1 | /********************************************************************** |
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2 | * $Id: lwgeom_functions_lrs.c 4745 2009-11-05 00:37:32Z pramsey $ |
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3 | * |
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4 | * PostGIS - Spatial Types for PostgreSQL |
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5 | * http://postgis.refractions.net |
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6 | * Copyright 2001-2005 Refractions Research Inc. |
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7 | * |
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8 | * This is free software; you can redistribute and/or modify it under |
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9 | * the terms of the GNU General Public Licence. See the COPYING file. |
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10 | * |
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11 | **********************************************************************/ |
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12 | |
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13 | #include "postgres.h" |
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14 | #include "fmgr.h" |
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15 | #include "liblwgeom.h" |
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16 | #include "lwgeom_pg.h" |
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17 | #include "math.h" |
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18 | |
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19 | |
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20 | Datum LWGEOM_locate_between_m(PG_FUNCTION_ARGS); |
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21 | |
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22 | typedef struct |
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23 | { |
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24 | POINTARRAY **ptarrays; |
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25 | uint32 nptarrays; |
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26 | } |
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27 | POINTARRAYSET; |
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28 | |
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29 | static POINTARRAYSET ptarray_locate_between_m( |
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30 | POINTARRAY *ipa, double m0, double m1); |
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31 | |
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32 | static LWGEOM *lwcollection_locate_between_m( |
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33 | LWCOLLECTION *lwcoll, double m0, double m1); |
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34 | |
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35 | static LWGEOM *lwgeom_locate_between_m( |
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36 | LWGEOM *lwin, double m0, double m1); |
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37 | |
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38 | static LWGEOM *lwline_locate_between_m( |
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39 | LWLINE *lwline_in, double m0, double m1); |
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40 | |
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41 | static LWGEOM *lwpoint_locate_between_m( |
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42 | LWPOINT *lwpoint, double m0, double m1); |
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43 | |
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44 | static int clip_seg_by_m_range( |
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45 | POINT4D *p1, POINT4D *p2, double m0, double m1); |
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46 | |
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47 | |
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48 | /* |
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49 | * Clip a segment by a range of measures. |
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50 | * Z and M values are interpolated in case of clipping. |
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51 | * |
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52 | * Returns a bitfield, flags being: |
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53 | * 0x0001 : segment intersects the range |
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54 | * 0x0010 : first point is modified |
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55 | * 0x0100 : second point is modified |
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56 | * |
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57 | * Values: |
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58 | * - 0 segment fully outside the range, no modifications |
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59 | * - 1 segment fully inside the range, no modifications |
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60 | * - 7 segment crosses the range, both points modified. |
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61 | * - 3 first point out, second in, first point modified |
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62 | * - 5 first point in, second out, second point modified |
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63 | */ |
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64 | static int |
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65 | clip_seg_by_m_range(POINT4D *p1, POINT4D *p2, double m0, double m1) |
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66 | { |
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67 | double dM0, dM1, dX, dY, dZ; |
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68 | POINT4D *tmp; |
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69 | int swapped=0; |
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70 | int ret=0; |
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71 | |
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72 | LWDEBUGF(3, "m0: %g m1: %g", m0, m1); |
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73 | |
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74 | /* Handle corner case of m values being the same */ |
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75 | if ( p1->m == p2->m ) |
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76 | { |
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77 | /* out of range, no clipping */ |
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78 | if ( p1->m < m0 || p1->m > m1 ) |
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79 | return 0; |
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80 | |
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81 | /* inside range, no clipping */ |
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82 | return 1; |
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83 | } |
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84 | |
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85 | /* |
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86 | * Order points so that p1 has the smaller M |
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87 | */ |
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88 | if ( p1->m > p2->m ) |
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89 | { |
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90 | tmp=p2; |
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91 | p2=p1; |
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92 | p1=tmp; |
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93 | swapped=1; |
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94 | } |
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95 | |
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96 | /* |
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97 | * The M range is not intersected, segment |
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98 | * fully out of range, no clipping. |
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99 | */ |
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100 | if ( p2->m < m0 || p1->m > m1 ) |
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101 | return 0; |
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102 | |
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103 | /* |
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104 | * The segment is fully inside the range, |
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105 | * no clipping. |
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106 | */ |
