Fix link for ASN1_generate_nconf
[openssl.git] / crypto / conf / conf_def.c
1 /* crypto/conf/conf.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3  * All rights reserved.
4  *
5  * This package is an SSL implementation written
6  * by Eric Young (eay@cryptsoft.com).
7  * The implementation was written so as to conform with Netscapes SSL.
8  * 
9  * This library is free for commercial and non-commercial use as long as
10  * the following conditions are aheared to.  The following conditions
11  * apply to all code found in this distribution, be it the RC4, RSA,
12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13  * included with this distribution is covered by the same copyright terms
14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15  * 
16  * Copyright remains Eric Young's, and as such any Copyright notices in
17  * the code are not to be removed.
18  * If this package is used in a product, Eric Young should be given attribution
19  * as the author of the parts of the library used.
20  * This can be in the form of a textual message at program startup or
21  * in documentation (online or textual) provided with the package.
22  * 
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
26  * 1. Redistributions of source code must retain the copyright
27  *    notice, this list of conditions and the following disclaimer.
28  * 2. Redistributions in binary form must reproduce the above copyright
29  *    notice, this list of conditions and the following disclaimer in the
30  *    documentation and/or other materials provided with the distribution.
31  * 3. All advertising materials mentioning features or use of this software
32  *    must display the following acknowledgement:
33  *    "This product includes cryptographic software written by
34  *     Eric Young (eay@cryptsoft.com)"
35  *    The word 'cryptographic' can be left out if the rouines from the library
36  *    being used are not cryptographic related :-).
37  * 4. If you include any Windows specific code (or a derivative thereof) from 
38  *    the apps directory (application code) you must include an acknowledgement:
39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40  * 
41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51  * SUCH DAMAGE.
52  * 
53  * The licence and distribution terms for any publically available version or
54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
55  * copied and put under another distribution licence
56  * [including the GNU Public Licence.]
57  */
58
59 /* Part of the code in here was originally in conf.c, which is now removed */
60
61 #include <stdio.h>
62 #include <string.h>
63 #include "cryptlib.h"
64 #include <openssl/stack.h>
65 #include <openssl/lhash.h>
66 #include <openssl/conf.h>
67 #include <openssl/conf_api.h>
68 #include "conf_def.h"
69 #include <openssl/buffer.h>
70 #include <openssl/err.h>
71
72 static char *eat_ws(CONF *conf, char *p);
73 static char *eat_alpha_numeric(CONF *conf, char *p);
74 static void clear_comments(CONF *conf, char *p);
75 static int str_copy(CONF *conf,char *section,char **to, char *from);
76 static char *scan_quote(CONF *conf, char *p);
77 static char *scan_dquote(CONF *conf, char *p);
78 #define scan_esc(conf,p)        (((IS_EOF((conf),(p)[1]))?((p)+1):((p)+2)))
79
80 static CONF *def_create(CONF_METHOD *meth);
81 static int def_init_default(CONF *conf);
82 static int def_init_WIN32(CONF *conf);
83 static int def_destroy(CONF *conf);
84 static int def_destroy_data(CONF *conf);
85 static int def_load(CONF *conf, const char *name, long *eline);
86 static int def_load_bio(CONF *conf, BIO *bp, long *eline);
87 static int def_dump(const CONF *conf, BIO *bp);
88 static int def_is_number(const CONF *conf, char c);
89 static int def_to_int(const CONF *conf, char c);
90
91 const char *CONF_def_version="CONF_def" OPENSSL_VERSION_PTEXT;
92
93 static CONF_METHOD default_method = {
94         "OpenSSL default",
95         def_create,
96         def_init_default,
97         def_destroy,
98         def_destroy_data,
99         def_load_bio,
100         def_dump,
101         def_is_number,
102         def_to_int,
103         def_load
104         };
105
106 static CONF_METHOD WIN32_method = {
107         "WIN32",
108         def_create,
109         def_init_WIN32,
110         def_destroy,
111         def_destroy_data,
112         def_load_bio,
113         def_dump,
114         def_is_number,
115         def_to_int,
116         def_load
117         };
118
119 CONF_METHOD *NCONF_default()
120         {
121         return &default_method;
122         }
123 CONF_METHOD *NCONF_WIN32()
124         {
125         return &WIN32_method;
126         }
127
128 static CONF *def_create(CONF_METHOD *meth)
129         {
130         CONF *ret;
131
132         ret = (CONF *)OPENSSL_malloc(sizeof(CONF) + sizeof(unsigned short *));
