From c035571d85e3d756804519d82de8b354f3910b29 Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Thu, 8 Feb 2024 21:19:38 +0200
Subject: project work phase 1

---
 src/debug.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 src/debug.c

(limited to 'src/debug.c')

diff --git a/src/debug.c b/src/debug.c
new file mode 100644
index 0000000..c146719
--- /dev/null
+++ b/src/debug.c
@@ -0,0 +1,81 @@
+#include <stdarg.h>
+#include <string.h>
+
+#include <posthaste/debug.h>
+
+/**
+ * Find position in file buffer where line number \p no
+ * starts. Lines are assumed to be one-indexed, with
+ * \p no = \c 0 and \p no = \c 1 both considered the first line.
+ *
+ * @param buf Buffer to look in.
+ * @param no Line number whose start to look for.
+ * @return Pointer to location in buffer where line number \p no
+ * starts.
+ */
+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;
+}
+
+void vsrc_issue(struct src_issue issue, const char *msg, va_list args)
+{
+	const char *line_start = find_lineno(issue.buf, issue.loc.first_line);
+	const char *line_end = strchr(line_start, '\n');
+	if (!line_end)
+		line_end = strchr(line_start, 0);
+
+	int line_len = line_end - line_start;
+
+	fprintf(stderr, "%s:%i:%i: ", issue.fname,
+	        issue.loc.first_line,
+	        issue.loc.first_col);
+
+	vfprintf(stderr, msg, args);
+	fputc('\n', stderr);
+
+	int lineno_len = snprintf(NULL, 0, "%i", issue.loc.first_line);
+	fputc(' ', stderr);
+	fprintf(stderr, "%i | ", issue.loc.first_line);
+
+	fprintf(stderr, "%.*s\n", line_len, line_start);
+
+	for (int i = 0; i < lineno_len + 2; ++i)
+		fputc(' ', stderr);
+
+	fprintf(stderr, "| ");
+
+	for (int i = 0; i < issue.loc.first_col - 1; ++i)
+		fputc(line_start[i] == '\t' ? '\t' : ' ', stderr);
+
+	for (int 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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