15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright 1999-2005 The RE2 Authors. All Rights Reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// license that can be found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "util/util.h" 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "re2/stringpiece.h" 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace re2 { 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// ---------------------------------------------------------------------- 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// CEscapeString() 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copies 'src' to 'dest', escaping dangerous characters using 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// C-style escape sequences. 'src' and 'dest' should not overlap. 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Returns the number of bytes written to 'dest' (not including the \0) 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// or -1 if there was insufficient space. 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// ---------------------------------------------------------------------- 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)int CEscapeString(const char* src, int src_len, char* dest, 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int dest_len) { 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const char* src_end = src + src_len; 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int used = 0; 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) for (; src < src_end; src++) { 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (dest_len - used < 2) // Need space for two letter escape 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return -1; 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned char c = *src; 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) switch (c) { 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case '\n': dest[used++] = '\\'; dest[used++] = 'n'; break; 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case '\r': dest[used++] = '\\'; dest[used++] = 'r'; break; 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case '\t': dest[used++] = '\\'; dest[used++] = 't'; break; 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case '\"': dest[used++] = '\\'; dest[used++] = '\"'; break; 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case '\'': dest[used++] = '\\'; dest[used++] = '\''; break; 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case '\\': dest[used++] = '\\'; dest[used++] = '\\'; break; 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) default: 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Note that if we emit \xNN and the src character after that is a hex 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // digit then that digit must be escaped too to prevent it being 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // interpreted as part of the character code by C. 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (c < ' ' || c > '~') { 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (dest_len - used < 4) // need space for 4 letter escape 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return -1; 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) sprintf(dest + used, "\\%03o", c); 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) used += 4; 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } else { 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) dest[used++] = c; break; 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (dest_len - used < 1) // make sure that there is room for \0 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return -1; 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) dest[used] = '\0'; // doesn't count towards return value though 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return used; 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// ---------------------------------------------------------------------- 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// CEscape() 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copies 'src' to result, escaping dangerous characters using 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// C-style escape sequences. 'src' and 'dest' should not overlap. 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// ---------------------------------------------------------------------- 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)string CEscape(const StringPiece& src) { 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const int dest_length = src.size() * 4 + 1; // Maximum possible expansion 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) char* dest = new char[dest_length]; 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const int len = CEscapeString(src.data(), src.size(), 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) dest, dest_length); 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) string s = string(dest, len); 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) delete[] dest; 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return s; 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)string PrefixSuccessor(const StringPiece& prefix) { 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // We can increment the last character in the string and be done 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // unless that character is 255, in which case we have to erase the 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // last character and increment the previous character, unless that 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // is 255, etc. If the string is empty or consists entirely of 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // 255's, we just return the empty string. 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool done = false; 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) string limit(prefix.data(), prefix.size()); 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int index = limit.length() - 1; 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) while (!done && index >= 0) { 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if ((limit[index]&255) == 255) { 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) limit.erase(index); 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) index--; 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } else { 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) limit[index]++; 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) done = true; 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!done) { 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ""; 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } else { 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return limit; 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace re2 98