/*** File libwcs/hput.c
 *** September 9, 2011
 *** By Jessica Mink, jmink@cfa.harvard.edu
 *** Harvard-Smithsonian Center for Astrophysics
 *** Copyright (C) 1995-2011
 *** Smithsonian Astrophysical Observatory, Cambridge, MA, USA

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.
    
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Correspondence concerning WCSTools should be addressed as follows:
           Internet email: jmink@cfa.harvard.edu
           Postal address: Jessica Mink
                           Smithsonian Astrophysical Observatory
                           60 Garden St.
                           Cambridge, MA 02138 USA

 * Module:	hput.c (Put FITS Header parameter values)
 * Purpose:	Implant values for parameters into FITS header string
 * Subroutine:	hputi4 (hstring,keyword,ival) sets int ival
 * Subroutine:	hputr4 (hstring,keyword,rval) sets real*4 rval
 * Subroutine:	hputr8 (hstring,keyword,dval) sets real*8 dval
 * Subroutine:	hputnr8 (hstring,keyword,ndec,dval) sets real*8 dval
 * Subroutine:	hputra (hstring,keyword,lval) sets right ascension as string
 * Subroutine:	hputdec (hstring,keyword,lval) sets declination as string
 * Subroutine:	hputl  (hstring,keyword,lval) sets logical lval
 * Subroutine:	hputs  (hstring,keyword,cval) sets character string adding ''
 * Subroutine:	hputm  (hstring,keyword,cval) sets multi-line character string
 * Subroutine:	hputc  (hstring,keyword,cval) sets character string cval
 * Subroutine:	hdel   (hstring,keyword) deletes entry for keyword keyword
 * Subroutine:	hadd   (hplace,keyword) adds entry for keyword at hplace
 * Subroutine:	hchange (hstring,keyword1,keyword2) changes keyword for entry
 * Subroutine:	hputcom (hstring,keyword,comment) sets comment for parameter keyword
 * Subroutine:	ra2str (out, lstr, ra, ndec) converts RA from degrees to string
 * Subroutine:	dec2str (out, lstr, dec, ndec) converts Dec from degrees to string
 * Subroutine:	deg2str (out, lstr, deg, ndec) converts degrees to string
 * Subroutine:	num2str (out, num, field, ndec) converts number to string
 * Subroutine:  getltime () returns current local time as ISO-style string
 * Subroutine:  getutime () returns current UT as ISO-style string
 */
#include "common.h"

#if !defined(_MSC_VER)
	#include <sys/time.h>
#endif
#include <string.h>             /* NULL, strlen, strstr, strcpy */
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#include "fitshead.h"

static int verbose=0;	/* Set to 1 to print error messages and other info */

static void fixnegzero();


/*  HPUTI4 - Set int keyword = ival in FITS header string */

int
hputi4 (hstring,keyword,ival)

char *hstring;		/* FITS-style header information in the format
			   <keyword>= <value> {/ <comment>}
			   each entry is padded with spaces to 80 characters */

const char *keyword;	/* Name of the variable in header to be returned.
			   If no line begins with this string, one is created.
		   	   The first 8 characters of keyword must be unique. */
int ival;		/* int number */
{
    char value[30];

    /* Translate value from binary to ASCII */
    sprintf (value,"%d",ival);

    /* Put value into header string */
    return (hputc (hstring,keyword,value));
}


/*  HPUTR4 - Set float keyword = rval in FITS header string */

int
hputr4 (hstring, keyword, rval)

char *hstring;		/* FITS header string */
const char *keyword;	/* Keyword name */
const float *rval;	/* float number */

{
    char value[30];

    /* Translate value from binary to ASCII */
    sprintf (value, "%f", *rval);

    /* Remove sign if string is -0 or extension thereof */
    fixnegzero (value);

    /* Put value into header string */
    return (hputc (hstring, keyword, value));
}


/*  HPUTR8 - Set double keyword = dval in FITS header string */

int
hputr8 (hstring, keyword, dval)

char	*hstring;	/* FITS header string */
const char *keyword;	/* Keyword name */
const double dval;	/* double number */
{
    char value[30];

    /* Translate value from binary to ASCII */
    sprintf (value, "%g", dval);

    /* Remove sign if string is -0 or extension thereof */
    fixnegzero (value);

    /* Put value into header string */
    return (hputc (hstring, keyword, value));
}


/*  HPUTNR8 - Set double keyword = dval in FITS header string */

int
hputnr8 (hstring, keyword, ndec, dval)

char	*hstring;	/* FITS header string */
const char *keyword;	/* Keyword name */
const int ndec;		/* Number of decimal places to print */
const double dval;	/* double number */
{
    char value[30];
    char format[8];
    int i, lval;

