1 files changed, 59 insertions, 0 deletions
diff --git a/src/source.c b/src/source.c
new file mode 100644
index 0000000..cc544e4
--- /dev/null
+++ b/src/source.c
@@ -0,0 +1,59 @@
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "source.h"
+
+void source_init(struct source *src, str name, str contents)
+{
+    src->name = name;
+    src->offset = 0;
+    src->contents = contents;
+    src->strings.len = src->strings.cap = 0;
+    src->strings.ptr = nullptr;
+}
+
+void source_error(struct source *src, struct range loc, const char *fmt, ...)
+{
+    char *p_start = src->contents.ptr + loc.start;
+    char *p_end = src->contents.ptr + loc.end;
+
+    unsigned int lineno = 0;
+    str iter = src->contents;
+    str line;
+    do {
+        line = str_walk(&iter, S("\n"));
+        lineno++;
+    } while (line.ptr + line.len <= p_start);
+
+    fprintf(stderr, "parse error in %.*s:%u: ", PSTR(src->name), lineno);
+
+    va_list args;
+    va_start(args, fmt);
+    vfprintf(stderr, fmt, args);
+    va_end(args);
+    
+    fprintf(stderr, "\n");
+
+    while (line.ptr && line.ptr < p_end) {
+        fprintf(stderr, " %4u: %.*s\n", lineno, PSTR(line));
+        fprintf(stderr, "       ");
+        for (size_t i = 0; i < line.len+1; i++) {
+            char *p = line.ptr + i;
+            fprintf(stderr, "%c", p >= p_start && p < p_end ? '^' : ' ');
+        }
+        fprintf(stderr, "\n");
+
+        line = str_walk(&iter, S("\n"));
+        lineno++;
+    }
+
+    exit(EXIT_FAILURE);
+}
+
+void source_free(struct source *src)
+{
+    free(src->contents.ptr);
+    for (size_t i = 0; i < src->strings.len; i++)
+        free(src->strings.ptr[i].ptr);
+    free(src->strings.ptr);
+}