Create a "utils" module

Also put configuration macros in a dedicated header. In the future the
configuration will be read at execution time.

1 files changed, 39 insertions, 0 deletions

diff --git a/src/utils.h b/src/utils.h
new file mode 100644
index 0000000..e382ace
--- /dev/null
+++ b/src/utils.h
@@ -0,0 +1,39 @@
+#ifndef UTILS_H
+#define UTILS_H
+
+/* Utility functions for manipulating strings, time, and error codes. */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <time.h>
+
+/* Internals of strbuild. */
+void __strbuild(char *buf, int size,
+		const char *file, int line,
+		const char *fmt, ...);
+
+/* Safely create a formatted string and write it to BUF. BUF shall be a buffer
+ * of size at least SIZE. BUF can be stack-allocated. If the formatting cannot
+ * be performed, exit(3) is called. This function is not meant to be called
+ * directly: the macro strbuild should be used. The code is adapted from the
+ * make_message function of the vsnprintf(3) manual page, section "examples". */
+#define strbuild(buf, fmt, ...) \
+	__strbuild(buf, sizeof(buf), __FILE__, __LINE__, fmt, __VA_ARGS__)
+
+#define strbuild_with_size(buf, size, fmt, ...)				\
+	__strbuild(buf, size, __FILE__, __LINE__, fmt, __VA_ARGS__)
+
+int str_has_suffix(const char *str, const char *suffix);
+
+/* Abort if the database does not exist. */
+void assert_db_exists(void);
+
+/* Compute something that identifies the content of FILE. Algorithm by Dan
+ * Bernstein from http://www.cse.yorku.ca/~oz/hash.html via
+ * https://stackoverflow.com/a/7666577/20138083. */
+uint32_t sum(const char *file);
+
+/* Return an integer timestamp from a date string of the format YYYY-MM-DD. */
+time_t time_from_str(const char *str);
+
+#endif