1 /* 2 * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.invoke.util; 27 28 /** 29 * Utility routines for dealing with bytecode-level names. 30 * Includes universal mangling rules for the JVM. 31 * 32 * <h3>Avoiding Dangerous Characters </h3> 33 * 34 * <p> 35 * The JVM defines a very small set of characters which are illegal 36 * in name spellings. We will slightly extend and regularize this set 37 * into a group of <cite>dangerous characters</cite>. 38 * These characters will then be replaced, in mangled names, by escape sequences. 39 * In addition, accidental escape sequences must be further escaped. 40 * Finally, a special prefix will be applied if and only if 41 * the mangling would otherwise fail to begin with the escape character. 42 * This happens to cover the corner case of the null string, 43 * and also clearly marks symbols which need demangling. 44 * </p> 45 * <p> 46 * Dangerous characters are the union of all characters forbidden 47 * or otherwise restricted by the JVM specification, 48 * plus their mates, if they are brackets 49 * (<code><big><b>[</b></big></code> and <code><big><b>]</b></big></code>, 50 * <code><big><b><</b></big></code> and <code><big><b>></b></big></code>), 51 * plus, arbitrarily, the colon character <code><big><b>:</b></big></code>. 52 * There is no distinction between type, method, and field names. 53 * This makes it easier to convert between mangled names of different 54 * types, since they do not need to be decoded (demangled). 55 * </p> 56 * <p> 57 * The escape character is backslash <code><big><b>\</b></big></code> 58 * (also known as reverse solidus). 59 * This character is, until now, unheard of in bytecode names, 60 * but traditional in the proposed role. 61 * 62 * </p> 63 * <h3> Replacement Characters </h3> 64 * 65 * 66 * <p> 67 * Every escape sequence is two characters 68 * (in fact, two UTF8 bytes) beginning with 69 * the escape character and followed by a 70 * <cite>replacement character</cite>. 71 * (Since the replacement character is never a backslash, 72 * iterated manglings do not double in size.) 73 * </p> 74 * <p> 75 * Each dangerous character has some rough visual similarity 76 * to its corresponding replacement character. 77 * This makes mangled symbols easier to recognize by sight. 78 * </p> 79 * <p> 80 * The dangerous characters are 81 * <code><big><b>/</b></big></code> (forward slash, used to delimit package components), 82 * <code><big><b>.</b></big></code> (dot, also a package delimiter), 83 * <code><big><b>;</b></big></code> (semicolon, used in signatures), 84 * <code><big><b>$</b></big></code> (dollar, used in inner classes and synthetic members), 85 * <code><big><b><</b></big></code> (left angle), 86 * <code><big><b>></b></big></code> (right angle), 87 * <code><big><b>[</b></big></code> (left square bracket, used in array types), 88 * <code><big><b>]</b></big></code> (right square bracket, reserved in this scheme for language use), 89 * and <code><big><b>:</b></big></code> (colon, reserved in this scheme for language use). 90 * Their replacements are, respectively, 91 * <code><big><b>|</b></big></code> (vertical bar), 92 * <code><big><b>,</b></big></code> (comma), 93 * <code><big><b>?</b></big></code> (question mark), 94 * <code><big><b>%</b></big></code> (percent), 95 * <code><big><b>^</b></big></code> (caret), 96 * <code><big><b>_</b></big></code> (underscore), and 97 * <code><big><b>{</b></big></code> (left curly bracket), 98 * <code><big><b>}</b></big></code> (right curly bracket), 99 * <code><big><b>!</b></big></code> (exclamation mark). 100 * In addition, the replacement character for the escape character itself is 101 * <code><big><b>-</b></big></code> (hyphen), 102 * and the replacement character for the null prefix is 103 * <code><big><b>=</b></big></code> (equal sign). 104 * </p> 105 * <p> 106 * An escape character <code><big><b>\</b></big></code> 107 * followed by any of these replacement characters 108 * is an escape sequence, and there are no other escape sequences. 