[REFACTOR] [Hacker Rank] Warmup: Time Conversion solved ✅. Triying to fix sonarlint detected issues.

Author: Gonzalo Diaz

src/lib/exercises/include/exercises/hackerrank/warmup/time_conversion.h

@@ -3,6 +3,12 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
+
+char *HACKERRANK_WARMUP_getStringFragment(const char *s, unsigned long len,
+                                          unsigned long from, unsigned long to);
+char *HACKERRANK_WARMUP_getFirst(const char *s, unsigned long n);
+char *HACKERRANK_WARMUP_getLast(const char *s, unsigned long n);
+
 char *HACKERRANK_WARMUP_firstN(const char *s, unsigned long n);
 char *HACKERRANK_WARMUP_lastN(const char *s, unsigned long n);
 

src/lib/exercises/src/hackerrank/warmup/time_conversion.c

@@ -54,21 +54,52 @@ char *HACKERRANK_WARMUP_lastN(const char *s, unsigned long n) {
   return result;
 }
 
+char *HACKERRANK_WARMUP_getFirst(const char *s, unsigned long n) {
+  return HACKERRANK_WARMUP_getStringFragment(s, strlen(s), 0, n);
+}
+
+char *HACKERRANK_WARMUP_getStringFragment(const char *s, unsigned long len,
+                                          unsigned long from,
+                                          unsigned long to) {
+  // unsigned long len = strlen(s);
+  if (to > len) {
+    return NULL;
+  }
+  if (to == 0) {
+    return NULL;
+  }
+
+  char *result = (char *)malloc((to + 1) * sizeof(char));
+  if (result == NULL) {
+    return NULL;
+  }
+
+  strncpy(result, s + from, to);
+
+  result[to] = '\0';
+
+  return result;
+}
+
 char *HACKERRANK_WARMUP_timeConversion(const char *s) {
   char *meridian = HACKERRANK_WARMUP_lastN(s, 2);
 
-  char *hour_str = HACKERRANK_WARMUP_firstN(s, 2);
+  // char *hour_str = HACKERRANK_WARMUP_firstN(s, 2);
+  char *hour_str = HACKERRANK_WARMUP_getFirst(s, 2);
+
   char *time_str = (char *)malloc((strlen(s) + 1) * sizeof(char));
   if (time_str == NULL) {
     free(hour_str);
     free(meridian);
     return NULL;
   }
   strcpy(time_str, s);
-  char *temp_time_str = HACKERRANK_WARMUP_lastN(time_str, strlen(time_str) - 2);
+  char *temp_time_str;
+  unsigned long time_str_len = strlen(time_str);
+  temp_time_str = HACKERRANK_WARMUP_lastN(time_str, time_str_len - 2);
   free(time_str);
   time_str = temp_time_str;
-  temp_time_str = HACKERRANK_WARMUP_firstN(time_str, strlen(time_str) - 2);
+  temp_time_str = HACKERRANK_WARMUP_firstN(time_str, time_str_len - 2);
   free(time_str);
   time_str = temp_time_str;