tor-browser

util_props.cpp (7054B)

---

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
**********************************************************************
*   Copyright (c) 2001-2016, International Business Machines
*   Corporation and others.  All Rights Reserved.
**********************************************************************
*   Date        Name        Description
*   11/19/2001  aliu        Creation.
**********************************************************************
*/

#include "unicode/uchar.h"
#include "unicode/utf16.h"
#include "patternprops.h"
#include "util.h"

U_NAMESPACE_BEGIN

/**
* Parse an integer at pos, either of the form \d+ or of the form
* 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
* or octal format.
* @param pos INPUT-OUTPUT parameter.  On input, the first
* character to parse.  On output, the character after the last
* parsed character.
*/
int32_t ICU_Utility::parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit) {
   int32_t count = 0;
   int32_t value = 0;
   int32_t p = pos;
   int8_t radix = 10;

   if (p < limit && rule.charAt(p) == 48 /*0*/) {
       if (p+1 < limit && (rule.charAt(p+1) == 0x78 /*x*/ || rule.charAt(p+1) == 0x58 /*X*/)) {
           p += 2;
           radix = 16;
       }
       else {
           p++;
           count = 1;
           radix = 8;
       }
   }

   while (p < limit) {
       int32_t d = u_digit(rule.charAt(p++), radix);
       if (d < 0) {
           --p;
           break;
       }
       ++count;
       int32_t v = (value * radix) + d;
       if (v <= value) {
           // If there are too many input digits, at some point
           // the value will go negative, e.g., if we have seen
           // "0x8000000" already and there is another '0', when
           // we parse the next 0 the value will go negative.
           return 0;
       }
       value = v;
   }
   if (count > 0) {
       pos = p;
   }
   return value;
}

/**
* Parse a pattern string starting at offset pos.  Keywords are
* matched case-insensitively.  Spaces may be skipped and may be
* optional or required.  Integer values may be parsed, and if
* they are, they will be returned in the given array.  If
* successful, the offset of the next non-space character is
* returned.  On failure, -1 is returned.
* @param pattern must only contain lowercase characters, which
* will match their uppercase equivalents as well.  A space
* character matches one or more required spaces.  A '~' character
* matches zero or more optional spaces.  A '#' character matches
* an integer and stores it in parsedInts, which the caller must
* ensure has enough capacity.
* @param parsedInts array to receive parsed integers.  Caller
* must ensure that parsedInts.length is >= the number of '#'
* signs in 'pattern'.
* @return the position after the last character parsed, or -1 if
* the parse failed
*/
int32_t ICU_Utility::parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
                             const UnicodeString& pattern, int32_t* parsedInts) {
   // TODO Update this to handle surrogates
   int32_t p;
   int32_t intCount = 0; // number of integers parsed
   for (int32_t i=0; i<pattern.length(); ++i) {
       char16_t cpat = pattern.charAt(i);
       char16_t c;
       switch (cpat) {
       case 32 /*' '*/:
           if (pos >= limit) {
               return -1;
           }
           c = rule.charAt(pos++);
           if (!PatternProps::isWhiteSpace(c)) {
               return -1;
           }
           // FALL THROUGH to skipWhitespace
           U_FALLTHROUGH;
       case 126 /*'~'*/:
           pos = skipWhitespace(rule, pos);
           break;
       case 35 /*'#'*/:
           p = pos;
           parsedInts[intCount++] = parseInteger(rule, p, limit);
           if (p == pos) {
               // Syntax error; failed to parse integer
               return -1;
           }
           pos = p;
           break;
       default:
           if (pos >= limit) {
               return -1;
           }
           c = static_cast<char16_t>(u_tolower(rule.charAt(pos++)));
           if (c != cpat) {
               return -1;
           }
           break;
       }
   }
   return pos;
}

/**
* Parse a Unicode identifier from the given string at the given
* position.  Return the identifier, or an empty string if there
* is no identifier.
* @param str the string to parse
* @param pos INPUT-OUTPUT parameter.  On INPUT, pos is the
* first character to examine.  It must be less than str.length(),
* and it must not point to a whitespace character.  That is, must
* have pos < str.length().  On
* OUTPUT, the position after the last parsed character.
* @return the Unicode identifier, or an empty string if there is
* no valid identifier at pos.
*/
UnicodeString ICU_Utility::parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos) {
   // assert(pos < str.length());
   UnicodeString buf;
   int p = pos;
   while (p < str.length()) {
       UChar32 ch = str.char32At(p);
       if (buf.length() == 0) {
           if (u_isIDStart(ch)) {
               buf.append(ch);
           } else {
               buf.truncate(0);
               return buf;
           }
       } else {
           if (u_isIDPart(ch)) {
               buf.append(ch);
           } else {
               break;
           }
       }
       p += U16_LENGTH(ch);
   }
   pos = p;
   return buf;
}

/**
* Parse an unsigned 31-bit integer at the given offset.  Use
* UCharacter.digit() to parse individual characters into digits.
* @param text the text to be parsed
* @param pos INPUT-OUTPUT parameter.  On entry, pos[0] is the
* offset within text at which to start parsing; it should point
* to a valid digit.  On exit, pos[0] is the offset after the last
* parsed character.  If the parse failed, it will be unchanged on
* exit.  Must be >= 0 on entry.
* @param radix the radix in which to parse; must be >= 2 and <=
* 36.
* @return a non-negative parsed number, or -1 upon parse failure.
* Parse fails if there are no digits, that is, if pos[0] does not
* point to a valid digit on entry, or if the number to be parsed
* does not fit into a 31-bit unsigned integer.
*/
int32_t ICU_Utility::parseNumber(const UnicodeString& text,
                                int32_t& pos, int8_t radix) {
   // assert(pos[0] >= 0);
   // assert(radix >= 2);
   // assert(radix <= 36);
   int32_t n = 0;
   int32_t p = pos;
   while (p < text.length()) {
       UChar32 ch = text.char32At(p);
       int32_t d = u_digit(ch, radix);
       if (d < 0) {
           break;
       }
       int64_t update = radix*static_cast<int64_t>(n) + d;
       if (update > INT32_MAX) {
           return -1;
       }
       n = static_cast<int32_t>(update);
       ++p;
   }
   if (p == pos) {
       return -1;
   }
   pos = p;
   return n;
}

U_NAMESPACE_END