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putty-source/wcwidth.c
Simon Tatham 5d718ef64b Whitespace rationalisation of entire code base. 
The number of people has been steadily increasing who read our source
code with an editor that thinks tab stops are 4 spaces apart, as
opposed to the traditional tty-derived 8 that the PuTTY code expects.

So I've been wondering for ages about just fixing it, and switching to
a spaces-only policy throughout the code. And I recently found out
about 'git blame -w', which should make this change not too disruptive
for the purposes of source-control archaeology; so perhaps now is the
time.

While I'm at it, I've also taken the opportunity to remove all the
trailing spaces from source lines (on the basis that git dislikes
them, and is the only thing that seems to have a strong opinion one
way or the other).
    
Apologies to anyone downstream of this code who has complicated patch
sets to rebase past this change. I don't intend it to be needed again.
2019-09-08 20:29:21 +01:00

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/*
* This is an implementation of wcwidth() and wcswidth() (defined in
* IEEE Std 1002.1-2001) for Unicode.
*
* http://www.opengroup.org/onlinepubs/007904975/functions/wcwidth.html
* http://www.opengroup.org/onlinepubs/007904975/functions/wcswidth.html
*
* In fixed-width output devices, Latin characters all occupy a single
* "cell" position of equal width, whereas ideographic CJK characters
* occupy two such cells. Interoperability between terminal-line
* applications and (teletype-style) character terminals using the
* UTF-8 encoding requires agreement on which character should advance
* the cursor by how many cell positions. No established formal
* standards exist at present on which Unicode character shall occupy
* how many cell positions on character terminals. These routines are
* a first attempt of defining such behavior based on simple rules
* applied to data provided by the Unicode Consortium.
*
* For some graphical characters, the Unicode standard explicitly
* defines a character-cell width via the definition of the East Asian
* FullWidth (F), Wide (W), Half-width (H), and Narrow (Na) classes.
* In all these cases, there is no ambiguity about which width a
* terminal shall use. For characters in the East Asian Ambiguous (A)
* class, the width choice depends purely on a preference of backward
* compatibility with either historic CJK or Western practice.
* Choosing single-width for these characters is easy to justify as
* the appropriate long-term solution, as the CJK practice of
* displaying these characters as double-width comes from historic
* implementation simplicity (8-bit encoded characters were displayed
* single-width and 16-bit ones double-width, even for Greek,
* Cyrillic, etc.) and not any typographic considerations.
*
* Much less clear is the choice of width for the Not East Asian
* (Neutral) class. Existing practice does not dictate a width for any
* of these characters. It would nevertheless make sense
* typographically to allocate two character cells to characters such
* as for instance EM SPACE or VOLUME INTEGRAL, which cannot be
* represented adequately with a single-width glyph. The following
* routines at present merely assign a single-cell width to all
* neutral characters, in the interest of simplicity. This is not
* entirely satisfactory and should be reconsidered before
* establishing a formal standard in this area. At the moment, the
* decision which Not East Asian (Neutral) characters should be
* represented by double-width glyphs cannot yet be answered by
* applying a simple rule from the Unicode database content. Setting
* up a proper standard for the behavior of UTF-8 character terminals
* will require a careful analysis not only of each Unicode character,
* but also of each presentation form, something the author of these
* routines has avoided to do so far.
*
* http://www.unicode.org/unicode/reports/tr11/
*
* Markus Kuhn -- 2007-05-26 (Unicode 5.0)
*
* Permission to use, copy, modify, and distribute this software
* for any purpose and without fee is hereby granted. The author
* disclaims all warranties with regard to this software.
*
* Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
*/
#include <wchar.h>
#include "putty.h" /* for prototypes */
struct interval {
unsigned int first;
unsigned int last;
};
/* auxiliary function for binary search in interval table */
static bool bisearch(unsigned int ucs, const struct interval *table, int max) {
int min = 0;
int mid;
if (ucs < table[0].first || ucs > table[max].last)
return false;
while (max >= min) {
mid = (min + max) / 2;
if (ucs > table[mid].last)
min = mid + 1;
else if (ucs < table[mid].first)
max = mid - 1;
else
return true;
}
return false;
}
/* The following two functions define the column width of an ISO 10646
* character as follows:
*
* - The null character (U+0000) has a column width of 0.
