SplitStringLineList split_line(unsigned wid, std::wstring_view s) {
SplitStringLineList ret;
if (wid < 2) { // Robustness. Avoid dead loops
for (size_t k = 0; k < s.length(); ++k) {
ret.push_back({k, 1, ucs_width(s[k])});
}
} else {
for (unsigned offset = 0; offset < s.length(); ) {
SplitStringLine line;
offset = split_line(&line, wid, s, offset, 0);
ret.push_back(std::move(line));
}
}
return ret;
}
unsigned split_line (SplitStringLine *result, unsigned max_lines, unsigned wid, std::wstring_view s) {
unsigned offset = 0;
unsigned lines = 0;
for (; lines < max_lines && offset < s.length(); ++lines) {
offset = split_line(result++, wid, s, offset, 0);
}
return lines;
}
size_t split_line(SplitStringLine *result, unsigned wid, std::wstring_view str, size_t offset, unsigned options) {
str.remove_prefix(offset);
const wchar_t *s = str.data();
size_t slen = str.length();
size_t cur = 0; // Current position
unsigned curwid = 0;// Used screen width
for (;;) {
if (cur >= slen) {
result->begin = offset;
result->len = slen;
result->wid = curwid;
return (offset + slen);
}
if (!(options & SPLIT_NEWLINE_AS_SPACE) && s[cur] == L'\n') {
result->begin = offset;
result->len = cur;
result->wid = curwid;
return (offset + cur + 1); // Skip the newline character
}
unsigned w = ucs_width (s[cur]);
if (curwid + w > wid) {
break;
}
curwid += w;
++cur;
}
// Not the whold string. Neither has a newline character been encountered
// Now scan backward to find a proper line-breaking point
unsigned extra_skip = 0;
if (!(options & SPLIT_CUT_WORD)) {
unsigned xcur = cur;
for (;;) {
if (xcur == 0) { // This means that a single word is longer than a line. We have to split it
break;
}
if ((!ucs_isalnum (s[xcur-1]) || !ucs_isalnum (s[xcur])) &&
allow_line_end (s[xcur-1]) &&
allow_line_beginning (s[xcur])) {
cur = xcur;
break;
}
curwid -= ucs_width (s[--xcur]);
}
while (cur+extra_skip+1<slen && s[cur+extra_skip]==L' ') {
++extra_skip;
}
}
result->begin = offset;
result->len = cur;
result->wid = curwid;
return (offset + cur + extra_skip);
}