1 | /*
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2 | * Python interface to libc functions.
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3 | */
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4 |
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5 | // - Enable GNU extensions in fnmatch.h for extended glob.
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6 | // - It's also apparently needed for wchar.h in combination with Python.
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7 | // https://github.com/python-pillow/Pillow/issues/1850
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8 | // - It's currently hard-coded in pyconfig.h.
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9 | #define _GNU_SOURCE 1
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10 |
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11 | #include <stdarg.h> // va_list, etc.
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12 | #include <stdio.h> // printf
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13 | #include <limits.h>
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14 | #include <wchar.h>
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15 | #include <stdlib.h>
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16 | #include <sys/ioctl.h>
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17 | #include <locale.h>
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18 | #include <fnmatch.h>
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19 | #include <glob.h>
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20 | #include <regex.h>
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21 |
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22 | #include <Python.h>
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23 |
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24 | // Log messages to stderr.
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25 | static void debug(const char* fmt, ...) {
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26 | #ifdef LIBC_VERBOSE
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27 | va_list args;
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28 | va_start(args, fmt);
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29 | vfprintf(stderr, fmt, args);
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30 | va_end(args);
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31 | fprintf(stderr, "\n");
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32 | #endif
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33 | }
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34 |
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35 | static PyObject *
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36 | func_realpath(PyObject *self, PyObject *args) {
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37 | const char *symlink;
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38 |
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39 | if (!PyArg_ParseTuple(args, "s", &symlink)) {
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40 | return NULL;
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41 | }
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42 | char target[PATH_MAX + 1];
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43 | char *status = realpath(symlink, target);
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44 |
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45 | // TODO: Throw exception like IOError here
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46 | if (status == NULL) {
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47 | debug("error from realpath()");
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48 | Py_RETURN_NONE;
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49 | }
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50 |
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51 | return PyString_FromString(target);
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52 | }
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53 |
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54 | static PyObject *
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55 | func_fnmatch(PyObject *self, PyObject *args) {
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56 | const char *pattern;
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57 | const char *str;
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58 | int flags = 0;
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59 |
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60 | if (!PyArg_ParseTuple(args, "ss|i", &pattern, &str, &flags)) {
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61 | return NULL;
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62 | }
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63 |
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64 | // NOTE: Testing for __GLIBC__ is the version detection anti-pattern. We
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65 | // should really use feature detection in our configure script. But I plan
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66 | // to get rid of the dependency on FNM_EXTMATCH because it doesn't work on
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67 | // musl libc (or OS X). Instead we should compile extended globs to extended
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68 | // regex syntax.
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69 | #ifdef __GLIBC__
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70 | flags |= FNM_EXTMATCH;
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71 | #else
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72 | debug("Warning: FNM_EXTMATCH is not defined");
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73 | #endif
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74 |
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75 | int ret = fnmatch(pattern, str, flags);
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76 |
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77 | switch (ret) {
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78 | case 0:
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79 | debug("matched: %s", str);
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80 | return PyLong_FromLong(1);
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81 | break;
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82 | case FNM_NOMATCH:
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83 | debug("no match: %s", str);
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84 | return PyLong_FromLong(0);
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85 | break;
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86 | default:
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87 | debug("other error: %s", str);
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88 | return PyLong_FromLong(-1);
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89 | break;
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90 | }
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91 | }
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92 |
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93 | // error callback to glob()
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94 | //
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95 | // Disabled because of spurious errors. For example, sed -i s/.*// (without
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96 | // quotes) is OK, but it would be treated as a glob, and prints an error if the
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97 | // directory 's' doesn't exist.
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98 | //
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99 | // Bash does its own globbing -- it doesn't use libc. Likewise, I think dash
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100 | // and mksh do their own globbing.
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101 |
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102 | int globerr(const char *path, int errno_) {
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103 | fprintf(stderr, "globerr: %s: %s\n", path, strerror(errno_));
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104 | return 0; // let glob() keep going
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105 | }
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106 |
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107 | static PyObject *
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108 | func_glob(PyObject *self, PyObject *args) {
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109 | const char* pattern;
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110 | if (!PyArg_ParseTuple(args, "s", &pattern)) {
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111 | return NULL;
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112 | }
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113 |
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114 | glob_t results;
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115 | // Hm, it's weird that the first one can't be called with GLOB_APPEND. You
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116 | // get a segfault.
