rle_getskip.c File Reference

#include "rle.h"
#include "rle_code.h"

Include dependency graph for rle_getskip.c:

Go to the source code of this file.

Macros
#define	VAXSHORT(var, fp)   { var = fgetc(fp)&0xFF; var |= (fgetc(fp)) << 8; }
#define	OPCODE(inst)   (inst[0] & ~LONG)
#define	LONGP(inst)   (inst[0] & LONG)
#define	DATUM(inst)   (inst[1] & 0xff) /* Make sure it's unsigned. */

Functions
unsigned int	rle_getskip (rle_hdr *the_hdr)

Macro Definition Documentation

#define DATUM

(

inst

)

(inst[1] & 0xff) /* Make sure it's unsigned. */

Definition at line 39 of file rle_getskip.c.

#define LONGP

(

inst

)

(inst[0] & LONG)

Definition at line 38 of file rle_getskip.c.

#define OPCODE

(

inst

)

(inst[0] & ~LONG)

Definition at line 37 of file rle_getskip.c.

#define VAXSHORT	(		var,
			fp
	)		{ var = fgetc(fp)&0xFF; var |= (fgetc(fp)) << 8; }

Definition at line 32 of file rle_getskip.c.

Function Documentation

unsigned int rle_getskip

(

rle_hdr *

the_hdr

)

Definition at line 57 of file rle_getskip.c.

{
    unsigned char inst[2];
    register FILE *infile = the_hdr->rle_file;
    int nc;

    /* Add in vertical skip from last scanline */
    if ( the_hdr->priv.get.vert_skip > 0) 
    the_hdr->priv.get.scan_y += the_hdr->priv.get.vert_skip;
    the_hdr->priv.get.vert_skip = 0;

    if ( the_hdr->priv.get.is_eof )
    return 32768;       /* too big for 16 bits, signal EOF */
    
    /* Otherwise, read and interpret instructions until a skipLines
     * instruction is encountered.
     */
    for (;;)
    {
        inst[0] = getc( infile );
    inst[1] = getc( infile );
    if ( feof(infile) )
    {
        the_hdr->priv.get.is_eof = 1;
        break;      /* <--- one of the exits */
    }

    switch( OPCODE(inst) )
    {
    case RSkipLinesOp:
        if ( LONGP(inst) )
        {
        VAXSHORT( the_hdr->priv.get.vert_skip, infile );
        }
        else
        the_hdr->priv.get.vert_skip = DATUM(inst);
        break;          /* need to break for() here, too */

    case RSetColorOp:
        /* No-op here. */
        break;

    case RSkipPixelsOp:
        if ( LONGP(inst) )
        {
        (void)getc( infile );
        (void)getc( infile );
        }
        break;

    case RByteDataOp:
        if ( LONGP(inst) )
        {
            VAXSHORT( nc, infile );
        }
        else
        nc = DATUM(inst);
        nc++;
        if ( the_hdr->priv.get.is_seek )
        fseek( infile, ((nc + 1) / 2) * 2, 1 );
        else
        {
        register int ii;
        for ( ii = ((nc + 1) / 2) * 2; ii > 0; ii-- )
            (void) getc( infile );  /* discard it */
        }

        break;

    case RRunDataOp:
        if ( LONGP(inst) )
        {
        (void)getc( infile );
        (void)getc( infile );
        }
        (void)getc( infile );
        (void)getc( infile );
        break;

    case REOFOp:
        the_hdr->priv.get.is_eof = 1;
        break;

    default:
        fprintf( stderr,
             "%s: rle_getskip: Unrecognized opcode: %d, reading %s\n",
             the_hdr->cmd, OPCODE(inst), the_hdr->file_name );
        exit(1);
    }
    if ( OPCODE(inst) == REOFOp )
        break;          /* <--- the other loop exit */
    if ( OPCODE(inst) == RSkipLinesOp )
        break;
    }

    /* Return the number of the NEXT scanline. */
    the_hdr->priv.get.scan_y +=
    the_hdr->priv.get.vert_skip;
    the_hdr->priv.get.vert_skip = 0;

    if ( the_hdr->priv.get.is_eof )
    return 32768;       /* too big for 16 bits, signal EOF */
    else
    return the_hdr->priv.get.scan_y;
}