tif_ojpeg.c

一个国人自己实现图像库的程序（有参考价值）

TIFFojpeg_read_header(register OJPEGState *sp,boolean require_image)
  {return CALLJPEG(sp,-1,jpeg_read_header(&sp->cinfo.d,require_image));}

static int
TIFFojpeg_read_raw_data(register OJPEGState *sp,JSAMPIMAGE data,int max_lines)
  {
    return
      CALLJPEG(sp,-1,(int)jpeg_read_raw_data(&sp->cinfo.d,data,(JDIMENSION)max_lines));
  }

static int
TIFFojpeg_read_scanlines(register OJPEGState *sp,JSAMPARRAY scanlines,
                        int max_lines)
  { return
      CALLJPEG(sp,-1,(int)jpeg_read_scanlines(&sp->cinfo.d,scanlines,(JDIMENSION)max_lines));
  }

static int
TIFFojpeg_start_decompress(register OJPEGState *sp)
  {return CALLVJPEG(sp,jpeg_start_decompress(&sp->cinfo.d));}
#ifdef never

/* The following subroutines comprise a JPEG Library "destination" data manager
   by directing compressed data from the JPEG Library to a TIFF Library output
   buffer.
*/
static void
std_init_destination(register j_compress_ptr cinfo){} /* "Dummy" stub */

static boolean
std_empty_output_buffer(register j_compress_ptr cinfo)
  {
#   define sp ((OJPEGState *)cinfo)
    register TIFF *tif = sp->tif;

    tif->tif_rawcc = tif->tif_rawdatasize; /* Entire buffer has been filled */
    TIFFFlushData1(tif);
    sp->dest.next_output_byte = (JOCTET *)tif->tif_rawdata;
    sp->dest.free_in_buffer = (size_t)tif->tif_rawdatasize;
    return TRUE;
#   undef sp
  }

static void
std_term_destination(register j_compress_ptr cinfo)
  {
#   define sp ((OJPEGState *)cinfo)
    register TIFF *tif = sp->tif;

 /* NB: The TIFF Library does the final buffer flush. */
    tif->tif_rawcp = (tidata_t)sp->dest.next_output_byte;
    tif->tif_rawcc = tif->tif_rawdatasize - (tsize_t)sp->dest.free_in_buffer;
#   undef sp
  }

/*ARGSUSED*/ static void
TIFFojpeg_data_dest(register OJPEGState *sp,TIFF *tif)
  {
    sp->cinfo.c.dest = &sp->dest;
    sp->dest.init_destination = std_init_destination;
    sp->dest.empty_output_buffer = std_empty_output_buffer;
    sp->dest.term_destination = std_term_destination;
  }


/* Alternate destination manager to output JPEGTables field: */

static void
tables_init_destination(register j_compress_ptr cinfo)
  {
#   define sp ((OJPEGState *)cinfo)
 /* The "jpegtables_length" field is the allocated buffer size while building */
    sp->dest.next_output_byte = (JOCTET *)sp->jpegtables;
    sp->dest.free_in_buffer = (size_t)sp->jpegtables_length;
#   undef sp
  }

static boolean
tables_empty_output_buffer(register j_compress_ptr cinfo)
  { void *newbuf;
#   define sp ((OJPEGState *)cinfo)

 /* The entire buffer has been filled, so enlarge it by 1000 bytes. */
    if (!( newbuf = _TIFFrealloc( (tdata_t)sp->jpegtables
                                , (tsize_t)(sp->jpegtables_length + 1000)
                                )
         )
       ) ERREXIT1(cinfo,JERR_OUT_OF_MEMORY,100);
    sp->dest.next_output_byte = (JOCTET *)newbuf + sp->jpegtables_length;
    sp->dest.free_in_buffer = (size_t)1000;
    sp->jpegtables = newbuf;
    sp->jpegtables_length += 1000;
    return TRUE;
#   undef sp
  }

static void
tables_term_destination(register j_compress_ptr cinfo)
  {
#   define sp ((OJPEGState *)cinfo)
 /* Set tables length to no. of Bytes actually emitted. */
    sp->jpegtables_length -= sp->dest.free_in_buffer;
#   undef sp
  }