    /* Translate value from binary to ASCII */
    if (ndec < 0) {
	sprintf (format, "%%.%dg", -ndec);
	sprintf (value, format, dval);
	lval = (int) strlen (value);
	for (i = 0; i < lval; i++)
	    if (value[i] == 'e') value[i] = 'E';
	}
    else {
	sprintf (format, "%%.%df", ndec);
	sprintf (value, format, dval);
	}

    /* Remove sign if string is -0 or extension thereof */
    fixnegzero (value);

    /* Put value into header string */
    return (hputc (hstring, keyword, value));
}


/*  HPUTRA - Set double keyword = hh:mm:ss.sss in FITS header string */

int
hputra (hstring, keyword, ra)

char *hstring;		/* FITS header string */
const char *keyword;	/* Keyword name */
const double ra;		/* Right ascension in degrees */
{
    char value[30];

    /* Translate value from binary to ASCII */
    ra2str (value, 30, ra, 3);

    /* Remove sign if string is -0 or extension thereof */
    fixnegzero (value);

    /* Put value into header string */
    return (hputs (hstring, keyword, value));
}


/*  HPUTDEC - Set double keyword = dd:mm:ss.sss in FITS header string */

int
hputdec (hstring, keyword, dec)

char *hstring;		/* FITS header string */
const char *keyword;	/* Keyword name */
const double dec;		/* Declination in degrees */
{
    char value[30];

    /* Translate value from binary to ASCII */
    dec2str (value, 30, dec, 2);

    /* Remove sign if string is -0 or extension thereof */
    fixnegzero (value);

    /* Put value into header string */
    return (hputs (hstring, keyword, value));
}


/* FIXNEGZERO -- Drop - sign from beginning of any string which is all zeros */

static void
fixnegzero (string)

char *string;
{
    int i, lstr;

    if (string[0] != '-')
	return;

    /* Drop out if any non-zero digits in this string */
    lstr = (int) strlen (string);
    for (i = 1; i < lstr; i++) {
	if (string[i] > '0' && string[i] <= '9')
	    return;
	if (string[i] == 'd' || string[i] == 'e' || string[i] == ' ')
	    break;
	}

    /* Drop - from start of string; overwrite string in place */
    for (i = 1; i < lstr; i++)
	string[i-1] = string[i];
    string[lstr-1] = (char) 0;

    return;
}



/*  HPUTL - Set keyword = F if lval=0, else T, in FITS header string */

int
hputl (hstring, keyword,lval)

char *hstring;		/* FITS header */
const char *keyword;	/* Keyword name */
const int lval;		/* logical variable (0=false, else true) */
{
    char value[8];

    /* Translate value from binary to ASCII */
    if (lval)
	strcpy (value, "T");
    else
	strcpy (value, "F");

    /* Put value into header string */
    return (hputc (hstring,keyword,value));
}


/*  HPUTM - Set multi-line character string in FITS header string */
/*          return number of keywords written */

int
hputm (hstring,keyword,cval)

char *hstring;	/* FITS header */
const char *keyword;	/* Keyword name root (6 characters or less) */
const char *cval;	/* character string containing the value for variable
		   keyword.  trailing and leading blanks are removed.  */
{
    int lroot, lcv, i, ii, nkw, lkw, lval;
    int comment = 0;
    const char *v;
    char keyroot[8], newkey[12], value[80];
    char squot = 39;

    /*  If COMMENT or HISTORY, use the same keyword on every line */
    lkw = (int) strlen (keyword);
    if (lkw == 7 && (strncmp (keyword,"COMMENT",7) == 0 ||
	strncmp (keyword,"HISTORY",7) == 0)) {
	comment = 1;
	lroot = 0;
	}

    /* Set up keyword root, shortening it to 6 characters, if necessary */
    else {
	comment = 0;
	strcpy (keyroot, keyword);
	lroot = (int) strlen (keyroot);
	if (lroot > 6) {
	    keyroot[6] = (char) 0;
	    lroot = 6;
	    }
	}

    /* Write keyword value one line of up to 67 characters at a time */
    ii = '1';
    nkw = 0;
    lcv = (int) strlen (cval);
    if (!comment) {
	strcpy (newkey, keyroot);
	strcat (newkey, "_");
	newkey[lroot+2] = (char) 0;
	}
    v = cval;
    while (lcv > 0) {
	if (lcv > 67)
	    lval = 67;
	else
	    lval = lcv;
	value[0] = squot;
	for (i = 1; i <= lval; i++)
	    value[i] = *v++;

