vis

a vi-like editor based on Plan 9's structural regular expressions
text-util.c

(2857B)
      1 #include "text-util.h"
      2 #include "util.h"
      3 #include <wchar.h>
      4 #include <errno.h>
      5 #include <stdlib.h>
      6 
      7 bool text_range_valid(const Filerange *r) {
      8 	return r->start != EPOS && r->end != EPOS && r->start <= r->end;
      9 }
     10 
     11 size_t text_range_size(const Filerange *r) {
     12 	return text_range_valid(r) ? r->end - r->start : 0;
     13 }
     14 
     15 Filerange text_range_empty(void) {
     16 	return (Filerange){ .start = EPOS, .end = EPOS };
     17 }
     18 
     19 Filerange text_range_union(const Filerange *r1, const Filerange *r2) {
     20 	if (!text_range_valid(r1))
     21 		return *r2;
     22 	if (!text_range_valid(r2))
     23 		return *r1;
     24 	return (Filerange) {
     25 		.start = MIN(r1->start, r2->start),
     26 		.end = MAX(r1->end, r2->end),
     27 	};
     28 }
     29 
     30 Filerange text_range_intersect(const Filerange *r1, const Filerange *r2) {
     31 	if (!text_range_overlap(r1, r2))
     32 		return text_range_empty();
     33 	return text_range_new(MAX(r1->start, r2->start), MIN(r1->end, r2->end));
     34 }
     35 
     36 Filerange text_range_new(size_t a, size_t b) {
     37 	return (Filerange) {
     38 		.start = MIN(a, b),
     39 		.end = MAX(a, b),
     40 	};
     41 }
     42 
     43 bool text_range_equal(const Filerange *r1, const Filerange *r2) {
     44 	if (!text_range_valid(r1) && !text_range_valid(r2))
     45 		return true;
     46 	return r1->start == r2->start && r1->end == r2->end;
     47 }
     48 
     49 bool text_range_overlap(const Filerange *r1, const Filerange *r2) {
     50 	if (!text_range_valid(r1) || !text_range_valid(r2))
     51 		return false;
     52 	return r1->start < r2->end && r2->start < r1->end;
     53 }
     54 
     55 bool text_range_contains(const Filerange *r, size_t pos) {
     56 	return text_range_valid(r) && r->start <= pos && pos <= r->end;
     57 }
     58 
     59 int text_char_count(const char *data, size_t len) {
     60 	int count = 0;
     61 	mbstate_t ps = { 0 };
     62 	while (len > 0) {
     63 		wchar_t wc;
     64 		size_t wclen = mbrtowc(&wc, data, len, &ps);
     65 		if (wclen == (size_t)-1 && errno == EILSEQ) {
     66 			ps = (mbstate_t){0};
     67 			count++;
     68 			while (!ISUTF8(*data))
     69 				data++, len--;
     70 		} else if (wclen == (size_t)-2) {
     71 			break;
     72                 } else if (wclen == 0) {
     73 			count++;
     74 			data++;
     75 			len--;
     76 		} else {
     77 			int width = wcwidth(wc);
     78 			if (width != 0)
     79 				count++;
     80 			data += wclen;
     81 			len -= wclen;
     82                 }
     83 	}
     84 	return count;
     85 }
     86 
     87 int text_string_width(const char *data, size_t len) {
     88 
     89 	int width = 0;
     90 	mbstate_t ps = { 0 };
     91 	const char *s = data;
     92 
     93 	while (len > 0) {
     94 		wchar_t wc;
     95 		size_t wclen = mbrtowc(&wc, s, len, &ps);
     96 		if (wclen == (size_t)-1 && errno == EILSEQ) {
     97 			ps = (mbstate_t){0};
     98 			/* assume a replacement symbol will be displayed */
     99 			width++;
    100 			wclen = 1;
    101 		} else if (wclen == (size_t)-2) {
    102 			/* do nothing, advance to next character */
    103 			wclen = 1;
    104 		} else if (wclen == 0) {
    105 			/* assume NUL byte will be displayed as ^@ */
    106 			width += 2;
    107 			wclen = 1;
    108 		} else if (wc == L'\t') {
    109 			width++;
    110 			wclen = 1;
    111 		} else {
    112 			int w = wcwidth(wc);
    113 			if (w == -1)
    114 				w = 2; /* assume non-printable will be displayed as ^{char} */
    115 			width += w;
    116 		}
    117 		len -= wclen;
    118 		s += wclen;
    119 	}
    120 
    121 	return width;
    122 }