fixed a couple minor things and fixed the [zone] only mode because i'm dumb

timetolocal.c

@@ -18,24 +18,28 @@ int findintable(char *what){
 return -1; 
 }
 
-davidtime strtimetoint(char *whattimeisit) {
-    davidtime timehoursandminutes = {0, 0};
+/*parses H or H:M (24hs)
+returns 0 on success, -1 if it's not a valid time*/
+int strtimetoint(const char *whattimeisit, davidtime *out) {
+    if (whattimeisit == NULL || out == NULL) return -1;
 
-    if (whattimeisit == NULL)return timehoursandminutes;
+    char *end;
+    long hour = strtol(whattimeisit, &end, 10);
+    if (end == whattimeisit) return -1;
 
-    char buf[16];
-    strncpy(buf, whattimeisit, sizeof(buf) - 1);
-    buf[sizeof(buf) - 1] = '\0';
+    long minutes = 0;
+    if (*end == ':') {
+        const char *mstart = end + 1;
+        minutes = strtol(mstart, &end, 10);
+        if (end == mstart) return -1;
+    }
+    if (*end != '\0') return -1;
 
-    char *token = strtok(buf, ":");
-    if (token == NULL) return timehoursandminutes;
-    timehoursandminutes.hour = atoi(token);
+    if (hour < 0 || hour > 23 || minutes < 0 || minutes > 59) return -1;
 
-    token = strtok(NULL, ":");
-    if (token == NULL) return timehoursandminutes;
-    timehoursandminutes.minutes = atoi(token);
-
-    return timehoursandminutes;
+    out->hour = (int)hour;
+    out->minutes = (int)minutes;
+    return 0;
 }
 
 char* gethhmm(char* buffer, size_t max_size) {
@@ -49,12 +53,15 @@ char* gethhmm(char* buffer, size_t max_size) {
     return buffer;
 }
 
-int convert(char *timey, char *zone){
+/*tozone = 0 time is in zone, print it as local time
+tozone = 1 time is local time, print it in zone
+returns 0 ok -1 zone not found and -2 if invalid time*/
+int convert(char *timey, char *zone, int tozone){
     time_t rawtime = time(NULL);
-    struct tm *ptm = gmtime(&rawtime);
-    
-    ptm->tm_isdst = -1;                
-    time_t gmt = mktime(ptm);
+    struct tm utc = *gmtime(&rawtime); //gmtime uses a static buffer so it just copies 
+
+    utc.tm_isdst = -1;
+    time_t gmt = mktime(&utc);
     int offset = difftime(rawtime, gmt) / 60;
     //this sould take even daylight savings too, i stole it from stack overflow i've been trying to not use llms to code shit like this
 
@@ -62,8 +69,10 @@ int convert(char *timey, char *zone){
     int zntime = findintable(zone);
     if(zntime == -1)return -1; 
 
-    davidtime eugh = strtimetoint(timey); 
-    int total = eugh.hour * 60 + eugh.minutes - zntime + offset; //ok this is better yeah
+    davidtime eugh;
+    if(strtimetoint(timey, &eugh) == -1) return -2;
+    int mins = eugh.hour * 60 + eugh.minutes;
+    int total = tozone ? mins - offset + zntime : mins - zntime + offset; //ok this is better yeah
     
     int day = 0;
     while (total < 0){
@@ -84,7 +93,7 @@ int main (int argc, char **argv){
 
     if((argc <= 1) || (argc > 3)){
         printf("%s: usage: %s [TIME (24hs)] [ZONE]\ne.g: %s 7:15 est\n\nalso get relative times like %s [ZONE]\ne.g: %s est\n", argv[0], argv[0], argv[0], argv[0], argv[0]);
-        exit(0);
+        exit(1);
     }
 
     char timestr[16];
@@ -94,15 +103,21 @@ int main (int argc, char **argv){
             printf("timezones don't have numbers in them\n");
             return 1;
         }
-        if (convert(timestr, argv[1]) == -1) {
+        if (convert(timestr, argv[1], 1) == -1) {
             printf("%s: time zone not found, did you write it correctly?\n", argv[0]);
             return 1;
         }
         return 0;
     }
 
-   if(convert(argv [1], argv[2]) == -1){
+    int res = convert(argv[1], argv[2], 0);
+    if (res == -1) {
         printf("%s: time zone not found, did you write it correctly?\n", argv[0]);
         return 1;
-   }else return 0;
+    }
+    if (res == -2) {
+        printf("%s: invalid time, use 24hs format like 7:15\n", argv[0]);
+        return 1;
+    }
+    return 0;
 }