writeheade.3

来自「speech signal process tools」· 3 代码 · 共 88 行

.\" Copyright (c) 1987 Entropic Speech, Inc.; All rights reserved
.\" @(#)writeheade.3	1.7 06 Aug 1991 ESI
.TH WRITE_HEADER 3\-ESPSu 06 Aug 1991
.ds ]W "\fI\s+4\ze\h'0.05'e\s-4\v'-0.4m'\fP\(*p\v'0.4m'\ Entropic Speech, Inc.
.SH NAME
write_header \- write a ESPS file header out to data file
.br
inhibit_hdr_date \- inhibit updating the header field date
.SH SYNOPSIS
.ft B
void write_header (hd,fd)
.br
struct header *hd;
.br
FILE *fd;
.ft
.br
.sp
.ft B
void inhibit_hdr_date ()
.ft
.SH DESCRIPTION
.I write_header
attempts to write a ESPS file header onto a stream 
.I fd.
It computes and fills in values for \fIcommon.hsize, common.fixsiz, and
common.check\fR.
Normally, it also udpates \fIcommon.date\fR with the current date and
time.   If \fIinhibit_hdr_date\fR is called prior to \fIwrite_header\fR
then \fIcommon.date\fR is not updated.   The next call to
\fIwrite_header\fR will behave normally; that is \fIinhibit_hdr_date\fR
must be called prior to each \fIwrite_header\fR call to disable updating
\fIcommon.date\fR.  
.PP
If an I/O error occurs, \fIwrite_header\fR prints
a message on stderr and terminates the calling program.
For file types FT_ANA, FT_PIT, FT_ROS, FT_SPEC, 
and FT_FILT, \fIwrite_header\fR calls the
appropriate function to fill in the data type fields in the header.
For file type FT_SD, the user program must call
\fIset_sd_type\fR(3\-ESPSu).
.PP
If the generic header item \fIforeign_hd_length\fR is defined and
greater than zero, and \fIforeign_hd_ptr\fR is non-NULL, then 
\fIforeign_hd_length\fR bytes
of memory pointed to by \fIforeign_hd_ptr\fR are written to the stream
\fIfd\fR after the ESPS header.  This would usually be a foreign header
which was created by using \fIaddfeahd\fR(1\-ESPS) or \fIbtosps\fR(1\-ESPS) 
with the \fB-F\fR option.
.SH EXAMPLE
.if n .ta 33
hd = new_header (FT_ANA);	/* get a new header */
.br
hd->sd.ana->order = foo;	/* do something */
.br
fd = fopen (outputfile, "w");	/* open the new file */
.br
(void) write_header (hd,fd);	/* write the header */
.PP
Normally, the data records in ESPS files are written in order of the
data type of the elements.   All doubles are written first, followed by
floats, longs, shorts, and characters (bytes).   For feature files
(FT_FEA) an option is to write the data elements in \fIfield_order\fR.
This means that the data fields are written to the file in the order
that the fields were created (with \fIadd_fea_fld\fR).   If the program
sets the header item \fIhd.fea->field_order\fR to YES before calling
\fIwrite_header\fR then the file will be written in field_order.
An alternative is for the user to define the \s-1UNIX\s+1 environment
variable \fIFIELD_ORDER\fR to any value other than \fIoff\fR.  If this
variable is defined (and does not equal \fIoff\fR) then
\fIwrite_header\fR will set \fIhd.fea->field_order\fR to YES before
writing the header to the file.  When the file is read back, the ESPS
input routines take note of the value of \fIhd.fea->field_order\fR and
ensure that the data is correctly read.
.SH DIAGNOSTICS
There are a number of error messages that might be output to stderr 
if parts of the header are bad.   The calling program is terminated
by exit(1).   Such an error would indicate a programming error.
.SH BUGS
None known.
.SH SEE ALSO
eopen(3\-ESPSu),
new_header(3\-ESPSu), read_header(3\-ESPSu), copy_header(3\-ESPSu)
.SH AUTHOR
Original version by Joe Buck.
.br
Modified by Alan Parker for new header structures.