*
* - Other C0/C1 control characters and DEL will lead to a return
* value of -1.
*
* - Non-spacing and enclosing combining characters (general
* category code Mn or Me in the Unicode database) have a
* column width of 0.
*
* - SOFT HYPHEN (U+00AD) has a column width of 1.
*
* - Other format characters (general category code Cf in the Unicode
* database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
*
* - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
* have a column width of 0.
*
* - Spacing characters in the East Asian Wide (W) or East Asian
* Full-width (F) category as defined in Unicode Technical
* Report #11 have a column width of 2.
*
* - All remaining characters (including all printable
* ISO 8859-1 and WGL4 characters, Unicode control characters,
* etc.) have a column width of 1.
*
* This implementation assumes that wchar_t characters are encoded
* in ISO 10646.
*/
int mk_wcwidth(unsigned int ucs)
{
/* sorted list of non-overlapping intervals of non-spacing characters */
/* generated by "uniset +cat=Me +cat=Mn +cat=Cf -00AD +1160-11FF +200B c" */
static const struct interval combining[] = {
{ 0x0300, 0x036F }, { 0x0483, 0x0486 }, { 0x0488, 0x0489 },
{ 0x0591, 0x05BD }, { 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 },
{ 0x05C4, 0x05C5 }, { 0x05C7, 0x05C7 }, { 0x0600, 0x0603 },
{ 0x0610, 0x0615 }, { 0x064B, 0x065E }, { 0x0670, 0x0670 },
{ 0x06D6, 0x06E4 }, { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED },
{ 0x070F, 0x070F }, { 0x0711, 0x0711 }, { 0x0730, 0x074A },
{ 0x07A6, 0x07B0 }, { 0x07EB, 0x07F3 }, { 0x0901, 0x0902 },
{ 0x093C, 0x093C }, { 0x0941, 0x0948 }, { 0x094D, 0x094D },
{ 0x0951, 0x0954 }, { 0x0962, 0x0963 }, { 0x0981, 0x0981 },
{ 0x09BC, 0x09BC }, { 0x09C1, 0x09C4 }, { 0x09CD, 0x09CD },
{ 0x09E2, 0x09E3 }, { 0x0A01, 0x0A02 }, { 0x0A3C, 0x0A3C },
{ 0x0A41, 0x0A42 }, { 0x0A47, 0x0A48 }, { 0x0A4B, 0x0A4D },
{ 0x0A70, 0x0A71 }, { 0x0A81, 0x0A82 }, { 0x0ABC, 0x0ABC },
{ 0x0AC1, 0x0AC5 }, { 0x0AC7, 0x0AC8 }, { 0x0ACD, 0x0ACD },
{ 0x0AE2, 0x0AE3 }, { 0x0B01, 0x0B01 }, { 0x0B3C, 0x0B3C },
{ 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B43 }, { 0x0B4D, 0x0B4D },
{ 0x0B56, 0x0B56 }, { 0x0B82, 0x0B82 }, { 0x0BC0, 0x0BC0 },
{ 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 }, { 0x0C46, 0x0C48 },
{ 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 }, { 0x0CBC, 0x0CBC },
{ 0x0CBF, 0x0CBF }, { 0x0CC6, 0x0CC6 }, { 0x0CCC, 0x0CCD },
{ 0x0CE2, 0x0CE3 }, { 0x0D41, 0x0D43 }, { 0x0D4D, 0x0D4D },
{ 0x0DCA, 0x0DCA }, { 0x0DD2, 0x0DD4 }, { 0x0DD6, 0x0DD6 },
