FACT++  1.0
palDfltin.c
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1 /*
2 *+
3 * Name:
4 * palDfltin
5 
6 * Purpose:
7 * Convert free-format input into double precision floating point
8 
9 * Language:
10 * Starlink ANSI C
11 
12 * Type of Module:
13 * Library routine
14 
15 * Invocation:
16 * void palDfltin( const char * string, int *nstrt,
17 * double *dreslt, int *jflag );
18 
19 * Arguments:
20 * string = const char * (Given)
21 * String containing number to be decoded.
22 * nstrt = int * (Given and Returned)
23 * Character number indicating where decoding should start.
24 * On output its value is updated to be the location of the
25 * possible next value. For compatibility with SLA the first
26 * character is index 1.
27 * dreslt = double * (Returned)
28 * Result. Not updated when jflag=1.
29 * jflag = int * (Returned)
30 * status: -1 = -OK, 0 = +OK, 1 = null, 2 = error
31 
32 * Description:
33 * Extracts a number from an input string starting at the specified
34 * index.
35 
36 * Authors:
37 * TIMJ: Tim Jenness (JAC, Hawaii)
38 * {enter_new_authors_here}
39 
40 * Notes:
41 * - Uses the strtod() system call to do the parsing. This may lead to
42 * subtle differences when compared to the SLA/F parsing.
43 * - All "D" characters are converted to "E" to handle fortran exponents.
44 * - Commas are recognized as a special case and are skipped if one happens
45 * to be the next character when updating nstrt. Additionally the output
46 * nstrt position will skip past any trailing space.
47 * - If no number can be found flag will be set to 1.
48 * - If the number overflows or underflows jflag will be set to 2. For overflow
49 * the returned result will have the value HUGE_VAL, for underflow it
50 * will have the value 0.0.
51 * - For compatiblity with SLA/F -0 will be returned as "0" with jflag == -1.
52 * - Unlike slaDfltin a standalone "E" will return status 1 (could not find
53 * a number) rather than 2 (bad number).
54 
55 * Implementation Status:
56 * - The code is more robust if the C99 copysign() function is available.
57 * This can recognize the -0.0 values returned by strtod. If copysign() is
58 * missing we try to scan the string looking for minus signs.
59 
60 * History:
61 * 2012-03-08 (TIMJ):
62 * Initial version based on strtod
63 * Adapted with permission from the Fortran SLALIB library
64 * although this is a completely distinct implementation of the SLA API.
65 * 2012-06-21 (TIMJ):
66 * Provide a backup for missing copysign.
67 * 2012-06-22 (TIMJ):
68 * Check __STDC_VERSION__
69 * {enter_further_changes_here}
70 
71 * Copyright:
72 * Copyright (C) 2012 Science and Technology Facilities Council.
73 * All Rights Reserved.
74 
75 * Licence:
76 * This program is free software; you can redistribute it and/or
77 * modify it under the terms of the GNU General Public License as
78 * published by the Free Software Foundation; either version 3 of
79 * the License, or (at your option) any later version.
80 *
81 * This program is distributed in the hope that it will be
82 * useful, but WITHOUT ANY WARRANTY; without even the implied
83 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
84 * PURPOSE. See the GNU General Public License for more details.
85 *
86 * You should have received a copy of the GNU General Public License
87 * along with this program; if not, write to the Free Software
88 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
89 * MA 02110-1301, USA.
