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#include <stdarg.h>
#include <string.h>
#include <posthaste/debug.h>
/* find the start of line number no in buffer buf */
static const char *find_lineno(const char *buf, size_t no)
{
if (no == 0 || no == 1)
return buf;
char c;
while ((c = *buf)) {
buf++;
if (c == '\n')
no--;
if (no == 1)
break;
}
return buf;
}
static void print_bar(int lineno_len)
{
fprintf(stderr, "%*s", lineno_len + 4, "| ");
}
static void vsrc_multi_line(struct src_issue issue, const char *line_start,
int lineno_len)
{
/* just dump lines as they are, adding bars to the left */
size_t line = issue.loc.first_line;
for (size_t i = 0;; ++i) {
char c = line_start[i];
if (c == 0) {
fputc('\n', stderr);
break;
}
fputc(c, stderr);
if (c == '\n') {
if (++line > issue.loc.last_line)
break;
print_bar(lineno_len);
}
}
}
void vsrc_issue(struct src_issue issue, const char *msg, va_list args)
{
/* with color support we could start coloring the actual error region at
* issue.loc.first_column on issue.loc.first_line, but messing with
* xterm color codes is a bit cumbersome so for now just stick to
* monochrome */
fprintf(stderr, "%s:%i:%i: ",
issue.fname,
issue.loc.first_line,
issue.loc.first_col);
vfprintf(stderr, msg, args);
fputc('\n', stderr);
/* figure out how many spaces line number takes up */
int lineno_len = snprintf(NULL, 0, "%i", issue.loc.first_line);
fprintf(stderr, " %i | ", issue.loc.first_line);
const char *line_start = find_lineno(issue.buf, issue.loc.first_line);
if (issue.loc.first_line != issue.loc.last_line) {
/* multiline location requires slightly different handling */
return vsrc_multi_line(issue, line_start, lineno_len);
}
/* print the offending line */
for (size_t i = 0;; ++i) {
char c = line_start[i];
if (c == 0 || c == '\n')
break;
fputc(c, stderr);
}
fputc('\n', stderr);
/* the rest is just to print a little squiggly line to highlight exact location */
print_bar(lineno_len);
/* print tabs on tabs, otherwise spaces to make start of squiggle line
* up with start of offending location */
for (size_t i = 0; i < issue.loc.first_col - 1; ++i)
fputc(line_start[i] == '\t' ? '\t' : ' ', stderr);
/* highlight the offending location */
for (size_t i = issue.loc.first_col; i < issue.loc.last_col; ++i) {
if (i == issue.loc.first_col)
fputc('^', stderr);
else
fputc('~', stderr);
}
fputc('\n', stderr);
}
void src_issue(struct src_issue issue, const char *msg, ...)
{
va_list args;
va_start(args, msg);
vsrc_issue(issue, msg, args);
va_end(args);
}
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