) offset)))
    {
      size_t
        quantum;

      struct stat
        file_info;

      /*
        Stream is not seekable.
      */
      quantum=(size_t) MagickMaxBufferSize;
      if ((fstat(file,&file_info) == 0) && (file_info.st_size != 0))
        quantum=MagickMin((size_t) file_info.st_size,MagickMaxBufferSize);
      blob=(unsigned char *) AcquireQuantumMemory(quantum,sizeof(*blob));
      for (i=0; blob != (unsigned char *) NULL; i+=count)
      {
        count=(ssize_t) read(file,blob+i,quantum);
        if (count <= 0)
          {
            count=0;
            if (errno != EINTR)
              break;
          }
        if (~(1UL*i) < (quantum+1))
          {
            blob=(unsigned char *) RelinquishMagickMemory(blob);
            break;
          }
        blob=(unsigned char *) ResizeQuantumMemory(blob,i+quantum+1,
          sizeof(*blob));
        if ((size_t) (i+count) >= extent)
          break;
      }
      file=close(file)-1;
      if (blob == (unsigned char *) NULL)
        {
          (void) ThrowMagickException(exception,GetMagickModule(),
            ResourceLimitError,"MemoryAllocationFailed","`%s'",filename);
          return((unsigned char *) NULL);
        }
      *length=MagickMin(i+count,extent);
      blob[*length]='\0';
      return(blob);
    }
  *length=MagickMin((size_t) offset,extent);
  blob=(unsigned char *) NULL;
  if (~(*length) >= MaxTextExtent)
    blob=(unsigned char *) AcquireQuantumMemory(*length+MaxTextExtent,
      sizeof(*blob));
  if (blob == (unsigned char *) NULL)
    {
      file=close(file)-1;
      (void) ThrowMagickException(exception,GetMagickModule(),
        ResourceLimitError,"MemoryAllocationFailed","`%s'",filename);
      return((unsigned char *) NULL);
    }
  map=MapBlob(file,ReadMode,0,*length);
  if (map != (unsigned char *) NULL)
    {
      (void) CopyMagickMemory(blob,map,*length);
      (void) UnmapBlob(map,*length);
    }
  else
    {
      (void) MagickSeek(file,0,SEEK_SET);
      for (i=0; i < *length; i+=count)
      {
        count=(ssize_t) read(file,blob+i,MagickMin(*length-i,(size_t)
          SSIZE_MAX));
        if (count <= 0)
          {
            count=0;
            if (errno != EINTR)
              break;
          }
      }
      if (i < *length)
        {
          file=close(file)-1;
          blob=(unsigned char *) RelinquishMagickMemory(blob);
          ThrowFileException(exception,BlobError,"UnableToReadBlob",filename);
          return((unsigned char *) NULL);
        }
    }
  file=close(file)-1;
  blob[*length]='\0';
  return(blob);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%   F i l e T o I m a g e                                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  FileToImage() write the contents of a file to an image.
%
%  The format of the FileToImage method is:
%
%      MagickBooleanType FileToImage(Image *,const char *filename)
%
%  A description of each parameter follows:
%
%    o image: The image.
%
%    o filename: The filename.
%
*/

static inline ssize_t WriteBlobStream(Image *image,const size_t length,
  const unsigned char *data)
{
  register unsigned char
    *q;

  assert(image->blob != (BlobInfo *) NULL);
  if (image->blob->type != BlobStream)
    return(WriteBlob(image,length,data));
  assert(image->blob->type != UndefinedStream);
  assert(data != (void *) NULL);
  if ((image->blob->offset+(MagickOffsetType) length) >=
      (MagickOffsetType) image->blob->extent)
    {
      if (image->blob->mapped != MagickFalse)
        return(0);
      image->blob->quantum<<=1;
      image->blob->extent+=length+image->blob->quantum;
      image->blob->data=(unsigned char *) ResizeQuantumMemory(image->blob->data,
        image->blob->extent+1,sizeof(*image->blob->data));
      (void) SyncBlob(image);
      if (image->blob->data == (unsigned char *) NULL)
        {
          (void) DetachBlob(image->blob);
          return(0);
        }
    }
  q=image->blob->data+image->blob->offset;
  switch (length)
  {
    default:
    {
      (void) CopyMagickMemory(q,data,length);
      break;
    }
    case 7: *q++=(*data++);
    case 6: *q++=(*data++);
    case 5: *q++=(*data++);
    case 4: *q++=(*data++);
    case 3: *q++=(*data++);
    case 2: *q++=(*data++);
    case 1: *q++=(*data++);
    case 0: break;
  }
  image->blob->offset+=length;
  if (image->blob->offset >= (MagickOffsetType) image->blob->length)
    image->blob->length=(size_t) image->blob->offset;
  return((ssize_t) length);
}

MagickExport MagickBooleanType FileToImage(Image *image,const char *filename)
{
  int
    file;
    
  size_t
    length,
    quantum;

  ssize_t
    count;

  struct stat
    file_info;

  unsigned char
    *blob;

  assert(image != (const Image *) NULL);
  assert(image->signature == MagickSignature);
  assert(filename != (const char *) NULL);
  (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",filename);
  file=open(filename,O_RDONLY | O_BINARY);
  if (file == -1)
    {
      ThrowFileException(&image->exception,BlobError,"UnableToOpenBlob",
        filename);
      return(MagickFalse);
    }
  quantum=(size_t) MagickMaxBufferSize;
  if ((fstat(file,&file_info) == 0) && (file_info.st_size != 0))
    quantum=MagickMin((size_t) file_info.st_size,MagickMaxBufferSize);
  blob=(unsigned char *) AcquireQuantumMemory(quantum,sizeof(*blob));