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try to calculate character width

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This commit is contained in:
Philipp Otterbein 2024-12-15 02:29:56 +01:00 • committed by Jörg Thalheim
parent 6a23803066
commit 92e30955b9
7 changed files with 1636 additions and 29 deletions
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90
src/libutil/terminal.cc
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@ -11,6 +11,53 @@
# include <sys/ioctl.h>
#endif
#include <unistd.h>
#include <widechar_width.h>
namespace {
inline std::pair<int, size_t> charWidthUTF8Helper(std::string_view s)
{
size_t bytes = 1;
uint32_t ch = s[0];
uint32_t max = 1U << 7;
if ((ch & 0x80U) == 0U) {
} else if ((ch & 0xe0U) == 0xc0U) {
ch &= 0x1fU;
bytes = 2;
max = 1U << 11;
} else if ((ch & 0xf0U) == 0xe0U) {
ch &= 0x0fU;
bytes = 3;
max = 1U << 16;
} else if ((ch & 0xf8U) == 0xf0U) {
ch &= 0x07U;
bytes = 4;
max = 0x110000U;
} else {
return {bytes, bytes}; // invalid UTF-8 start byte
}
for (size_t i = 1; i < bytes; i++) {
if (i < s.size() && (s[i] & 0xc0) == 0x80) {
ch = (ch << 6) | (s[i] & 0x3f);
} else {
return {i, i}; // invalid UTF-8 encoding; assume one character per byte
}
}
int width = bytes; // in case of overlong encoding
if (ch < max) {
width = widechar_wcwidth(ch);
if (width == widechar_ambiguous) {
width = 1; // just a guess...
} else if (width == widechar_widened_in_9) {
width = 2;
} else if (width < 0) {
width = 0;
}
}
return {width, bytes};
}
}
namespace nix {
@ -30,7 +77,7 @@ std::string filterANSIEscapes(std::string_view s, bool filterAll, unsigned int w
size_t w = 0;
auto i = s.begin();
while (w < (size_t) width && i != s.end()) {
while (i != s.end()) {
if (*i == '\e') {
std::string e;
@ -61,10 +108,12 @@ std::string filterANSIEscapes(std::string_view s, bool filterAll, unsigned int w
}
else if (*i == '\t') {
i++; t += ' '; w++;
while (w < (size_t) width && w % 8) {
t += ' '; w++;
}
do {
if (++w > (size_t) width)
return t;
t += ' ';
} while (w % 8);
i++;
}
else if (*i == '\r' || *i == '\a')
@ -72,35 +121,18 @@ std::string filterANSIEscapes(std::string_view s, bool filterAll, unsigned int w
i++;
else {
w++;
// Copy one UTF-8 character.
if ((*i & 0xe0) == 0xc0) {
t += *i++;
if (i != s.end() && ((*i & 0xc0) == 0x80)) t += *i++;
} else if ((*i & 0xf0) == 0xe0) {
t += *i++;
if (i != s.end() && ((*i & 0xc0) == 0x80)) {
t += *i++;
if (i != s.end() && ((*i & 0xc0) == 0x80)) t += *i++;
}
} else if ((*i & 0xf8) == 0xf0) {
t += *i++;
if (i != s.end() && ((*i & 0xc0) == 0x80)) {
t += *i++;
if (i != s.end() && ((*i & 0xc0) == 0x80)) {
t += *i++;
if (i != s.end() && ((*i & 0xc0) == 0x80)) t += *i++;
}
}
} else
t += *i++;
auto [chWidth, bytes] = charWidthUTF8Helper({i, s.end()});
w += chWidth;
if (w > (size_t) width) {
break;
}
t += {i, i + bytes};
i += bytes;
}
}
return t;
}
//////////////////////////////////////////////////////////////////////
static Sync<std::pair<unsigned short, unsigned short>> windowSize{{0, 0}};