109 * An equal sign is only part of an escape sequence 110 * if it is the second character in the whole string, following a backslash. 111 * Two consecutive backslashes do <em>not</em> form an escape sequence. 112 * </p> 113 * <p> 114 * Each escape sequence replaces a so-called <cite>original character</cite> 115 * which is either one of the dangerous characters or the escape character. 116 * A null prefix replaces an initial null string, not a character. 117 * </p> 118 * <p> 119 * All this implies that escape sequences cannot overlap and may be 120 * determined all at once for a whole string. Note that a spelling 121 * string can contain <cite>accidental escapes</cite>, apparent escape 122 * sequences which must not be interpreted as manglings. 123 * These are disabled by replacing their leading backslash with an 124 * escape sequence (<code><big><b>\-</b></big></code>). To mangle a string, three logical steps 125 * are required, though they may be carried out in one pass: 126 * </p> 127 * <ol> 128 * <li>In each accidental escape, replace the backslash with an escape sequence 129 * (<code><big><b>\-</b></big></code>).</li> 130 * <li>Replace each dangerous character with an escape sequence 131 * (<code><big><b>\|</b></big></code> for <code><big><b>/</b></big></code>, etc.).</li> 132 * <li>If the first two steps introduced any change, <em>and</em> 133 * if the string does not already begin with a backslash, prepend a null prefix (<code><big><b>\=</b></big></code>).</li> 134 * </ol> 135 * 136 * To demangle a mangled string that begins with an escape, 137 * remove any null prefix, and then replace (in parallel) 138 * each escape sequence by its original character. 139 * <p>Spelling strings which contain accidental 140 * escapes <em>must</em> have them replaced, even if those 141 * strings do not contain dangerous characters. 142 * This restriction means that mangling a string always 143 * requires a scan of the string for escapes. 144 * But then, a scan would be required anyway, 145 * to check for dangerous characters. 146 * 147 * </p> 148 * <h3> Nice Properties </h3> 149 * 150 * <p> 151 * If a bytecode name does not contain any escape sequence, 152 * demangling is a no-op: The string demangles to itself. 153 * Such a string is called <cite>self-mangling</cite>. 154 * Almost all strings are self-mangling. 155 * In practice, to demangle almost any name “found in nature”, 156 * simply verify that it does not begin with a backslash. 157 * </p> 158 * <p> 159 * Mangling is a one-to-one function, while demangling 160 * is a many-to-one function. 161 * A mangled string is defined as <cite>validly mangled</cite> if 162 * it is in fact the unique mangling of its spelling string. 163 * Three examples of invalidly mangled strings are <code><big><b>\=foo</b></big></code>, 164 * <code><big><b>\-bar</b></big></code>, and <code><big><b>baz\!</b></big></code>, which demangle to <code><big><b>foo</b></big></code>, <code><big><b>\bar</b></big></code>, and 165 * <code><big><b>baz\!</b></big></code>, but then remangle to <code><big><b>foo</b></big></code>, <code><big><b>\bar</b></big></code>, and <code><big><b>\=baz\-!</b></big></code>. 166 * If a language back-end or runtime is using mangled names, 167 * it should never present an invalidly mangled bytecode 168 * name to the JVM. If the runtime encounters one, 169 * it should also report an error, since such an occurrence 170 * probably indicates a bug in name encoding which 171 * will lead to errors in linkage. 172 * However, this note does not propose that the JVM verifier 173 * detect invalidly mangled names. 174 * </p> 175 * <p> 176 * As a result of these rules, it is a simple matter to 177 * compute validly mangled substrings and concatenations 178 * of validly mangled strings, and (with a little care) 179 * these correspond to corresponding operations on their 180 * spelling strings. 