format_number_with_delim: simplified

Author: MartinPulec

src/gpujpeg_common.c

@@ -2176,37 +2176,20 @@ format_number_with_delim(size_t num, char* buf, size_t buflen)
     assert(buflen >= 1);
     buf[buflen - 1] = '\0';
     char* ptr = buf + buflen - 1;
-    while ( 1 ) {
-        const int tmp = num % 1000;
-        num /= 1000;
-        if ( num == 0 ) {
-            ptr -= 1;
-            if ( tmp >= 10 ) {
-                ptr -= 1;
-                if ( tmp >= 100 ) {
-                    ptr -= 1;
-                }
-            }
-            if ( ptr < buf ) {
-                snprintf(buf, buflen, "%s", "ERR");
-                return buf;
-            }
-            char numbuf[4];
-            snprintf(numbuf, sizeof numbuf, "%i", tmp);
-            // NOLINTNEXTLINE(bugprone-not-null-terminated-result): prepending, no null-termination
-            memcpy(ptr, numbuf, strlen(numbuf));
-            return ptr;
-        }
-        ptr -= 4;
-        if ( ptr < buf ) {
+    int grp_count = 0;
+    do {
+        if ( ptr == buf || (grp_count == 3 && ptr == buf + 1) ) {
             snprintf(buf, buflen, "%s", "ERR");
             return buf;
         }
-        char numbuf[5];
-        snprintf(numbuf, sizeof numbuf, ",%03d", tmp);
-        // NOLINTNEXTLINE(bugprone-not-null-terminated-result): prepending, no null-termination
-        memcpy(ptr, numbuf, 4);
-    }
+        if ( grp_count++ == 3 ) {
+            grp_count = 1;
+            *--ptr = ',';
+        }
+        *--ptr = (char)('0' + (num % 10));
+        num /= 10;
+    } while ( num != 0 );
+
     return ptr;
 }