0ddf702c3b
This commit updates the enet version from 2013 !!! to the latest commit (74cea7abf52ddd355146aeb0a4077d2b95368122) Since 2013 there have been MANY improvements to the library and we should absolutely use them since it can improve the gameplay.
166 lines
3.8 KiB
C
166 lines
3.8 KiB
C
/**
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@file packet.c
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@brief ENet packet management functions
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*/
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#include <string.h>
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#define ENET_BUILDING_LIB 1
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#include "enet/enet.h"
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/** @defgroup Packet ENet packet functions
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@{
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*/
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/** Creates a packet that may be sent to a peer.
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@param data initial contents of the packet's data; the packet's data will remain uninitialized if data is NULL.
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@param dataLength size of the data allocated for this packet
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@param flags flags for this packet as described for the ENetPacket structure.
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@returns the packet on success, NULL on failure
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*/
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ENetPacket *
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enet_packet_create (const void * data, size_t dataLength, enet_uint32 flags)
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{
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ENetPacket * packet = (ENetPacket *) enet_malloc (sizeof (ENetPacket));
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if (packet == NULL)
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return NULL;
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if (flags & ENET_PACKET_FLAG_NO_ALLOCATE)
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packet -> data = (enet_uint8 *) data;
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else
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if (dataLength <= 0)
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packet -> data = NULL;
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else
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{
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packet -> data = (enet_uint8 *) enet_malloc (dataLength);
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if (packet -> data == NULL)
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{
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enet_free (packet);
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return NULL;
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}
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if (data != NULL)
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memcpy (packet -> data, data, dataLength);
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}
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packet -> referenceCount = 0;
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packet -> flags = flags;
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packet -> dataLength = dataLength;
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packet -> freeCallback = NULL;
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packet -> userData = NULL;
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return packet;
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}
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/** Destroys the packet and deallocates its data.
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@param packet packet to be destroyed
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*/
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void
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enet_packet_destroy (ENetPacket * packet)
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{
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if (packet == NULL)
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return;
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if (packet -> freeCallback != NULL)
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(* packet -> freeCallback) (packet);
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if (! (packet -> flags & ENET_PACKET_FLAG_NO_ALLOCATE) &&
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packet -> data != NULL)
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enet_free (packet -> data);
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enet_free (packet);
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}
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/** Attempts to resize the data in the packet to length specified in the
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dataLength parameter
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@param packet packet to resize
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@param dataLength new size for the packet data
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@returns 0 on success, < 0 on failure
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*/
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int
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enet_packet_resize (ENetPacket * packet, size_t dataLength)
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{
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enet_uint8 * newData;
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if (dataLength <= packet -> dataLength || (packet -> flags & ENET_PACKET_FLAG_NO_ALLOCATE))
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{
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packet -> dataLength = dataLength;
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return 0;
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}
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newData = (enet_uint8 *) enet_malloc (dataLength);
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if (newData == NULL)
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return -1;
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memcpy (newData, packet -> data, packet -> dataLength);
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enet_free (packet -> data);
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packet -> data = newData;
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packet -> dataLength = dataLength;
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return 0;
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}
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static int initializedCRC32 = 0;
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static enet_uint32 crcTable [256];
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static enet_uint32
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reflect_crc (int val, int bits)
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{
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int result = 0, bit;
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for (bit = 0; bit < bits; bit ++)
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{
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if(val & 1) result |= 1 << (bits - 1 - bit);
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val >>= 1;
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}
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return result;
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}
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static void
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initialize_crc32 (void)
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{
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int byte;
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for (byte = 0; byte < 256; ++ byte)
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{
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enet_uint32 crc = reflect_crc (byte, 8) << 24;
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int offset;
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for(offset = 0; offset < 8; ++ offset)
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{
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if (crc & 0x80000000)
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crc = (crc << 1) ^ 0x04c11db7;
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else
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crc <<= 1;
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}
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crcTable [byte] = reflect_crc (crc, 32);
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}
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initializedCRC32 = 1;
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}
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enet_uint32
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enet_crc32 (const ENetBuffer * buffers, size_t bufferCount)
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{
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enet_uint32 crc = 0xFFFFFFFF;
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if (! initializedCRC32) initialize_crc32 ();
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while (bufferCount -- > 0)
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{
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const enet_uint8 * data = (const enet_uint8 *) buffers -> data,
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* dataEnd = & data [buffers -> dataLength];
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while (data < dataEnd)
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{
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crc = (crc >> 8) ^ crcTable [(crc & 0xFF) ^ *data++];
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}
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++ buffers;
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}
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return ENET_HOST_TO_NET_32 (~ crc);
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}
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/** @} */
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