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1 /* |
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2 |
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3 Copyright (C) 2009 Jaroslav Hajek |
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4 |
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5 This file is part of Octave. |
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6 |
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7 Octave is free software; you can redistribute it and/or modify it |
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8 under the terms of the GNU General Public License as published by the |
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9 Free Software Foundation; either version 3 of the License, or (at your |
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10 option) any later version. |
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11 |
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12 Octave is distributed in the hope that it will be useful, but WITHOUT |
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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15 for more details. |
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16 |
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17 You should have received a copy of the GNU General Public License |
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18 along with Octave; see the file COPYING. If not, see |
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19 <http://www.gnu.org/licenses/>. |
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20 |
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21 */ |
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22 |
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23 #ifdef HAVE_CONFIG_H |
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24 #include <config.h> |
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25 #endif |
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26 |
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27 #include <string> |
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28 #include <climits> |
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29 #include <algorithm> |
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30 |
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31 #include "Cell.h" |
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32 #include "ov.h" |
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33 #include "defun-dld.h" |
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34 #include "unwind-prot.h" |
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35 #include "gripes.h" |
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36 #include "utils.h" |
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37 |
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38 // This allows safe indexing with char. In C++, char may be (and often is) signed! |
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39 #define ORD(ch) static_cast<unsigned char>(ch) |
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40 |
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41 // This is the quick search algorithm, as described at |
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42 // http://www-igm.univ-mlv.fr/~lecroq/string/node19.html |
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43 static void |
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44 qs_preprocess (const Array<char>& needle, |
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45 octave_idx_type table[UCHAR_MAX]) |
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46 { |
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47 const char *x = needle.data (); |
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48 octave_idx_type m = needle.numel (); |
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49 |
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50 for (octave_idx_type i = 0; i < UCHAR_MAX; i++) |
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51 table[i] = m + 1; |
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52 for (octave_idx_type i = 0; i < m; i++) |
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53 table[ORD(x[i])] = m - i; |
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54 } |
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55 |
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56 |
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57 static octave_value |
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58 qs_search (const Array<char>& needle, |
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59 const Array<char>& haystack, |
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60 const octave_idx_type table[UCHAR_MAX]) |
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61 { |
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62 const char *x = needle.data (); |
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63 octave_idx_type m = needle.numel (); |
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64 const char *y = haystack.data (); |
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65 octave_idx_type n = haystack.numel (); |
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66 |
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67 std::vector<octave_idx_type> accum; |
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68 if (n >= m) |
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69 { |
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70 octave_idx_type j = 0; |
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71 while (j < n - m) { |
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72 if (std::equal (x, x + m, y + j)) |
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73 accum.push_back (j); |
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74 j += table[ORD(y[j + m])]; |
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75 } |
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76 |
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77 if (std::equal (x, x + m, y + n - m)) |
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78 accum.push_back (n - m); |
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79 } |
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80 |
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81 octave_idx_type nmatch = accum.size (); |
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82 NoAlias<Matrix> result (std::min (1, nmatch), nmatch); |
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83 for (octave_idx_type i = 0; i < nmatch; i++) |
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84 result(i) = accum[i] + 1; |
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85 |
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86 return result; |
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87 } |
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88 |
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89 DEFUN_DLD (strfind, args, , |
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90 "-*- texinfo -*-\n\ |
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91 @deftypefn {Loadable Function} {@var{idx} =} strfind (@var{str}, @var{pattern})\n\ |
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92 @deftypefnx {Loadable Function} {@var{idx} =} strfind (@var{cellstr}, @var{pattern})\n\ |
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93 Search for @var{pattern} in the string @var{str} and return the\n\ |
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94 starting index of every such occurrence in the vector @var{idx}.\n\ |
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95 If there is no such occurrence, or if @var{pattern} is longer\n\ |
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96 than @var{str}, then @var{idx} is the empty array @code{[]}.\n\ |
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97 \n\ |
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98 If the cell array of strings @var{cellstr} is specified instead of the\n\ |
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99 string @var{str}, then @var{idx} is a cell array of vectors, as specified\n\ |
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100 above. Examples:\n\ |
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101 \n\ |
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102 @example\n\ |
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103 @group\n\ |
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104 strfind (\"abababa\", \"aba\")\n\ |
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105 @result{} [1, 3, 5]\n\ |
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106 \n\ |
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107 strfind (@{\"abababa\", \"bebebe\", \"ab\"@}, \"aba\")\n\ |
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108 @result{} ans =\n\ |
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109 @{\n\ |
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110 [1,1] =\n\ |
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111 \n\ |
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112 1 3 5\n\ |
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113 \n\ |
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114 [1,2] = [](1x0)\n\ |
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115 [1,3] = [](1x0)\n\ |
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116 @}\n\ |
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117 @end group\n\ |
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118 @end example\n\ |
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119 @seealso{findstr, strmatch, strcmp, strncmp, strcmpi, strncmpi, find}\n\ |
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120 @end deftypefn") |
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121 { |
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122 octave_value retval; |
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123 int nargin = args.length (); |
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124 |
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125 if (nargin == 2) |
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126 { |
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127 octave_value argstr = args(0), argp = args(1); |
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128 if (argp.is_string ()) |
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129 { |
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130 Array<char> needle = argp.char_array_value (); |
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131 OCTAVE_LOCAL_BUFFER (octave_idx_type, table, UCHAR_MAX); |
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132 qs_preprocess (needle, table); |
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133 |
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134 if (argstr.is_string ()) |
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135 retval = qs_search (needle, argstr.char_array_value (), table); |
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136 else if (argstr.is_cell ()) |
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137 { |
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138 const Cell argsc = argstr.cell_value (); |
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139 Cell retc (argsc.dims ()); |
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140 octave_idx_type ns = argsc.numel (); |
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141 |
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142 for (octave_idx_type i = 0; i < ns; i++) |
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143 { |
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144 octave_value argse = argsc(i); |
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145 if (argse.is_string ()) |
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146 retc(i) = qs_search (needle, argse.char_array_value (), table); |
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147 else |
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148 { |
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149 error ("strfind: each cell element must be a string"); |
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150 break; |
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151 } |
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152 } |
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153 |
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154 retval = retc; |
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155 } |
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156 else |
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157 error ("strfind: first argument must be a string or cell array of strings"); |
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158 } |
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159 else |
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160 error ("strfind: pattern must be a string"); |
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161 } |
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162 else |
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163 print_usage (); |
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164 |
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165 return retval; |
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166 } |
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167 |
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168 /* |
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169 |
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170 %!error strfind (); |
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171 %!error strfind ("foo", "bar", 1); |
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172 %!error strfind ("foo", 100); |
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173 %!error strfind (100, "foo"); |
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174 |
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175 %!assert (strfind ("abababa", "aba"), [1, 3, 5]); |
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176 %!assert (strfind ({"abababa", "bla", "bla"}, "a"), {[1, 3, 5, 7], 3, 3}); |
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177 %!assert (strfind ("Linux _is_ user-friendly. It just isn't ignorant-friendly or idiot-friendly.", "friendly"), [17, 50, 68]); |
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178 |
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179 */ |