90 
91 * Bugs:
92 * {note_any_bugs_here}
93 *-
94 */
95 
96 /* Use the config file if we have one, else look at
97  compiler defines to see if we have C99 */
98 #if HAVE_CONFIG_H
99 #include <config.h>
100 #else
101 #ifdef __STDC_VERSION__
102 # if (__STDC_VERSION__ >= 199901L)
103 # define HAVE_COPYSIGN 1
104 # endif
105 #endif
106 #endif
107 
108 /* isblank() is a C99 feature so we just reimplement it if it is missing */
109 #if HAVE_ISBLANK
110 #define _POSIX_C_SOURCE 200112L
111 #define _ISOC99_SOURCE
112 #include <ctype.h>
113 # define ISBLANK isblank
114 #else
115 
116 static int ISBLANK( int c ) {
117  return ( c == ' ' || c == '\t' );
118 }
119 
120 #endif
121 
122 #ifdef HAVE_BSD_STRING_H
123 #include <bsd/string.h>
124 #endif
125 
126 /* System include files */
127 #include <stdlib.h>
128 #include <string.h>
129 #include <errno.h>
130 #include <ctype.h>
131 
132 #include "pal.h"
133 
134 #if HAVE_COPYSIGN
135 # define SCAN_FOR_MINUS 0
136 #else
137 # define SCAN_FOR_MINUS 1
138 #endif
139 
140 /* We prefer to use the starutil package */
141 #if HAVE_STAR_UTIL_H
142 # include "star/util.h"
143 #else
144 #endif
145 
146 void palDfltin( const char * string, int *nstrt,
147  double *dreslt, int *jflag ) {
148 
149  char * ctemp = NULL; /* Pointer into string */
150  char * endptr = NULL;/* Pointer to string after number */
151  double retval; /* Return value from strtod */
152 
153  /* We have to copy the string in order to modify the exponents
154  from Fortran style. Rather than using malloc we have a static
155  buffer. Technically we only have to do the copy if we have a
156  D or d in the string. */
157  char tempbuf[256];
158 
159 #if SCAN_FOR_MINUS
160  int dreslt_sign = 1;
161  int ipos = *nstrt;
162  const char * cctemp = NULL;
163 
164  /* Scan the string looking for a minus sign. Then update the
165  start position for the subsequent copy iff we find a '-'.
166  Note that commas are a special delimiter so we stop looking for a
167  minus if we find one or if we find a digit. */
168  cctemp = &(string[ipos-1]);
169  while (!isdigit(*cctemp) && (*cctemp != ',') && (*cctemp != '\0')) {
170  if (*cctemp == '-') {
171  *nstrt = ipos;
172  dreslt_sign = -1;
173  break;
174  }
175  ipos++;
176  cctemp++;
177  }
178 #endif
179 
180  /* Correct for SLA use of fortran convention */
181 #if HAVE_STAR_UTIL_H
182  star_strlcpy( tempbuf, &(string[*nstrt-1]), sizeof(tempbuf) );
183 #else
184 # if HAVE_STRLCPY
185  strlcpy( tempbuf, &(string[*nstrt-1]), sizeof(tempbuf) );
186 # else
187  /* Use standard C interface */
188  strncpy( tempbuf, &(string[*nstrt-1]), sizeof(tempbuf));
189  tempbuf[sizeof(tempbuf)-1] = '\0';
190 # endif
191 #endif
192 
193  /* Convert d or D to E */
194  ctemp = tempbuf;
195  while (*ctemp != '\0') {
196  if (*ctemp == 'd' || *ctemp == 'D') *ctemp = 'E';
197  ctemp++;
198  }
199 
200  /* strtod man page indicates that we should reset errno before
201  calling strtod */
202  errno = 0;
203 
204  /* We know we are starting at the beginning of the string now */
205  retval = strtod( tempbuf, &endptr );
206  if (retval == 0.0 && endptr == tempbuf) {
207  /* conversion did not find anything */
208  *jflag = 1;
209 
210  /* but SLA compatibility requires that we step
211  through to remove leading spaces. We also step
212  through alphabetic characters since they can never
213  be numbers standalone (no number starts with an 'E') */
214  while (ISBLANK(*endptr) || isalpha(*endptr) ) {
215  endptr++;
216  }
217 
218  } else if ( errno == ERANGE ) {
219  *jflag = 2;
220  } else {
221 #if SCAN_FOR_MINUS
222  *jflag = (dreslt_sign < 0 ? -1 : 0);
223 #else
224  if ( retval < 0.0 ) {
225  *jflag = -1;
226  } else if ( retval == 0.0 ) {
227  /* Need to distinguish -0 from +0 */
228  double test = copysign( 1.0, retval );
229  if ( test < 0.0 ) {
230  *jflag = -1;
231  } else {
232  *jflag = 0;
233  }
234  } else {
235  *jflag = 0;
236  }
237 #endif
238  }
239 
240  /* Sort out the position for the next index */
241  *nstrt += endptr - tempbuf;
242 
243  /* Skip a comma */
244  if (*endptr == ',') {
245  (*nstrt)++;
246  } else {
247  /* jump past any leading spaces for the next part of the string */
248  ctemp = endptr;
249  while ( ISBLANK(*ctemp) ) {
250  (*nstrt)++;
251  ctemp++;
252  }
253  }
254 
255  /* And the result unless we found nothing */
256  if (*jflag != 1) *dreslt = retval;
257 
258 }
void palDfltin(const char *string, int *nstrt, double *dreslt, int *jflag)
Definition: palDfltin.c:146
static int ISBLANK(int c)
Definition: palDfltin.c:116