75 lines
2.0 KiB
C
75 lines
2.0 KiB
C
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#include "patprep.h"
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#include <stdio.h>
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#include <string.h>
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#include <strings.h>
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// This is a copy of the patprep() function from the original 1983 version of
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// locate.c. I have annotated it heavily in order to document, in my own mind at
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// any rate, exactly what it does, step by step.
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// Globfree is limited to 100 characters.
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static char globfree[100];
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char *patprep(name)
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char *name;
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{
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register char *endmark, *p, *subp;
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subp = globfree;
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*subp++ = '\0';
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// Go to the very end of the string passed in.
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p = name + strlen(name) - 1;
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/* starting from the END of the string, skip trailing metacharacters (and
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[] ranges) */
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for (; p >= name; p--)
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// Index is mis-named; it returns a pointer to the first
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// instance of the character '*p' in the content of the
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// static string here. In this case, it's saying that
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// if there is no metacharacter, break out?
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if (index("*?", *p) == 0)
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break;
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if (p < name)
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p = name;
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// Skip past a range operator.
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if (*p == ']')
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for (p--; p >= name; p--)
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if (*p == '[') {
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p--;
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break;
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}
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if (p < name)
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p = name;
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/*
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* if pattern has only metacharacters, check every path (force '/'
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* search)
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*/
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// We got to the start of the string. At least give it an anchoring '/',
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// so the matcher has something it can makes sense of.
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if ((p == name) && index("?*[]", *p) != 0)
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*subp++ = '/';
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else {
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// Okay, from where we were, scan backwards until we find another
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// metacharacter or the root of the search string, in which case we have
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// a literal substring.
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for (endmark = p; p >= name; p--)
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if (index("]*?", *p) != 0)
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break;
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// From the first non-metacharacter found to the first metacharacter (or
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// EOL), copy that substring into the 100-byte reserve.
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for (++p; (p <= endmark) && subp < (globfree + sizeof(globfree));)
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*subp++ = *p++;
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}
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// Give a null ending.
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*subp = '\0';
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// Return a pointer to the last byte of the pattern reserve.
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return (--subp);
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}
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