1 files changed, 111 insertions, 0 deletions
diff --git a/src/common/error.c b/src/common/error.c
new file mode 100644
index 0000000..dbc1d81
--- /dev/null
+++ b/src/common/error.c
@@ -0,0 +1,111 @@
+/*
+ * blogc: A blog compiler.
+ * Copyright (C) 2015-2016 Rafael G. Martins <rafael@rafaelmartins.eng.br>
+ *
+ * This program can be distributed under the terms of the BSD License.
+ * See the file LICENSE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include "error.h"
+#include "utils.h"
+
+
+bc_error_t*
+bc_error_new(int type, const char *msg)
+{
+    bc_error_t *err = bc_malloc(sizeof(bc_error_t));
+    err->type = type;
+    err->msg = bc_strdup(msg);
+    return err;
+}
+
+
+bc_error_t*
+bc_error_new_printf(int type, const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    char *tmp = bc_strdup_vprintf(format, ap);
+    va_end(ap);
+    bc_error_t *rv = bc_error_new(type, tmp);
+    free(tmp);
+    return rv;
+}
+
+
+bc_error_t*
+bc_error_parser(int type, const char *src, size_t src_len,
+    size_t current, const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    char *msg = bc_strdup_vprintf(format, ap);
+    va_end(ap);
+
+    size_t lineno = 1;
+    size_t linestart = 0;
+    size_t lineend = 0;
+    size_t pos = 1;
+
+    for (size_t i = 0; i < src_len; i++) {
+        char c = src[i];
+        if (i < current) {
+            if ((i + 1) < src_len) {
+                if ((c == '\n' && src[i + 1] == '\r') ||
+                    (c == '\r' && src[i + 1] == '\n'))
+                {
+                    lineno++;
+                    i++;
+                    pos = 1;
+                    if ((i + 1) < src_len)
+                        linestart = i + 1;
+                    continue;
+                }
+            }
+            if (c == '\n' || c == '\r') {
+                lineno++;
+                pos = 1;
+                if ((i + 1) < src_len)
+                    linestart = i + 1;
+                continue;
+            }
+            pos++;
+        }
+        else if (c == '\n' || c == '\r') {
+            lineend = i;
+            break;
+        }
+    }
+
+    if (lineend <= linestart && src_len >= linestart)
+        lineend = src_len;
+
+    char *line = bc_strndup(src + linestart, lineend - linestart);
+
+    bc_error_t *rv = NULL;
+
+    if (line[0] == '\0')  // "near" message isn't useful if line is empty
+        rv = bc_error_new(type, msg);
+    else
+        rv = bc_error_new_printf(type,
+            "%s\nError occurred near line %d, position %d: %s", msg, lineno,
+            pos, line);
+
+    free(msg);
+    free(line);
+
+    return rv;
+}
+
+
+void
+bc_error_free(bc_error_t *err)
+{
+    if (err == NULL)
+        return;
+    free(err->msg);
+    free(err);
+}