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107 | if ( p1->m >= m0 && p2->m <= m1 ) |
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108 | return 1; |
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109 | |
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110 | /* |
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111 | * Segment intersects range, lets compute |
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112 | * the proportional location of the two |
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113 | * measures wrt p1/p2 m range. |
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114 | * |
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115 | * if p1 and p2 have the same measure |
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116 | * this should never be reached (either |
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117 | * both inside or both outside) |
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118 | * |
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119 | */ |
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120 | dM0=(m0-p1->m)/(p2->m-p1->m); /* delta-M0 */ |
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121 | dM1=(m1-p2->m)/(p2->m-p1->m); /* delta-M1 */ |
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122 | dX=p2->x-p1->x; |
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123 | dY=p2->y-p1->y; |
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124 | dZ=p2->z-p1->z; |
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125 | |
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126 | LWDEBUGF(3, "dM0:%g dM1:%g", dM0, dM1); |
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127 | LWDEBUGF(3, "dX:%g dY:%g dZ:%g", dX, dY, dZ); |
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128 | LWDEBUGF(3, "swapped: %d", swapped); |
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129 | |
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130 | /* |
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131 | * First point out of range, project |
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132 | * it on the range |
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133 | */ |
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134 | if ( p1->m < m0 ) |
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135 | { |
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136 | /* |
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137 | * To prevent rounding errors, then if m0==m1 and p2 lies within the range, copy |
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138 | * p1 as a direct copy of p2 |
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139 | */ |
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140 | if (m0 == m1 && p2->m <= m1) |
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141 | { |
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142 | memcpy(p1, p2, sizeof(POINT4D)); |
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143 | |
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144 | LWDEBUG(3, "Projected p1 on range (as copy of p2)"); |
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145 | } |
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146 | else |
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147 | { |
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148 | /* Otherwise interpolate coordinates */ |
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149 | p1->x += (dX*dM0); |
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150 | p1->y += (dY*dM0); |
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151 | p1->z += (dZ*dM0); |
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152 | p1->m = m0; |
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153 | |
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154 | LWDEBUG(3, "Projected p1 on range"); |
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155 | } |
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156 | |
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157 | if ( swapped ) ret |= 0x0100; |
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158 | else ret |= 0x0010; |
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159 | } |
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160 | |
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161 | /* |
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162 | * Second point out of range, project |
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163 | * it on the range |
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164 | */ |
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165 | if ( p2->m > m1 ) |
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166 | { |
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167 | /* |
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168 | * To prevent rounding errors, then if m0==m1 and p1 lies within the range, copy |
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169 | * p2 as a direct copy of p1 |
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170 | */ |
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171 | if (m0 == m1 && p1->m >= m0) |
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172 | { |
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173 | memcpy(p2, p1, sizeof(POINT4D)); |
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174 | |
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175 | LWDEBUG(3, "Projected p2 on range (as copy of p1)"); |
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176 | } |
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177 | else |
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178 | { |
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179 | /* Otherwise interpolate coordinates */ |
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180 | p2->x += (dX*dM1); |
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181 | p2->y += (dY*dM1); |
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182 | p2->z += (dZ*dM1); |
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183 | p2->m = m1; |
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184 | |
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185 | LWDEBUG(3, "Projected p2 on range"); |
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186 | } |
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187 | |
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188 | if ( swapped ) ret |= 0x0010; |
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189 | else ret |= 0x0100; |
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190 | } |
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191 | |
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192 | /* Clipping occurred */ |
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193 | return ret; |
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194 | |
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195 | } |
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196 | |
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197 | static POINTARRAYSET |
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198 | ptarray_locate_between_m(POINTARRAY *ipa, double m0, double m1) |
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199 | { |
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200 | POINTARRAYSET ret; |
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201 | DYNPTARRAY *dpa=NULL; |
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202 | int i; |
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203 | |
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204 | ret.nptarrays=0; |
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205 | |
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206 | /* |
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207 | * We allocate space for as many pointarray as |
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208 | * segments in the input POINTARRAY, as worst |
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209 | * case is for each segment to cross the M range |
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210 | * window. |
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211 | * TODO: rework this to reduce used memory |
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212 | */ |
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213 | ret.ptarrays=lwalloc(sizeof(POINTARRAY *)*ipa->npoints-1); |
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214 | |
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215 | LWDEBUGF(2, "ptarray_locate...: called for pointarray %x, m0:%g, m1:%g", |