{ 0x0E31, 0x0E31 }, { 0x0E34, 0x0E3A }, { 0x0E47, 0x0E4E },
{ 0x0EB1, 0x0EB1 }, { 0x0EB4, 0x0EB9 }, { 0x0EBB, 0x0EBC },
{ 0x0EC8, 0x0ECD }, { 0x0F18, 0x0F19 }, { 0x0F35, 0x0F35 },
{ 0x0F37, 0x0F37 }, { 0x0F39, 0x0F39 }, { 0x0F71, 0x0F7E },
{ 0x0F80, 0x0F84 }, { 0x0F86, 0x0F87 }, { 0x0F90, 0x0F97 },
{ 0x0F99, 0x0FBC }, { 0x0FC6, 0x0FC6 }, { 0x102D, 0x1030 },
{ 0x1032, 0x1032 }, { 0x1036, 0x1037 }, { 0x1039, 0x1039 },
{ 0x1058, 0x1059 }, { 0x1160, 0x11FF }, { 0x135F, 0x135F },
{ 0x1712, 0x1714 }, { 0x1732, 0x1734 }, { 0x1752, 0x1753 },
{ 0x1772, 0x1773 }, { 0x17B4, 0x17B5 }, { 0x17B7, 0x17BD },
{ 0x17C6, 0x17C6 }, { 0x17C9, 0x17D3 }, { 0x17DD, 0x17DD },
{ 0x180B, 0x180D }, { 0x18A9, 0x18A9 }, { 0x1920, 0x1922 },
{ 0x1927, 0x1928 }, { 0x1932, 0x1932 }, { 0x1939, 0x193B },
{ 0x1A17, 0x1A18 }, { 0x1B00, 0x1B03 }, { 0x1B34, 0x1B34 },
{ 0x1B36, 0x1B3A }, { 0x1B3C, 0x1B3C }, { 0x1B42, 0x1B42 },
{ 0x1B6B, 0x1B73 }, { 0x1DC0, 0x1DCA }, { 0x1DFE, 0x1DFF },
{ 0x200B, 0x200F }, { 0x202A, 0x202E }, { 0x2060, 0x2063 },
{ 0x206A, 0x206F }, { 0x20D0, 0x20EF }, { 0x302A, 0x302F },
{ 0x3099, 0x309A }, { 0xA806, 0xA806 }, { 0xA80B, 0xA80B },
{ 0xA825, 0xA826 }, { 0xFB1E, 0xFB1E }, { 0xFE00, 0xFE0F },
{ 0xFE20, 0xFE23 }, { 0xFEFF, 0xFEFF }, { 0xFFF9, 0xFFFB },
{ 0x10A01, 0x10A03 }, { 0x10A05, 0x10A06 }, { 0x10A0C, 0x10A0F },
{ 0x10A38, 0x10A3A }, { 0x10A3F, 0x10A3F }, { 0x1D167, 0x1D169 },
{ 0x1D173, 0x1D182 }, { 0x1D185, 0x1D18B }, { 0x1D1AA, 0x1D1AD },
{ 0x1D242, 0x1D244 }, { 0xE0001, 0xE0001 }, { 0xE0020, 0xE007F },
{ 0xE0100, 0xE01EF }
};
/* A sorted list of intervals of double-width characters generated by:
* https://raw.githubusercontent.com/GNOME/glib/37d4c2941bd0326b8b6e6bb22c81bd424fcc040b/glib/gen-unicode-tables.pl
* from the Unicode 9.0.0 data files available at:
* http://www.unicode.org/Public/9.0.0/ucd/
*/
static const struct interval wide[] = {
{0x1100, 0x115F},
{0x231A, 0x231B},
{0x2329, 0x232A},
{0x23E9, 0x23EC},
{0x23F0, 0x23F0},
{0x23F3, 0x23F3},
{0x25FD, 0x25FE},
{0x2614, 0x2615},
{0x2648, 0x2653},
{0x267F, 0x267F},
{0x2693, 0x2693},
{0x26A1, 0x26A1},
{0x26AA, 0x26AB},
{0x26BD, 0x26BE},
{0x26C4, 0x26C5},
{0x26CE, 0x26CE},
{0x26D4, 0x26D4},
{0x26EA, 0x26EA},
{0x26F2, 0x26F3},
{0x26F5, 0x26F5},
{0x26FA, 0x26FA},
{0x26FD, 0x26FD},
{0x2705, 0x2705},
{0x270A, 0x270B},
{0x2728, 0x2728},
{0x274C, 0x274C},
{0x274E, 0x274E},
{0x2753, 0x2755},
{0x2757, 0x2757},
{0x2795, 0x2797},
{0x27B0, 0x27B0},
{0x27BF, 0x27BF},
{0x2B1B, 0x2B1C},
{0x2B50, 0x2B50},
