output_tspan.c

seed格式数据解压程序,地震分析人员必备

/*===========================================================================*/
/* UTIG DMC        |          output_tspan                 | Output_phase    */
/*===========================================================================*/
/*
	Name:	output_tspan.c

	Purpose:to transmit the memory images of the time span control
			headers to the output SEED logical volume.

	Usage:	struct logrec_list *output_tspan( file, t, err )

	Input:
		FILE	file	output file pointer, already open
		struct	logrec_list 	*t
		linked list of tspan header logical recs
	Output:		
		int	*err	0 if no errors
		function value	pointer to next unused tspan logrec,
		or NULL if at end of list
	Externals:	
	Warnings:	
	Errors:		
	Fatals:
	Called by:	
	Calls to:	
	Algorithm:	
	Notes:		
	Problems:	
	References:	
	Language:	Sun OS 3.5 C
	Author:		Mark Wiederspahn, who knows when; March 1989?
	Revisions:	mm/dd/yy  pgmr name  change
			07/14/89 mw Whoops! old code traversed logrec_list looking
			for T type records (timespan logical records)
			and quit when the next record was not T or
			was T but was not * continuation. This logic
			was based on an incorrect understanding of
			what the continuation flag means. It means only
			that a blockette has been split across a
			logical record, NOT that a logical record
			type has been continued. The proper condition
			is to quit if another T with an 070 blockette
			is seen - this means we point to the next
			T logrec in a volume which has more than one
			tspan. Thanks to Tim Ahern, aka The
			Destroyer, for finding this one.
04/13/90	mw	Friday the 13th! bugfix
			previous "fix" did strncmp( (char *)p+8, which
			is most emphatically not a pointer to a 
			timespan header +8. This failed the first time
			that multiple timespans per volume was
			attempted. (Thanks Becky!)

*/

#include "output.h"

#define SPACE 32	/* ascii space character */

struct logrec_list *output_tspan( file, t, err )
FILE	*file;		/* output file pointer, already open */
struct	logrec_list *t;	/* list of time span control headers */
int *err;		/* return status */
{
register struct logrec_list *p;	/* link traversal */
struct	io_buf	buf;		/* where to put them, from logrec package */
int		ntspan;		/* number of tspans seen this call */

	if( Debug >= D_MIN ) fprintf( D_OUT,"[output_tspan] start\n");
/*
 * for each logical record in the linked list, output it. Quit on
 * any error, since this is the directory of the volume.
 *
 * For each call to this routine, we output only one tspan. This
 * means the inital logical record of type T, which starts with 070 blockette,
 * plus however many additional logrecs there in this tspan: 
 * There may be other Tspans in the logrec_list linked list; we identify
 * such be the non-presence of a continuation flag AND a first blockette
 * type of 070. To restate: if a logrec of type T with a continuation is
 * seen, OR type T without continuation but not 070, then this logrec
 * belongs to the current tspan, and is output here.
 * Just in case, we check for a NULL input.
 */
	p = t;
	if( p != NULL )
	{
		do
		{
			if( Debug >= D_SOME ) fprintf( D_OUT,"[output_tspan] tspan hdr\n");
			buf = put_logrec( file, p->record, Lrecl, 0, err );
			if( *err )
				if( (*err=error_handler( FATAL,"[output_tspan] put_logrec")) )
					return( p );
			p = p->next;
		}
		while( p != NULL &&
			( (struct hdr_logrec *)p->record )->type == 'T'  &&
			( ( (struct hdr_logrec *)p->record )->cont != SPACE ||
			     strncmp( (char *)( (struct hdr_logrec *)p->record )+8,
							"070", 3 ) ) );
/*
 * if we are at the end of the list OR the next is not a Timespan, done.
 */
		if( p != NULL )
			if( ( (struct hdr_logrec *)p->record )->type != 'T' ) p = NULL;
	}

	if( Debug >= D_MIN ) fprintf( D_OUT,"[output_tspan] end\n");
	return( p );
}