	/* Pad short strings to 8 characters */
	if (lval < 8) {
	    for (i = lval+1; i < 9; i++)
		value[i] = ' ';
	    lval = 8;
	    }
	value[lval+1] = squot;
	value[lval+2] = (char) 0;

	/* Add this line to the header */
	if (comment)
	    i = hputc (hstring, keyroot, value);
	else {
	    newkey[lroot+1] = ii;
	    ii++;
	    i = hputc (hstring, newkey, value);
	    }
	if (i != 0) return (i);
	nkw++;
	if (lcv > 67)
	    lcv = lcv - 67;
	else
	    break;
	}
    return (nkw);
}


/*  HPUTS - Set character string keyword = 'cval' in FITS header string */

int
hputs (hstring,keyword,cval)

char *hstring;	/* FITS header */
const char *keyword; /* Keyword name */
const char *cval; /* character string containing the value for variable
		   keyword.  trailing and leading blanks are removed.  */
{
    char squot = 39;
    char value[80];
    int lcval, i, lkeyword;

    /*  If COMMENT or HISTORY, just add it as is */
    lkeyword = (int) strlen (keyword);
    if (lkeyword == 7 && (strncmp (keyword,"COMMENT",7) == 0 ||
	strncmp (keyword,"HISTORY",7) == 0))
	return (hputc (hstring,keyword,cval));

    /*  find length of variable string */
    lcval = (int) strlen (cval);
    if (lcval > 67)
	lcval = 67;

    /* Put single quote at start of string */
    value[0] = squot;
    strncpy (&value[1],cval,lcval);

    /* If string is less than eight characters, pad it with spaces */
    if (lcval < 8) {
	for (i = lcval; i < 8; i++) {
	    value[i+1] = ' ';
	    }
	lcval = 8;
	}

    /* Add single quote and null to end of string */
    value[lcval+1] = squot;
    value[lcval+2] = (char) 0;

    /* Put value into header string */
    return (hputc (hstring,keyword,value));
}


/*  HPUTC - Set character string keyword = value in FITS header string */
/*          Return -1 if error, 0 if OK */

int
hputc (hstring,keyword,value)

char *hstring;
const char *keyword;
const char *value; /* character string containing the value for variable
		   keyword.  trailing and leading blanks are removed.  */
{
    char squot = 39;
    char line[100];
    char newcom[50];
    char *vp, *v1, *v2, *q1, *q2, *c1, *ve;
    int lkeyword, lcom, lval, lc, lv1, lhead, lblank, ln, nc, i;

    /* Find length of keyword, value, and header */
    lkeyword = (int) strlen (keyword);
    lval = (int) strlen (value);
    lhead = gethlength (hstring);

    /*  If COMMENT or HISTORY, always add it just before the END */
    if (lkeyword == 7 && (strncmp (keyword,"COMMENT",7) == 0 ||
	strncmp (keyword,"HISTORY",7) == 0)) {
	
	/* First look for blank lines before END */
        v1 = blsearch (hstring, "END");
    
	/*  Otherwise, create a space for it at the end of the header */
	if (v1 == NULL) {

	    /* Find end of header */
	    v1 = ksearch (hstring,"END");

	    /* Align pointer at start of 80-character line */
	    lc = v1 - hstring;
	    ln = lc / 80;
	    nc = ln * 80;
	    v1 = hstring + nc;
	    v2 = v1 + 80;

	    /* If header length is exceeded, return error code */
	    if (v2 - hstring > lhead) {
		return (-1);
		}

	    /* Move END down 80 characters */
	    strncpy (v2, v1, 80);
	    }
	else
	    v2 = v1 + 80;

	/* Insert keyword */
	strncpy (v1,keyword,7);

	/* Pad with spaces */
	for (vp = v1+lkeyword; vp < v2; vp++)
	    *vp = ' ';

	if (lval > 71)
	    lv1 = 71;
	else
	    lv1 = lval;

	/* Insert comment */
	strncpy (v1+9,value,lv1);
	return (0);
	}

    /* Otherwise search for keyword */
    else
	v1 = ksearch (hstring,keyword);

    /*  If parameter is not found, find a place to put it */
    if (v1 == NULL) {
	
	/* First look for blank lines before END */
        v1 = blsearch (hstring, "END");
    
	/*  Otherwise, create a space for it at the end of the header */
	if (v1 == NULL) {
	    ve = ksearch (hstring,"END");
	    v1 = ve;

	    /* Align pointer at start of 80-character line */
	    lc = v1 - hstring;
	    ln = lc / 80;
	    nc = ln * 80;
	    v1 = hstring + nc;
	    v2 = v1 + 80;

