diff options
Diffstat (limited to 'urt/rle_getskip.c')
| -rw-r--r-- | urt/rle_getskip.c | 201 |
1 files changed, 102 insertions, 99 deletions
diff --git a/urt/rle_getskip.c b/urt/rle_getskip.c index 1366e162..2482f2bf 100644 --- a/urt/rle_getskip.c +++ b/urt/rle_getskip.c @@ -1,27 +1,27 @@ /* * This software is copyrighted as noted below. It may be freely copied, - * modified, and redistributed, provided that the copyright notice is + * modified, and redistributed, provided that the copyright notice is * preserved on all copies. - * + * * There is no warranty or other guarantee of fitness for this software, * it is provided solely "as is". Bug reports or fixes may be sent * to the author, who may or may not act on them as he desires. * * You may not include this software in a program or other software product - * without supplying the source, or without informing the end-user that the + * without supplying the source, or without informing the end-user that the * source is available for no extra charge. * * If you modify this software, you should include a notice giving the * name of the person performing the modification, the date of modification, * and the reason for such modification. */ -/* +/* * rle_getskip.c - Skip scanlines on input. - * - * Author: Spencer W. Thomas - * EECS Dept. - * University of Michigan - * Date: Wed Jun 27 1990 + * + * Author: Spencer W. Thomas + * EECS Dept. + * University of Michigan + * Date: Wed Jun 27 1990 * Copyright (c) 1990, University of Michigan */ @@ -32,133 +32,136 @@ /* Read a two-byte "short" that started in VAX (LITTLE_ENDIAN) order */ #define VAXSHORT( var, fp )\ - { var = fgetc(fp)&0xFF; var |= (fgetc(fp)) << 8; } - + { var = fgetc(fp)&0xFF; var |= (fgetc(fp)) << 8; } + /* Instruction format -- first byte is opcode, second is datum. */ #define OPCODE(inst) (inst[0] & ~LONG) #define LONGP(inst) (inst[0] & LONG) -#define DATUM(inst) (inst[1] & 0xff) /* Make sure it's unsigned. */ +#define DATUM(inst) (inst[1] & 0xff) /* Make sure it's unsigned. */ /***************************************************************** * TAG( rle_getskip ) - * + * * Skip the next scanline with data on it. * Most useful for skipping to end-of-image. * Inputs: - * the_hdr: Describes input image. + * the_hdr: Describes input image. * Outputs: - * Returns the number of the next scanline. At EOF returns 32768. + * Returns the number of the next scanline. At EOF returns 32768. * Assumptions: - * rle_get_setup has been called. + * rle_get_setup has been called. * Algorithm: - * Read input to the beginning of the next scanline, or to EOF or - * end of image. + * Read input to the beginning of the next scanline, or to EOF or + * end of image. */ unsigned int rle_getskip( the_hdr ) rle_hdr *the_hdr; { unsigned char inst[2]; - register FILE *infile = the_hdr->rle_file; + 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; + 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 */ - + 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; + 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 + { + 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; the_hdr->priv.get.vert_skip = 0; if ( the_hdr->priv.get.is_eof ) - return 32768; /* too big for 16 bits, signal EOF */ + return 32768; /* too big for 16 bits, signal EOF */ else - return the_hdr->priv.get.scan_y; + return the_hdr->priv.get.scan_y; } + + + |