add various escaping/path handling utility functions

This commit is contained in:
Lennart Poettering 2010-01-29 01:48:57 +01:00
parent 25ac040b48
commit 4fe88d28a4
2 changed files with 337 additions and 0 deletions

323
util.c
View File

@ -553,3 +553,326 @@ char hexchar(int x) {
return table[x & 15];
}
int unhexchar(char c) {
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a';
if (c >= 'A' && c <= 'F')
return c - 'A';
return -1;
}
char octchar(int x) {
return '0' + (x & 7);
}
int unoctchar(char c) {
if (c >= '0' && c <= '7')
return c - '0';
return -1;
}
char *cescape(const char *s) {
char *r, *t;
const char *f;
assert(s);
/* Does C style string escaping. */
if (!(r = new(char, strlen(s)*4 + 1)))
return NULL;
for (f = s, t = r; *f; f++)
switch (*f) {
case '\a':
*(t++) = '\\';
*(t++) = 'a';
break;
case '\b':
*(t++) = '\\';
*(t++) = 'b';
break;
case '\f':
*(t++) = '\\';
*(t++) = 'f';
break;
case '\n':
*(t++) = '\\';
*(t++) = 'n';
break;
case '\r':
*(t++) = '\\';
*(t++) = 'r';
break;
case '\t':
*(t++) = '\\';
*(t++) = 't';
break;
case '\v':
*(t++) = '\\';
*(t++) = 'v';
break;
case '\\':
*(t++) = '\\';
*(t++) = '\\';
break;
case '"':
*(t++) = '\\';
*(t++) = '"';
break;
case '\'':
*(t++) = '\\';
*(t++) = '\'';
break;
default:
/* For special chars we prefer octal over
* hexadecimal encoding, simply because glib's
* g_strescape() does the same */
if ((*f < ' ') || (*f >= 127)) {
*(t++) = '\\';
*(t++) = octchar((unsigned char) *f >> 6);
*(t++) = octchar((unsigned char) *f >> 3);
*(t++) = octchar((unsigned char) *f);
} else
*(t++) = *f;
break;
}
*t = 0;
return r;
}
char *cunescape(const char *s) {
char *r, *t;
const char *f;
assert(s);
/* Undoes C style string escaping */
if (!(r = new(char, strlen(s)+1)))
return r;
for (f = s, t = r; *f; f++) {
if (*f != '\\') {
*(t++) = *f;
continue;
}
f++;
switch (*f) {
case 'a':
*(t++) = '\a';
break;
case 'b':
*(t++) = '\b';
break;
case 'f':
*(t++) = '\f';
break;
case 'n':
*(t++) = '\n';
break;
case 'r':
*(t++) = '\r';
break;
case 't':
*(t++) = '\t';
break;
case 'v':
*(t++) = '\v';
break;
case '\\':
*(t++) = '\\';
break;
case '"':
*(t++) = '"';
break;
case '\'':
*(t++) = '\'';
break;
case 'x': {
/* hexadecimal encoding */
int a, b;
if ((a = unhexchar(f[1])) < 0 ||
(b = unhexchar(f[2])) < 0) {
/* Invalid escape code, let's take it literal then */
*(t++) = '\\';
*(t++) = 'x';
} else {
*(t++) = (char) ((a << 4) | b);
f += 2;
}
break;
}
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7': {
/* octal encoding */
int a, b, c;
if ((a = unoctchar(f[0])) < 0 ||
(b = unoctchar(f[1])) < 0 ||
(c = unoctchar(f[2])) < 0) {
/* Invalid escape code, let's take it literal then */
*(t++) = '\\';
*(t++) = f[0];
} else {
*(t++) = (char) ((a << 6) | (b << 3) | c);
f += 2;
}
break;
}
case 0:
/* premature end of string.*/
*(t++) = '\\';
goto finish;
default:
/* Invalid escape code, let's take it literal then */
*(t++) = '\\';
*(t++) = 'f';
break;
}
}
finish:
*t = 0;
return r;
}
char *xescape(const char *s, const char *bad) {
char *r, *t;
const char *f;
/* Escapes all chars in bad, in addition to \ and all special
* chars, in \xFF style escaping. May be reversed with
* cunescape. */
if (!(r = new(char, strlen(s)*4+1)))
return NULL;
for (f = s, t = r; *f; f++) {
if (*f < ' ' || *f >= 127 ||
*f == '\\' || strchr(bad, *f)) {
*(t++) = '\\';
*(t++) = 'x';
*(t++) = hexchar(*f >> 4);
*(t++) = hexchar(*f);
} else
*(t++) = *f;
}
*t = 0;
return r;
}
char *path_kill_slashes(char *path) {
char *f, *t;
bool slash = false;
/* Removes redundant inner and trailing slashes. Modifies the
* passed string in-place.
*
* ///foo///bar/ becomes /foo/bar
*/
for (f = path, t = path; *f; f++) {
if (*f == '/') {
slash = true;
continue;
}
if (slash) {
slash = false;
*(t++) = '/';
}
*(t++) = *f;
}
/* Special rule, if we are talking of the root directory, a
trailing slash is good */
if (t == path && slash)
*(t++) = '/';
*t = 0;
return path;
}
bool path_startswith(const char *path, const char *prefix) {
assert(path);
assert(prefix);
if ((path[0] == '/') != (prefix[0] == '/'))
return false;
for (;;) {
size_t a, b;
path += strspn(path, "/");
prefix += strspn(prefix, "/");
if (*prefix == 0)
return true;
if (*path == 0)
return false;
a = strcspn(path, "/");
b = strcspn(prefix, "/");
if (a != b)
return false;
if (memcmp(path, prefix, a) != 0)
return false;
path += a;
prefix += b;
}
}
char *ascii_strlower(char *path) {
char *p;
assert(path);
for (p = path; *p; p++)
if (*p >= 'A' && *p <= 'Z')
*p = *p - 'A' + 'a';
return p;
}

14
util.h
View File

@ -106,5 +106,19 @@ char *strstrip(char *s);
char *file_in_same_dir(const char *path, const char *filename);
char hexchar(int x);
int unhexchar(char c);
char octchar(int x);
int unoctchar(char c);
char *cescape(const char *s);
char *cunescape(const char *s);
char *path_kill_slashes(char *path);
bool path_startswith(const char *path, const char *prefix);
char *ascii_strlower(char *path);
char *xescape(const char *s, const char *bad);
#endif