1 | /* |
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2 | * This file Copyright (C) 2008 Charles Kerr <charles@transmissionbt.com> |
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3 | * |
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4 | * This file is licensed by the GPL version 2. Works owned by the |
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5 | * Transmission project are granted a special exemption to clause 2(b) |
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6 | * so that the bulk of its code can remain under the MIT license. |
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7 | * This exemption does not extend to derived works not owned by |
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8 | * the Transmission project. |
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9 | * |
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10 | * $Id: bandwidth.h 7579 2009-01-02 17:46:22Z charles $ |
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11 | */ |
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12 | |
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13 | #ifndef __TRANSMISSION__ |
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14 | #error only libtransmission should #include this header. |
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15 | #endif |
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16 | |
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17 | #ifndef TR_BANDWIDTH_H |
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18 | #define TR_BANDWIDTH_H |
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19 | |
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20 | #include "transmission.h" |
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21 | #include "ptrarray.h" |
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22 | |
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23 | struct tr_peerIo; |
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24 | |
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25 | /* these are PRIVATE IMPLEMENTATION details that should not be touched. |
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26 | * it's included in the header for inlining and composition. */ |
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27 | enum |
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28 | { |
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29 | HISTORY_MSEC = 2000, |
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30 | INTERVAL_MSEC = HISTORY_MSEC, |
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31 | GRANULARITY_MSEC = 50, |
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32 | HISTORY_SIZE = ( INTERVAL_MSEC / GRANULARITY_MSEC ), |
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33 | MAGIC_NUMBER = 43143 |
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34 | }; |
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35 | |
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36 | /* these are PRIVATE IMPLEMENTATION details that should not be touched. |
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37 | * it's included in the header for inlining and composition. */ |
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38 | struct bratecontrol |
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39 | { |
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40 | int newest; |
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41 | struct { uint64_t date, size; } transfers[HISTORY_SIZE]; |
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42 | }; |
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43 | |
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44 | /* these are PRIVATE IMPLEMENTATION details that should not be touched. |
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45 | * it's included in the header for inlining and composition. */ |
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46 | struct tr_band |
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47 | { |
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48 | tr_bool isLimited; |
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49 | tr_bool honorParentLimits; |
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50 | size_t bytesLeft; |
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51 | double desiredSpeed; |
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52 | struct bratecontrol raw; |
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53 | struct bratecontrol piece; |
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54 | }; |
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55 | |
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56 | /** |
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57 | * Bandwidth is an object for measuring and constraining bandwidth speeds. |
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58 | * |
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59 | * Bandwidth objects can be "stacked" so that a peer can be made to obey |
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60 | * multiple constraints (for example, obeying the global speed limit and a |
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61 | * per-torrent speed limit). |
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62 | * |
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63 | * HIERARCHY |
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64 | * |
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65 | * Transmission's bandwidth hierarchy is a tree. |
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66 | * At the top is the global bandwidth object owned by tr_session. |
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67 | * Its children are per-torrent bandwidth objects owned by tr_torrent. |
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68 | * Underneath those are per-peer bandwidth objects owned by tr_peer. |
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69 | * |
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70 | * tr_session also owns a tr_handshake's bandwidths, so that the handshake |
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71 | * I/O can be counted in the global raw totals. When the handshake is done, |
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72 | * the bandwidth's ownership passes to a tr_peer. |
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73 | * |
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74 | * MEASURING |
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75 | * |
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76 | * When you ask a bandwidth object for its speed, it gives the speed of the |
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77 | * subtree underneath it as well. So you can get Transmission's overall |
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78 | * speed by quering tr_session's bandwidth, per-torrent speeds by asking |
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79 | * tr_torrent's bandwidth, and per-peer speeds by asking tr_peer's bandwidth. |
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80 | * |
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81 | * CONSTRAINING |
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82 | * |
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83 | * Call tr_bandwidthAllocate() periodically. tr_bandwidth knows its current |
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84 | * speed and will decide how many bytes to make available over the |
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85 | * user-specified period to reach the user-specified desired speed. |
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86 | * If appropriate, it notifies its peer-ios that new bandwidth is available. |
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87 | * |
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88 | * tr_bandwidthAllocate() operates on the tr_bandwidth subtree, so usually |
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89 | * you'll only need to invoke it for the top-level tr_session bandwidth. |
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90 | * |
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91 | * The peer-ios all have a pointer to their associated tr_bandwidth object, |
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92 | * and call tr_bandwidthClamp() before performing I/O to see how much |
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93 | * bandwidth they can safely use. |
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94 | */ |
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95 | typedef struct tr_bandwidth |
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96 | { |
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97 | /* these are PRIVATE IMPLEMENTATION details that should not be touched. |
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98 | * it's included in the header for inlining and composition. */ |
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99 | |
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100 | struct tr_band band[2]; |
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101 | struct tr_bandwidth * parent; |
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102 | int magicNumber; |
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103 | tr_session * session; |
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104 | tr_ptrArray children; /* struct tr_bandwidth */ |
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105 | tr_ptrArray peers; /* tr_peerIo */ |
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106 | } |
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107 | tr_bandwidth; |
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108 | |
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109 | |
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110 | /** |
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111 | *** |
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112 | **/ |
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113 | |
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114 | /** @brief create a new tr_bandwidth object */ |
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115 | tr_bandwidth* |
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116 | tr_bandwidthNew ( tr_session * session, |
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117 | tr_bandwidth * parent ); |
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118 | |
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119 | /** @brief destroy a tr_bandwidth object */ |
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120 | void tr_bandwidthFree ( tr_bandwidth * bandwidth ); |
