This is a dump from Google's source control system of the change
that removed UCS-2 support from RE2. As the explanation below
says, UCS-2 mode is fundamentally at odds with things like ^ and $,
so it never really worked very well. But if you are interested in using
it without those operators, it did work for that. It assumed that the
UCS-2 data was in the native host byte order.
If you are interested in adding UCS-2 mode back, this patch might
be a good starting point.
Change 12780686 by rsc@rsc-re2 on 2009/09/16 15:30:15
Retire UCS-2 mode.
I added it as an experiment for V8, but it
requires 2-byte lookahead to do completely,
and RE2 has 1-byte lookahead (enough for UTF-8)
as a fairly deep fundamental assumption,
so it did not support ^ or $.
==== re2/bitstate.cc#2 - re2/bitstate.cc#3 ====
re2/bitstate.cc#2:314,321 - re2/bitstate.cc#3:314,319
cap_[0] = p;
if (TrySearch(prog_->start(), p)) // Match must be leftmost; done.
return true;
- if (prog_->flags() & Regexp::UCS2)
- p++;
}
return false;
}
==== re2/compile.cc#17 - re2/compile.cc#18 ====
re2/compile.cc#17:95,101 - re2/compile.cc#18:95,100
// Input encodings.
enum Encoding {
kEncodingUTF8 = 1, // UTF-8 (0-10FFFF)
- kEncodingUCS2, // UCS-2 (0-FFFF), native byte order
kEncodingLatin1, // Latin1 (0-FF)
};
re2/compile.cc#17:168,176 - re2/compile.cc#18:167,172
void AddRuneRangeLatin1(Rune lo, Rune hi, bool foldcase);
void AddRuneRangeUTF8(Rune lo, Rune hi, bool foldcase);
void Add_80_10ffff();
- void AddRuneRangeUCS2(Rune lo, Rune hi, bool foldcase);
- void AddUCS2Pair(uint8 lo1, uint8 hi1, bool fold1,
- uint8 lo2, uint8 hi2, bool fold2);
// New suffix that matches the byte range lo-hi, then goes to next.
Inst* RuneByteSuffix(uint8 lo, uint8 hi, bool foldcase, Inst* next);
re2/compile.cc#17:475,481 - re2/compile.cc#18:471,477
// Converts rune range lo-hi into a fragment that recognizes
// the bytes that would make up those runes in the current
- // encoding (Latin 1, UTF-8, or UCS-2).
+ // encoding (Latin 1 or UTF-8).
// This lets the machine work byte-by-byte even when
// using multibyte encodings.
re2/compile.cc#17:488,496 - re2/compile.cc#18:484,489
case kEncodingLatin1:
AddRuneRangeLatin1(lo, hi, foldcase);
break;
- case kEncodingUCS2:
- AddRuneRangeUCS2(lo, hi, foldcase);
- break;
}
}
re2/compile.cc#17:503,581 - re2/compile.cc#18:496,501
AddSuffix(RuneByteSuffix(lo, hi, foldcase, NULL));
}
- // Test whether 16-bit values are big or little endian.
- static bool BigEndian() {
- union {
- char byte[2];
- int16 endian;
- } u;
-
- u.byte[0] = 1;
- u.byte[1] = 2;
- return u.endian == 0x0102;
- }
-
- void Compiler::AddUCS2Pair(uint8 lo1, uint8 hi1, bool fold1,
- uint8 lo2, uint8 hi2, bool fold2) {
- Inst* ip;
- if (reversed_) {
- ip = RuneByteSuffix(lo1, hi1, fold1, NULL);
- ip = RuneByteSuffix(lo2, hi2, fold2, ip);
- } else {
- ip = RuneByteSuffix(lo2, hi2, fold2, NULL);
- ip = RuneByteSuffix(lo1, hi1, fold1, ip);
- }
- AddSuffix(ip);
- }
-
- void Compiler::AddRuneRangeUCS2(Rune lo, Rune hi, bool foldcase) {
- if (lo > hi || lo > 0xFFFF)
- return;
- if (hi > 0xFFFF)
- hi = 0xFFFF;
-
- // We'll assemble a pattern assuming big endian.
- // If the machine isn't, tell Cat to reverse its arguments.
- bool oldreversed = reversed_;
- if (!BigEndian()) {
- reversed_ = !oldreversed;
- }
-
- // Split into bytes.
- int lo1 = lo >> 8;
- int lo2 = lo & 0xFF;
- int hi1 = hi >> 8;
- int hi2 = hi & 0xFF;
-
- if (lo1 == hi1) {
- // Easy case: high bits are same in both.
