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basic/escape: merge utf8 and non-utf8 paths in cunescape_one

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Not every byte sequence is valid utf8. We allow escaping of non-utf8
sequences in strings by using octal and hexadecimal escape sequences
(\123 and \0xAB) for bytes at or above 128. Users of cunescape_one
could infer whether such use occured when they received an answer
between 128 and 256 in *ret (a non-ascii one byte character). But this
is subtle and misleading: the comments were wrong, because ascii is a
subset of unicode, so c != 0 did not mean non-unicode, but rather
ascii-subset-of-unicode-or-raw-byte. This was all rather confusing, so
make the "single byte" condition explicit.

I'm not convinced that allowing non-utf8 sequences to be produced is
useful in all cases where we allow it (e.g. in config files), but that
behaviour is unchanged, just made more explicit.

This also fixes an (invalid) gcc warning about unitialized variable
(*ret_unicode) in callers of cunescape_one.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2016-01-18 15:20:32 -05:00
parent cb51e6b734
commit 3565e09594
3 changed files with 25 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/basic/escape.c
+19 -34
View File
@@ -119,16 +119,18 @@ char *cescape(const char *s) {
return cescape_length(s, strlen(s));
}
int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode) {
int cunescape_one(const char *p, size_t length, uint32_t *ret, bool *eight_bit) {
int r = 1;
assert(p);
assert(*p);
assert(ret);
/* Unescapes C style. Returns the unescaped character in ret,
* unless we encountered a \u sequence in which case the full
* unicode character is returned in ret_unicode, instead. */
/* Unescapes C style. Returns the unescaped character in ret.
* Sets *eight_bit to true if the escaped sequence either fits in
* one byte in UTF-8 or is a non-unicode literal byte and should
* instead be copied directly.
*/
if (length != (size_t) -1 && length < 1)
return -EINVAL;
@@ -190,7 +192,8 @@ int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode
if (a == 0 && b == 0)
return -EINVAL;
*ret = (char) ((a << 4U) | b);
*ret = (a << 4U) | b;
*eight_bit = true;
r = 3;
break;
}
@@ -217,16 +220,7 @@ int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode
if (c == 0)
return -EINVAL;
if (c < 128)
*ret = c;
else {
if (!ret_unicode)
return -EINVAL;
*ret = 0;
*ret_unicode = c;
}
*ret = c;
r = 5;
break;
}
@@ -258,16 +252,7 @@ int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode
if (!unichar_is_valid(c))
return -EINVAL;
if (c < 128)
*ret = c;
else {
if (!ret_unicode)
return -EINVAL;
*ret = 0;
*ret_unicode = c;
}
*ret = c;
r = 9;
break;
}
@@ -309,6 +294,7 @@ int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode
return -EINVAL;
*ret = m;
*eight_bit = true;
r = 3;
break;
}
@@ -342,7 +328,7 @@ int cunescape_length_with_prefix(const char *s, size_t length, const char *prefi
for (f = s, t = r + pl; f < s + length; f++) {
size_t remaining;
uint32_t u;
char c;
bool eight_bit = false;
int k;
remaining = s + length - f;
@@ -365,7 +351,7 @@ int cunescape_length_with_prefix(const char *s, size_t length, const char *prefi
return -EINVAL;
}
k = cunescape_one(f + 1, remaining - 1, &c, &u);
k = cunescape_one(f + 1, remaining - 1, &u, &eight_bit);
if (k < 0) {
if (flags & UNESCAPE_RELAX) {
/* Invalid escape code, let's take it literal then */
@@ -377,14 +363,13 @@ int cunescape_length_with_prefix(const char *s, size_t length, const char *prefi
return k;
}
if (c != 0)
/* Non-Unicode? Let's encode this directly */
*(t++) = c;
else
/* Unicode? Then let's encode this in UTF-8 */
t += utf8_encode_unichar(t, u);
f += k;
if (eight_bit)
/* One byte? Set directly as specified */
*(t++) = u;
else
/* Otherwise encode as multi-byte UTF-8 */
t += utf8_encode_unichar(t, u);
}
*t = 0;
src/basic/escape.h
+1 -1
View File
@@ -45,7 +45,7 @@ size_t cescape_char(char c, char *buf);
int cunescape(const char *s, UnescapeFlags flags, char **ret);
int cunescape_length(const char *s, size_t length, UnescapeFlags flags, char **ret);
int cunescape_length_with_prefix(const char *s, size_t length, const char *prefix, UnescapeFlags flags, char **ret);
int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode);
int cunescape_one(const char *p, size_t length, uint32_t *ret, bool *eight_bit);
char *xescape(const char *s, const char *bad);
src/basic/extract-word.c
+5 -4
View File
@@ -108,8 +108,9 @@ int extract_first_word(const char **p, char **ret, const char *separators, Extra
if (flags & EXTRACT_CUNESCAPE) {
uint32_t u;
bool eight_bit = false;
r = cunescape_one(*p, (size_t) -1, &c, &u);
r = cunescape_one(*p, (size_t) -1, &u, &eight_bit);
if (r < 0) {
if (flags & EXTRACT_CUNESCAPE_RELAX) {
s[sz++] = '\\';
@@ -119,10 +120,10 @@ int extract_first_word(const char **p, char **ret, const char *separators, Extra
} else {
(*p) += r - 1;
if (c != 0)
s[sz++] = c; /* normal explicit char */
if (eight_bit)
s[sz++] = u;
else
sz += utf8_encode_unichar(s + sz, u); /* unicode chars we'll encode as utf8 */
sz += utf8_encode_unichar(s + sz, u);
}
} else
s[sz++] = c;