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117 | int flags = 0;
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118 | // int flags = GLOB_APPEND;
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119 | //flags |= GLOB_NOMAGIC;
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120 | int ret = glob(pattern, flags, NULL, &results);
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121 |
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122 | const char *err_str = NULL;
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123 | switch (ret) {
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124 | case 0: // no error
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125 | break;
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126 | case GLOB_ABORTED:
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127 | err_str = "read error";
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128 | break;
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129 | case GLOB_NOMATCH:
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130 | // No error, because not matching isn't necessarily a problem.
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131 | // NOTE: This can be turned on to log overaggressive calls to glob().
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132 | //err_str = "nothing matched";
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133 | break;
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134 | case GLOB_NOSPACE:
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135 | err_str = "no dynamic memory";
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136 | break;
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137 | default:
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138 | err_str = "unknown problem";
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139 | break;
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140 | }
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141 | if (err_str) {
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142 | //fprintf(stderr, "func_glob: %s: %s\n", pattern, err_str);
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143 | PyErr_SetString(PyExc_RuntimeError, err_str);
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144 | return NULL;
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145 | }
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146 |
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147 | // http://stackoverflow.com/questions/3512414/does-this-pylist-appendlist-py-buildvalue-leak
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148 | size_t n = results.gl_pathc;
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149 | PyObject* matches = PyList_New(n);
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150 |
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151 | // Print array of results
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152 | size_t i;
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153 | for (i = 0; i < n; i++) {
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154 | //printf("%s\n", results.gl_pathv[i]);
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155 | PyObject* m = Py_BuildValue("s", results.gl_pathv[i]);
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156 | PyList_SetItem(matches, i, m);
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157 | }
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158 | globfree(&results);
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159 |
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160 | return matches;
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161 | }
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162 |
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163 | static PyObject *
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164 | func_regex_search(PyObject *self, PyObject *args) {
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165 | const char* pattern;
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166 | const char* str;
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167 | int cflags = 0;
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168 | int eflags = 0;
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169 | int pos = 0;
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170 |
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171 | if (!PyArg_ParseTuple(args, "sisi|i", &pattern, &cflags, &str, &eflags, &pos)) {
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172 | return NULL;
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173 | }
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174 |
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175 | cflags |= REG_EXTENDED;
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176 | regex_t pat;
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177 | int status = regcomp(&pat, pattern, cflags);
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178 | if (status != 0) {
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179 | char error_desc[50];
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180 | regerror(status, &pat, error_desc, 50);
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181 |
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182 | char error_message[80];
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183 | snprintf(error_message, 80, "Invalid regex %s (%s)", pattern, error_desc);
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184 |
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185 | PyErr_SetString(PyExc_ValueError, error_message);
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186 | return NULL;
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187 | }
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188 |
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189 | int num_groups = pat.re_nsub + 1;
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190 | PyObject *ret = PyList_New(num_groups * 2);
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191 |
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192 | if (ret == NULL) {
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193 | regfree(&pat);
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194 | return NULL;
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195 | }
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196 |
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197 | regmatch_t *pmatch = (regmatch_t*) malloc(sizeof(regmatch_t) * num_groups);
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198 | int match = regexec(&pat, str + pos, num_groups, pmatch, eflags);
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199 | if (match == 0) {
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200 | int i;
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201 | for (i = 0; i < num_groups; i++) {
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202 | int start = pmatch[i].rm_so;
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203 | if (start != -1) {
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204 | start += pos;
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205 | }
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206 | PyList_SetItem(ret, 2*i, PyInt_FromLong(start));
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207 |
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208 | int end = pmatch[i].rm_eo;
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209 | if (end != -1) {
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210 | end += pos;
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211 | }
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212 | PyList_SetItem(ret, 2*i + 1, PyInt_FromLong(end));
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213 | }
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214 | }
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215 |
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216 | free(pmatch);
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217 | regfree(&pat);
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218 |
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219 | if (match != 0) {
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220 | Py_RETURN_NONE;
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221 | }
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222 |
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223 | return ret;
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224 | }
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225 |
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226 | // For ${//}, the number of groups is always 1, so we want 2 match position
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227 | // results -- the whole regex (which we ignore), and then first group.