- // Only do ASCII case folding on the second byte if the top byte is 00.
- AddUCS2Pair(lo1, lo1, false, lo2, hi2, lo1==0 && foldcase);
- } else {
- // Harder case: different second byte ranges depending on first byte.
-
- // Initial fragment.
- if (lo2 > 0) {
- AddUCS2Pair(lo1, lo1, false, lo2, 0xFF, lo1==0 && foldcase);
- lo1++;
- }
-
- // Trailing fragment.
- if (hi2 < 0xFF) {
- AddUCS2Pair(hi1, hi1, false, 0, hi2, false);
- hi1--;
- }
-
- // Inner ranges.
- if (lo1 <= hi1) {
- AddUCS2Pair(lo1, hi1, false, 0, 0xFF, false);
- }
- }
-
- // Restore reverse setting.
- reversed_ = oldreversed;
- }
-
// Table describing how to make a UTF-8 matching machine
// for the rune range 80-10FFFF (Runeself-Runemax).
// This range happens frequently enough (for example /./ and /[^a-z]/)
re2/compile.cc#17:707,716 - re2/compile.cc#18:627,634
Frag Compiler::Literal(Rune r, bool foldcase) {
switch (encoding_) {
- default: // UCS-2 or something new
- BeginRange();
- AddRuneRange(r, r, foldcase);
- return EndRange();
+ default:
+ return kNullFrag;
case kEncodingLatin1:
return ByteRange(r, r, foldcase);
re2/compile.cc#17:927,934 - re2/compile.cc#18:845,850
if (re->parse_flags() & Regexp::Latin1)
c.encoding_ = kEncodingLatin1;
- else if (re->parse_flags() & Regexp::UCS2)
- c.encoding_ = kEncodingUCS2;
c.reversed_ = reversed;
if (max_mem <= 0) {
c.max_inst_ = 100000; // more than enough
re2/compile.cc#17:983,993 - re2/compile.cc#18:899,905
c.prog_->set_start_unanchored(c.prog_->start());
} else {
Frag dot;
- if (c.encoding_ == kEncodingUCS2) {
- dot = c.Cat(c.ByteRange(0x00, 0xFF, false), c.ByteRange(0x00, 0xFF, false));
- } else {
- dot = c.ByteRange(0x00, 0xFF, false);
- }
+ dot = c.ByteRange(0x00, 0xFF, false);
Frag dotloop = c.Star(dot, true);
Frag unanchored = c.Cat(dotloop, all);
c.prog_->set_start_unanchored(unanchored.begin);
==== re2/nfa.cc#8 - re2/nfa.cc#9 ====
re2/nfa.cc#8:426,432 - re2/nfa.cc#9:426,431
const char* bp = context.begin();
int c = -1;
int wasword = 0;
- bool ucs2 = prog_->flags() & Regexp::UCS2;
if (text.begin() > context.begin()) {
c = text.begin()[-1] & 0xFF;
re2/nfa.cc#8:492,498 - re2/nfa.cc#9:491,497
// If there's a required first byte for an unanchored search
// and we're not in the middle of any possible matches,
// use memchr to search for the byte quickly.
- if (!ucs2 && !anchored && first_byte_ >= 0 && runq->size() == 0 &&
+ if (!anchored && first_byte_ >= 0 && runq->size() == 0 &&
p < text.end() && (p[0] & 0xFF) != first_byte_) {
p = reinterpret_cast<const char*>(memchr(p, first_byte_,
text.end() - p));
re2/nfa.cc#8:505,526 - re2/nfa.cc#9:504,514
flag = Prog::EmptyFlags(context, p);
}
- // In UCS-2 mode, if we need to start a new thread,
- // make sure to do it on an even boundary.
- if(ucs2 && runq->size() == 0 &&
- (p - context.begin()) % 2 && p < text.end()) {
- p++;
- flag = Prog::EmptyFlags(context, p);
- }
-
// Steal match storage (cleared but unused as of yet)
// temporarily to hold match boundaries for new thread.
- // In UCS-2 mode, only start the thread on a 2-byte boundary.
- if(!ucs2 || (p - context.begin()) % 2 == 0) {
- match_[0] = p;
- AddToThreadq(runq, start_, flag, p, match_);
- match_[0] = NULL;
- }
+ match_[0] = p;
+ AddToThreadq(runq, start_, flag, p, match_);
+ match_[0] = NULL;
}
// If all the threads have died, stop early.
