root / branches / wireless / code / projects / libwireless / wireless_receive.c @ 1757
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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 | 1689 | dsschult | * byte 1: length of source+data
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46 | 1591 | dsschult | * 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 | 1689 | dsschult | * byte 1: length of group+source+data
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51 | 1591 | dsschult | * 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 | 1676 | dsschult | extern uint8_t xbee_basic_buf_get(uint8_t *ptr); // get byte from basic buf |
64 | extern uint8_t xbee_other_buf_get(uint8_t *ptr); // get byte from other buf |
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65 | 1589 | alevkoy | |
66 | 1676 | dsschult | |
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 | 1676 | dsschult | uint8_t buf_pos = basic_buf_first; // start at beginning of first (oldest) basic packet
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101 | uint8_t data_length = 0xFF;
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102 | 1704 | dsschult | while((data_length = xbee_basic_buf_get(&buf_pos)) == 0xFF) { // get packet length |
103 | if (buf_pos == basic_buf_last)
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104 | break;
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105 | } |
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106 | 1706 | dsschult | if (buf_pos == basic_buf_last)
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107 | return WL_SUCCESS;
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108 | 1676 | dsschult | if (data_length - 3 > length) // not enough room for data in destination |
109 | return WL_ERROR_TOO_SMALL;
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110 | 1689 | dsschult | |
111 | WL_DEBUG_PRINT_P("entered wl_get_basic\r\n");
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112 | 1612 | alevkoy | |
113 | 1676 | dsschult | // packet has not fully arrived yet
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114 | if (buf_pos + data_length >= PACKET_BUFFER_SIZE) {
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115 | if ((buf_pos + data_length - PACKET_BUFFER_SIZE) > basic_buf_last)
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116 | return WL_SUCCESS;
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117 | } else {
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118 | if ((buf_pos + data_length) > basic_buf_last)
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119 | return WL_SUCCESS;
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120 | 1689 | dsschult | } |
121 | WL_DEBUG_PRINT_P("wl_get_basic() - packet has arrived\r\n");
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122 | 1676 | dsschult | |
123 | // ignore the source ID
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124 | xbee_basic_buf_get(&buf_pos); |
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125 | xbee_basic_buf_get(&buf_pos); |
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126 | |||
127 | // copy data to destination, byte by byte to account for circular buffer
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128 | data_length-=2;
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129 | 1689 | dsschult | uint8_t i; |
130 | for(i=0;i<data_length;i++) { |
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131 | 1676 | dsschult | data[i] = xbee_basic_buf_get(&buf_pos); |
132 | } |
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133 | 1689 | dsschult | WL_DEBUG_PRINT_P("we advanced ");
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134 | WL_DEBUG_PRINT_INT(i+3);
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135 | 1734 | dsschult | WL_DEBUG_PRINT_P(" bytes");
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136 | WL_DEBUG_PRINT_P("|first=");
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137 | 1689 | dsschult | WL_DEBUG_PRINT_INT(basic_buf_first); |
138 | 1734 | dsschult | WL_DEBUG_PRINT_P("|last=");
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139 | WL_DEBUG_PRINT_INT(basic_buf_last); |
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140 | 1676 | dsschult | |
141 | 1689 | dsschult | // "free up" this packet's buffer space
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142 | if (buf_pos == 0) |
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143 | basic_buf_first = PACKET_BUFFER_SIZE-1;
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144 | else
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145 | 1702 | dsschult | basic_buf_first = buf_pos-1;
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146 | 1689 | dsschult | |
147 | 1739 | dsschult | xbee_basic_buf[basic_buf_first] = 0xFF;
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148 | |||
149 | 1734 | dsschult | WL_DEBUG_PRINT_P("|first=");
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150 | 1689 | dsschult | WL_DEBUG_PRINT_INT(basic_buf_first); |
151 | 1734 | dsschult | WL_DEBUG_PRINT_P("|last=");
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152 | WL_DEBUG_PRINT_INT(basic_buf_last); |
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153 | 1689 | dsschult | WL_DEBUG_PRINT_P("\r\n");
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154 | 1612 | alevkoy | |
155 | 1676 | dsschult | return data_length;
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156 | 1576 | dsschult | } |
157 | |||
158 | 1577 | dsschult | /*
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159 | * function to dispatch all registered packet handlers for received packets on non-default groups
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160 | *
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161 | 1620 | alevkoy | * @return error codes
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162 | 1577 | dsschult | */
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163 | 1576 | dsschult | int8_t wl_dispatch(void) {