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216 | ipa, m0, m1); |
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217 | |
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218 | |
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219 | for (i=1; i<ipa->npoints; i++) |
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220 | { |
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221 | POINT4D p1, p2; |
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222 | int clipval; |
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223 | |
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224 | getPoint4d_p(ipa, i-1, &p1); |
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225 | getPoint4d_p(ipa, i, &p2); |
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226 | |
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227 | LWDEBUGF(3, " segment %d-%d [ %g %g %g %g - %g %g %g %g ]", |
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228 | i-1, i, |
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229 | p1.x, p1.y, p1.z, p1.m, |
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230 | p2.x, p2.y, p2.z, p2.m); |
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231 | |
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232 | clipval = clip_seg_by_m_range(&p1, &p2, m0, m1); |
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233 | |
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234 | /* segment completely outside, nothing to do */ |
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235 | if (! clipval ) continue; |
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236 | |
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237 | LWDEBUGF(3, " clipped to: [ %g %g %g %g - %g %g %g %g ] clipval: %x", p1.x, p1.y, p1.z, p1.m, |
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238 | p2.x, p2.y, p2.z, p2.m, clipval); |
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239 | |
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240 | /* If no points have been accumulated so far, then if clipval != 0 the first point must be the |
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241 | start of the intersection */ |
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242 | if (dpa == NULL) |
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243 | { |
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244 | LWDEBUGF(3, " 1 creating new POINTARRAY with first point %g,%g,%g,%g", p1.x, p1.y, p1.z, p1.m); |
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245 | |
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246 | dpa = dynptarray_create(ipa->npoints-i, ipa->dims); |
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247 | dynptarray_addPoint4d(dpa, &p1, 1); |
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248 | } |
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249 | |
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250 | /* Otherwise always add the next point, avoiding duplicates */ |
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251 | if (dpa) |
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252 | dynptarray_addPoint4d(dpa, &p2, 0); |
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253 | |
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254 | /* |
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255 | * second point has been clipped |
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256 | */ |
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257 | if ( clipval & 0x0100 || i == ipa->npoints-1 ) |
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258 | { |
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259 | LWDEBUGF(3, " closing pointarray %x with %d points", dpa->pa, dpa->pa->npoints); |
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260 | |
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261 | ret.ptarrays[ret.nptarrays++] = dpa->pa; |
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262 | lwfree(dpa); |
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263 | dpa=NULL; |
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264 | } |
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265 | } |
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266 | |
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267 | /* |
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268 | * if dpa!=NULL it means we didn't close it yet. |
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269 | * this should never happen. |
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270 | */ |
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271 | if ( dpa != NULL ) lwerror("Something wrong with algorithm"); |
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272 | |
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273 | return ret; |
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274 | } |
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275 | |
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276 | /* |
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277 | * Point is assumed to have an M value. |
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278 | * Return NULL if point is not in the given range (inclusive) |
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279 | * Return an LWPOINT *copy* otherwise. |
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280 | */ |
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281 | static LWGEOM * |
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282 | lwpoint_locate_between_m(LWPOINT *lwpoint, double m0, double m1) |
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283 | { |
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284 | POINT3DM p3dm; |
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285 | |
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286 | LWDEBUGF(2, "lwpoint_locate_between called for lwpoint %x", lwpoint); |
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287 | |
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288 | lwpoint_getPoint3dm_p(lwpoint, &p3dm); |
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289 | if ( p3dm.m >= m0 && p3dm.m <= m1) |
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290 | { |
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291 | LWDEBUG(3, " lwpoint... returning a clone of input"); |
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292 | |
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293 | return (LWGEOM *)lwpoint_clone(lwpoint); |
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294 | } |
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295 | else |
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296 | { |
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297 | LWDEBUG(3, " lwpoint... returning a clone of input"); |
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298 | |
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299 | return NULL; |
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300 | } |
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301 | } |
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302 | |
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303 | /* |
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304 | * Line is assumed to have an M value. |
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305 | * |
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306 | * Return NULL if no parts of the line are in the given range (inclusive) |
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307 | * |
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308 | * Return an LWCOLLECTION with LWLINES and LWPOINT being consecutive |
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309 | * and isolated points on the line falling in the range. |
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310 | * |
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311 | * X,Y and Z (if present) ordinates are interpolated. |
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312 | * |
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313 | */ |
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314 | static LWGEOM * |
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315 | lwline_locate_between_m(LWLINE *lwline_in, double m0, double m1) |
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316 | { |
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317 | POINTARRAY *ipa=lwline_in->points; |
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318 | int i; |
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319 | LWGEOM **geoms; |
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320 | int ngeoms; |