	    /* If header length is exceeded, return error code */
	    if (v2 - hstring > lhead) {
		return (-1);
		}

	    strncpy (v2, ve, 80);
	    }
	else
	    v2 = v1 + 80;
	lcom = 0;
	newcom[0] = 0;
	}

    /*  Otherwise, extract the entry for this keyword from the header */
    else {

	/* Align pointer at start of 80-character line */
	lc = v1 - hstring;
	ln = lc / 80;
	nc = ln * 80;
	v1 = hstring + nc;
	v2 = v1 + 80;

	strncpy (line, v1, 80);
	line[80] = 0;
	v2 = v1 + 80;

	/*  check for quoted value */
	q1 = strchr (line, squot);
	if (q1 != NULL) {
	    q2 = strchr (q1+1,squot);
	    if (q2 != NULL)
		c1 = strchr (q2,'/');
	    else
		c1 = strrchr (line+79,'/');
	    }
	else
	    c1 = strchr (line,'/');

	/*  extract comment and discount trailing spaces */
	if (c1 != NULL) {
	    lcom = 80 - (c1 + 2 - line);
	    strncpy (newcom, c1+2, lcom);
	    vp = newcom + lcom - 1;
	    while (vp-- > newcom && *vp == ' ')
		lcom--;
	    }
	else {
	    newcom[0] = 0;
	    lcom = 0;
	    }
	}

    /* Fill new entry with spaces */
    for (vp = v1; vp < v2; vp++)
	*vp = ' ';

    /*  Copy keyword to new entry */
    strncpy (v1, keyword, lkeyword);

    /*  Add parameter value in the appropriate place */
    vp = v1 + 8;
    *vp = '=';
    vp = v1 + 9;
    *vp = ' ';
    vp = vp + 1;
    if (*value == squot) {
	strncpy (vp, value, lval);
	if (lval+12 > 31)
	    lc = lval + 12;
	else
	    lc = 30;
	}
    else {
	vp = v1 + 30 - lval;
	strncpy (vp, value, lval);
	lc = 30;
	}

    /* Add comment in the appropriate place */
	if (lcom > 0) {
	    if (lc+2+lcom > 80)
		lcom = 77 - lc;
	    vp = v1 + lc;     /* Jul 16 1997: was vp = v1 + lc * 2 */
	    *vp++ = ' ';
	    *vp++ = '/';
	    *vp++ = ' ';
	    lblank = v2 - vp;
	    for (i = 0; i < lblank; i++)
		vp[i] = ' ';
	    if (lcom > lblank)
		lcom = lblank;
	    strncpy (vp, newcom, lcom);
	    }

	if (verbose) {
	    if (lcom > 0)
		fprintf (stderr,"HPUT: %s  = %s  / %s\n",keyword, value, newcom);
	    else
		fprintf (stderr,"HPUT: %s  = %s\n",keyword, value);
	    }

	return (0);
}


/*  HPUTCOM - Set comment for keyword or on line in FITS header string */

int
hputcom (hstring,keyword,comment)

  char *hstring;
  const char *keyword;
  const char *comment;
{
    char squot, slash, space;
    char line[100];
    int lkeyword, lcom, lhead, i, lblank, ln, nc, lc;
    char *vp, *v1, *v2, *c0, *c1, *q1, *q2;

    squot = (char) 39;
    slash = (char) 47;
    space = (char) 32;

    /*  Find length of variable name */
    lkeyword = (int) strlen (keyword);
    lhead = gethlength (hstring);
    lcom = (int) strlen (comment);

    /*  If COMMENT or HISTORY, always add it just before the END */
    if (lkeyword == 7 && (strncmp (keyword,"COMMENT",7) == 0 ||
	strncmp (keyword,"HISTORY",7) == 0)) {

	/* Find end of header */
	v1 = ksearch (hstring,"END");

	/* Align pointer at start of 80-character line */
	lc = v1 - hstring;
	ln = lc / 80;
	nc = ln * 80;
	v1 = hstring + nc;
	v2 = v1 + 80;

	/* If header length is exceeded, return error code */
	if (v2 - hstring > lhead) {
	    return (-1);
	    }

	/* Move END down 80 characters */
	strncpy (v2, v1, 80);

	/*  blank out new line and insert keyword */
	for (vp = v1; vp < v2; vp++)
	    *vp = ' ';
	strncpy (v1, keyword, lkeyword);
	c0 = v1 + lkeyword;
	}

    /* Search header string for variable name */
    else {
	v1 = ksearch (hstring,keyword);

	/* If parameter is not found, return without doing anything */
	if (v1 == NULL) {
	    if (verbose)
		fprintf (stderr,"HPUTCOM: %s not found\n",keyword);
	    return (-1);
	    }