==== re2/parse.cc#22 - re2/parse.cc#23 ====
re2/parse.cc#22:160,167 - re2/parse.cc#23:160,165
status_(status), stacktop_(NULL), ncap_(0) {
if (flags_ & Latin1)
rune_max_ = 0xFF;
- else if (flags & UCS2)
- rune_max_ = 0xFFFF;
else
rune_max_ = Runemax;
}
re2/parse.cc#22:365,387 - re2/parse.cc#23:363,374
bool Regexp::ParseState::PushCarat() {
if (flags_ & OneLine) {
return PushSimpleOp(kRegexpBeginText);
- } else {
- if (flags_ & UCS2) {
- status_->set_code(kRegexpUnsupported);
- status_->set_error_arg("multiline ^ in UCS-2 mode");
- return false;
- }
- return PushSimpleOp(kRegexpBeginLine);
}
+ return PushSimpleOp(kRegexpBeginLine);
}
// Pushes a \b or \B onto the stack.
bool Regexp::ParseState::PushWordBoundary(bool word) {
- if (flags_ & UCS2) {
- status_->set_code(kRegexpUnsupported);
- status_->set_error_arg("\\b or \\B in UCS-2 mode");
- return false;
- }
if (word)
return PushSimpleOp(kRegexpWordBoundary);
return PushSimpleOp(kRegexpNoWordBoundary);
re2/parse.cc#22:397,407 - re2/parse.cc#23:384,389
bool ret = PushSimpleOp(kRegexpEndText);
flags_ = oflags;
return ret;
- }
- if (flags_ & UCS2) {
- status_->set_code(kRegexpUnsupported);
- status_->set_error_arg("multiline $ in UCS-2 mode");
- return false;
}
return PushSimpleOp(kRegexpEndLine);
}
==== re2/re2.cc#34 - re2/re2.cc#35 ====
re2/re2.cc#34:79,86 - re2/re2.cc#35:79,84
return RE2::ErrorBadUTF8;
case re2::kRegexpBadNamedCapture:
return RE2::ErrorBadNamedCapture;
- case re2::kRegexpUnsupported:
- return RE2::ErrorUnsupported;
}
return RE2::ErrorInternal;
}
re2/re2.cc#34:122,130 - re2/re2.cc#35:120,125
break;
case RE2::Options::EncodingLatin1:
flags |= Regexp::Latin1;
- break;
- case RE2::Options::EncodingUCS2:
- flags |= Regexp::UCS2;
break;
}
==== re2/re2.h#36 - re2/re2.h#37 ====
re2/re2.h#36:246,252 - re2/re2.h#37:246,251
ErrorBadUTF8, // invalid UTF-8 in regexp
ErrorBadNamedCapture, // bad named capture group
ErrorPatternTooLarge, // pattern too large (compile failed)
- ErrorUnsupported, // unsupported feature (in UCS-2 mode)
};
// Predefined common options.
re2/re2.h#36:570,576 - re2/re2.h#37:569,574
enum Encoding {
EncodingUTF8 = 1,
- EncodingUCS2, // 16-bit Unicode 0-FFFF only
EncodingLatin1
};
==== re2/regexp.cc#15 - re2/regexp.cc#16 ====
re2/regexp.cc#15:324,333 - re2/regexp.cc#16:324,329
// the regexp that remains after the prefix. The prefix might
// be ASCII case-insensitive.
bool Regexp::RequiredPrefix(string *prefix, bool *foldcase, Regexp** suffix) {
- // Don't even bother for UCS-2; it's time to throw that code away.
- if (parse_flags_ & UCS2)
- return false;
-
// No need for a walker: the regexp must be of the form
// 1. some number of ^ anchors
// 2. a literal char or string
==== re2/regexp.h#20 - re2/regexp.h#21 ====
re2/regexp.h#20:187,193 - re2/regexp.h#21:187,192
kRegexpBadPerlOp, // bad perl operator
kRegexpBadUTF8, // invalid UTF-8 in regexp
kRegexpBadNamedCapture, // bad named capture
- kRegexpUnsupported, // unsupported operator
};
// Error status for certain operations.
re2/regexp.h#20:307,316 - re2/regexp.h#21:306,314
// \Q and \E to disable/enable metacharacters
// (?P<name>expr) for named captures
// \C to match any single byte
- UCS2 = 1<<10, // Text is in UCS-2, regexp is in UTF-8.