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121 | |
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122 | /** @brief test to see if the pointer refers to a live bandwidth object */ |
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123 | static inline tr_bool tr_isBandwidth( const tr_bandwidth * b ) |
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124 | { |
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125 | return ( b != NULL ) && ( b->magicNumber == MAGIC_NUMBER ); |
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126 | } |
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127 | |
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128 | /****** |
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129 | ******* |
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130 | ******/ |
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131 | |
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132 | /** |
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133 | * @brief Set the desired speed (in KiB/s) for this bandwidth subtree. |
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134 | * @see tr_bandwidthAllocate |
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135 | * @see tr_bandwidthGetDesiredSpeed |
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136 | */ |
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137 | static inline void tr_bandwidthSetDesiredSpeed( tr_bandwidth * bandwidth, |
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138 | tr_direction dir, |
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139 | double desiredSpeed ) |
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140 | { |
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141 | bandwidth->band[dir].desiredSpeed = desiredSpeed; |
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142 | } |
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143 | |
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144 | /** |
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145 | * @brief Get the desired speed (in KiB/s) for ths bandwidth subtree. |
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146 | * @see tr_bandwidthSetDesiredSpeed |
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147 | */ |
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148 | static inline double |
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149 | tr_bandwidthGetDesiredSpeed( const tr_bandwidth * bandwidth, |
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150 | tr_direction dir ) |
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151 | { |
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152 | return bandwidth->band[dir].desiredSpeed; |
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153 | } |
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154 | |
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155 | /** |
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156 | * @brief Set whether or not this bandwidth should throttle its peer-io's speeds |
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157 | */ |
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158 | static inline void tr_bandwidthSetLimited( tr_bandwidth * bandwidth, |
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159 | tr_direction dir, |
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160 | tr_bool isLimited ) |
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161 | { |
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162 | bandwidth->band[dir].isLimited = isLimited; |
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163 | } |
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164 | |
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165 | /** |
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166 | * @return nonzero if this bandwidth throttles its peer-ios speeds |
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167 | */ |
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168 | static inline tr_bool tr_bandwidthIsLimited( const tr_bandwidth * bandwidth, |
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169 | tr_direction dir ) |
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170 | { |
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171 | return bandwidth->band[dir].isLimited; |
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172 | } |
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173 | |
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174 | /** |
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175 | * @brief allocate the next period_msec's worth of bandwidth for the peer-ios to consume |
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176 | */ |
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177 | void tr_bandwidthAllocate ( tr_bandwidth * bandwidth, |
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178 | tr_direction direction, |
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179 | int period_msec ); |
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180 | |
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181 | /** |
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182 | * @brief clamps byteCount down to a number that this bandwidth will allow to be consumed |
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183 | */ |
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184 | size_t tr_bandwidthClamp ( const tr_bandwidth * bandwidth, |
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185 | tr_direction direction, |
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186 | size_t byteCount ); |
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187 | |
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188 | /****** |
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189 | ******* |
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190 | ******/ |
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191 | |
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192 | /** @brief Get the raw total of bytes read or sent by this bandwidth subtree. */ |
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193 | double tr_bandwidthGetRawSpeed( const tr_bandwidth * bandwidth, |
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194 | tr_direction direction ); |
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195 | |
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196 | /** @brief Get the number of piece data bytes read or sent by this bandwidth subtree. */ |
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197 | double tr_bandwidthGetPieceSpeed( const tr_bandwidth * bandwidth, |
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198 | tr_direction direction ); |
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199 | |
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200 | /** |
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201 | * @brief Notify the bandwidth object that some of its allocated bandwidth has been consumed. |
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202 | * This is is usually invoked by the peer-io after a read or write. |
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203 | */ |
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204 | void tr_bandwidthUsed ( tr_bandwidth * bandwidth, |
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205 | tr_direction direction, |
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206 | size_t byteCount, |
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207 | tr_bool isPieceData ); |
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208 | |
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209 | /****** |
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210 | ******* |
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211 | ******/ |
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212 | |
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213 | void tr_bandwidthSetParent ( tr_bandwidth * bandwidth, |
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214 | tr_bandwidth * parent ); |
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215 | |
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216 | /** |
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217 | * Almost all the time we do want to honor a parents' bandwidth cap, so that |
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218 | * (for example) a peer is constrained by a per-torrent cap and the global cap. |
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219 | * But when we set a torrent's speed mode to TR_SPEEDLIMIT_UNLIMITED, then |
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220 | * in that particular case we want to ignore the global speed limit... |
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221 | */ |
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222 | void tr_bandwidthHonorParentLimits ( tr_bandwidth * bandwidth, |
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223 | tr_direction direction, |
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224 | tr_bool isEnabled ); |
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225 | |
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226 | /****** |
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227 | ******* |
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228 | ******/ |
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229 | |
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230 | /** |
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231 | * @brief add a tr_peerIo to this bandwidth's list. |
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232 | * They will be notified when more bandwidth is made available for them to consume. |
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233 | */ |
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234 | void tr_bandwidthAddPeer( tr_bandwidth * bandwidth, |
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235 | struct tr_peerIo * peerIo ); |
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236 | |
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237 | /** |
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238 | * @brief remove a peer-io from this bandwidth's list. |
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239 | */ |
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240 | void tr_bandwidthRemovePeer( tr_bandwidth * bandwidth, |
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241 | struct tr_peerIo * peerIo ); |
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242 | |
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243 | #endif |
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