/*ARGSUSED*/ static int
TIFFojpeg_tables_dest(register OJPEGState *sp, TIFF *tif)
  {

 /* Allocate a working buffer for building tables.  The initial size is 1000
    Bytes, which is usually adequate.
 */
    if (sp->jpegtables) _TIFFfree(sp->jpegtables);
    if (!(sp->jpegtables = (void*)
                           _TIFFmalloc((tsize_t)(sp->jpegtables_length = 1000))
         )
       )
      {
        sp->jpegtables_length = 0;
        TIFFError("TIFFojpeg_tables_dest",no_jtable_space);
        return 0;
      };
    sp->cinfo.c.dest = &sp->dest;
    sp->dest.init_destination = tables_init_destination;
    sp->dest.empty_output_buffer = tables_empty_output_buffer;
    sp->dest.term_destination = tables_term_destination;
    return 1;
  }
#endif /* never */

/* The following subroutines comprise a JPEG Library "source" data manager by
   by directing compressed data to the JPEG Library from a TIFF Library input
   buffer.
*/
static void
std_init_source(register j_decompress_ptr cinfo)
  {
#   define sp ((OJPEGState *)cinfo)
    register TIFF *tif = sp->tif;

    if (sp->src.bytes_in_buffer == 0)
      {
        sp->src.next_input_byte = (const JOCTET *)tif->tif_rawdata;
        sp->src.bytes_in_buffer = (size_t)tif->tif_rawcc;
      };
#   undef sp
  }

static boolean
std_fill_input_buffer(register j_decompress_ptr cinfo)
  { static const JOCTET dummy_EOI[2]={0xFF,JPEG_EOI};
#   define sp ((OJPEGState *)cinfo)

 /* Control should never get here, since an entire strip/tile is read into
    memory before the decompressor is called; thus, data should have been
    supplied by the "init_source" method.  ...But, sometimes things fail.
 */
    WARNMS(cinfo,JWRN_JPEG_EOF);
    sp->src.next_input_byte = dummy_EOI; /* Insert a fake EOI marker */
    sp->src.bytes_in_buffer = sizeof dummy_EOI;
    return TRUE;
#   undef sp
  }

static void
std_skip_input_data(register j_decompress_ptr cinfo,long num_bytes)
  {
#   define sp ((OJPEGState *)cinfo)

    if (num_bytes > 0)
      if (num_bytes > (long)sp->src.bytes_in_buffer) /* oops: buffer overrun */
        (void)std_fill_input_buffer(cinfo);
      else
        {
          sp->src.next_input_byte += (size_t)num_bytes;
          sp->src.bytes_in_buffer -= (size_t)num_bytes;
        }
#   undef sp
  }

/*ARGSUSED*/ static void
std_term_source(register j_decompress_ptr cinfo){} /* "Dummy" stub */

/* Allocate temporary I/O buffers for downsampled data, using values computed in
   "jpeg_start_{de}compress()".  We use the JPEG Library's allocator so that
   buffers will be released automatically when done with a strip/tile.  This is
   also a handy place to compute samplesperclump, bytesperline, etc.
*/
static int
alloc_downsampled_buffers(TIFF *tif,jpeg_component_info *comp_info,
                          int num_components)
  { register OJPEGState *sp = OJState(tif);

    sp->samplesperclump = 0;
    if (num_components > 0)
      { int ci = 0;
        register jpeg_component_info *compptr = comp_info;

        do
          { JSAMPARRAY buf;

            sp->samplesperclump +=
              compptr->h_samp_factor * compptr->v_samp_factor;
            if (!(buf = TIFFojpeg_alloc_sarray( sp
                                              , JPOOL_IMAGE
                                              , compptr->width_in_blocks*DCTSIZE
                                              , compptr->v_samp_factor  *DCTSIZE
                                              )
                 )
               ) return 0;
            sp->ds_buffer[ci] = buf;
          }
        while (++compptr,++ci < num_components);
      };
    return 1;
  }
#ifdef never

