/* Forms new line with highlights of matcher of the re regular expression using
* escape sequences that invert colors. Returns NULL when no match found or
* memory allocation error occured. */
static char *
add_pattern_highlights(const char line[], size_t len, const char no_esc[],
const int offsets[], const regex_t *re)
{
regmatch_t match;
char *next = NULL;
char *processed;
int shift = 0;
int overhead = 0;
if(regexec(re, no_esc, 1, &match, 0) != 0)
{
return NULL;
}
if((processed = malloc(len + 1)) == NULL)
{
return NULL;
}
/* Before the first match. */
strncpy(processed, line, offsets[match.rm_so]);
next = processed + offsets[match.rm_so];
/* All matches. */
do
{
size_t match_len;
size_t new_overhead;
int so_offset;
void *ptr;
const int empty_match = (match.rm_so == match.rm_eo);
match.rm_so += shift;
match.rm_eo += shift;
so_offset = offsets[match.rm_so];
if(empty_match)
{
if(no_esc[match.rm_eo] == '\0')
{
shift = match.rm_eo;
break;
}
}
/* Between matches. */
if(shift != 0)
{
const int corrected = correct_offset(line, offsets, shift);
strncpy(next, line + corrected, so_offset - corrected);
}
if(empty_match)
{
const int corrected = (shift == 0)
? (size_t)(next - processed)
: correct_offset(line, offsets, shift);
const int len = offsets[match.rm_so + 1] - corrected;
strncpy(next, line + corrected, len);
next += len;
++shift;
}
else
{
new_overhead = INV_OVERHEAD*count_substr_chars(no_esc, &match);
len += new_overhead;
if((ptr = realloc(processed, len + 1)) == NULL)
{
free(processed);
return NULL;
}
processed = ptr;
match_len = correct_offset(line, offsets, match.rm_eo) - so_offset;
next = processed + so_offset + overhead;
next = add_highlighted_substr(line + so_offset, match_len, next);
shift = match.rm_eo;
overhead += new_overhead;
}
}
while(regexec(re, no_esc + shift, 1, &match, 0) == 0);
/* Abort if there were no non-empty matches. */
if(next == NULL)
{
free(processed);
return 0;
}
/* After the last match. */
strcpy(next, line + (shift == 0 ? 0 : correct_offset(line, offsets, shift)));
return processed;
}
/* Forms new line with highlights of matcher of the re regular expression using
* escape sequences that invert colors. Returns NULL when no match found or
* memory allocation error occurred. */
static char *
add_pattern_highlights(const char line[], size_t len, const char no_esc[],
const int offsets[], const regex_t *re)
{
/* XXX: this might benefit from a rewrite, logic of when escape sequences are
* copied is unclear (sometimes along with first matched character,
* sometimes before the match). */
regmatch_t match;
char *next;
char *processed;
int no_esc_pos = 0;
int overhead = 0;
int offset;
if(regexec(re, no_esc, 1, &match, 0) != 0)
{
return NULL;
}
if((processed = malloc(len + 1)) == NULL)
{
return NULL;
}
/* Before the first match. */
if(match.rm_so != 0 && no_esc[match.rm_so] == '\0')
{
/* This is needed to handle possibility of immediate break from the loop
* below. */
offset = correct_offset(line, offsets, match.rm_so);
}
else
{
offset = offsets[match.rm_so];
}
strncpy(processed, line, offset);
next = processed + offset;
/* All matches. */
do
{
int so_offset;
void *ptr;
const int empty_match = (match.rm_so == match.rm_eo);
match.rm_so += no_esc_pos;
match.rm_eo += no_esc_pos;
so_offset = offsets[match.rm_so];
if(empty_match)
{
if(no_esc[match.rm_eo] == '\0')
{
no_esc_pos = match.rm_eo;
break;
}
}
/* Between matches. */
if(no_esc_pos != 0)
{
const int corrected = correct_offset(line, offsets, no_esc_pos);
strncpy(next, line + corrected, so_offset - corrected);
}
if(empty_match)
{
/* Copy single character after the match to advance forward. */
/* Position inside the line string. */
const int esc_pos = (no_esc_pos == 0)
? (size_t)(next - processed)
: correct_offset(line, offsets, no_esc_pos);
/* Number of characters to copy from the line string. */
const int len = (match.rm_so == 0)
? utf8_chrw(no_esc)
: correct_offset(line, offsets, match.rm_so + 1) - esc_pos;
strncpy(next, line + esc_pos, len);
next += len;
no_esc_pos += utf8_chrw(&no_esc[no_esc_pos]);
}
else
{
size_t new_overhead;
size_t match_len;
new_overhead = INV_OVERHEAD*count_substr_chars(no_esc, &match);
len += new_overhead;
if((ptr = realloc(processed, len + 1)) == NULL)
{
free(processed);
return NULL;
}
processed = ptr;
match_len = correct_offset(line, offsets, match.rm_eo) - so_offset;
next = processed + so_offset + overhead;
next = add_highlighted_substr(line + so_offset, match_len, next);
no_esc_pos = match.rm_eo;
overhead += new_overhead;
}
}
while(regexec(re, no_esc + no_esc_pos, 1, &match, 0) == 0);
/* Abort if there were no non-empty matches. */
if(overhead == 0)
{
free(processed);
return 0;
}
/* After the last match. */
strcpy(next, line +
(no_esc_pos == 0 ? (size_t)(next - processed) :
correct_offset(line, offsets, no_esc_pos)));
return processed;
}