181 * </p> 182 * <ul> 183 * <li>Any prefix of a validly mangled string is also validly mangled, 184 * although a null prefix may need to be removed.</li> 185 * <li>Any suffix of a validly mangled string is also validly mangled, 186 * although a null prefix may need to be added.</li> 187 * <li>Two validly mangled strings, when concatenated, 188 * are also validly mangled, although any null prefix 189 * must be removed from the second string, 190 * and a trailing backslash on the first string may need escaping, 191 * if it would participate in an accidental escape when followed 192 * by the first character of the second string.</li> 193 * </ul> 194 * <p>If languages that include non-Java symbol spellings use this 195 * mangling convention, they will enjoy the following advantages: 196 * </p> 197 * <ul> 198 * <li>They can interoperate via symbols they share in common.</li> 199 * <li>Low-level tools, such as backtrace printers, will have readable displays.</li> 200 * <li>Future JVM and language extensions can safely use the dangerous characters 201 * for structuring symbols, but will never interfere with valid spellings.</li> 202 * <li>Runtimes and compilers can use standard libraries for mangling and demangling.</li> 203 * <li>Occasional transliterations and name composition will be simple and regular, 204 * for classes, methods, and fields.</li> 205 * <li>Bytecode names will continue to be compact. 206 * When mangled, spellings will at most double in length, either in 207 * UTF8 or UTF16 format, and most will not change at all.</li> 208 * </ul> 209 * 210 * 211 * <h3> Suggestions for Human Readable Presentations </h3> 212 * 213 * 214 * <p> 215 * For human readable displays of symbols, 216 * it will be better to present a string-like quoted 217 * representation of the spelling, because JVM users 218 * are generally familiar with such tokens. 219 * We suggest using single or double quotes before and after 220 * mangled symbols which are not valid Java identifiers, 221 * with quotes, backslashes, and non-printing characters 222 * escaped as if for literals in the Java language. 223 * </p> 224 * <p> 225 * For example, an HTML-like spelling 226 * <code><big><b><pre></b></big></code> mangles to 227 * <code><big><b>\^pre\_</b></big></code> and could 228 * display more cleanly as 229 * <code><big><b>'<pre>'</b></big></code>, 230 * with the quotes included. 231 * Such string-like conventions are <em>not</em> suitable 232 * for mangled bytecode names, in part because 233 * dangerous characters must be eliminated, rather 234 * than just quoted. Otherwise internally structured 235 * strings like package prefixes and method signatures 236 * could not be reliably parsed. 237 * </p> 238 * <p> 239 * In such human-readable displays, invalidly mangled 240 * names should <em>not</em> be demangled and quoted, 241 * for this would be misleading. Likewise, JVM symbols 242 * which contain dangerous characters (like dots in field 243 * names or brackets in method names) should not be 244 * simply quoted. The bytecode names 245 * <code><big><b>\=phase\,1</b></big></code> and 246 * <code><big><b>phase.1</b></big></code> are distinct, 247 * and in demangled displays they should be presented as 248 * <code><big><b>'phase.1'</b></big></code> and something like 249 * <code><big><b>'phase'.1</b></big></code>, respectively. 250 * </p> 251 * 252 * @author John Rose 253 * @version 1.2, 02/06/2008 254 * @see http://blogs.sun.com/jrose/entry/symbolic_freedom_in_the_vm 255 */ 256 public class BytecodeName { 257 private BytecodeName() { } // static only class 258 259 /** Given a source name, produce the corresponding bytecode name. 260 * The source name should not be qualified, because any syntactic 261 * markers (dots, slashes, dollar signs, colons, etc.) will be mangled. 