Upstream | cc2ee17 | 1970-01-12 13:46:40 +0000 | [diff] [blame^] | 1 | /** |
| 2 | * @file op_regex.cpp |
| 3 | * This file contains implementation for a lightweight wrapper around |
| 4 | * libc regex, providing regular expression match and replace facility. |
| 5 | * |
| 6 | * @remark Copyright 2003 OProfile authors |
| 7 | * @remark Read the file COPYING |
| 8 | * @remark Idea comes from TextFilt project <http://textfilt.sourceforge.net> |
| 9 | * |
| 10 | * @author Philippe Elie |
| 11 | */ |
| 12 | |
| 13 | #include <cerrno> |
| 14 | |
| 15 | #include <iostream> |
| 16 | #include <fstream> |
| 17 | |
| 18 | #include "string_manip.h" |
| 19 | |
| 20 | #include "op_regex.h" |
| 21 | |
| 22 | using namespace std; |
| 23 | |
| 24 | namespace { |
| 25 | |
| 26 | string op_regerror(int err, regex_t const & regexp) |
| 27 | { |
| 28 | size_t needed_size = regerror(err, ®exp, 0, 0); |
| 29 | char * buffer = new char[needed_size]; |
| 30 | regerror(err, ®exp, buffer, needed_size); |
| 31 | |
| 32 | return buffer; |
| 33 | } |
| 34 | |
| 35 | |
| 36 | void op_regcomp(regex_t & regexp, string const & pattern) |
| 37 | { |
| 38 | int err = regcomp(®exp, pattern.c_str(), REG_EXTENDED); |
| 39 | if (err) { |
| 40 | throw bad_regex("regcomp error: " + op_regerror(err, regexp) |
| 41 | + " for pattern : " + pattern); |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | |
| 46 | bool op_regexec(regex_t const & regex, string const & str, regmatch_t * match, |
| 47 | size_t nmatch) |
| 48 | { |
| 49 | return regexec(®ex, str.c_str(), nmatch, match, 0) != REG_NOMATCH; |
| 50 | } |
| 51 | |
| 52 | |
| 53 | void op_regfree(regex_t & regexp) |
| 54 | { |
| 55 | regfree(®exp); |
| 56 | } |
| 57 | |
| 58 | |
| 59 | // return the index number associated with a char seen in a "\x". |
| 60 | // Allowed range are for x is [0-9a-z] return size_t(-1) if x is not in |
| 61 | // these ranges. |
| 62 | size_t subexpr_index(char ch) |
| 63 | { |
| 64 | if (isdigit(ch)) |
| 65 | return ch - '0'; |
| 66 | if (ch >= 'a' && ch <= 'z') |
| 67 | return ch - 'a' + 10; |
| 68 | return size_t(-1); |
| 69 | } |
| 70 | |
| 71 | } // anonymous namespace |
| 72 | |
| 73 | |
| 74 | bad_regex::bad_regex(string const & pattern) |
| 75 | : op_exception(pattern) |
| 76 | { |
| 77 | } |
| 78 | |
| 79 | |
| 80 | regular_expression_replace::regular_expression_replace(size_t limit_, |
| 81 | size_t limit_defs) |
| 82 | : |
| 83 | limit(limit_), |
| 84 | limit_defs_expansion(limit_defs) |
| 85 | { |
| 86 | } |
| 87 | |
| 88 | |
| 89 | regular_expression_replace::~regular_expression_replace() |
| 90 | { |
| 91 | for (size_t i = 0 ; i < regex_replace.size() ; ++i) |
| 92 | op_regfree(regex_replace[i].regexp); |
| 93 | } |
| 94 | |
| 95 | |
| 96 | void regular_expression_replace::add_definition(string const & name, |
| 97 | string const & definition) |
| 98 | { |
| 99 | defs[name] = expand_string(definition); |
| 100 | } |
| 101 | |
| 102 | |
| 103 | void regular_expression_replace::add_pattern(string const & pattern, |
| 104 | string const & replace) |
| 105 | { |
| 106 | string expanded_pattern = expand_string(pattern); |
| 107 | |
| 108 | regex_t regexp; |
| 109 | op_regcomp(regexp, expanded_pattern); |
| 110 | replace_t regex = { regexp, replace }; |
| 111 | regex_replace.push_back(regex); |
| 112 | } |