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164 | 1751 | dsschult | uint8_t buf_pos = other_buf_first; // start at beginning of first (oldest) basic packet
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165 | uint8_t data_length = 0xFF;
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166 | 1676 | dsschult | uint8_t group; // group of packet under consideration
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167 | FNPTR; // pointer to handler
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168 | 1751 | dsschult | uint8_t source=0; // robot ID of sender of packet under consideration |
169 | |||
170 | 1756 | dsschult | WL_DEBUG_PRINT_P("entered wl_dispatch\r\n");
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171 | |||
172 | 1751 | dsschult | while(1) { |
173 | while((data_length = xbee_other_buf_get(&buf_pos)) == 0xFF) { // get packet length |
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174 | 1757 | dsschult | WL_DEBUG_PRINT_P("|searching - data_length=");
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175 | WL_DEBUG_PRINT_HEX(data_length); |
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176 | WL_DEBUG_PRINT_P(" on pos=");
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177 | WL_DEBUG_PRINT_INT(buf_pos); |
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178 | 1751 | dsschult | if (buf_pos == other_buf_last)
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179 | break;
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180 | } |
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181 | 1757 | dsschult | if (buf_pos == other_buf_last) {
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182 | WL_DEBUG_PRINT_P("|buf_pos=other_buf_last\r\n");
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183 | return WL_SUCCESS;
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184 | } |
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185 | 1751 | dsschult | |
186 | // packet has not fully arrived yet
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187 | 1676 | dsschult | if (buf_pos + data_length >= PACKET_BUFFER_SIZE) {
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188 | if ((buf_pos + data_length - PACKET_BUFFER_SIZE) > other_buf_last)
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189 | break;
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190 | } else {
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191 | if ((buf_pos + data_length) > other_buf_last)
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192 | break;
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193 | 1751 | dsschult | } |
194 | WL_DEBUG_PRINT_P("wl_dispatch() - packet has arrived\r\n");
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195 | 1676 | dsschult | |
196 | // get group number
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197 | group = xbee_other_buf_get(&buf_pos); |
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198 | if (group >= MAX_PACKET_GROUPS || wl_packet_handlers[group].FUNC == NULL) { |
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199 | // this is an invalid group, so go to next packet
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200 | 1751 | dsschult | if (buf_pos + data_length - 2 >= PACKET_BUFFER_SIZE) |
201 | buf_pos += data_length - 2 - PACKET_BUFFER_SIZE;
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202 | else
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203 | buf_pos += data_length - 2;
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204 | 1676 | dsschult | } else {
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205 | // this is a valid group number, so get handler
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206 | FUNC = wl_packet_handlers[group].FUNC; |
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207 | xbee_other_buf_get(&buf_pos); // ignore first byte of source id
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208 | source = xbee_other_buf_get(&buf_pos); // get low byte of source id
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209 | |||
210 | // call handler
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211 | (*FUNC)(xbee_other_buf+buf_pos,data_length-4,source);
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212 | |||
213 | // go to next packet
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214 | 1751 | dsschult | if (buf_pos + data_length - 4 >= PACKET_BUFFER_SIZE) |
215 | buf_pos += data_length - 4 - PACKET_BUFFER_SIZE;
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216 | else
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217 | buf_pos += data_length - 4;
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218 | 1676 | dsschult | } |
219 | } |
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220 | |||
221 | 1756 | dsschult | WL_DEBUG_PRINT_P("other_buf_first=");
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222 | WL_DEBUG_PRINT_INT(other_buf_first); |
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223 | |||
224 | |||
225 | 1676 | dsschult | // mark packets as read
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226 | other_buf_first = (buf_pos==0)?(PACKET_BUFFER_SIZE-1):(buf_pos-1); |
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227 | 1751 | dsschult | xbee_other_buf[other_buf_first] = 0xFF;
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228 | 1612 | alevkoy | |
229 | 1756 | dsschult | WL_DEBUG_PRINT_P("Exit wl dispatch\r\n");
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230 | WL_DEBUG_PRINT_P("other_buf_first=");
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231 | WL_DEBUG_PRINT_INT(other_buf_first); |
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232 | WL_DEBUG_PRINT_P("\r\n");
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233 | |||
234 | 1676 | dsschult | return WL_SUCCESS;
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235 | 1576 | dsschult | } |
236 | |||
237 | 1577 | dsschult | |
238 | /**@} **/ //end defgroup |
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239 | |||
240 | |||
241 | // Define all private functions down here
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242 | |||
243 |