{0x2B55, 0x2B55},
{0x2E80, 0x2E99},
{0x2E9B, 0x2EF3},
{0x2F00, 0x2FD5},
{0x2FF0, 0x2FFB},
{0x3000, 0x303E},
{0x3041, 0x3096},
{0x3099, 0x30FF},
{0x3105, 0x312D},
{0x3131, 0x318E},
{0x3190, 0x31BA},
{0x31C0, 0x31E3},
{0x31F0, 0x321E},
{0x3220, 0x3247},
{0x3250, 0x32FE},
{0x3300, 0x4DBF},
{0x4E00, 0xA48C},
{0xA490, 0xA4C6},
{0xA960, 0xA97C},
{0xAC00, 0xD7A3},
{0xF900, 0xFAFF},
{0xFE10, 0xFE19},
{0xFE30, 0xFE52},
{0xFE54, 0xFE66},
{0xFE68, 0xFE6B},
{0xFF01, 0xFF60},
{0xFFE0, 0xFFE6},
{0x16FE0, 0x16FE0},
{0x17000, 0x187EC},
{0x18800, 0x18AF2},
{0x1B000, 0x1B001},
{0x1F004, 0x1F004},
{0x1F0CF, 0x1F0CF},
{0x1F18E, 0x1F18E},
{0x1F191, 0x1F19A},
{0x1F200, 0x1F202},
{0x1F210, 0x1F23B},
{0x1F240, 0x1F248},
{0x1F250, 0x1F251},
{0x1F300, 0x1F320},
{0x1F32D, 0x1F335},
{0x1F337, 0x1F37C},
{0x1F37E, 0x1F393},
{0x1F3A0, 0x1F3CA},
{0x1F3CF, 0x1F3D3},
{0x1F3E0, 0x1F3F0},
{0x1F3F4, 0x1F3F4},
{0x1F3F8, 0x1F43E},
{0x1F440, 0x1F440},
{0x1F442, 0x1F4FC},
{0x1F4FF, 0x1F53D},
{0x1F54B, 0x1F54E},
{0x1F550, 0x1F567},
{0x1F57A, 0x1F57A},
{0x1F595, 0x1F596},
{0x1F5A4, 0x1F5A4},
{0x1F5FB, 0x1F64F},
{0x1F680, 0x1F6C5},
{0x1F6CC, 0x1F6CC},
{0x1F6D0, 0x1F6D2},
{0x1F6EB, 0x1F6EC},
{0x1F6F4, 0x1F6F6},
{0x1F910, 0x1F91E},
{0x1F920, 0x1F927},
{0x1F930, 0x1F930},
{0x1F933, 0x1F93E},
{0x1F940, 0x1F94B},
{0x1F950, 0x1F95E},
{0x1F980, 0x1F991},
{0x1F9C0, 0x1F9C0},
{0x20000, 0x2FFFD},
{0x30000, 0x3FFFD},
};
/* test for 8-bit control characters */
if (ucs == 0)
return 0;
if (ucs < 32 || (ucs >= 0x7f && ucs < 0xa0))
return -1;
/* binary search in table of non-spacing characters */
if (bisearch(ucs, combining,
sizeof(combining) / sizeof(struct interval) - 1))
return 0;
/* if we arrive here, ucs is not a combining or C0/C1 control character */
/* binary search in table of double-width characters */
if (bisearch(ucs, wide,
sizeof(wide) / sizeof(struct interval) - 1))
return 2;
/* normal width character */
return 1;
}
int mk_wcswidth(const unsigned int *pwcs, size_t n)
{
int w, width = 0;
for (;*pwcs && n-- > 0; pwcs++)
if ((w = mk_wcwidth(*pwcs)) < 0)
return -1;
else
width += w;
return width;
}
/*
* The following functions are the same as mk_wcwidth() and
* mk_wcswidth(), except that spacing characters in the East Asian
* Ambiguous (A) category as defined in Unicode Technical Report #11
* have a column width of 2. This variant might be useful for users of
* CJK legacy encodings who want to migrate to UCS without changing
* the traditional terminal character-width behaviour. It is not
* otherwise recommended for general use.
