dataqueue: Removed non-public SDL_ReserveSpaceInDataQueue function

This wasn't used, and it was just asking for trouble.

(cherry picked from commit f833e005e10f63979fd545d8bc29b4f1a7c36486)

src/SDL_dataqueue.c

@@ -288,43 +288,4 @@ SDL_CountDataQueue(SDL_DataQueue *queue)
     return queue ? queue->queued_bytes : 0;
 }
 
-void *
-SDL_ReserveSpaceInDataQueue(SDL_DataQueue *queue, const size_t len)
-{
-    SDL_DataQueuePacket *packet;
-
-    if (queue == NULL) {
-        SDL_InvalidParamError("queue");
-        return NULL;
-    } else if (len == 0) {
-        SDL_InvalidParamError("len");
-        return NULL;
-    } else if (len > queue->packet_size) {
-        SDL_SetError("len is larger than packet size");
-        return NULL;
-    }
-
-    packet = queue->head;
-    if (packet) {
-        const size_t avail = queue->packet_size - packet->datalen;
-        if (len <= avail) { /* we can use the space at end of this packet. */
-            void *retval = packet->data + packet->datalen;
-            packet->datalen += len;
-            queue->queued_bytes += len;
-            return retval;
-        }
-    }
-
-    /* Need a fresh packet. */
-    packet = AllocateDataQueuePacket(queue);
-    if (packet == NULL) {
-        SDL_OutOfMemory();
-        return NULL;
-    }
-
-    packet->datalen = len;
-    queue->queued_bytes += len;
-    return packet->data;
-}
-
 /* vi: set ts=4 sw=4 expandtab: */

src/SDL_dataqueue.h

@@ -34,21 +34,6 @@ size_t SDL_ReadFromDataQueue(SDL_DataQueue *queue, void *buf, const size_t len);
 size_t SDL_PeekIntoDataQueue(SDL_DataQueue *queue, void *buf, const size_t len);
 size_t SDL_CountDataQueue(SDL_DataQueue *queue);
 
-/* this sets a section of the data queue aside (possibly allocating memory for it)
-   as if it's been written to, but returns a pointer to that space. You may write
-   to this space until a read would consume it. Writes (and other calls to this
-   function) will safely append their data after this reserved space and can
-   be in flight at the same time. There is no thread safety.
-   If there isn't an existing block of memory that can contain the reserved
-   space, one will be allocated for it. You can not (currently) allocate
-   a space larger than the packetlen requested in SDL_NewDataQueue.
-   Returned buffer is uninitialized.
-   This lets you avoid an extra copy in some cases, but it's safer to use
-   SDL_WriteToDataQueue() unless you know what you're doing.
-   Returns pointer to buffer of at least (len) bytes, NULL on error.
-*/
-void *SDL_ReserveSpaceInDataQueue(SDL_DataQueue *queue, const size_t len);
-
 #endif /* SDL_dataqueue_h_ */
 
 /* vi: set ts=4 sw=4 expandtab: */