root / branches / wireless / code / projects / libwireless / wireless_receive.c @ 1611
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1 | 1576 | dsschult | /**
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2 | * Copyright (c) 2009 Colony Project
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3 | *
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4 | * Permission is hereby granted, free of charge, to any person
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5 | * obtaining a copy of this software and associated documentation
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6 | * files (the "Software"), to deal in the Software without
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7 | * restriction, including without limitation the rights to use,
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8 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
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9 | * copies of the Software, and to permit persons to whom the
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10 | * Software is furnished to do so, subject to the following
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11 | * conditions:
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12 | *
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13 | * The above copyright notice and this permission notice shall be
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14 | * included in all copies or substantial portions of the Software.
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15 | *
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16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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17 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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18 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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19 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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20 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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21 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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22 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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23 | * OTHER DEALINGS IN THE SOFTWARE.
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24 | **/
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25 | |||
26 | /**
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27 | * @file wireless_receive.c
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28 | * @brief Wireless library receive functions
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29 | *
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30 | * Implementation of high level wireless communication.
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31 | * This is the receive functions portion of the library.
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32 | *
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33 | * @author Colony Project, CMU Robotics Club
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34 | **/
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35 | |||
36 | 1589 | alevkoy | #include <string.h> |
37 | 1576 | dsschult | #include "wl_defs.h" |
38 | #include "wireless.h" |
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39 | 1589 | alevkoy | #include "xbee.h" |
40 | 1576 | dsschult | |
41 | 1577 | dsschult | /**
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42 | 1591 | dsschult | * Definition for wireless library receive packet structure
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43 | *
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44 | * Basic Buffer Packet:
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45 | * byte 1: length of data
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46 | * bytes 2-3: source
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47 | * bytes 4-n: data
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48 | *
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49 | * Other Buffer Packet:
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50 | * byte 1: length of data
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51 | * byte 2: group number
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52 | * bytes 3-4: source
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53 | * bytes 5-n: data
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54 | *
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55 | 1577 | dsschult | **/
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56 | |||
57 | 1589 | alevkoy | extern uint8_t xbee_basic_buf[PACKET_BUFFER_SIZE]; // buffer for basic-group packets |
58 | extern uint8_t xbee_other_buf[PACKET_BUFFER_SIZE]; // buffer for non-basic-group packets |
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59 | extern uint8_t basic_buf_first; // beginning of first packet in basic buffer |
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60 | extern uint8_t basic_buf_last; // end of last packet in basic buffer |
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61 | extern uint8_t other_buf_first; // beginning of first packet in other buffer |
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62 | extern uint8_t other_buf_last; // end of last packet in other buffer |
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63 | 1591 | dsschult | |
64 | |||
65 | // the receive functions
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66 | 1589 | alevkoy | |
67 | 1577 | dsschult | /**
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68 | 1591 | dsschult | * @addtogroup wireless Wireless
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69 | * @{
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70 | **/
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71 | |||
72 | /**
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73 | 1577 | dsschult | * the main receive function (similar to wl_do)
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74 | *
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75 | * when called, this function will receive the next packet on the default packet group
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76 | * it will also dispatch registered packet handler functions for any other packet groups it has received
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77 | *
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78 | * @param data an already-initialized array to store the default group packet data in
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79 | * @param length the length of the initialized data array
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80 | *
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81 | * @return the length of the used portion of data array or error (<0)
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82 | **/
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83 | 1576 | dsschult | int8_t wl_get(char *data, uint8_t length) {
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84 | 1577 | dsschult | int8_t return_code = wl_dispatch(); // run dispatch of other packet groups
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85 | if (return_code != 0) |
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86 | return return_code; // error, so end early |
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87 | 1589 | alevkoy | return wl_get_basic(data, length); // get a basic packet |
88 | 1576 | dsschult | } |
89 | |||
90 | 1577 | dsschult | /**
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91 | * function to receive only packets on the default group
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92 | * this function is only meant to receive packets sent using wl_send_basic()
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93 | *
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94 | * @param data an already-initialized array to store the default group packet data in
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95 | * @param length the length of the initialized data array
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96 | *
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97 | * @return the length of the used portion of data array or error (<0)
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98 | **/
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99 | 1576 | dsschult | int8_t wl_get_basic(char *data, uint8_t length) {
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100 | 1589 | alevkoy | uint8_t buf_pos = basic_buf_first; // start at beginning of first (oldest) basic packet
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101 | uint8_t data_length = xbee_basic_buf[buf_pos]; // get packet length
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102 | uint8_t packet_num; // number of packet (may eventually be used to weed out duplicates)
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103 | 1576 | dsschult | |
104 | 1589 | alevkoy | if (data_length > length) // not enough room for packet in destination |
105 | return WL_ERROR_TOO_SMALL;
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106 | |||
107 | buf_pos++; |
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108 | packet_num = xbee_basic_buf[buf_pos]; // get packet number
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109 | buf_pos++; |
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110 | buf_pos++; // ignore the group code. it will always be the same.
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111 | |||
112 | memcpy(data, xbee_basic_buf + buf_pos, data_length); // get the data
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113 | basic_buf_first += data_length; // "free up" this packet's buffer space
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114 | |||
115 | return 0; |
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116 | 1576 | dsschult | } |
117 | |||
118 | 1577 | dsschult | /*
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119 | * function to dispatch all registered packet handlers for received packets on non-default groups
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120 | *
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121 | * @return error codes (TBD)
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122 | */
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123 | 1576 | dsschult | int8_t wl_dispatch(void) {
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124 | |||
125 | return 0; |
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126 | } |
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127 | |||
128 | 1577 | dsschult | |
129 | /**@} **/ //end defgroup |
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130 | |||
131 | |||
132 | // Define all private functions down here
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133 | |||
134 |