	/* Align pointer at start of 80-character line */
	lc = v1 - hstring;
	ln = lc / 80;
	nc = ln * 80;
	v1 = hstring + nc;
	v2 = v1 + 80;

	/* Extract entry for this variable from the header */
	strncpy (line, v1, 80);
	line[80] = '\0'; /* Null-terminate line before strchr call */

	/* check for quoted value */
	q1 = strchr (line,squot);
	c1 = strchr (line,slash);
	if (q1 != NULL) {
	    if (c1 != NULL && q1 < c1) {
		q2 = strchr (q1+1, squot);
		if (q2 == NULL) {
		    q2 = c1 - 1;
		    while (*q2 == space)
			q2--;
		    q2++;
		    }
		else if (c1 < q2)
		    c1 = strchr (q2, slash);
		}
	    else if (c1 == NULL) {
		q2 = strchr (q1+1, squot);
		if (q2 == NULL) {
		    q2 = line + 79;
		    while (*q2 == space)
			q2--;
		    q2++;
		    }
		}
	    else
		q1 = NULL;
		q2 = NULL;
	    }

	else
	    q2 = NULL;

	if (c1 != NULL)
	    c0 = v1 + (c1 - line) - 1;
	else if (q2 == NULL || q2-line < 30)
	    c0 = v1 + 30;
	else
	    c0 = v1 + (q2 - line) + 1; /* allan: 1997-09-30, was c0=q2+2 */

	/* If comment will not fit at all, return */
	if (c0 - v1 > 77)
	    return (-1);
	strncpy (c0, " / ",3);
	}

    /* Create new entry */
    if (lcom > 0) {
	c1 = c0 + 3;
	lblank = v1 + 79 - c1;
	if (lcom > lblank)
	    lcom = lblank;
	for (i = 0; i < lblank; i++)
	    c1[i] = ' ';
	strncpy (c1, comment, lcom);
	}

    if (verbose) {
	fprintf (stderr,"HPUTCOM: %s / %s\n",keyword,comment);
	}
    return (0);
}


static int leaveblank = 0;	/* If 1, leave blank line when deleting */
void
setleaveblank (lb)
int lb; { leaveblank = lb; return; }

static int headshrink=1; /* Set to 1 to drop line after deleting keyword */
void
setheadshrink (hsh)
int hsh;
{headshrink = hsh; return;}

/*  HDEL - Set character string keyword = value in FITS header string
 *	    returns 1 if entry deleted, else 0
 */

int
hdel (hstring,keyword)

char *hstring;		/* FITS header */
const char *keyword;	/* Keyword of entry to be deleted */
{
    char *v, *v1, *v2, *ve;

    /* Search for keyword */
    v1 = ksearch (hstring,keyword);

    /*  If keyword is not found, return header unchanged */
    if (v1 == NULL) {
	return (0);
	}

    /*  Find end of header */
    ve = ksearch (hstring,"END");

    /* If headshrink is 0, leave END where it is */
    if (!leaveblank && !headshrink)
	ve = ve - 80;

    /* Cover deleted keyword line with spaces */
    if (leaveblank) {
	v2 = v1 + 80;
	for (v = ve; v < v2; v++)
	    *v = ' ';
	}

    /* Shift rest of header up one line */
    else {
	for (v = v1; v < ve; v = v + 80) {
	    v2 = v + 80;
	    strncpy (v, v2, 80);
	    }

	/* Cover former last line with spaces */
	v2 = ve + 80;
	for (v = ve; v < v2; v++)
	    *v = ' ';
	}

    return (1);
}


/*  HADD - Add character string keyword = value to FITS header string
 *	    returns 1 if entry added, else 0
 *	    Call hputx() to put value into entry
 */

int
hadd (hplace, keyword)

char *hplace;		/* FITS header position for new keyword */
const char *keyword;	/* Keyword of entry to be deleted */
{
    char *v, *v1, *v2, *ve;
    int i, lkey;

    /*  Find end of header */
    ve = ksearch (hplace,"END");

    /*  If END is not found, return header unchanged */
    if (ve == NULL) {
	return (0);
	}

    v1 = hplace;

    /* Shift rest of header down one line */
    /* limit bug found by Paolo Montegriffo fixed 2000-04-19 */
    for (v = ve; v >= v1; v = v - 80) {
	v2 = v + 80;
	strncpy (v2, v, 80);
	}