133         if (ret)
134                 if (meth->init(ret) == 0)
135                         {
136                         OPENSSL_free(ret);
137                         ret = NULL;
138                         }
139         return ret;
140         }
141         
142 static int def_init_default(CONF *conf)
143         {
144         if (conf == NULL)
145                 return 0;
146
147         conf->meth = &default_method;
148         conf->meth_data = (void *)CONF_type_default;
149         conf->data = NULL;
150
151         return 1;
152         }
153
154 static int def_init_WIN32(CONF *conf)
155         {
156         if (conf == NULL)
157                 return 0;
158
159         conf->meth = &WIN32_method;
160         conf->meth_data = (void *)CONF_type_win32;
161         conf->data = NULL;
162
163         return 1;
164         }
165
166 static int def_destroy(CONF *conf)
167         {
168         if (def_destroy_data(conf))
169                 {
170                 OPENSSL_free(conf);
171                 return 1;
172                 }
173         return 0;
174         }
175
176 static int def_destroy_data(CONF *conf)
177         {
178         if (conf == NULL)
179                 return 0;
180         _CONF_free_data(conf);
181         return 1;
182         }
183
184 static int def_load(CONF *conf, const char *name, long *line)
185         {
186         int ret;
187         BIO *in=NULL;
188
189 #ifdef OPENSSL_SYS_VMS
190         in=BIO_new_file(name, "r");
191 #else
192         in=BIO_new_file(name, "rb");
193 #endif
194         if (in == NULL)
195                 {
196                 if (ERR_GET_REASON(ERR_peek_last_error()) == BIO_R_NO_SUCH_FILE)
197                         CONFerr(CONF_F_DEF_LOAD,CONF_R_NO_SUCH_FILE);
198                 else
199                         CONFerr(CONF_F_DEF_LOAD,ERR_R_SYS_LIB);
200                 return 0;
201                 }
202
203         ret = def_load_bio(conf, in, line);
204         BIO_free(in);
205
206         return ret;
207         }
208
209 static int def_load_bio(CONF *conf, BIO *in, long *line)
210         {
211 /* The macro BUFSIZE conflicts with a system macro in VxWorks */
212 #define CONFBUFSIZE     512
213         int bufnum=0,i,ii;
214         BUF_MEM *buff=NULL;
215         char *s,*p,*end;
216         int again,n;
217         long eline=0;
218         char btmp[DECIMAL_SIZE(eline)+1];
219         CONF_VALUE *v=NULL,*tv;
220         CONF_VALUE *sv=NULL;
221         char *section=NULL,*buf;
222         STACK_OF(CONF_VALUE) *section_sk=NULL,*ts;
223         char *start,*psection,*pname;
224         void *h = (void *)(conf->data);
225
226         if ((buff=BUF_MEM_new()) == NULL)
227                 {
228                 CONFerr(CONF_F_DEF_LOAD_BIO,ERR_R_BUF_LIB);
229                 goto err;
230                 }
231
232         section=(char *)OPENSSL_malloc(10);
233         if (section == NULL)
234                 {
235                 CONFerr(CONF_F_DEF_LOAD_BIO,ERR_R_MALLOC_FAILURE);
236                 goto err;
237                 }
238         BUF_strlcpy(section,"default",10);
239
240         if (_CONF_new_data(conf) == 0)
241                 {
242                 CONFerr(CONF_F_DEF_LOAD_BIO,ERR_R_MALLOC_FAILURE);
243                 goto err;
244                 }
245
246         sv=_CONF_new_section(conf,section);
247         if (sv == NULL)
248                 {
249                 CONFerr(CONF_F_DEF_LOAD_BIO,
250                                         CONF_R_UNABLE_TO_CREATE_NEW_SECTION);
251                 goto err;
252                 }
253         section_sk=(STACK_OF(CONF_VALUE) *)sv->value;
254
255         bufnum=0;
256         again=0;
257         for (;;)
258                 {
259                 if (!BUF_MEM_grow(buff,bufnum+CONFBUFSIZE))
260                         {
261                         CONFerr(CONF_F_DEF_LOAD_BIO,ERR_R_BUF_LIB);
262                         goto err;
263                         }
264                 p= &(buff->data[bufnum]);
265                 *p='\0';
266                 BIO_gets(in, p, CONFBUFSIZE-1);
267                 p[CONFBUFSIZE-1]='\0';
268                 ii=i=strlen(p);
269                 if (i == 0 && !again) break;
270                 again=0;
271                 while (i > 0)
272                         {
273                         if ((p[i-1] != '\r') && (p[i-1] != '\n'))
274                                 break;
275                         else
276                                 i--;
277                         }
278                 /* we removed some trailing stuff so there is a new
279                  * line on the end. */
280                 if (ii && i == ii)
281                         again=1; /* long line */
282                 else
283                         {
284                         p[i]='\0';