262 * @param s the source name 263 * @return a valid bytecode name which represents the source name 264 */ 265 public static String toBytecodeName(String s) { 266 String bn = mangle(s); 267 assert((Object)bn == s || looksMangled(bn)) : bn; 268 assert(s.equals(toSourceName(bn))) : s; 269 return bn; 270 } 271 272 /** Given an unqualified bytecode name, produce the corresponding source name. 273 * The bytecode name must not contain dangerous characters. 274 * In particular, it must not be qualified or segmented by colon {@code ':'}. 275 * @param s the bytecode name 276 * @return the source name, which may possibly have unsafe characters 277 * @throws IllegalArgumentException if the bytecode name is not {@link #isSafeBytecodeName safe} 278 * @see #isSafeBytecodeName(java.lang.String) 279 */ 280 public static String toSourceName(String s) { 281 checkSafeBytecodeName(s); 282 String sn = s; 283 if (looksMangled(s)) { 284 sn = demangle(s); 285 assert(s.equals(mangle(sn))) : s+" => "+sn+" => "+mangle(sn); 286 } 287 return sn; 288 } 289 290 /** 291 * Given a bytecode name from a classfile, separate it into 292 * components delimited by dangerous characters. 293 * Each resulting array element will be either a dangerous character, 294 * or else a safe bytecode name. 295 * (The safe name might possibly be mangled to hide further dangerous characters.) 296 * For example, the qualified class name {@code java/lang/String} 297 * will be parsed into the array {@code {"java", '/', "lang", '/', "String"}}. 298 * The name {@code <init>} will be parsed into {@code {'<', "init", '>'}}. 299 * The name {@code foo/bar$:baz} will be parsed into 300 * {@code {"foo", '/', "bar", '$', ':', "baz"}}. 301 * The name {@code ::\=:foo:\=bar\!baz} will be parsed into 302 * {@code {':', ':', "", ':', "foo", ':', "bar:baz"}}. 303 */ 304 public static Object[] parseBytecodeName(String s) { 305 int slen = s.length(); 306 Object[] res = null; 307 for (int pass = 0; pass <= 1; pass++) { 308 int fillp = 0; 309 int lasti = 0; 310 for (int i = 0; i <= slen; i++) { 311 int whichDC = -1; 312 if (i < slen) { 313 whichDC = DANGEROUS_CHARS.indexOf(s.charAt(i)); 314 if (whichDC < DANGEROUS_CHAR_FIRST_INDEX) continue; 315 } 316 // got to end of string or next dangerous char 317 if (lasti < i) { 318 // normal component 319 if (pass != 0) 320 res[fillp] = toSourceName(s.substring(lasti, i)); 321 fillp++; 322 lasti = i+1; 323 } 324 if (whichDC >= DANGEROUS_CHAR_FIRST_INDEX) { 325 if (pass != 0) 326 res[fillp] = DANGEROUS_CHARS_CA[whichDC]; 327 fillp++; 328 lasti = i+1; 329 } 330 } 331 if (pass != 0) break; 332 // between passes, build the result array 333 res = new Object[fillp]; 334 if (fillp <= 1 && lasti == 0) { 335 if (fillp != 0) res[0] = toSourceName(s); 336 break; 337 } 338 } 339 return res; 340 } 341 342 /** 343 * Given a series of components, create a bytecode name for a classfile. 344 * This is the inverse of {@link #parseBytecodeName(java.lang.String)}. 345 * Each component must either be an interned one-character string of 346 * a dangerous character, or else a safe bytecode name. 347 * @param components a series of name components 348 * @return the concatenation of all components 349 * @throws IllegalArgumentException if any component contains an unsafe 350 * character, and is not an interned one-character string 351 * @throws NullPointerException if any component is null 352 */ 353 public static String unparseBytecodeName(Object[] components) { 354 Object[] components0 = components; 355 for (int i = 0; i < components.length; i++) { 356 Object c = components[i]; 357 if (c instanceof String) { 358 String mc = toBytecodeName((String) c); 359 if (i == 0 && components.length == 1) 360 return mc; // usual case 361 if ((Object)mc != c) { 362 if (components == components0) 363 components = components.clone(); 364 components[i] = c = mc; 365 } 366 } 367 } 368 return appendAll(components); 369 } 370 private static String appendAll(Object[] components) { 371 if (components.length <= 1) { 372 if (components.length == 1) { 373 return String.valueOf(components[0]); 374 } 375 return ""; 376 } 377 int slen = 0; 378 for (Object c : components) { 379 if (c instanceof String) 380 slen += String.valueOf(c).length(); 381 else 382 slen += 1; 383 } 384 StringBuilder sb = new StringBuilder(slen); 385 for (Object c : components) { 386 sb.append(c); 387 } 388 return sb.toString(); 389 } 390 391 /** 392 * Given a bytecode name, produce the corresponding display name. 393 * This is the source name, plus quotes if needed. 