| 113 | |
| 114 | |
| 115 | string regular_expression_replace::expand_string(string const & input) |
| 116 | { |
| 117 | string last, expanded(input); |
| 118 | size_t i = 0; |
| 119 | for (i = 0 ; i < limit_defs_expansion ; ++i) { |
| 120 | last = expanded; |
| 121 | expanded = substitute_definition(last); |
| 122 | if (expanded == last) |
| 123 | break; |
| 124 | } |
| 125 | |
| 126 | if (i == limit_defs_expansion) |
| 127 | throw bad_regex("too many substitution for: + input"); |
| 128 | |
| 129 | return last; |
| 130 | } |
| 131 | |
| 132 | |
| 133 | string regular_expression_replace::substitute_definition(string const & pattern) |
| 134 | { |
| 135 | string result; |
| 136 | bool previous_is_escape = false; |
| 137 | |
| 138 | for (size_t i = 0 ; i < pattern.length() ; ++i) { |
| 139 | if (pattern[i] == '$' && !previous_is_escape) { |
| 140 | size_t pos = pattern.find('{', i); |
| 141 | if (pos != i + 1) { |
| 142 | throw bad_regex("invalid $ in pattern: " + pattern); |
| 143 | } |
| 144 | size_t end = pattern.find('}', i); |
| 145 | if (end == string::npos) { |
| 146 | throw bad_regex("no matching '}' in pattern: " + pattern); |
| 147 | } |
| 148 | string def_name = pattern.substr(pos+1, (end-pos) - 1); |
| 149 | if (defs.find(def_name) == defs.end()) { |
| 150 | throw bad_regex("definition not found and used in pattern: (" + def_name + ") " + pattern); |
| 151 | } |
| 152 | result += defs[def_name]; |
| 153 | i = end; |
| 154 | } else { |
| 155 | if (pattern[i] == '\\' && !previous_is_escape) { |
| 156 | previous_is_escape = true; |
| 157 | } else { |
| 158 | previous_is_escape = false; |
| 159 | } |
| 160 | result += pattern[i]; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | return result; |
| 165 | } |
| 166 | |
| 167 | |
| 168 | // FIXME limit output string size ? (cause we can have exponential growing |
| 169 | // of output string through a rule "a" = "aa") |
| 170 | bool regular_expression_replace::execute(string & str) const |
| 171 | { |
| 172 | bool changed = true; |
| 173 | for (size_t nr_iter = 0; changed && nr_iter < limit ; ++nr_iter) { |
| 174 | changed = false; |
| 175 | for (size_t i = 0 ; i < regex_replace.size() ; ++i) { |
| 176 | if (do_execute(str, regex_replace[i])) { |
| 177 | changed = true; |
| 178 | } |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | // this don't return if the input string has been changed but if |
| 183 | // we reach the limit number of iteration. |
| 184 | return changed == false; |
| 185 | } |
| 186 | |
| 187 | |
| 188 | bool regular_expression_replace::do_execute(string & str, |
| 189 | replace_t const & regexp) const |
| 190 | { |
| 191 | bool changed = false; |
| 192 | |
| 193 | regmatch_t match[max_match]; |
| 194 | for (size_t iter = 0; |
| 195 | op_regexec(regexp.regexp, str, match, max_match) && iter < limit; |
| 196 | iter++) { |
| 197 | changed = true; |
| 198 | do_replace(str, regexp.replace, match); |
| 199 | } |
| 200 | |
| 201 | return changed; |
| 202 | } |
| 203 | |
| 204 | |
| 205 | regmatch_t const & |
| 206 | regular_expression_replace::get_match(regmatch_t const * match, char idx) const |
| 207 | { |
| 208 | size_t sub_expr = subexpr_index(idx); |
| 209 | if (sub_expr == size_t(-1)) |
| 210 | throw bad_regex("expect group index: " + idx); |
| 211 | if (sub_expr >= max_match) |
