readrast.c

来自「NIST Handwriting OCR Testbed」· C语言 代码 · 共 114 行

/*
# proc: ReadBinaryRaster - reads the contents of a binary IHead image file
# proc:                    into an IHead structure and image memory.
*/

/************************************************************/
/*         File Name: ReadRast.c                            */
/*         Package:   Image Read Routines                   */
/*                                                          */
/*         Contents:  ReadBinaryRaster()                    */
/************************************************************/

#include <stdio.h>
#include <math.h>
#include <malloc.h>
#include <ihead.h>

/************************************************************/
/*         Routine:   ReadBinaryRaster()                    */
/*         Author:    Michael D. Garris                     */
/*         Date:      4/28/89                               */
/*         Modifications:                                   */
/*           8/90 Stan Janet                                */
/*                     only malloc 1 buffer if data is not  */
/*                        compressed                        */
/*                     free() up temp buffer                */
/*           9/20/90 Stan Janet                             */
/*                     check return codes                   */
/*           1/11/91 Stan Janet                             */
/*                     put filename in error messages       */
/************************************************************/
/************************************************************/
/* ReadBinaryRaster() reads in a "headered" binary raster   */
/* file and returns an ihead structure, raster data, and    */
/* integer file specs.                                      */
/************************************************************/

void ReadBinaryRaster(file,head,data,bpi,width,height)
char *file;
IHEAD **head;
unsigned char **data;
int *bpi,*width,*height;
{
   FILE *fp;
   IHEAD *readihdr();
   IHEAD *ihead;
   int outbytes, depth, comp, filesize, complen, n;
   unsigned char *indata, *outdata;

   /* open the image file */
   fp = fopen(file,"rb");
   if (fp == NULL)
      syserr("ReadBinaryRaster",file,"fopen");

   /* read in the image header */
   (*head) = readihdr(fp);
   ihead = *head;

   depth = get_depth(ihead);
   if(depth != 1)
      fatalerr("ReadBinaryRaster",file,"not a binary file");
   (*width) = get_width(ihead);
   (*height) = get_height(ihead);
   (*bpi) = get_density(ihead);
   comp = get_compression(ihead);
   complen = get_complen(ihead);

   /* allocate a raster data buffer */
   filesize = SizeFromDepth(*width, *height, depth);
   malloc_uchar(&outdata, filesize, "ReadIheadRaster : outdata");

   /* read in the raster data */
   if(comp == UNCOMP) {   /* file is uncompressed */
      n = fread(outdata,1,filesize,fp);
      if (n != filesize) {
	 (void) fprintf(stderr,
		"ReadBinaryRaster: %s: fread returned %d (expected %d)\n",
		file,n,filesize);
         exit(1);
      } /* IF */
   } else {
      malloc_uchar(&indata, complen, "ReadBinaryRaster : indata");
      n = fread(indata,1,complen,fp); /* file compressed */
      if (n != complen) {
         (void) fprintf(stderr,
		"ReadBinaryRaster: %s: fread returned %d (expected %d)\n",
		file,n,complen);
      } /* IF */
   }

   switch (comp) {
      case CCITT_G4:
         if((*head)->sigbit == LSBF) {
           inv_bytes(indata, complen);
           (*head)->sigbit = MSBF;
           (*head)->byte_order = HILOW;
         }
	 grp4decomp(indata,complen,*width,*height,outdata,&outbytes);
         set_compression(ihead, UNCOMP);
         set_complen(ihead, 0);
         free((char *)indata);
         break;
      case UNCOMP:
         break;
      default:
         fatalerr("ReadBinaryRaster",file,"Unsupported compression code");
      break;
   }

   *data = outdata;
   /* close the image file */
   (void) fclose(fp);
}