Update space requirements of cJSON_PrintPreallocated

cJSON.h

@@ -133,7 +133,7 @@ CJSON_PUBLIC(char *) cJSON_PrintUnformatted(const cJSON *item);
 /* Render a cJSON entity to text using a buffered strategy. prebuffer is a guess at the final size. guessing well reduces reallocation. fmt=0 gives unformatted, =1 gives formatted */
 CJSON_PUBLIC(char *) cJSON_PrintBuffered(const cJSON *item, int prebuffer, cJSON_bool fmt);
 /* Render a cJSON entity to text using a buffer already allocated in memory with given length. Returns 1 on success and 0 on failure. */
-/* NOTE: If you are printing numbers, the buffer hat to be 63 bytes bigger then the printed JSON (worst case) */
+/* NOTE: cJSON is not always 100% accurate in estimating how much memory it will use, so to be safe allocate 5 bytes more than you actually need */
 CJSON_PUBLIC(cJSON_bool) cJSON_PrintPreallocated(cJSON *item, char *buffer, const int length, const cJSON_bool format);
 /* Delete a cJSON entity and all subentities. */
 CJSON_PUBLIC(void) cJSON_Delete(cJSON *c);

test.c

@@ -53,8 +53,8 @@ static int print_preallocated(cJSON *root)
     out = cJSON_Print(root);
 
     /* create buffer to succeed */
-    /* the extra 64 bytes are in case a floating point value is printed */
-    len = strlen(out) + 64;
+    /* the extra 5 bytes are because of inaccuracies when reserving memory */
+    len = strlen(out) + 5;
     buf = (char*)malloc(len);
     if (buf == NULL)
     {