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pcg |
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/* |
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ROHC Project 2003 at Lulea University of Technology, Sweden. |
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Authors: Andreas Vernersson <andver-8@student.luth.se> |
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Daniel Pettersson <danpet-7@student.luth.se> |
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Erik Soderstrom <soderstrom@yahoo.com> |
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Fredrik Lindstrom <frelin-9@student.luth.se> |
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Johan Stenmark <johste-8@student.luth.se> |
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Martin Juhlin <juhlin@users.sourceforge.net> |
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Mikael Larsson <larmik-9@student.luth.se> |
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Robert Maxe <robmax-1@student.luth.se> |
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Copyright (C) 2003 Andreas Vernersson, Daniel Pettersson, |
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Erik Soderström, Fredrik Lindström, Johan Stenmark, |
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Martin Juhlin, Mikael Larsson, Robert Maxe. |
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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/*************************************************************************** |
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* File: c_util.h * |
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* Description: utility functions for the compressor * |
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***************************************************************************/ |
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#ifndef _C_UTIL_H |
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#define _C_UTIL_H |
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#include "rohc.h" |
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///////////////////////////////////////////////////////////////////// |
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// W-LSB: Window based Least Significant Bits encoding |
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struct sc_window { |
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int sn; |
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int time; |
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int value; |
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boolean used; |
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}; |
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struct sc_wlsb { |
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int windowWidth; |
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struct sc_window *window; // windowWidth number of sc_window.. |
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int oldest; // points to the oldest entry in the window |
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int next; // keeps track of the current position in the window |
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int bits; |
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int p; |
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}; |
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// Create new window.. |
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struct sc_wlsb *c_create_wlsb(int bits, int windowWidth, int p); |
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// Print window content |
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void print_wlsb_stats(struct sc_wlsb * s); |
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// Add value to window with the given sequence number and timestamp |
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void c_add_wlsb(struct sc_wlsb *, int sn, int time, int value); |
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// Get minimum number of bits necessary (k) of value needed for |
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// decompressor to decode correctly |
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int c_get_k_wlsb(struct sc_wlsb *, int value); |
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// Acknowledge (remove older values) from window based on the sequence number |
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void c_ack_sn_wlsb(struct sc_wlsb *, int sn); |
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// Acknowledge (remove odler values) from window based on the timestamp |
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void c_ack_time_wlsb(struct sc_wlsb *, int time); |
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// Unallocate all memory used in the WLSB structure |
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void c_destroy_wlsb(struct sc_wlsb *); |
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// Calculate the sum of the values in window (used for a statistics window) |
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int c_sum_wlsb(struct sc_wlsb *); |
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// Calculate the mean-value in window (used for a statistics window) |
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int c_mean_wlsb(struct sc_wlsb *); |
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void c_print_wlsb(struct sc_wlsb *); |
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///////////////////////////////////////////////////////////////////// |
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// SDVL: Self Described Variable Length encoding |
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// returns number of bytes needed to represent value |
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int c_bytesSdvl(int value); |
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// returns false if value is to big (value>2^29) |
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boolean c_encodeSdvl(unsigned char *dest, int value); |
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// returns add-cid value |
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unsigned char c_add_cid(int cid); |
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/* Function that sets the cid_values it will set the cids proper in the |
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pointer dest, the function takes a pointer called first_position where you get the position |
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to place your first byte, the second byte can be placed in the value that this function returns. |
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*/ |
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int code_cid_values(struct sc_context *context,unsigned char *dest,int max_size,int *first_position); |
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///////////////////////////////////////////////////////////////////// |
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// CRC |
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#define CRC_TYPE_3 1 |
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#define CRC_TYPE_7 2 |
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#define CRC_TYPE_8 3 |
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unsigned int crc_calculate(int type, unsigned char *, int length); |
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int crc_get_polynom(int type); |
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void crc_init_table(unsigned char *table, unsigned char polynum); |
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#endif |
