130 lines
3.1 KiB
C
130 lines
3.1 KiB
C
/*
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* case-mapping stuff
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*
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* We exploit the fact that we are dealing only with headers here, and
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* headers are limited to the ASCII characters by RFC822. It is barely
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* possible that we might be dealing with a translation into another
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* character set, but in particular it's very unlikely for a header
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* character to be outside -128..255.
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*
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* Life would be a whole lot simpler if tolower() could safely and portably
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* be applied to any char.
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*/
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#include <stdio.h>
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#include "string.h"
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#include "case.h"
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/* note that case.h knows the value of OFFSET */
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#define OFFSET 128 /* avoid trouble with negative chars */
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#define MAPSIZE (256+OFFSET)
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char casemap[MAPSIZE]; /* relies on init to '\0' */
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static int primed = 0; /* has casemap been set up? */
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/*
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- prime - set up case-mapping stuff
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*/
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static void
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prime()
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{
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register char *lp;
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register char *up;
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register int c;
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register int i;
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static char lower[] = "abcdefghijklmnopqrstuvwxyz";
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static char upper[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
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for (lp = lower, up = upper; *lp != '\0'; lp++, up++) {
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c = *lp;
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casemap[c+OFFSET] = c;
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casemap[*up+OFFSET] = c;
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}
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for (i = 0; i < MAPSIZE; i++)
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if (casemap[i] == '\0')
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casemap[i] = (char)(i-OFFSET);
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primed = 1;
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}
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/*
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- cistrncmp - case-independent strncmp
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*/
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int /* < == > 0 */
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cistrncmp(s1, s2, len)
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char *s1;
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char *s2;
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int len;
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{
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register char *p1;
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register char *p2;
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register int n;
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if (!primed)
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prime();
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p1 = s1;
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p2 = s2;
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n = len;
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while (--n >= 0 && *p1 != '\0' && TOLOW(*p1) == TOLOW(*p2)) {
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p1++;
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p2++;
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}
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if (n < 0)
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return(0);
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/*
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* The following case analysis is necessary so that characters
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* which look negative collate low against normal characters but
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* high against the end-of-string NUL.
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*/
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if (*p1 == '\0' && *p2 == '\0')
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return(0);
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else if (*p1 == '\0')
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return(-1);
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else if (*p2 == '\0')
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return(1);
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else
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return(TOLOW(*p1) - TOLOW(*p2));
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}
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/*
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- rfc822ize - do the bizarre case conversion needed for rfc822 message-ids
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*
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* Actually, this is not quite complete. Absolute, total, full RFC822
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* compliance requires a horrible parsing job, because of the arcane
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* quoting conventions -- abc"def"ghi is not equivalent to abc"DEF"ghi,
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* for example. There are three or four things that might occur in the
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* domain part of a message-id that are case-sensitive. They don't seem
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* to ever occur in real news, thank Cthulhu. (What? You were expecting
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* a merciful and forgiving deity to be invoked in connection with RFC822?
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* Forget it; none of them would come near it.)
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*/
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char * /* returns the argument */
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rfc822ize(s)
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char *s;
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{
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register char *p;
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static char post[] = "postmaster";
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static int postlen = sizeof(post)-1;
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if (!primed)
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prime();
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p = strrchr(s, '@');
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if (p == NULL) /* no local/domain split */
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p = ""; /* assume all local */
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else if (p - (s+1) == postlen && CISTREQN(s+1, post, postlen)) {
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/* crazy special case -- "postmaster" is case-insensitive */
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p = s;
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}
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#ifdef NONSTANDARD
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#ifdef RFCVIOLATION
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#ifdef B_2_11_MISTAKE
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p = s; /* all case-insensitive */
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#endif
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#endif
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#endif
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for (; *p != '\0'; p++)
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*p = TOLOW(*p);
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return(s);
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}
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