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228 | //
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229 | // For [[ =~ ]], do we need to count how many matches the user gave?
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230 |
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231 | #define NMATCH 2
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232 |
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233 | static PyObject *
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234 | func_regex_first_group_match(PyObject *self, PyObject *args) {
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235 | const char* pattern;
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236 | const char* str;
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237 | int pos;
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238 | if (!PyArg_ParseTuple(args, "ssi", &pattern, &str, &pos)) {
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239 | return NULL;
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240 | }
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241 |
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242 | regex_t pat;
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243 | regmatch_t m[NMATCH];
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244 |
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245 | // Could have been checked by regex_parse for [[ =~ ]], but not for glob
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246 | // patterns like ${foo/x*/y}.
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247 |
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248 | int status = regcomp(&pat, pattern, REG_EXTENDED);
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249 | if (status != 0) {
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250 | char error_string[80];
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251 | regerror(status, &pat, error_string, 80);
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252 | PyErr_SetString(PyExc_RuntimeError, error_string);
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253 | return NULL;
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254 | }
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255 |
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256 | debug("first_group_match pat %s str %s pos %d", pattern, str, pos);
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257 |
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258 | // Match at offset 'pos'
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259 | int result = regexec(&pat, str + pos, NMATCH, m, 0 /*flags*/);
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260 | regfree(&pat);
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261 |
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262 | if (result != 0) {
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263 | Py_RETURN_NONE; // no match
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264 | }
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265 |
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266 | // Assume there is a match
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267 | regoff_t start = m[1].rm_so;
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268 | regoff_t end = m[1].rm_eo;
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269 | return Py_BuildValue("(i,i)", pos + start, pos + end);
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270 | }
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271 |
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272 | // We do this in C so we can remove '%f' % 0.1 from the CPython build. That
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273 | // involves dtoa.c and pystrod.c, which are thousands of lines of code.
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274 | static PyObject *
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275 | func_print_time(PyObject *self, PyObject *args) {
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276 | double real, user, sys;
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277 | if (!PyArg_ParseTuple(args, "ddd", &real, &user, &sys)) {
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278 | return NULL;
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279 | }
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280 | fprintf(stderr, "real\t%.3f\n", real);
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281 | fprintf(stderr, "user\t%.3f\n", user);
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282 | fprintf(stderr, "sys\t%.3f\n", sys);
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283 | Py_RETURN_NONE;
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284 | }
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285 |
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286 | // A copy of socket.gethostname() from socketmodule.c. That module brings in
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287 | // too many dependencies.
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288 |
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289 | static PyObject *errno_error;
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290 |
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291 | static PyObject *
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292 | socket_gethostname(PyObject *self, PyObject *unused)
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293 | {
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294 | char buf[1024];
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295 | int res;
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296 | Py_BEGIN_ALLOW_THREADS
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297 | res = gethostname(buf, (int) sizeof buf - 1);
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298 | //res = gethostname(buf, 0); // For testing errors
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299 | Py_END_ALLOW_THREADS
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300 | if (res < 0)
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301 | return PyErr_SetFromErrno(errno_error);
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302 | buf[sizeof buf - 1] = '\0';
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303 | return PyString_FromString(buf);
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304 | }
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305 |
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306 | static PyObject *
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307 | func_get_terminal_width(PyObject *self, PyObject *unused) {
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308 | struct winsize w;
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309 | int res;
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310 | res = ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
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311 | if (res < 0)
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312 | return PyErr_SetFromErrno(errno_error);
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313 | return PyLong_FromLong(w.ws_col);
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314 | }
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315 |
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316 | static PyObject *
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317 | func_wcswidth(PyObject *self, PyObject *args){
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318 | char *string;
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319 | if (!PyArg_ParseTuple(args, "s", &string)) {
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320 | return NULL;
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321 | }
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322 |
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323 | int num_wide_chars = mbstowcs(NULL, string, 0);
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324 | if (num_wide_chars == -1) {
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325 | PyErr_SetString(PyExc_UnicodeError, "mbstowcs() 1");
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326 | return NULL;
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327 | }
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328 | int buf_size = (num_wide_chars + 1) * sizeof(wchar_t);
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329 | wchar_t* wide_chars = (wchar_t*)malloc(buf_size);
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330 | assert(wide_chars != NULL);
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331 |
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332 | num_wide_chars = mbstowcs(wide_chars, string, num_wide_chars);
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333 | if (num_wide_chars == -1) {
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334 | PyErr_SetString(PyExc_UnicodeError, "mbstowcs() 2");
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335 | return NULL;
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336 | }
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337 |
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338 | int width = wcswidth(wide_chars, num_wide_chars);
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339 | if (width == -1) {
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340 | PyErr_SetString(PyExc_UnicodeError, "wcswidth()");
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341 | return NULL;
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342 | }
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343 |
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344 | return PyInt_FromLong(width);
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345 | }
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346 |
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347 | static PyObject *
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348 | func_cpython_reset_locale(PyObject *self, PyObject *unused)
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349 | {
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350 | // From man setlocale:
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351 | // The locale "C" or "POSIX" is a portable locale; it exists on all conforming systems.
