[ENet-discuss] [near-PATCH] speed optimisation and bugfix: do one memory allocat ion per packet instead of two

[Lee Salzman]

I have committed all the other bug fixes except this one. I remain
unconvinced that ENet's performance is significantly dependent on 
malloc. If you can show actual profiles of ENet running under
significant network load where malloc is dragging ENet down, I'd 
consider it.

Lee

On Thu, Dec 09, 2004 at 09:16:21PM +0800, Benoit Germain wrote:
> Hello,
> 
> Sorry, I don't have a patch utility handy to do this cleanly, but the
> changes are pretty localized. Also, I have made other changes that are not
> submitted here that would spoil the patch anyway.
> 
> BTW, this also fixes a bug: packet->data was allocated with enet_malloc(),
> but freed with free(). Well, now, packet->data no longer exists :-)
> 
> Apart from that, there is no functionnal change.
> 
> Enet.h:
> 
> typedef struct _ENetPacket
> {
>    size_t               referenceCount;  /**< internal use only */
>    enet_uint32          flags;           /**< bitwise or of ENetPacketFlag
> constants */
> -  enet_uint8 *         data;            /**< allocated data for packet */
>    size_t               dataLength;      /**< length of data */
> } ENetPacket;
> + #define packet_data(_packet) ((enet_uint8 *)(((ENetPacket *)(_packet))+1))
> 
> 
> - ENET_API int          enet_packet_resize  (ENetPacket *packet, size_t
> dataLength );
> + ENET_API ENetPacket * enet_packet_resize  (ENetPacket *packet, size_t
> dataLength );
> 
> Protocol.c:
> Replace the 3 occurrences of <some packet> -> data with packet_data(<some
> packet>)
> 
> Packet.c:
> The easiest thing to do is to replace everything with:
> 
> ################################ BEGIN ##############################
> 
> /** 
>  @file  packet.c
>  @brief ENet packet management functions
> */
> #include <string.h>
> #define ENET_BUILDING_LIB 1
> #include "enet/enet.h"
> 
> /** @defgroup Packet ENet packet functions 
>     @{ 
> */
> 
> /** Creates a packet that may be sent to a peer.
>     @param dataContents initial contents of the packet's data; the packet's
> data will remain uninitialized if dataContents is NULL.
>     @param dataLength   size of the data allocated for this packet
>     @param flags        flags for this packet as described for the
> ENetPacket structure.
>     @returns the packet on success, NULL on failure
> */
> ENetPacket *
> enet_packet_create (const void * data, size_t dataLength, enet_uint32 flags)
> {
>     ENetPacket * packet = (ENetPacket *) enet_malloc (sizeof (ENetPacket) +
> dataLength);
>     if ( packet != NULL )
>     {
>       memcpy (packet_data(packet), data, dataLength);
> 
>       packet -> referenceCount = 0;
>       packet -> flags = flags;
>       packet -> dataLength = dataLength;
>     }
>     return packet;
> }
> 
> /** Destroys the packet and deallocates its data.
>     @param packet packet to be destroyed
> */
> void
> enet_packet_destroy (ENetPacket * packet)
> {
>     enet_free (packet);
> }
> 
> /** Attempts to resize the data in the packet to length specified in the 
>     dataLength parameter 
>     @param packet packet to resize
>     @param dataLength new size for the packet data
>     @returns the new packet address on success, NULL on failure (length is
> unchanged)
> */
> ENetPacket *
> enet_packet_resize (ENetPacket * packet, size_t dataLength)
> {
>     ENetPacket * newPacket ;
>     /* reducing length is faster done by leaving the block unchanged... */
>     if (dataLength <= packet -> dataLength)
>     {
>        packet -> dataLength = dataLength;
> 
>        return packet;
>     }
> 
>     newPacket = (ENetPacket *) enet_malloc (sizeof (ENetPacket) +
> dataLength);
>     if ( newPacket != NULL )
>     {
>       memcpy (newPacket, packet, sizeof (ENetPacket) + packet ->
> dataLength);
>       enet_free (packet);
> 
>       newPacket -> dataLength = dataLength;
>     }
>     return newPacket;
> }
> 
> /** @} */
> 
> ################################ END ##############################
> __________________________________
> Benoit Germain
> mailto:bgermain at ubisoft.fr <mailto:bgermain at ubisoft.fr> 
> 
> Person who says it cannot be done should not interrupt person doing it.
> -- Chinese Proverb
> 
> People who think they're smart annoy those of us who are.
> -- double-U's Proverb ?
> __________________________________
> 

> _______________________________________________
> ENet-discuss mailing list
> ENet-discuss at cubik.org
> http://lists.cubik.org/mailman/listinfo/enet-discuss