*/
int mk_wcwidth_cjk(unsigned int ucs)
{
/* A sorted list of intervals of ambiguous width characters generated by:
* https://raw.githubusercontent.com/GNOME/glib/37d4c2941bd0326b8b6e6bb22c81bd424fcc040b/glib/gen-unicode-tables.pl
* from the Unicode 9.0.0 data files available at:
* http://www.unicode.org/Public/9.0.0/ucd/
*/
static const struct interval ambiguous[] = {
{0x00A1, 0x00A1},
{0x00A4, 0x00A4},
{0x00A7, 0x00A8},
{0x00AA, 0x00AA},
{0x00AD, 0x00AE},
{0x00B0, 0x00B4},
{0x00B6, 0x00BA},
{0x00BC, 0x00BF},
{0x00C6, 0x00C6},
{0x00D0, 0x00D0},
{0x00D7, 0x00D8},
{0x00DE, 0x00E1},
{0x00E6, 0x00E6},
{0x00E8, 0x00EA},
{0x00EC, 0x00ED},
{0x00F0, 0x00F0},
{0x00F2, 0x00F3},
{0x00F7, 0x00FA},
{0x00FC, 0x00FC},
{0x00FE, 0x00FE},
{0x0101, 0x0101},
{0x0111, 0x0111},
{0x0113, 0x0113},
{0x011B, 0x011B},
{0x0126, 0x0127},
{0x012B, 0x012B},
{0x0131, 0x0133},
{0x0138, 0x0138},
{0x013F, 0x0142},
{0x0144, 0x0144},
{0x0148, 0x014B},
{0x014D, 0x014D},
{0x0152, 0x0153},
{0x0166, 0x0167},
{0x016B, 0x016B},
{0x01CE, 0x01CE},
{0x01D0, 0x01D0},
{0x01D2, 0x01D2},
{0x01D4, 0x01D4},
{0x01D6, 0x01D6},
{0x01D8, 0x01D8},
{0x01DA, 0x01DA},
{0x01DC, 0x01DC},
{0x0251, 0x0251},
{0x0261, 0x0261},
{0x02C4, 0x02C4},
{0x02C7, 0x02C7},
{0x02C9, 0x02CB},
{0x02CD, 0x02CD},
{0x02D0, 0x02D0},
{0x02D8, 0x02DB},
{0x02DD, 0x02DD},
{0x02DF, 0x02DF},
{0x0300, 0x036F},
{0x0391, 0x03A1},
{0x03A3, 0x03A9},
{0x03B1, 0x03C1},
{0x03C3, 0x03C9},
{0x0401, 0x0401},
{0x0410, 0x044F},
{0x0451, 0x0451},
{0x2010, 0x2010},
{0x2013, 0x2016},
{0x2018, 0x2019},
{0x201C, 0x201D},
{0x2020, 0x2022},
{0x2024, 0x2027},
{0x2030, 0x2030},
{0x2032, 0x2033},
{0x2035, 0x2035},
{0x203B, 0x203B},
{0x203E, 0x203E},
{0x2074, 0x2074},
{0x207F, 0x207F},
{0x2081, 0x2084},
{0x20AC, 0x20AC},
{0x2103, 0x2103},
{0x2105, 0x2105},
{0x2109, 0x2109},
{0x2113, 0x2113},
{0x2116, 0x2116},
{0x2121, 0x2122},
{0x2126, 0x2126},
{0x212B, 0x212B},
{0x2153, 0x2154},
{0x215B, 0x215E},
{0x2160, 0x216B},
{0x2170, 0x2179},
{0x2189, 0x2189},
{0x2190, 0x2199},
{0x21B8, 0x21B9},