394 * If the bytecode name contains dangerous characters, 395 * assume that they are being used as punctuation, 396 * and pass them through unchanged. 397 * Non-empty runs of non-dangerous characters are demangled 398 * if necessary, and the resulting names are quoted if 399 * they are not already valid Java identifiers, or if 400 * they contain a dangerous character (i.e., dollar sign "$"). 401 * Single quotes are used when quoting. 402 * Within quoted names, embedded single quotes and backslashes 403 * are further escaped by prepended backslashes. 404 * 405 * @param s the original bytecode name (which may be qualified) 406 * @return a human-readable presentation 407 */ 408 public static String toDisplayName(String s) { 409 Object[] components = parseBytecodeName(s); 410 for (int i = 0; i < components.length; i++) { 411 if (!(components[i] instanceof String)) 412 continue; 413 String sn = (String) components[i]; 414 // note that the name is already demangled! 415 //sn = toSourceName(sn); 416 if (!isJavaIdent(sn) || sn.indexOf('$') >=0 ) { 417 components[i] = quoteDisplay(sn); 418 } 419 } 420 return appendAll(components); 421 } 422 private static boolean isJavaIdent(String s) { 423 int slen = s.length(); 424 if (slen == 0) return false; 425 if (!Character.isJavaIdentifierStart(s.charAt(0))) 426 return false; 427 for (int i = 1; i < slen; i++) { 428 if (!Character.isJavaIdentifierPart(s.charAt(i))) 429 return false; 430 } 431 return true; 432 } 433 private static String quoteDisplay(String s) { 434 // TO DO: Replace wierd characters in s by C-style escapes. 435 return "'"+s.replaceAll("['\\\\]", "\\\\$0")+"'"; 436 } 437 438 private static void checkSafeBytecodeName(String s) 439 throws IllegalArgumentException { 440 if (!isSafeBytecodeName(s)) { 441 throw new IllegalArgumentException(s); 442 } 443 } 444 445 /** 446 * Report whether a simple name is safe as a bytecode name. 447 * Such names are acceptable in class files as class, method, and field names. 448 * Additionally, they are free of "dangerous" characters, even if those 449 * characters are legal in some (or all) names in class files. 450 * @param s the proposed bytecode name 451 * @return true if the name is non-empty and all of its characters are safe 452 */ 453 public static boolean isSafeBytecodeName(String s) { 454 if (s.isEmpty()) return false; 455 // check occurrences of each DANGEROUS char 456 for (char xc : DANGEROUS_CHARS_A) { 457 if (xc == ESCAPE_C) continue; // not really that dangerous 458 if (s.indexOf(xc) >= 0) return false; 459 } 460 return true; 461 } 462 463 /** 464 * Report whether a character is safe in a bytecode name. 465 * This is true of any unicode character except the following 466 * <em>dangerous characters</em>: {@code ".;:$[]<>/"}. 467 * @param c the proposed character 468 * @return true if the character is safe to use in classfiles 469 */ 470 public static boolean isSafeBytecodeChar(char c) { 471 return DANGEROUS_CHARS.indexOf(c) < DANGEROUS_CHAR_FIRST_INDEX; 472 } 473 474 private static boolean looksMangled(String s) { 475 return s.charAt(0) == ESCAPE_C; 476 } 477 478 private static String mangle(String s) { 479 if (s.isEmpty()) 480 return NULL_ESCAPE; 481 482 // build this lazily, when we first need an escape: 483 StringBuilder sb = null; 484 485 for (int i = 0, slen = s.length(); i < slen; i++) { 486 char c = s.charAt(i); 487 488 boolean needEscape = false; 489 if (c == ESCAPE_C) { 490 if (i+1 < slen) { 491 char c1 = s.charAt(i+1); 492 if ((i == 0 && c1 == NULL_ESCAPE_C) 493 || c1 != originalOfReplacement(c1)) { 494 // an accidental escape 495 needEscape = true; 496 } 497 } 498 } else { 499 needEscape = isDangerous(c); 500 } 501 502 if (!needEscape) { 503 if (sb != null) sb.append(c); 504 continue; 505 } 506 507 // build sb if this is the first escape 508 if (sb == null) { 509 sb = new StringBuilder(s.length()+10); 510 // mangled names must begin with a backslash: 511 if (s.charAt(0) != ESCAPE_C && i > 0) 512 sb.append(NULL_ESCAPE); 513 // append the string so far, which is unremarkable: 514 sb.append(s, 0, i); 515 } 516 517 // rewrite \ to \-, / to \|, etc. 518 sb.append(ESCAPE_C); 519 sb.append(replacementOf(c)); 520 } 521 522 if (sb != null) return sb.toString(); 523 524 return s; 525 } 526 527 private static String demangle(String s) { 528 // build this lazily, when we first meet an escape: 529 StringBuilder sb = null; 530 531 int stringStart = 0; 532 if (s.startsWith(NULL_ESCAPE)) 533 stringStart = 2; 534 535 for (int i = stringStart, slen = s.length(); i < slen; i++) { 536 char c = s.charAt(i); 537 538 if (c == ESCAPE_C && i+1 < slen) { 539 // might be an escape sequence 540 char rc = s.charAt(i+1); 541 char oc = originalOfReplacement(rc); 542 if (oc != rc) { 543 // build sb if this is the first escape 544 if (sb == null) { 545 sb = new StringBuilder(s.length()); 546 // append the string so far, which is unremarkable: 547 sb.append(s, stringStart, i); 548 } 549 ++i; // skip both characters 550 c = oc; 551 } 552 } 553 554 if (sb != null) 555 sb.append(c); 556 } 557 558 if (sb != null) return sb.toString(); 559 560 return s.substring(stringStart); 561 } 562 563 static char ESCAPE_C = '\\'; 564 // empty escape sequence to avoid a null name or illegal prefix 565 static char NULL_ESCAPE_C = '='; 566 static String NULL_ESCAPE = ESCAPE_C+""+NULL_ESCAPE_C; 567 568 static final String DANGEROUS_CHARS = "\\/.;:$[]<>"; // \\ must be first 569 static final String REPLACEMENT_CHARS = "-|,?!%{}^_"; 570 static final int DANGEROUS_CHAR_FIRST_INDEX = 1; // index after \\ 571 static char[] DANGEROUS_CHARS_A = DANGEROUS_CHARS.toCharArray(); 572 static char[] REPLACEMENT_CHARS_A = REPLACEMENT_CHARS.toCharArray(); 573 static final Character[] DANGEROUS_CHARS_CA; 574 static { 575 Character[] dcca = new Character[DANGEROUS_CHARS.length()]; 576 for (int i = 0; i < dcca.length; i++) 577 dcca[i] = Character.valueOf(DANGEROUS_CHARS.charAt(i)); 578 DANGEROUS_CHARS_CA = dcca; 579 } 580 581 static final long[] SPECIAL_BITMAP = new long[2]; // 128 bits 582 static { 583 String SPECIAL = DANGEROUS_CHARS + REPLACEMENT_CHARS; 584 //System.out.println("SPECIAL = "+SPECIAL); 585 for (char c : SPECIAL.toCharArray()) { 586 SPECIAL_BITMAP[c >>> 6] |= 1L << c; 587 } 588 } 589 static boolean isSpecial(char c) { 590 if ((c >>> 6) < SPECIAL_BITMAP.length) 591 return ((SPECIAL_BITMAP[c >>> 6] >> c) & 1) != 0; 592 else 593 return false; 594 } 595 static char replacementOf(char c) { 596 if (!isSpecial(c)) return c; 597 int i = DANGEROUS_CHARS.indexOf(c); 598 if (i < 0) return c; 599 return REPLACEMENT_CHARS.charAt(i); 600 } 601 static char originalOfReplacement(char c) { 602 if (!isSpecial(c)) return c; 603 int i = REPLACEMENT_CHARS.indexOf(c); 604 if (i < 0) return c; 605 return DANGEROUS_CHARS.charAt(i); 606 } 607 static boolean isDangerous(char c) { 608 if (!isSpecial(c)) return false; 609 return (DANGEROUS_CHARS.indexOf(c) >= DANGEROUS_CHAR_FIRST_INDEX); 610 } 611 static int indexOfDangerousChar(String s, int from) { 612 for (int i = from, slen = s.length(); i < slen; i++) { 613 if (isDangerous(s.charAt(i))) 614 return i; 615 } 616 return -1; 617 } 618 static int lastIndexOfDangerousChar(String s, int from) { 619 for (int i = Math.min(from, s.length()-1); i >= 0; i--) { 620 if (isDangerous(s.charAt(i))) 621 return i; 622 } 623 return -1; 624 } 625 626 627 }