285                         eline++; /* another input line */
286                         }
287
288                 /* we now have a line with trailing \r\n removed */
289
290                 /* i is the number of bytes */
291                 bufnum+=i;
292
293                 v=NULL;
294                 /* check for line continuation */
295                 if (bufnum >= 1)
296                         {
297                         /* If we have bytes and the last char '\\' and
298                          * second last char is not '\\' */
299                         p= &(buff->data[bufnum-1]);
300                         if (IS_ESC(conf,p[0]) &&
301                                 ((bufnum <= 1) || !IS_ESC(conf,p[-1])))
302                                 {
303                                 bufnum--;
304                                 again=1;
305                                 }
306                         }
307                 if (again) continue;
308                 bufnum=0;
309                 buf=buff->data;
310
311                 clear_comments(conf, buf);
312                 n=strlen(buf);
313                 s=eat_ws(conf, buf);
314                 if (IS_EOF(conf,*s)) continue; /* blank line */
315                 if (*s == '[')
316                         {
317                         char *ss;
318
319                         s++;
320                         start=eat_ws(conf, s);
321                         ss=start;
322 again:
323                         end=eat_alpha_numeric(conf, ss);
324                         p=eat_ws(conf, end);
325                         if (*p != ']')
326                                 {
327                                 if (*p != '\0')
328                                         {
329                                         ss=p;
330                                         goto again;
331                                         }
332                                 CONFerr(CONF_F_DEF_LOAD_BIO,
333                                         CONF_R_MISSING_CLOSE_SQUARE_BRACKET);
334                                 goto err;
335                                 }
336                         *end='\0';
337                         if (!str_copy(conf,NULL,&section,start)) goto err;
338                         if ((sv=_CONF_get_section(conf,section)) == NULL)
339                                 sv=_CONF_new_section(conf,section);
340                         if (sv == NULL)
341                                 {
342                                 CONFerr(CONF_F_DEF_LOAD_BIO,
343                                         CONF_R_UNABLE_TO_CREATE_NEW_SECTION);
344                                 goto err;
345                                 }
346                         section_sk=(STACK_OF(CONF_VALUE) *)sv->value;
347                         continue;
348                         }
349                 else
350                         {
351                         pname=s;
352                         psection=NULL;
353                         end=eat_alpha_numeric(conf, s);
354                         if ((end[0] == ':') && (end[1] == ':'))
355                                 {
356                                 *end='\0';
357                                 end+=2;
358                                 psection=pname;
359                                 pname=end;
360                                 end=eat_alpha_numeric(conf, end);
361                                 }
362                         p=eat_ws(conf, end);
363                         if (*p != '=')
364                                 {
365                                 CONFerr(CONF_F_DEF_LOAD_BIO,
366                                                 CONF_R_MISSING_EQUAL_SIGN);
367                                 goto err;
368                                 }
369                         *end='\0';
370                         p++;
371                         start=eat_ws(conf, p);
372                         while (!IS_EOF(conf,*p))
373                                 p++;
374                         p--;
375                         while ((p != start) && (IS_WS(conf,*p)))
376                                 p--;
377                         p++;
378                         *p='\0';
379
380                         if (!(v=(CONF_VALUE *)OPENSSL_malloc(sizeof(CONF_VALUE))))
381                                 {
382                                 CONFerr(CONF_F_DEF_LOAD_BIO,
383                                                         ERR_R_MALLOC_FAILURE);
384                                 goto err;
385                                 }
386                         if (psection == NULL) psection=section;
387                         v->name=(char *)OPENSSL_malloc(strlen(pname)+1);
388                         v->value=NULL;
389                         if (v->name == NULL)