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321 | int outtype; |
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322 | int typeflag=0; /* see flags below */ |
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323 | const int pointflag=0x01; |
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324 | const int lineflag=0x10; |
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325 | POINTARRAYSET paset=ptarray_locate_between_m(ipa, m0, m1); |
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326 | |
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327 | LWDEBUGF(2, "lwline_locate_between called for lwline %x", lwline_in); |
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328 | |
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329 | LWDEBUGF(3, " ptarray_locate... returned %d pointarrays", |
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330 | paset.nptarrays); |
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331 | |
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332 | if ( paset.nptarrays == 0 ) |
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333 | { |
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334 | return NULL; |
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335 | } |
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336 | |
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337 | ngeoms=paset.nptarrays; |
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338 | /* TODO: rework this to reduce used memory */ |
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339 | geoms=lwalloc(sizeof(LWGEOM *)*ngeoms); |
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340 | for (i=0; i<ngeoms; i++) |
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341 | { |
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342 | LWPOINT *lwpoint; |
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343 | LWLINE *lwline; |
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344 | |
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345 | POINTARRAY *pa=paset.ptarrays[i]; |
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346 | |
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347 | /* This is a point */ |
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348 | if ( pa->npoints == 1 ) |
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349 | { |
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350 | lwpoint=lwalloc(sizeof(LWPOINT)); |
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351 | lwpoint->type=lwgeom_makeType_full( |
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352 | TYPE_HASZ(pa->dims), |
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353 | TYPE_HASM(pa->dims), |
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354 | lwline_in->SRID, |
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355 | POINTTYPE, |
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356 | 0); |
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357 | lwpoint->SRID=lwline_in->SRID; |
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358 | lwpoint->bbox=NULL; |
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359 | lwpoint->point=pa; |
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360 | geoms[i]=(LWGEOM *)lwpoint; |
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361 | typeflag|=pointflag; |
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362 | } |
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363 | |
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364 | /* This is a line */ |
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365 | else if ( pa->npoints > 1 ) |
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366 | { |
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367 | lwline=lwalloc(sizeof(LWLINE)); |
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368 | lwline->type=lwgeom_makeType_full( |
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369 | TYPE_HASZ(pa->dims), |
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370 | TYPE_HASM(pa->dims), |
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371 | lwline_in->SRID, |
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372 | LINETYPE, |
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373 | 0); |
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374 | lwline->SRID=lwline_in->SRID; |
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375 | lwline->bbox=NULL; |
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376 | lwline->points=pa; |
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377 | geoms[i]=(LWGEOM *)lwline; |
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378 | typeflag|=lineflag; |
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379 | } |
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380 | |
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381 | /* This is a bug */ |
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382 | else |
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383 | { |
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384 | lwerror("ptarray_locate_between_m returned a POINARRAY set containing POINTARRAY with 0 points"); |
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385 | } |
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386 | |
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387 | } |
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388 | |
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389 | if ( ngeoms == 1 ) |
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390 | { |
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391 | return geoms[0]; |
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392 | } |
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393 | else |
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394 | { |
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395 | /* Choose best type */ |
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396 | if ( typeflag == 1 ) outtype=MULTIPOINTTYPE; |
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397 | else if ( typeflag == 2 ) outtype=MULTILINETYPE; |
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398 | else outtype = COLLECTIONTYPE; |
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399 | |
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400 | return (LWGEOM *)lwcollection_construct(outtype, |
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401 | lwline_in->SRID, NULL, ngeoms, geoms); |
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402 | } |
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403 | } |
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404 | |
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405 | /* |
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406 | * Return a fully new allocated LWCOLLECTION |
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407 | * always tagged as COLLECTIONTYPE. |
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408 | */ |
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409 | static LWGEOM * |
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410 | lwcollection_locate_between_m(LWCOLLECTION *lwcoll, double m0, double m1) |
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411 | { |
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412 | int i; |
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413 | int ngeoms=0; |
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414 | LWGEOM **geoms; |
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415 | |
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416 | LWDEBUGF(2, "lwcollection_locate_between_m called for lwcoll %x", lwcoll); |
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417 | |
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418 | geoms=lwalloc(sizeof(LWGEOM *)*lwcoll->ngeoms); |
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419 | for (i=0; i<lwcoll->ngeoms; i++) |
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420 | { |
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421 | LWGEOM *sub=lwgeom_locate_between_m(lwcoll->geoms[i], |
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422 | m0, m1); |
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423 | if ( sub != NULL ) |
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424 | geoms[ngeoms++] = sub; |
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425 | } |
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426 | |
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427 | if ( ngeoms == 0 ) return NULL; |
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428 | |