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352 | // On startup of the main program, the portable "C" locale is selected as default.
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353 |
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354 | // Python overrides this, so we set it back.
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355 | if (setlocale(LC_CTYPE, "C.UTF-8") == NULL) {
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356 | // Our CI machines don't work with C.UTF-8, even though it's supposed
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357 | // to exist?
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358 | if (setlocale(LC_CTYPE, "en_US.UTF-8") == NULL) {
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359 | PyErr_SetString(PyExc_SystemError, "Couldn't set locale to C.UTF-8 or en_US.UTF-8");
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360 | return NULL;
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361 | }
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362 | }
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363 | Py_RETURN_NONE;
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364 | }
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365 |
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366 | #ifdef OVM_MAIN
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367 | #include "pyext/libc.c/methods.def"
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368 | #else
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369 | static PyMethodDef methods[] = {
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370 | // Return the canonical version of a path with symlinks, or None if there is
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371 | // an error.
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372 | {"realpath", func_realpath, METH_VARARGS, ""},
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373 |
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374 | // Return whether a string matches a pattern."
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375 | {"fnmatch", func_fnmatch, METH_VARARGS, ""},
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376 |
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377 | // Return a list of files that match a pattern.
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378 | // We need this since Python's glob doesn't have char classes.
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379 | {"glob", func_glob, METH_VARARGS, ""},
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380 |
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381 | // Search a string for regex. Returns a list of matches, None if no
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382 | // match. Raises RuntimeError if the regex is invalid.
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383 | {"regex_search", func_regex_search, METH_VARARGS, ""},
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384 |
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385 | // If the regex matches the string, return the start and end position of the
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386 | // first group. Returns None if there is no match. Raises RuntimeError if
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387 | // the regex is invalid.
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388 | {"regex_first_group_match", func_regex_first_group_match, METH_VARARGS, ""},
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389 |
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390 | // "Print three floating point values for the 'time' builtin.
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391 | {"print_time", func_print_time, METH_VARARGS, ""},
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392 |
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393 | {"gethostname", socket_gethostname, METH_NOARGS, ""},
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394 |
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395 | // ioctl() to get the terminal width.
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396 | {"get_terminal_width", func_get_terminal_width, METH_NOARGS, ""},
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397 |
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398 | // Get the display width of a string. Throw an exception if the string is invalid UTF8.
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399 | {"wcswidth", func_wcswidth, METH_VARARGS, ""},
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400 |
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401 | // Workaround for CPython's calling setlocale() in pythonrun.c. ONLY used
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402 | // by tests and bin/oil.py.
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403 | {"cpython_reset_locale", func_cpython_reset_locale, METH_NOARGS, ""},
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404 | {NULL, NULL},
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405 | };
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406 | #endif
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407 |
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408 | void initlibc(void) {
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409 | PyObject *module;
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410 |
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411 | module = Py_InitModule("libc", methods);
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412 | if (module != NULL) {
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413 | PyModule_AddIntConstant(module, "FNM_CASEFOLD", FNM_CASEFOLD);
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414 | PyModule_AddIntConstant(module, "REG_ICASE", REG_ICASE);
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415 | PyModule_AddIntConstant(module, "REG_NEWLINE", REG_NEWLINE);
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416 | PyModule_AddIntConstant(module, "REG_NOTBOL", REG_NOTBOL);
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417 | }
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418 |
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419 | errno_error = PyErr_NewException("libc.error",
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420 | PyExc_IOError, NULL);
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421 | }
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