    /* Cover former first line with new keyword */
    lkey = (int) strlen (keyword);
    strncpy (hplace, keyword, lkey);
    if (lkey < 8) {
	for (i = lkey; i < 8; i++)
	    hplace[i] = ' ';
	hplace[8] = '=';
	}
    for (i = 9; i < 80; i++)
	hplace[i] = ' ';

    return (1);
}


/*  HCHANGE - Changes keyword for entry from keyword1 to keyword2 in FITS
              header string
 *	      returns 1 if entry changed, else 0
 */

int
hchange (hstring, keyword1, keyword2)

char *hstring;		/* FITS header */
const char *keyword1;	/* Keyword to be changed */
const char *keyword2;	/* New keyword name */
{
    char *v, *v1;
    const char *v2;
    int lv2, i;

    /* Search for keyword */
    v1 = ksearch (hstring,keyword1);

    /*  If keyword is not found, return header unchanged */
    if (!v1)
	return (0);

    else {
	lv2 = (int) strlen (keyword2);
	v = v1;
	v2 = keyword2;
	for (i = 0; i < 8; i++) {
	    if (i < lv2)
		v[i] = v2[i];
	    else
		v[i] = ' ';
	    }
	}

    return (1);
}


/* Write the right ascension ra in sexagesimal format into string*/

void
ra2str (string, lstr, ra, ndec)

char	*string;	/* Character string (returned) */
int	lstr;		/* Maximum number of characters in string */
double	ra;		/* Right ascension in degrees */
int	ndec;		/* Number of decimal places in seconds */

{
    double a,b;
    double seconds;
    char tstring[64];
    int hours;
    int minutes;
    int isec, ltstr;
    double dsgn;

    /* Keep RA between 0 and 360 */
    if (ra < 0.0 ) {
	ra = -ra;
	dsgn = -1.0;
	}
    else
	dsgn = 1.0;
    ra = fmod(ra, 360.0);
    ra *= dsgn;
    if (ra < 0.0)
	ra = ra + 360.0;

    a = ra / 15.0;

    /* Convert to hours */
    hours = (int) a;

    /* Compute minutes */
    b =  (a - (double)hours) * 60.0;
    minutes = (int) b;

    /* Compute seconds */
    seconds = (b - (double)minutes) * 60.0;

    if (ndec > 5) {
	if (seconds > 59.999999) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    hours = hours + 1;
	    }
	hours = hours % 24;
	(void) sprintf (tstring,"%02d:%02d:%09.6f",hours,minutes,seconds);
	}
    else if (ndec > 4) {
	if (seconds > 59.99999) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    hours = hours + 1;
	    }
	hours = hours % 24;
	(void) sprintf (tstring,"%02d:%02d:%08.5f",hours,minutes,seconds);
	}
    else if (ndec > 3) {
	if (seconds > 59.9999) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    hours = hours + 1;
	    }
	hours = hours % 24;
	(void) sprintf (tstring,"%02d:%02d:%07.4f",hours,minutes,seconds);
	}
    else if (ndec > 2) {
	if (seconds > 59.999) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    hours = hours + 1;
	    }
	hours = hours % 24;
	(void) sprintf (tstring,"%02d:%02d:%06.3f",hours,minutes,seconds);
	}
    else if (ndec > 1) {
	if (seconds > 59.99) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    hours = hours + 1;
	    }
	hours = hours % 24;
	(void) sprintf (tstring,"%02d:%02d:%05.2f",hours,minutes,seconds);
	}
    else if (ndec > 0) {
	if (seconds > 59.9) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    hours = hours + 1;
	    }
	hours = hours % 24;
	(void) sprintf (tstring,"%02d:%02d:%04.1f",hours,minutes,seconds);
	}
    else {
	isec = (int)(seconds + 0.5);
	if (isec > 59) {
	    isec = 0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    hours = hours + 1;
	    }
	hours = hours % 24;
	(void) sprintf (tstring,"%02d:%02d:%02d",hours,minutes,isec);
	}

    /* Move formatted string to returned string */
    ltstr = (int) strlen (tstring);
    if (ltstr < lstr-1)
	strcpy (string, tstring);
    else {
	strncpy (string, tstring, lstr-1);
	string[lstr-1] = 0;
	}
    return;
}


/* Write the variable a in sexagesimal format into string */

void
dec2str (string, lstr, dec, ndec)

char	*string;	/* Character string (returned) */
int	lstr;		/* Maximum number of characters in string */
double	dec;		/* Declination in degrees */
int	ndec;		/* Number of decimal places in arcseconds */

{
    double a, b, dsgn, deg1;
    double seconds;
    char sign;
    int degrees;
    int minutes;
    int isec, ltstr;
    char tstring[64];