| 212 | throw bad_regex("illegal group index :" + idx); |
| 213 | return match[sub_expr]; |
| 214 | } |
| 215 | |
| 216 | void regular_expression_replace::do_replace |
| 217 | (string & str, string const & replace, regmatch_t const * match) const |
| 218 | { |
| 219 | string inserted; |
| 220 | for (size_t i = 0 ; i < replace.length() ; ++i) { |
| 221 | if (replace[i] == '\\') { |
| 222 | if (i == replace.length() - 1) { |
| 223 | throw bad_regex("illegal \\ trailer: " + |
| 224 | replace); |
| 225 | } |
| 226 | ++i; |
| 227 | if (replace[i] == '\\') { |
| 228 | inserted += '\\'; |
| 229 | } else { |
| 230 | regmatch_t const & matched = get_match(match, |
| 231 | replace[i]); |
| 232 | if (matched.rm_so == -1 && |
| 233 | matched.rm_eo == -1) { |
| 234 | // empty match: nothing todo |
| 235 | } else if (matched.rm_so == -1 || |
| 236 | matched.rm_eo == -1) { |
| 237 | throw bad_regex("illegal match: " + |
| 238 | replace); |
| 239 | } else { |
| 240 | inserted += str.substr(matched.rm_so, |
| 241 | matched.rm_eo - matched.rm_so); |
| 242 | } |
| 243 | } |
| 244 | } else { |
| 245 | inserted += replace[i]; |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | size_t first = match[0].rm_so; |
| 250 | size_t count = match[0].rm_eo - match[0].rm_so; |
| 251 | |
| 252 | str.replace(first, count, inserted); |
| 253 | } |
| 254 | |
| 255 | |
| 256 | void setup_regex(regular_expression_replace & regex, |
| 257 | string const & filename) |
| 258 | { |
| 259 | ifstream in(filename.c_str()); |
| 260 | if (!in) { |
| 261 | throw op_runtime_error("Can't open file " + filename + |
| 262 | " for reading", errno); |
| 263 | } |
| 264 | |
| 265 | regular_expression_replace var_name_rule; |
| 266 | var_name_rule.add_pattern("^\\$([_a-zA-Z][_a-zA-Z0-9]*)[ ]*=.*", "\\1"); |
| 267 | regular_expression_replace var_value_rule; |
| 268 | var_value_rule.add_pattern(".*=[ ]*\"(.*)\"", "\\1"); |
| 269 | |
| 270 | regular_expression_replace left_rule; |
| 271 | left_rule.add_pattern("[ ]*\"(.*)\"[ ]*=.*", "\\1"); |
| 272 | regular_expression_replace right_rule; |
| 273 | right_rule.add_pattern(".*=[ ]*\"(.*)\"", "\\1"); |
| 274 | |
| 275 | string line; |
| 276 | while (getline(in, line)) { |
| 277 | line = trim(line); |
| 278 | if (line.empty() || line[0] == '#') |
| 279 | continue; |
| 280 | |
| 281 | string temp = line; |
| 282 | var_name_rule.execute(temp); |
| 283 | if (temp == line) { |
| 284 | string left = line; |
| 285 | left_rule.execute(left); |
| 286 | if (left == line) { |
| 287 | throw bad_regex("invalid input file: " + |
| 288 | '"' + line + '"'); |
| 289 | } |
| 290 | |
| 291 | string right = line; |
| 292 | right_rule.execute(right); |
| 293 | if (right == line) { |
| 294 | throw bad_regex("invalid input file: " |
| 295 | + '"' + line + '"'); |
| 296 | } |
| 297 | |
| 298 | regex.add_pattern(left, right); |
| 299 | } else { |
| 300 | // temp != line ==> var_name_rule succeed to substitute |
| 301 | // into temp the var_name present in line |
| 302 | string var_name = temp; |
| 303 | string var_value = line; |
| 304 | var_value_rule.execute(var_value); |
| 305 | if (var_value == line) { |
| 306 | throw bad_regex("invalid input file: " + |
| 307 | '"' + line + '"'); |
| 308 | } |
| 309 | |
| 310 | regex.add_definition(var_name, var_value); |
| 311 | } |
| 312 | } |
| 313 | } |