scoutfs-utils: add string parsing functions

We're starting to collect a few of these.  Let's put them in one place.

Signed-off-by: Zach Brown <zab@versity.com>

utils/src/parse.c

@@ -0,0 +1,71 @@
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <stdio.h>
+
+#include "sparse.h"
+#include "util.h"
+#include "format.h"
+
+#include "parse.h"
+
+int parse_u64(char *str, u64 *val_ret)
+{
+	unsigned long long ull;
+	char *endptr = NULL;
+
+	ull = strtoull(str, &endptr, 0);
+	if (*endptr != '\0' ||
+	    ((ull == LLONG_MIN || ull == LLONG_MAX) &&
+	     errno == ERANGE)) {
+		fprintf(stderr, "invalid 64bit value: '%s'\n", str);
+		*val_ret = 0;
+		return -EINVAL;
+	}
+
+	*val_ret = ull;
+
+	return 0;
+}
+
+int parse_u32(char *str, u32 *val_ret)
+{
+	u64 val;
+	int ret;
+
+	ret = parse_u64(str, &val);
+	if (ret)
+		return ret;
+
+	if (val > UINT_MAX)
+		return -EINVAL;
+
+	*val_ret = val;
+	return 0;
+}
+
+int parse_timespec(char *str, struct scoutfs_timespec *ts)
+{
+	unsigned long long sec;
+	unsigned int nsec;
+	int ret;
+
+	memset(ts, 0, sizeof(struct scoutfs_timespec));
+
+	ret = sscanf(str, "%llu.%u", &sec, &nsec);
+	if (ret != 2)  {
+		fprintf(stderr, "invalid timespec string: '%s'\n", str);
+		return -EINVAL;
+	}
+
+	if (nsec > 1000000000) {
+		fprintf(stderr, "invalid timespec nsec value: '%s'\n", str);
+		return -EINVAL;
+	}
+
+	ts->sec = cpu_to_le64(sec);
+	ts->nsec = cpu_to_le32(nsec);
+
+	return 0;
+}

utils/src/parse.h

@@ -0,0 +1,10 @@
+#ifndef _PARSE_H_
+#define _PARSE_H_
+
+struct scoutfs_timespec;
+
+int parse_u64(char *str, u64 *val_ret);
+int parse_u32(char *str, u32 *val_ret);
+int parse_timespec(char *str, struct scoutfs_timespec *ts);
+
+#endif