Add string functions:

* isdigit_s()
* tolower_s()

2 files changed, 29 insertions, 0 deletions

diff --git a/include/str.h b/include/str.h
index 468f674..ae54997 100644
--- a/include/str.h
+++ b/include/str.h
@@ -34,5 +34,7 @@ int isquoted(char *sptr);
 char *normalize_space(char *s);
 char **strdup_array(char **array);
 int strcmp_array(const char **a, const char **b);
+int isdigit_s(char *s);
+char *tolower_s(char *s);
 
 #endif //SPM_STR_H
diff --git a/lib/str.c b/lib/str.c
index 9b5b201..5fbb8ad 100644
--- a/lib/str.c
+++ b/lib/str.c
@@ -817,3 +817,30 @@ int strcmp_array(const char **a, const char **b) {
     }
     return result;
 }
+
+/**
+ * Determine whether a string is comprised of digits
+ * @param s
+ * @return 0=no, 1=yes
+ */
+int isdigit_s(char *s) {
+    for (size_t i = 0; s[i] != '\0'; i++) {
+        if (isdigit(s[i]) == 0) {
+            return 0;   // non-digit found, fail
+        }
+    }
+    return 1;   // all digits, succeed
+}
+
+/**
+ * Convert input string to lowercase
+ * @param s
+ * @return pointer to input string
+ */
+char *tolower_s(char *s) {
+    for (size_t i = 0; s[i] != '\0'; i++) {
+        s[i] = (char)tolower(s[i]);
+    }
+    return s;
+}
+