Commit 44b25b87 authored by Junio C Hamano's avatar Junio C Hamano

utf8_width(): allow non NUL-terminated input

The original interface assumed that the input string is
always terminated with a NUL, but that wasn't too useful.
Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
parent 396ccf1f
......@@ -153,74 +153,94 @@ static int git_wcwidth(ucs_char_t ch)
/*
* Pick one ucs character starting from the location *start points at,
* and return it, while updating the *start pointer to point at the
* end of that character.
* end of that character. When remainder_p is not NULL, the location
* holds the number of bytes remaining in the string that we are allowed
* to pick from. Otherwise we are allowed to pick up to the NUL that
* would eventually appear in the string. *remainder_p is also reduced
* by the number of bytes we have consumed.
*
* If the string was not a valid UTF-8, *start pointer is set to NULL
* and the return value is undefined.
*/
ucs_char_t pick_one_utf8_char(const char **start)
ucs_char_t pick_one_utf8_char(const char **start, size_t *remainder_p)
{
unsigned char *s = (unsigned char *)*start;
ucs_char_t ch;
size_t remainder, incr;
if (*s < 0x80) {
/*
* A caller that assumes NUL terminated text can choose
* not to bother with the remainder length. We will
* stop at the first NUL.
*/
remainder = (remainder_p ? *remainder_p : 999);
if (remainder < 1) {
goto invalid;
} else if (*s < 0x80) {
/* 0xxxxxxx */
ch = *s;
*start += 1;
incr = 1;
} else if ((s[0] & 0xe0) == 0xc0) {
/* 110XXXXx 10xxxxxx */
if ((s[1] & 0xc0) != 0x80 ||
/* overlong? */
(s[0] & 0xfe) == 0xc0)
if (remainder < 2 ||
(s[1] & 0xc0) != 0x80 ||
(s[0] & 0xfe) == 0xc0)
goto invalid;
ch = ((s[0] & 0x1f) << 6) | (s[1] & 0x3f);
*start += 2;
incr = 2;
} else if ((s[0] & 0xf0) == 0xe0) {
/* 1110XXXX 10Xxxxxx 10xxxxxx */
if ((s[1] & 0xc0) != 0x80 ||
(s[2] & 0xc0) != 0x80 ||
/* overlong? */
(s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) ||
/* surrogate? */
(s[0] == 0xed && (s[1] & 0xe0) == 0xa0) ||
/* U+FFFE or U+FFFF? */
(s[0] == 0xef && s[1] == 0xbf &&
(s[2] & 0xfe) == 0xbe))
if (remainder < 3 ||
(s[1] & 0xc0) != 0x80 ||
(s[2] & 0xc0) != 0x80 ||
/* overlong? */
(s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) ||
/* surrogate? */
(s[0] == 0xed && (s[1] & 0xe0) == 0xa0) ||
/* U+FFFE or U+FFFF? */
(s[0] == 0xef && s[1] == 0xbf &&
(s[2] & 0xfe) == 0xbe))
goto invalid;
ch = ((s[0] & 0x0f) << 12) |
((s[1] & 0x3f) << 6) | (s[2] & 0x3f);
*start += 3;
incr = 3;
} else if ((s[0] & 0xf8) == 0xf0) {
/* 11110XXX 10XXxxxx 10xxxxxx 10xxxxxx */
if ((s[1] & 0xc0) != 0x80 ||
(s[2] & 0xc0) != 0x80 ||
(s[3] & 0xc0) != 0x80 ||
/* overlong? */
(s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) ||
/* > U+10FFFF? */
(s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4)
if (remainder < 4 ||
(s[1] & 0xc0) != 0x80 ||
(s[2] & 0xc0) != 0x80 ||
(s[3] & 0xc0) != 0x80 ||
/* overlong? */
(s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) ||
/* > U+10FFFF? */
(s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4)
goto invalid;
ch = ((s[0] & 0x07) << 18) | ((s[1] & 0x3f) << 12) |
((s[2] & 0x3f) << 6) | (s[3] & 0x3f);
*start += 4;
incr = 4;
} else {
invalid:
*start = NULL;
return 0;
}
*start += incr;
if (remainder_p)
*remainder_p = remainder - incr;
return ch;
}
/*
* This function returns the number of columns occupied by the character
* pointed to by the variable start. The pointer is updated to point at
* the next character. If it was not valid UTF-8, the pointer is set to
* NULL.
* the next character. When remainder_p is not NULL, it points at the
* location that stores the number of remaining bytes we can use to pick
* a character (see pick_one_utf8_char() above).
*/
int utf8_width(const char **start)
int utf8_width(const char **start, size_t *remainder_p)
{
ucs_char_t ch = pick_one_utf8_char(start);
ucs_char_t ch = pick_one_utf8_char(start, remainder_p);
if (!*start)
return 0;
return git_wcwidth(ch);
......@@ -233,7 +253,7 @@ int is_utf8(const char *text)
text++;
continue;
}
utf8_width(&text);
utf8_width(&text, NULL);
if (!text)
return 0;
}
......@@ -293,7 +313,7 @@ int print_wrapped_text(const char *text, int indent, int indent2, int width)
continue;
}
if (assume_utf8)
w += utf8_width(&text);
w += utf8_width(&text, NULL);
else {
w++;
text++;
......
......@@ -3,8 +3,8 @@
typedef unsigned int ucs_char_t; /* assuming 32bit int */
ucs_char_t pick_one_utf8_char(const char **start);
int utf8_width(const char **start);
ucs_char_t pick_one_utf8_char(const char **start, size_t *remainder_p);
int utf8_width(const char **start, size_t *remainder_p);
int is_utf8(const char *text);
int is_encoding_utf8(const char *name);
......
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