+#include "libsigrok.h"
+#include "libsigrok-internal.h"
+
+/* Message logging helpers with subsystem-specific prefix string. */
+#define LOG_PREFIX "strutil: "
+#define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
+#define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
+#define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
+#define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
+#define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
+#define sr_err(s, args...) sr_err(LOG_PREFIX s, ## args)
+
+/**
+ * @file
+ *
+ * Helper functions for handling or converting libsigrok-related strings.
+ */
+
+/**
+ * @defgroup grp_strutil String utilities
+ *
+ * Helper functions for handling or converting libsigrok-related strings.
+ *
+ * @{
+ */
+
+/**
+ * Convert a numeric value value to its "natural" string representation
+ * in SI units.
+ *
+ * E.g. a value of 3000000, with units set to "W", would be converted
+ * to "3 MW", 20000 to "20 kW", 31500 would become "31.5 kW".
+ *
+ * @param x The value to convert.
+ * @param unit The unit to append to the string, or NULL if the string
+ * has no units.
+ *
+ * @return A g_try_malloc()ed string representation of the samplerate value,
+ * or NULL upon errors. The caller is responsible to g_free() the
+ * memory.
+ */
+SR_API char *sr_si_string_u64(uint64_t x, const char *unit)
+{
+ uint8_t i;
+ uint64_t quot, divisor[] = {
+ SR_HZ(1), SR_KHZ(1), SR_MHZ(1), SR_GHZ(1),
+ SR_GHZ(1000), SR_GHZ(1000 * 1000), SR_GHZ(1000 * 1000 * 1000),
+ };
+ const char *p, prefix[] = "\0kMGTPE";
+ char fmt[8], fract[20] = "", *f;
+
+ if (unit == NULL)
+ unit = "";
+
+ for (i = 0; (quot = x / divisor[i]) >= 1000; i++);
+
+ if (i) {
+ sprintf(fmt, ".%%0%dlu", i * 3);
+ f = fract + sprintf(fract, fmt, x % divisor[i]) - 1;
+
+ while (f >= fract && strchr("0.", *f))
+ *f-- = 0;
+ }
+
+ p = prefix + i;
+
+ return g_strdup_printf("%" PRIu64 "%s %.1s%s", quot, fract, p, unit);
+}