{0x21D2, 0x21D2},
{0x21D4, 0x21D4},
{0x21E7, 0x21E7},
{0x2200, 0x2200},
{0x2202, 0x2203},
{0x2207, 0x2208},
{0x220B, 0x220B},
{0x220F, 0x220F},
{0x2211, 0x2211},
{0x2215, 0x2215},
{0x221A, 0x221A},
{0x221D, 0x2220},
{0x2223, 0x2223},
{0x2225, 0x2225},
{0x2227, 0x222C},
{0x222E, 0x222E},
{0x2234, 0x2237},
{0x223C, 0x223D},
{0x2248, 0x2248},
{0x224C, 0x224C},
{0x2252, 0x2252},
{0x2260, 0x2261},
{0x2264, 0x2267},
{0x226A, 0x226B},
{0x226E, 0x226F},
{0x2282, 0x2283},
{0x2286, 0x2287},
{0x2295, 0x2295},
{0x2299, 0x2299},
{0x22A5, 0x22A5},
{0x22BF, 0x22BF},
{0x2312, 0x2312},
{0x2460, 0x24E9},
{0x24EB, 0x254B},
{0x2550, 0x2573},
{0x2580, 0x258F},
{0x2592, 0x2595},
{0x25A0, 0x25A1},
{0x25A3, 0x25A9},
{0x25B2, 0x25B3},
{0x25B6, 0x25B7},
{0x25BC, 0x25BD},
{0x25C0, 0x25C1},
{0x25C6, 0x25C8},
{0x25CB, 0x25CB},
{0x25CE, 0x25D1},
{0x25E2, 0x25E5},
{0x25EF, 0x25EF},
{0x2605, 0x2606},
{0x2609, 0x2609},
{0x260E, 0x260F},
{0x261C, 0x261C},
{0x261E, 0x261E},
{0x2640, 0x2640},
{0x2642, 0x2642},
{0x2660, 0x2661},
{0x2663, 0x2665},
{0x2667, 0x266A},
{0x266C, 0x266D},
{0x266F, 0x266F},
{0x269E, 0x269F},
{0x26BF, 0x26BF},
{0x26C6, 0x26CD},
{0x26CF, 0x26D3},
{0x26D5, 0x26E1},
{0x26E3, 0x26E3},
{0x26E8, 0x26E9},
{0x26EB, 0x26F1},
{0x26F4, 0x26F4},
{0x26F6, 0x26F9},
{0x26FB, 0x26FC},
{0x26FE, 0x26FF},
{0x273D, 0x273D},
{0x2776, 0x277F},
{0x2B56, 0x2B59},
{0x3248, 0x324F},
{0xE000, 0xF8FF},
{0xFE00, 0xFE0F},
{0xFFFD, 0xFFFD},
{0x1F100, 0x1F10A},
{0x1F110, 0x1F12D},
{0x1F130, 0x1F169},
{0x1F170, 0x1F18D},
{0x1F18F, 0x1F190},
{0x1F19B, 0x1F1AC},
{0xE0100, 0xE01EF},
{0xF0000, 0xFFFFD},
{0x100000, 0x10FFFD},
};
/* binary search in table of non-spacing characters */
if (bisearch(ucs, ambiguous,
sizeof(ambiguous) / sizeof(struct interval) - 1))
return 2;
return mk_wcwidth(ucs);
}
int mk_wcswidth_cjk(const unsigned int *pwcs, size_t n)
{
int w, width = 0;
for (;*pwcs && n-- > 0; pwcs++)
if ((w = mk_wcwidth_cjk(*pwcs)) < 0)
return -1;
else
width += w;
return width;
}
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