ref: f65633b5f50be8581ec2de7c06ca9a225d48b82a
dir: /src/net_packet.c/
// Emacs style mode select -*- C++ -*- //----------------------------------------------------------------------------- // // $Id: net_packet.c 236 2006-01-01 23:51:41Z fraggle $ // // Copyright(C) 2005 Simon Howard // // This program is free software; you can redistribute it and/or // modify it under the terms of the GNU General Public License // as published by the Free Software Foundation; either version 2 // of the License, or (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA // 02111-1307, USA. // // $Log$ // Revision 1.2 2006/01/01 23:51:41 fraggle // String read/write functions // // Revision 1.1 2005/10/30 19:56:15 fraggle // Add foundation code for the new networking system // // // DESCRIPTION: // Network packet manipulation (net_packet_t) // //----------------------------------------------------------------------------- #include <string.h> #include "net_packet.h" #include "z_zone.h" net_packet_t *NET_NewPacket(int initial_size) { net_packet_t *packet; packet = (net_packet_t *) Z_Malloc(sizeof(net_packet_t), PU_STATIC, 0); if (initial_size == 0) initial_size = 256; packet->alloced = initial_size; packet->data = Z_Malloc(initial_size, PU_STATIC, 0); packet->len = 0; packet->pos = 0; return packet; } // duplicates an existing packet net_packet_t *NET_PacketDup(net_packet_t *packet) { net_packet_t *newpacket; newpacket = NET_NewPacket(packet->len); memcpy(newpacket->data, packet->data, packet->len); newpacket->len = packet->len; return newpacket; } void NET_FreePacket(net_packet_t *packet) { Z_Free(packet->data); Z_Free(packet); } // Read a byte from the packet, returning true if read // successfully boolean NET_ReadInt8(net_packet_t *packet, unsigned int *data) { if (packet->pos + 1 > packet->len) return false; *data = packet->data[packet->pos]; packet->pos += 1; return true; } // Read a 16-bit integer from the packet, returning true if read // successfully boolean NET_ReadInt16(net_packet_t *packet, unsigned int *data) { byte *p; if (packet->pos + 2 > packet->len) return false; p = packet->data + packet->pos; *data = (p[0] << 8) | p[1]; packet->pos += 2; return true; } // Read a 32-bit integer from the packet, returning true if read // successfully boolean NET_ReadInt32(net_packet_t *packet, unsigned int *data) { byte *p; if (packet->pos + 4 > packet->len) return false; p = packet->data + packet->pos; *data = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]; packet->pos += 4; return true; } // Read a string from the packet. Returns NULL if a terminating // NUL character was not found before the end of the packet. char *NET_ReadString(net_packet_t *packet) { char *start; start = (char *) packet->data + packet->pos; // Search forward for a NUL character while (packet->pos < packet->len && packet->data[packet->pos] != '\0') { ++packet->pos; } if (packet->pos >= packet->len) { // Reached the end of the packet return NULL; } // packet->data[packet->pos] == '\0': We have reached a terminating // NULL. Skip past this NULL and continue reading immediately // after it. ++packet->pos; return start; } // Dynamically increases the size of a packet static void NET_IncreasePacket(net_packet_t *packet) { byte *newdata; packet->alloced *= 2; newdata = Z_Malloc(packet->alloced, PU_STATIC, 0); memcpy(newdata, packet->data, packet->len); Z_Free(packet->data); packet->data = newdata; } // Write a single byte to the packet void NET_WriteInt8(net_packet_t *packet, unsigned int i) { if (packet->len + 1 > packet->alloced) NET_IncreasePacket(packet); packet->data[packet->len] = i; packet->len += 1; } // Write a 16-bit integer to the packet void NET_WriteInt16(net_packet_t *packet, unsigned int i) { byte *p; if (packet->len + 2 > packet->alloced) NET_IncreasePacket(packet); p = packet->data + packet->len; p[0] = (i >> 8) & 0xff; p[1] = i & 0xff; packet->len += 2; } // Write a single byte to the packet void NET_WriteInt32(net_packet_t *packet, unsigned int i) { byte *p; if (packet->len + 4 > packet->alloced) NET_IncreasePacket(packet); p = packet->data + packet->len; p[0] = (i >> 24) & 0xff; p[1] = (i >> 16) & 0xff; p[2] = (i >> 8) & 0xff; p[3] = i & 0xff; packet->len += 4; } void NET_WriteString(net_packet_t *packet, char *string) { byte *p; // Increase the packet size until large enough to hold the string while (packet->len + strlen(string) + 1 > packet->alloced) { NET_IncreasePacket(packet); } p = packet->data + packet->len; strcpy((char *) p, string); packet->len += strlen(string) + 1; }