390                                 {
391                                 CONFerr(CONF_F_DEF_LOAD_BIO,
392                                                         ERR_R_MALLOC_FAILURE);
393                                 goto err;
394                                 }
395                         BUF_strlcpy(v->name,pname,strlen(pname)+1);
396                         if (!str_copy(conf,psection,&(v->value),start)) goto err;
397
398                         if (strcmp(psection,section) != 0)
399                                 {
400                                 if ((tv=_CONF_get_section(conf,psection))
401                                         == NULL)
402                                         tv=_CONF_new_section(conf,psection);
403                                 if (tv == NULL)
404                                         {
405                                         CONFerr(CONF_F_DEF_LOAD_BIO,
406                                            CONF_R_UNABLE_TO_CREATE_NEW_SECTION);
407                                         goto err;
408                                         }
409                                 ts=(STACK_OF(CONF_VALUE) *)tv->value;
410                                 }
411                         else
412                                 {
413                                 tv=sv;
414                                 ts=section_sk;
415                                 }
416 #if 1
417                         if (_CONF_add_string(conf, tv, v) == 0)
418                                 {
419                                 CONFerr(CONF_F_DEF_LOAD_BIO,
420                                                         ERR_R_MALLOC_FAILURE);
421                                 goto err;
422                                 }
423 #else
424                         v->section=tv->section; 
425                         if (!sk_CONF_VALUE_push(ts,v))
426                                 {
427                                 CONFerr(CONF_F_DEF_LOAD_BIO,
428                                                         ERR_R_MALLOC_FAILURE);
429                                 goto err;
430                                 }
431                         vv=(CONF_VALUE *)lh_insert(conf->data,v);
432                         if (vv != NULL)
433                                 {
434                                 sk_CONF_VALUE_delete_ptr(ts,vv);
435                                 OPENSSL_free(vv->name);
436                                 OPENSSL_free(vv->value);
437                                 OPENSSL_free(vv);
438                                 }
439 #endif
440                         v=NULL;
441                         }
442                 }
443         if (buff != NULL) BUF_MEM_free(buff);
444         if (section != NULL) OPENSSL_free(section);
445         return(1);
446 err:
447         if (buff != NULL) BUF_MEM_free(buff);
448         if (section != NULL) OPENSSL_free(section);
449         if (line != NULL) *line=eline;
450         BIO_snprintf(btmp,sizeof btmp,"%ld",eline);
451         ERR_add_error_data(2,"line ",btmp);
452         if ((h != conf->data) && (conf->data != NULL))
453                 {
454                 CONF_free(conf->data);
455                 conf->data=NULL;
456                 }
457         if (v != NULL)
458                 {
459                 if (v->name != NULL) OPENSSL_free(v->name);
460                 if (v->value != NULL) OPENSSL_free(v->value);
461                 if (v != NULL) OPENSSL_free(v);
462                 }
463         return(0);
464         }
465
466 static void clear_comments(CONF *conf, char *p)
467         {
468         char *to;
469
470         to=p;
471         for (;;)
472                 {
473                 if (IS_FCOMMENT(conf,*p))
474                         {
475                         *p='\0';
476                         return;
477                         }
478                 if (!IS_WS(conf,*p))
479                         {
480                         break;
481                         }
482                 p++;
483                 }
484
485         for (;;)
486                 {
487                 if (IS_COMMENT(conf,*p))
488                         {
489                         *p='\0';
490                         return;
491                         }
492                 if (IS_DQUOTE(conf,*p))
493                         {
494                         p=scan_dquote(conf, p);
495                         continue;
496                         }
497                 if (IS_QUOTE(conf,*p))
498                         {
499                         p=scan_quote(conf, p);
500                         continue;
501                         }
502                 if (IS_ESC(conf,*p))
503                         {
504                         p=scan_esc(conf,p);
505                         continue;
