On Mon, Aug 04, 2003 at 02:33:31AM +0200, Simon Barner wrote:
> Hi Terry,
>
> > You need to add '\\' to the list of characters that can be escaped,
> > or you've just traded the inability to specify '\t' or ' ' for an
> > inability to speciy '\\'.
>
> Oh yes, I have overlook this special case. I revised my patch in order
> to get this right.
>
> Simon
helo.
imho - expensive algorithm... i want to see anything more simple...
like "gtok()" instead "es_strsep() + remove_escapes()"?
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char *gtok(char **s, char const *delim)
{
int quoted, escaped;
static char const esc_set[] = { 't', 'r', 'n', 'a', 0 };
static char const esc_rep[] = { '\t', '\r', '\n', '\a', 0 };
char *tok, *r, *w, *p;
if (!s || !*s || !*(tok = *s + strspn(*s, delim)) || *tok == '#')
return NULL;
for (quoted = escaped = 0, r = w = tok; *r; r++) {
if (!escaped) {
if (*r == '\\') {
escaped = 1;
continue;
}
if (*r == '\"') {
quoted ^= -1;
continue;
}
if (!quoted && strchr(delim, *r)) {
r++;
break;
}
} else {
escaped = 0;
if ((p = strchr(esc_set, *r)) != NULL) {
*w++ = esc_rep[p - esc_set];
continue;
}
}
*w++ = *r;
}
*w = 0;
*s = r;
return tok;
}
#if 0
main()
{
char *s, *t, buf[0x1000];
while (fgets(buf, sizeof buf, stdin))
for (s = buf; t = gtok(&s, " \t\r\n"); )
printf("\"%s\"\n", t);
return 0;
}
#endif
/swp
> --- fstab.c.orig Fri Aug 1 17:18:00 2003
> +++ fstab.c Mon Aug 4 01:46:55 2003
> @@ -49,6 +49,7 @@
> #include <errno.h>
> #include <fstab.h>
> #include <paths.h>
> +#include <stdbool.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> @@ -84,6 +85,140 @@
> _fs_fstab.fs_spec = buf;
> }
>
> +/*
> + * Get next token from string *stringp, where tokens are possibly-empty
> + * strings separated by characters from delim.
> + *
> + * Writes NULs into the string at *stringp to end tokens.
> + * delim need not remain constant from call to call.
> + * On return, *stringp points past the last NUL written (if there might
> + * be further tokens), or is NULL (if there are definitely no more tokens).
> + *
> + * If *stringp is NULL, es_strsep returns NULL.
> + *
> + * In contrast to strsep(3), es_strsep will allow escaped delimiters
> + * within a token. These escaped characters as well as the special case
> + * '\\' will be converted appropriately ('\<delim>' -> '<delim>, '\\' -> '\'
> + *
> + */
> +char *
> +es_strsep(char **stringp, const char *delim)
> +{
> + bool escaped=false;
> + char *s, *t, *u;
> + int i;
> +
> +
> + if (*stringp == '\0') /* empty string */
> + return NULL;
> + s = *stringp;
> + s += strspn (s, delim); /* skip delimiters */
> +
> + if (*s == '\0') /* string consists only of delimiters */
> + return NULL;
> +
> + /*
> + * skip a string consisting of non-delimiters,
> + * escapted delimiters or '\\'
> + */
> + for (t = s; *t != '\0'; ++t) {
> + if (*t == '\\') {
> + if (escaped) { /* convert \\ to \ */
> + --t;
> + u = t;
> + escaped = false;
> + while (u[0] != '\0') {
> + u[0] = u[1];
> + ++u;
> + }
> + } else /* start \-Sequence */
> + escaped = true;
> + continue;
> + }
> +
> + /* search for delimiter */
> + for (i=0; delim[i] != '\0'; ++i) {
> + if (*t == delim[i])
> + break;
> + }
> +
> + /* un-escaped delimiter found => end of token */
> + if (!escaped && delim[i] != '\0')
> + break;
> +
> + /* escaped delimiter found => remove / */
> + if (escaped) {
> + --t;
> + u = t;
> + escaped = false;
> + while (u[0] != '\0') {
> + u[0] = u[1];
> + ++u;
> + }
> + }
> + }
> +
> + if (*t != '\0') {
> + *t = '\0'; /* end current token */
> + *stringp = t+1; /* *t != '\0' => *(t+1) is valid */
> + } else
> + *stringp = 0; /* end of string reached */
> +
> + return s; /* return current token */
> +}
> +
> +/*
> + * This function converts escaped characters:
> + * '\<delim>' -> '<delim>', '\\' -> '\'
> + *
> + * If there are unescaped delimiters, 'false' will be return to indicate
> + * an error, otherwise remove_escape returns 'true'.
> + */
> +bool remove_escapes (char **s, const char* delim) {
> + bool escaped=false;
> + char *t, *u;
> + int i;
> +
> + for (t = *s; *t != '\0'; ++t) {
> + if (*t == '\\') {
> + if (escaped) { /* convert \\ to \ */
> + --t;
> + u = t;
> + escaped = false;
> + while (u[0] != '\0') {
> + u[0] = u[1];
> + ++u;
> + }
> + } else /* start \-Sequence */
> + escaped = true;
> + continue;
> + }
> +
> + /* search for delimiter */
> + for (i=0; delim[i] != '\0'; ++i) {
> + if (*t == delim[i])
> + break;
> + }
> +
> + /* un-escaped delimiter found => error */
> + if (!escaped && delim[i] != '\0')
> + return false;
> +
> + /* escaped delimiter found => remove / */
> + if (escaped) {
> + --t;
> + u = t;
> + escaped = false;
> + while (u[0] != '\0') {
> + u[0] = u[1];
> + ++u;
> + }
> + }
> + }
> +
> + return true;
> +}
> +
> static int
> fstabscan()
> {
> @@ -101,9 +236,19 @@
> ++LineNo;
> if (*line == '#' || *line == '\n')
> continue;
> - if (!strpbrk(p, " \t")) {
> +
> + /* escapted white-spaces only are allowed in old-style format */
> + cp = p;
> + while ((cp = strpbrk(cp, " \t")) != 0 &&
> + cp != p && cp[-1] == '\\')
> + ++cp;
> + if (cp == 0) {
> _fs_fstab.fs_spec = strsep(&p, ":\n");
> + if (!remove_escapes (&_fs_fstab.fs_spec, " \t"))
> + goto bad;
> _fs_fstab.fs_file = strsep(&p, ":\n");
> + if (!remove_escapes (&_fs_fstab.fs_file, " \t"))
> + goto bad;
> fixfsfile();
> _fs_fstab.fs_type = strsep(&p, ":\n");
> if (_fs_fstab.fs_type) {
> @@ -124,13 +269,15 @@
> goto bad;
> }
> /* OLD_STYLE_FSTAB */
> - while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
> + while ((cp = es_strsep(&p, " \t\n")) != NULL && *cp == '\0')
> ;
> _fs_fstab.fs_spec = cp;
> if (!_fs_fstab.fs_spec || *_fs_fstab.fs_spec == '#')
> continue;
> - while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
> + while ((cp = es_strsep(&p, " \t\n")) != NULL && *cp == '\0')
> ;
> + if (cp == 0)
> + goto bad;
> _fs_fstab.fs_file = cp;
> fixfsfile();
> while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
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