    /* Keep angle between -180 and 360 degrees */
    deg1 = dec;
    if (deg1 < 0.0 ) {
	deg1 = -deg1;
	dsgn = -1.0;
	}
    else
	dsgn = 1.0;
    deg1 = fmod(deg1, 360.0);
    deg1 *= dsgn;
    if (deg1 <= -180.0)
	deg1 = deg1 + 360.0;

    a = deg1;

    /* Set sign and do all the rest with a positive */
    if (a < 0) {
	sign = '-';
	a = -a;
	}
    else
	sign = '+';

    /* Convert to degrees */
    degrees = (int) a;

    /* Compute minutes */
    b =  (a - (double)degrees) * 60.0;
    minutes = (int) b;

    /* Compute seconds */
    seconds = (b - (double)minutes) * 60.0;

    if (ndec > 5) {
	if (seconds > 59.999999) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    degrees = degrees + 1;
	    }
	(void) sprintf (tstring,"%c%02d:%02d:%09.6f",sign,degrees,minutes,seconds);
	}
    else if (ndec > 4) {
	if (seconds > 59.99999) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    degrees = degrees + 1;
	    }
	(void) sprintf (tstring,"%c%02d:%02d:%08.5f",sign,degrees,minutes,seconds);
	}
    else if (ndec > 3) {
	if (seconds > 59.9999) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    degrees = degrees + 1;
	    }
	(void) sprintf (tstring,"%c%02d:%02d:%07.4f",sign,degrees,minutes,seconds);
	}
    else if (ndec > 2) {
	if (seconds > 59.999) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    degrees = degrees + 1;
	    }
	(void) sprintf (tstring,"%c%02d:%02d:%06.3f",sign,degrees,minutes,seconds);
	}
    else if (ndec > 1) {
	if (seconds > 59.99) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    degrees = degrees + 1;
	    }
	(void) sprintf (tstring,"%c%02d:%02d:%05.2f",sign,degrees,minutes,seconds);
	}
    else if (ndec > 0) {
	if (seconds > 59.9) {
	    seconds = 0.0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    degrees = degrees + 1;
	    }
	(void) sprintf (tstring,"%c%02d:%02d:%04.1f",sign,degrees,minutes,seconds);
	}
    else {
	isec = (int)(seconds + 0.5);
	if (isec > 59) {
	    isec = 0;
	    minutes = minutes + 1;
	    }
	if (minutes > 59) {
	    minutes = 0;
	    degrees = degrees + 1;
	    }
	(void) sprintf (tstring,"%c%02d:%02d:%02d",sign,degrees,minutes,isec);
	}

    /* Move formatted string to returned string */
    ltstr = (int) strlen (tstring);
    if (ltstr < lstr-1)
	strcpy (string, tstring);
    else {
	strncpy (string, tstring, lstr-1);
	string[lstr-1] = 0;
	}
   return;
}


/* Write the angle a in decimal format into string */

void
deg2str (string, lstr, deg, ndec)

char	*string;	/* Character string (returned) */
int	lstr;		/* Maximum number of characters in string */
double	deg;		/* Angle in degrees */
int	ndec;		/* Number of decimal places in degree string */

{
    char degform[8];
    int field, ltstr;
    char tstring[64];
    double deg1;
    double dsgn;

    /* Keep angle between -180 and 360 degrees */
    deg1 = deg;
    if (deg1 < 0.0 ) {
	deg1 = -deg1;
	dsgn = -1.0;
	}
    else
	dsgn = 1.0;
    deg1 = fmod(deg1, 360.0);
    deg1 *= dsgn;
    if (deg1 <= -180.0)
	deg1 = deg1 + 360.0;

    /* Write angle to string, adding 4 digits to number of decimal places */
    field = ndec + 4;
    if (ndec > 0) {
	sprintf (degform, "%%%d.%df", field, ndec);
	sprintf (tstring, degform, deg1);
	}
    else {
	sprintf (degform, "%%%4d", field);
	sprintf (tstring, degform, (int)deg1);
	}

    /* Move formatted string to returned string */
    ltstr = (int) strlen (tstring);
    if (ltstr < lstr-1)
	strcpy (string, tstring);
    else {
	strncpy (string, tstring, lstr-1);
	string[lstr-1] = 0;
	}
    return;
}


/* Write the variable a in decimal format into field-character string  */

void
num2str (string, num, field, ndec)

char	*string;	/* Character string (returned) */
double	num;		/* Number */
int	field;		/* Number of characters in output field (0=any) */
int	ndec;		/* Number of decimal places in degree string */