506                         }
507                 if (IS_EOF(conf,*p))
508                         return;
509                 else
510                         p++;
511                 }
512         }
513
514 static int str_copy(CONF *conf, char *section, char **pto, char *from)
515         {
516         int q,r,rr=0,to=0,len=0;
517         char *s,*e,*rp,*p,*rrp,*np,*cp,v;
518         BUF_MEM *buf;
519
520         if ((buf=BUF_MEM_new()) == NULL) return(0);
521
522         len=strlen(from)+1;
523         if (!BUF_MEM_grow(buf,len)) goto err;
524
525         for (;;)
526                 {
527                 if (IS_QUOTE(conf,*from))
528                         {
529                         q= *from;
530                         from++;
531                         while (!IS_EOF(conf,*from) && (*from != q))
532                                 {
533                                 if (IS_ESC(conf,*from))
534                                         {
535                                         from++;
536                                         if (IS_EOF(conf,*from)) break;
537                                         }
538                                 buf->data[to++]= *(from++);
539                                 }
540                         if (*from == q) from++;
541                         }
542                 else if (IS_DQUOTE(conf,*from))
543                         {
544                         q= *from;
545                         from++;
546                         while (!IS_EOF(conf,*from))
547                                 {
548                                 if (*from == q)
549                                         {
550                                         if (*(from+1) == q)
551                                                 {
552                                                 from++;
553                                                 }
554                                         else
555                                                 {
556                                                 break;
557                                                 }
558                                         }
559                                 buf->data[to++]= *(from++);
560                                 }
561                         if (*from == q) from++;
562                         }
563                 else if (IS_ESC(conf,*from))
564                         {
565                         from++;
566                         v= *(from++);
567                         if (IS_EOF(conf,v)) break;
568                         else if (v == 'r') v='\r';
569                         else if (v == 'n') v='\n';
570                         else if (v == 'b') v='\b';
571                         else if (v == 't') v='\t';
572                         buf->data[to++]= v;
573                         }
574                 else if (IS_EOF(conf,*from))
575                         break;
576                 else if (*from == '$')
577                         {
578                         /* try to expand it */
579                         rrp=NULL;
580                         s= &(from[1]);
581                         if (*s == '{')
582                                 q='}';
583                         else if (*s == '(')
584                                 q=')';
585                         else q=0;
586
587                         if (q) s++;
588                         cp=section;
589                         e=np=s;
590                         while (IS_ALPHA_NUMERIC(conf,*e))
591                                 e++;
592                         if ((e[0] == ':') && (e[1] == ':'))
593                                 {
594                                 cp=np;
595                                 rrp=e;
596                                 rr= *e;
597                                 *rrp='\0';
598                                 e+=2;
599                                 np=e;
600                                 while (IS_ALPHA_NUMERIC(conf,*e))
601                                         e++;
602                                 }
603                         r= *e;
604                         *e='\0';
605                         rp=e;
606                         if (q)
607                                 {
608                                 if (r != q)
609                                         {
610                                         CONFerr(CONF_F_STR_COPY,CONF_R_NO_CLOSE_BRACE);
611                                         goto err;
612                                         }
613                                 e++;
614                                 }
615                         /* So at this point we have
616                          * np which is the start of the name string which is
617                          *   '\0' terminated. 