/* JPEG Encoding begins here. */

static void
unsuppress_quant_table(register OJPEGState *sp,int tblno)
  { register JQUANT_TBL *qtbl;

    if (qtbl = sp->cinfo.c.quant_tbl_ptrs[tblno]) qtbl->sent_table = FALSE;
  }

static void
unsuppress_huff_table(register OJPEGState *sp,register int tblno)
  { register JHUFF_TBL *htbl;

    if (   (htbl = sp->cinfo.c.dc_huff_tbl_ptrs[tblno])
        || (htbl = sp->cinfo.c.ac_huff_tbl_ptrs[tblno])
       ) htbl->sent_table = FALSE;
  }

static int
prepare_JPEGTables(register TIFF *tif)
  { register OJPEGState *sp = OJState(tif);

 /* Initialize quantization tables for the current quality setting, and mark for
    output only the tables that we want.  Note that chrominance tables are
    currently used only with YCbCr.
 */
    if (   !TIFFojpeg_set_quality(sp,sp->jpegquality,FALSE);
        || !TIFFojpeg_suppress_tables(sp,TRUE)
       ) return 0;
    if (sp->jpegtablesmode & JPEGTABLESMODE_QUANT)
      {
        unsuppress_quant_table(sp,0);
        if (sp->photometric == PHOTOMETRIC_YCBCR) unsuppress_quant_table(sp,1);
      }
    if (sp->jpegtablesmode & JPEGTABLESMODE_HUFF)
      {
        unsuppress_huff_table(sp,0);
        if (sp->photometric == PHOTOMETRIC_YCBCR) unsuppress_huff_table(sp,1);
      };
    return TIFFojpeg_tables_dest(sp,tif) && TIFFojpeg_write_tables(sp);
  }

static int
OJPEGSetupEncode(register TIFF *tif)
  { static const char module[]={"OJPEGSetupEncode"};
    register OJPEGState *sp = OJState(tif);
#   define td (&tif->tif_dir)

 /* Verify miscellaneous parameters.  This will need work if the TIFF Library
    ever supports different depths for different components, or if the JPEG
    Library ever supports run-time depth selection.  Neither seems imminent.
 */
    if (td->td_bitspersample != BITS_IN_JSAMPLE)
      {
        TIFFError(module,bad_bps,td->td_bitspersample);
        return 0;
      };

 /* Initialize all JPEG parameters to default values.  Note that the JPEG
    Library's "jpeg_set_defaults()" method needs legal values for the
    "in_color_space" and "input_components" fields.
 */
    sp->cinfo.c.in_color_space = JCS_UNKNOWN;
    sp->cinfo.c.input_components = 1;
    if (!TIFFojpeg_set_defaults(sp)) return 0;
    switch (sp->photometric = td->td_photometric) /* set per-file parameters */
      {
        case PHOTOMETRIC_YCBCR:
          sp->h_sampling = td->td_ycbcrsubsampling[0];
          sp->v_sampling = td->td_ycbcrsubsampling[1];
#         ifdef COLORIMETRY_SUPPORT

       /* A ReferenceBlackWhite field MUST be present, since the default value
          is inapproriate for YCbCr.  Fill in the proper value if application
          didn't set it.
       */
          if (!TIFFFieldSet(tif,FIELD_REFBLACKWHITE))
            { float refbw[6];
              long top = 1L << td->td_bitspersample;

              refbw[0] = 0;
              refbw[1] = (float)(top-1L);
              refbw[2] = (float)(top>>1);
              refbw[3] = refbw[1];
              refbw[4] = refbw[2];
              refbw[5] = refbw[1];
              TIFFSetField(tif,TIFFTAG_REFERENCEBLACKWHITE,refbw);
            };
#         endif /* COLORIMETRY_SUPPORT */
          break;
        case PHOTOMETRIC_PALETTE: /* disallowed by Tech Note */
        case PHOTOMETRIC_MASK:
          TIFFError(module,"PhotometricInterpretation %d not allowed for JPEG",
            (int)sp->photometric);
          return 0;

     /* TIFF 6.0 forbids subsampling of all other color spaces */

        default: sp->h_sampling = sp->v_sampling = 1;
      };
    sp->cinfo.c.data_precision = td->td_bitspersample;
    if (isTiled(tif))
      {
        if (td->td_tilelength % (sp->v_sampling*DCTSIZE))
          {