{
    char numform[8];

    if (field > 0) {
	if (ndec > 0) {
	    sprintf (numform, "%%%d.%df", field, ndec);
	    sprintf (string, numform, num);
	    }
	else {
	    sprintf (numform, "%%%dd", field);
	    sprintf (string, numform, (int)num);
	    }
	}
    else {
	if (ndec > 0) {
	    sprintf (numform, "%%.%df", ndec);
	    sprintf (string, numform, num);
	    }
	else {
	    sprintf (string, "%d", (int)num);
	    }
	}
    return;
}

/* Dec 14 1995	Original subroutines

 * Feb  5 1996	Added HDEL to delete keyword entry from FITS header
 * Feb  7 1996	Add EOS to LINE in HPUTC
 * Feb 21 1996	Add RA2STR and DEC2STR string routines
 * Jul 19 1996	Add HPUTRA and HPUTDEC
 * Jul 22 1996	Add HCHANGE to change keywords
 * Aug  5 1996	Add HPUTNR8 to save specific number of decimal places
 * Oct 15 1996	Fix spelling
 * Nov  1 1996	Add DEG2STR to set specific number of decimal places
 * Nov  1 1996	Allow DEC2STR to handle upt to 6 decimal places
 *
 * Mar 20 1997	Fix format error in DEG2STR
 * Jul  7 1997	Fix 2 errors in HPUTCOM found by Allan Brighton
 * Jul 16 1997	Fix error in HPUTC found by Allan Brighton
 * Jul 17 1997	Fix error in HPUTC found by Allan Brighton
 * Sep 30 1997	Fix error in HPUTCOM found by Allan Brighton
 * Dec 15 1997	Fix minor bugs after lint
 * Dec 31 1997	Always put two hour digits in RA2STR
 *
 * Feb 25 1998	Add HADD to insert keywords at specific locations
 * Mar 27 1998	If n is negative, write g format in HPUTNR8()
 * Apr 24 1998	Add NUM2STR() for easy output formatting
 * Apr 30 1998	Use BLSEARCH() to overwrite blank lines before END
 * May 27 1998	Keep Dec between -90 and +90 in DEC2STR()
 * May 28 1998	Keep RA between 0 and 360 in RA2STR()
 * Jun  2 1998	Fix bug when filling in blank lines before END
 * Jun 24 1998	Add string length to ra2str(), dec2str(), and deg2str()
 * Jun 25 1998	Make string converstion subroutines more robust
 * Aug 31 1998	Add getltime() and getutime()
 * Sep 28 1998	Null-terminate comment in HPUTCOM (Allan Brighton)
 * Oct  1 1998	Change clock declaration in getltime() from int (Allan Brighton)
 *
 * Jan 28 1999	Fix bug to avoid writing HISTORY or COMMENT past 80 characters
 * Jul 14 1999	Pad string in hputs() to minimum of 8 characters
 * Aug 16 1999	Keep angle between -180 and +360 in dec2str()
 * Oct  6 1999	Reallocate header buffer if it is too small in hputc()
 * Oct 14 1999	Do not reallocate header; return error if not successful
 *
 * Mar  2 2000	Do not add quotes if adding HISTORY or COMMENT with hputs()
 * Mar 22 2000	Move getutime() and getltime() to dateutil.c
 * Mar 27 2000	Add hputm() for muti-line keywords
 * Mar 27 2000	Fix bug testing for space to fit comment in hputcom()
 * Apr 19 2000	Fix bug in hadd() which overwrote line
 * Jun  2 2000	Dropped unused variable lv in hputm() after lint
 * Jul 20 2000	Drop unused variables blank and i in hputc()
 *
 * Jan 11 2001	Print all messages to stderr
 * Jan 18 2001	Drop declaration of blsearch(); it is in fitshead.h
 *
 * Jan  4 2002	Fix placement of comments
 *
 * Jul  1 2004	Add headshrink to optionally keep blank lines in header
 * Sep  3 2004	Fix bug so comments are not pushed onto next line if long value
 * Sep 16 2004	Add fixnegzero() to avoid putting signed zero values in header
 *
 * May 22 2006	Add option to leave blank line when deleting a keyword
 * Jun 15 2006	Fix comment alignment in hputc() and hputcom()
 * Jun 20 2006	Initialized uninitialized variables in hputm() and hputcom()
 *
 * Jan  4 2007	Declare keyword to be const
 * Jan  4 2007	Drop unused subroutine hputi2()
 * Jan  5 2007	Drop ksearch() declarations; it is now in fitshead.h
 * Jan 16 2007	Fix bugs in ra2str() and dec2str() so ndec=0 works
 * Aug 20 2007	Fix bug so comments after quoted keywords work
 * Aug 22 2007	If closing quote not found, make one up
 *
 * Sep  9 2011	Always initialize q2 and lroot
 */
