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1 // Range.cc -*- C++ -*- |
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2 /* |
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3 |
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4 Copyright (C) 1992, 1993 John W. Eaton |
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5 |
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6 This file is part of Octave. |
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7 |
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8 Octave is free software; you can redistribute it and/or modify it |
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9 under the terms of the GNU General Public License as published by the |
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10 Free Software Foundation; either version 2, or (at your option) any |
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11 later version. |
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12 |
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13 Octave is distributed in the hope that it will be useful, but WITHOUT |
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14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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16 for more details. |
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17 |
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18 You should have received a copy of the GNU General Public License |
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19 along with Octave; see the file COPYING. If not, write to the Free |
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20 Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
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21 |
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22 */ |
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23 |
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238
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24 #ifdef HAVE_CONFIG_H |
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25 #include "config.h" |
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26 #endif |
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27 |
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238
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28 #include <iostream.h> |
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29 #include <limits.h> |
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30 |
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31 #include "Range.h" |
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32 |
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208
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33 // NOTE: max and min only return useful values if nelem > 0. |
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34 |
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35 double |
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36 Range::min (void) const |
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37 { |
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38 double retval = 0.0; |
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39 if (rng_nelem > 0) |
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40 { |
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41 if (rng_inc > 0) |
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42 retval = rng_base; |
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43 else |
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44 retval = rng_base + (rng_nelem - 1) * rng_inc; |
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45 } |
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46 return retval; |
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47 } |
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48 |
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49 double |
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50 Range::max (void) const |
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51 { |
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52 double retval = 0.0; |
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53 if (rng_nelem > 0) |
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54 { |
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55 if (rng_inc > 0) |
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56 retval = rng_base + (rng_nelem - 1) * rng_inc; |
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57 else |
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58 retval = rng_base; |
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59 } |
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60 return retval; |
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61 } |
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62 |
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63 void |
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64 Range::sort (void) |
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65 { |
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66 if (rng_base > rng_limit && rng_inc < 0.0) |
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67 { |
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68 double tmp = rng_base; |
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69 rng_base = min (); |
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70 rng_limit = tmp; |
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71 rng_inc = -rng_inc; |
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72 } |
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73 } |
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74 |
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75 void |
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76 Range::print_range (void) |
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77 { |
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78 cerr << "Range: rng_base = " << rng_base |
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79 << " rng_limit " << rng_limit |
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80 << " rng_inc " << rng_inc |
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81 << " rng_nelem " << rng_nelem << "\n"; |
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82 } |
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83 |
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84 ostream& |
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85 operator << (ostream& os, const Range& a) |
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86 { |
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87 double b = a.base (); |
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88 double increment = a.inc (); |
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89 int num_elem = a.nelem (); |
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90 |
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91 for (int i = 0; i < num_elem; i++) |
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92 os << b + i * increment << " "; |
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93 |
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94 os << "\n"; |
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95 |
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96 return os; |
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97 } |
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98 |
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99 istream& |
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100 operator >> (istream& is, Range& a) |
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101 { |
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102 is >> a.rng_base; |
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103 if (is) |
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104 { |
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105 is >> a.rng_limit; |
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106 if (is) |
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107 { |
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108 is >> a.rng_inc; |
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109 a.rng_nelem = a.nelem_internal (); |
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110 } |
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111 } |
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112 |
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113 return is; |
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114 } |
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115 |
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116 int |
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117 Range::nelem_internal (void) const |
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118 { |
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119 // Find an approximate number of elements, then do the best we can to |
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120 // find the number of elements that we would get if we had done |
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121 // something like |
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122 // |
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123 // nelem = 0; |
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124 // while (base + nelem * inc <= limit) |
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125 // nelem++; |
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126 // |
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127 // (for limit > base && inc > 0) |
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128 |
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129 double ntry = (rng_limit - rng_base) / rng_inc; |
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130 double max_val = (double) INT_MAX; |
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131 |
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132 if (ntry > max_val) |
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133 return -1; |
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134 |
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135 if (rng_limit > rng_base && rng_inc > 0) |
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136 { |
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137 // Our approximation may have been too big. |
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138 |
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139 while (rng_base + ntry * rng_inc > rng_limit && ntry > 0) |
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140 ntry = ntry - 1; |
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141 |
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142 // Now that we are close, get the actual number. |
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143 |
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144 while (rng_base + ntry * rng_inc <= rng_limit && ntry <= max_val) |
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145 ntry = ntry + 1; |
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146 } |
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147 else if (rng_limit < rng_base && rng_inc < 0) |
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148 { |
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149 // Our approximation may have been too big. |
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150 |
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151 while (rng_base + ntry * rng_inc < rng_limit && ntry > 0) |
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152 ntry = ntry - 1; |
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153 |
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154 // Now that we are close, get the actual number. |
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155 |
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156 while (rng_base + ntry * rng_inc >= rng_limit && ntry <= max_val) |
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157 ntry = ntry + 1; |
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158 } |
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159 else if (rng_limit == rng_base) |
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160 ntry = 1; |
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161 else |
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162 ntry = 0; |
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163 |
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164 if (ntry > max_val) |
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165 return -1; |
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166 else |
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167 return (int) ntry; |
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168 } |
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169 |
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170 /* |
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171 ;;; Local Variables: *** |
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172 ;;; mode: C++ *** |
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173 ;;; page-delimiter: "^/\\*" *** |
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174 ;;; End: *** |
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175 */ |