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429 | return (LWGEOM *)lwcollection_construct(COLLECTIONTYPE, |
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430 | lwcoll->SRID, NULL, ngeoms, geoms); |
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431 | } |
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432 | |
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433 | /* |
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434 | * Return a fully allocated LWGEOM containing elements |
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435 | * intersected/interpolated with the given M range. |
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436 | * Return NULL if none of the elements fall in the range. |
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437 | * |
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438 | * m0 is assumed to be less-or-equal to m1. |
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439 | * input LWGEOM is assumed to contain an M value. |
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440 | * |
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441 | */ |
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442 | static LWGEOM * |
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443 | lwgeom_locate_between_m(LWGEOM *lwin, double m0, double m1) |
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444 | { |
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445 | LWDEBUGF(2, "lwgeom_locate_between called for lwgeom %x", lwin); |
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446 | |
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447 | switch (TYPE_GETTYPE(lwin->type)) |
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448 | { |
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449 | case POINTTYPE: |
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450 | return lwpoint_locate_between_m( |
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451 | (LWPOINT *)lwin, m0, m1); |
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452 | case LINETYPE: |
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453 | return lwline_locate_between_m( |
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454 | (LWLINE *)lwin, m0, m1); |
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455 | |
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456 | case MULTIPOINTTYPE: |
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457 | case MULTILINETYPE: |
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458 | case COLLECTIONTYPE: |
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459 | return lwcollection_locate_between_m( |
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460 | (LWCOLLECTION *)lwin, m0, m1); |
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461 | |
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462 | /* Polygon types are not supported */ |
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463 | case POLYGONTYPE: |
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464 | case MULTIPOLYGONTYPE: |
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465 | lwerror("Areal geometries are not supported by locate_between_measures"); |
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466 | return NULL; |
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467 | } |
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468 | |
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469 | lwerror("Unkonwn geometry type (%s:%d)", __FILE__, __LINE__); |
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470 | return NULL; |
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471 | } |
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472 | |
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473 | /* |
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474 | * Return a derived geometry collection value with elements that match |
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475 | * the specified range of measures inclusively. |
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476 | * |
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477 | * Implements SQL/MM ST_LocateBetween(measure, measure) method. |
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478 | * See ISO/IEC CD 13249-3:200x(E) |
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479 | * |
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480 | */ |
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481 | PG_FUNCTION_INFO_V1(LWGEOM_locate_between_m); |
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482 | Datum LWGEOM_locate_between_m(PG_FUNCTION_ARGS) |
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483 | { |
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484 | PG_LWGEOM *gin = (PG_LWGEOM *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0)); |
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485 | PG_LWGEOM *gout; |
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486 | double start_measure = PG_GETARG_FLOAT8(1); |
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487 | double end_measure = PG_GETARG_FLOAT8(2); |
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488 | LWGEOM *lwin, *lwout; |
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489 | int type; |
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490 | |
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491 | if ( end_measure < start_measure ) |
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492 | { |
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493 | lwerror("locate_between_m: 2nd arg must be bigger then 1st arg"); |
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494 | PG_RETURN_NULL(); |
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495 | } |
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496 | |
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497 | /* |
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498 | * Return error if input doesn't have a measure |
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499 | */ |
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500 | if ( ! lwgeom_hasM(gin->type) ) |
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501 | { |
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502 | lwerror("Geometry argument does not have an 'M' ordinate"); |
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503 | PG_RETURN_NULL(); |
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504 | } |
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505 | |
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506 | /* |
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507 | * Raise an error if input is a polygon, a multipolygon |
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508 | * or a collection |
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509 | */ |
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510 | type=lwgeom_getType(gin->type); |
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511 | |
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512 | if ( type == POLYGONTYPE || type == MULTIPOLYGONTYPE || type == COLLECTIONTYPE ) |
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513 | { |
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514 | lwerror("Areal or Collection types are not supported"); |
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515 | PG_RETURN_NULL(); |
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516 | } |
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517 | |
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518 | lwin = pglwgeom_deserialize(gin); |
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519 | |
---|
520 | lwout = lwgeom_locate_between_m(lwin, |
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521 | start_measure, end_measure); |
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522 | |
---|
523 | lwgeom_release(lwin); |
---|
524 | |
---|
525 | if ( lwout == NULL ) |
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526 | { |
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527 | lwout = (LWGEOM *)lwcollection_construct_empty( |
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528 | pglwgeom_getSRID(gin), lwgeom_hasZ(gin->type), |
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529 | lwgeom_hasM(gin->type)); |
---|
530 | } |
---|
531 | |
---|
532 | gout = pglwgeom_serialize(lwout); |
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533 | lwgeom_release(lwout); |
---|
534 | |
---|
535 | PG_RETURN_POINTER(gout); |
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536 | } |
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537 | |
---|