1 files changed, 45 insertions, 0 deletions
diff --git a/err.h b/err.h
new file mode 100644
index 0000000..897deee
--- /dev/null
+++ b/err.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define TF_ERRORS \
+	TF_ERROR(SUCCESS, "success"), \
+	TF_ERROR(ATOI_OVERFLOW, "value too large"), \
+	TF_ERROR(ATOI_NO_DIGITS, "no digits found in string"), \
+	TF_ERROR(ATOI_JUNK_AT_END, "further characters after number"), \
+	TF_ERROR(TXP, "tag expression parse error"), \
+	TF_ERROR(REGEX, "regular expression error"), \
+	TF_ERROR(LOPSUB, "lopsub error"), \
+
+/*
+ * This is temporarily defined to expand to its first argument (prefixed by
+ * 'E_') and gets later redefined to expand to the error text only
+ */
+#define TF_ERROR(err, msg) E_ ## err
+enum tf_error_codes {TF_ERRORS};
+#undef TF_ERROR
+#define TF_ERROR(err, msg) msg
+#define DEFINE_TF_ERRLIST char *tf_errlist[] = {TF_ERRORS}
+
+extern char *tf_errlist[];
+
+/**
+ * This bit indicates whether a number is considered a system error number
+ * If yes, the system errno is just the result of clearing this bit from
+ * the given number.
+ */
+#define SYSTEM_ERROR_BIT 30
+
+/** Check whether the system error bit is set. */
+#define IS_SYSTEM_ERROR(num) (!!((num) & (1 << SYSTEM_ERROR_BIT)))
+
+/** Set the system error bit for the given number. */
+#define ERRNO_TO_TF_ERROR(num) ((num) | (1 << SYSTEM_ERROR_BIT))
+
+static inline char *tf_strerror(int num)
+{
+	assert(num > 0);
+	if (IS_SYSTEM_ERROR(num))
+		return strerror((num) & ((1 << SYSTEM_ERROR_BIT) - 1));
+	else
+		return tf_errlist[num];
+}
+