618                          * cp which is the start of the section string which is
619                          *   '\0' terminated.
620                          * e is the 'next point after'.
621                          * r and rr are the chars replaced by the '\0'
622                          * rp and rrp is where 'r' and 'rr' came from.
623                          */
624                         p=_CONF_get_string(conf,cp,np);
625                         if (rrp != NULL) *rrp=rr;
626                         *rp=r;
627                         if (p == NULL)
628                                 {
629                                 CONFerr(CONF_F_STR_COPY,CONF_R_VARIABLE_HAS_NO_VALUE);
630                                 goto err;
631                                 }
632                         BUF_MEM_grow_clean(buf,(strlen(p)+buf->length-(e-from)));
633                         while (*p)
634                                 buf->data[to++]= *(p++);
635
636                         /* Since we change the pointer 'from', we also have
637                            to change the perceived length of the string it
638                            points at.  /RL */
639                         len -= e-from;
640                         from=e;
641
642                         /* In case there were no braces or parenthesis around
643                            the variable reference, we have to put back the
644                            character that was replaced with a '\0'.  /RL */
645                         *rp = r;
646                         }
647                 else
648                         buf->data[to++]= *(from++);
649                 }
650         buf->data[to]='\0';
651         if (*pto != NULL) OPENSSL_free(*pto);
652         *pto=buf->data;
653         OPENSSL_free(buf);
654         return(1);
655 err:
656         if (buf != NULL) BUF_MEM_free(buf);
657         return(0);
658         }
659
660 static char *eat_ws(CONF *conf, char *p)
661         {
662         while (IS_WS(conf,*p) && (!IS_EOF(conf,*p)))
663                 p++;
664         return(p);
665         }
666
667 static char *eat_alpha_numeric(CONF *conf, char *p)
668         {
669         for (;;)
670                 {
671                 if (IS_ESC(conf,*p))
672                         {
673                         p=scan_esc(conf,p);
674                         continue;
675                         }
676                 if (!IS_ALPHA_NUMERIC_PUNCT(conf,*p))
677                         return(p);
678                 p++;
679                 }
680         }
681
682 static char *scan_quote(CONF *conf, char *p)
683         {
684         int q= *p;
685
686         p++;
687         while (!(IS_EOF(conf,*p)) && (*p != q))
688                 {
689                 if (IS_ESC(conf,*p))
690                         {
691                         p++;
692                         if (IS_EOF(conf,*p)) return(p);
693                         }
694                 p++;
695                 }
696         if (*p == q) p++;
697         return(p);
698         }
699
700
701 static char *scan_dquote(CONF *conf, char *p)
702         {
703         int q= *p;
704
705         p++;
706         while (!(IS_EOF(conf,*p)))
707                 {
708                 if (*p == q)
709                         {
710                         if (*(p+1) == q)
711                                 {
712                                 p++;
713                                 }
714                         else
715                                 {
716                                 break;
717                                 }
718                         }
719                 p++;
720                 }
721         if (*p == q) p++;
722         return(p);
723         }
724
725 static void dump_value(CONF_VALUE *a, BIO *out)
726         {
727         if (a->name)
728                 BIO_printf(out, "[%s] %s=%s\n", a->section, a->name, a->value);
729         else
730                 BIO_printf(out, "[[%s]]\n", a->section);
731         }
732
733 static IMPLEMENT_LHASH_DOALL_ARG_FN(dump_value, CONF_VALUE *, BIO *)
734
735 static int def_dump(const CONF *conf, BIO *out)
736         {
737         lh_doall_arg(conf->data, LHASH_DOALL_ARG_FN(dump_value), out);
738         return 1;
739         }
740
741 static int def_is_number(const CONF *conf, char c)
742         {
743         return IS_NUMBER(conf,c);
744         }
745
746 static int def_to_int(const CONF *conf, char c)
747         {
748         return c - '0';
749         }
750