- UnicodeGroups = 1<<11, // Allow \p{Han} for Unicode Han group
+ UnicodeGroups = 1<<10, // Allow \p{Han} for Unicode Han group
// and \P{Han} for its negation.
- NeverNL = 1<<12, // Never match NL, even if the regexp mentions
+ NeverNL = 1<<11, // Never match NL, even if the regexp mentions
// it explicitly.
// As close to Perl as we can get.
==== re2/testing/backtrack.cc#4 - re2/testing/backtrack.cc#5 ====
re2/testing/backtrack.cc#4:134,141 - re2/testing/backtrack.cc#5:134,139
cap_[0] = p;
if (Visit(prog_->start(), p)) // Match must be leftmost; done.
return true;
- if (prog_->flags() & Regexp::UCS2)
- p++;
}
return false;
}
==== re2/testing/tester.cc#12 - re2/testing/tester.cc#13 ====
re2/testing/tester.cc#12:144,154 - re2/testing/tester.cc#13:144,152
static ParseMode parse_modes[] = {
{ single_line, "single-line" },
{ single_line|Regexp::Latin1, "single-line, latin1" },
- { single_line|Regexp::UCS2, "single-line, ucs2" },
{ multi_line, "multiline" },
{ multi_line|Regexp::NonGreedy, "multiline, nongreedy" },
{ multi_line|Regexp::Latin1, "multiline, latin1" },
- { multi_line|Regexp::UCS2, "multiline, ucs2" },
};
static string FormatMode(Regexp::ParseFlags flags) {
re2/testing/tester.cc#12:179,189 - re2/testing/tester.cc#13:177,185
RegexpStatus status;
regexp_ = Regexp::Parse(regexp_str, flags, &status);
if (regexp_ == NULL) {
- if (status.code() != kRegexpUnsupported) {
- LOG(INFO) << "Cannot parse: " << CEscape(regexp_str_)
- << " mode: " << FormatMode(flags);
- error_ = true;
- }
+ LOG(INFO) << "Cannot parse: " << CEscape(regexp_str_)
+ << " mode: " << FormatMode(flags);
+ error_ = true;
return;
}
prog_ = regexp_->CompileToProg(0);
re2/testing/tester.cc#12:230,237 - re2/testing/tester.cc#13:226,231
RE2::Options options;
if (flags & Regexp::Latin1)
options.set_encoding(RE2::Options::EncodingLatin1);
- else if (flags & Regexp::UCS2)
- options.set_encoding(RE2::Options::EncodingUCS2);
if (kind_ == Prog::kLongestMatch)
options.set_longest_match(true);
re2_ = new RE2(re, options);
re2/testing/tester.cc#12:281,379 - re2/testing/tester.cc#13:275,280
delete re2_;
}
- // Converts UTF-8 string in text into UCS-2 string in new_text.
- static bool ConvertUTF8ToUCS2(const StringPiece& text, StringPiece* new_text) {
- const char* p = text.begin();
- const char* ep = text.end();
- uint16* q = new uint16[ep - p];
- uint16* q0 = q;
-
- int n;
- Rune r;
- for (; p < ep; p += n) {
- if (!fullrune(p, ep - p)) {
- delete[] q0;
- return false;
- }
- n = chartorune(&r, p);
- if (r > 0xFFFF) {
- delete[] q0;
- return false;
- }
- *q++ = r;
- }
- *new_text = StringPiece(reinterpret_cast<char*>(q0), 2*(q - q0));
- return true;
- }
-
- // Rewrites *sp from being a pointer into text8 (UTF-8)
- // to being a pointer into text16 (equivalent text but in UCS-2).
- static void AdjustUTF8ToUCS2(const StringPiece& text8, const StringPiece& text16,
- StringPiece *sp) {
- if (sp->begin() == NULL && text8.begin() != NULL)
- return;
-
- int nrune = 0;
- int n;
- Rune r;
- const char* p = text8.begin();
- const char* ep = text8.end();
- const char* spbegin = NULL;
- const char* spend = NULL;
- for (;;) {
- if (p == sp->begin())
- spbegin = text16.begin() + sizeof(uint16)*nrune;
- if (p == sp->end())
- spend = text16.begin() + sizeof(uint16)*nrune;
- if (p >= ep)
- break;
- n = chartorune(&r, p);
- p += n;
- nrune++;
- }
- if (spbegin == NULL || spend == NULL) {
- LOG(FATAL) << "Error in AdjustUTF8ToUCS2 "
- << CEscape(text8) << " "
- << (int)(sp->begin() - text8.begin()) << " "
- << (int)(sp->end() - text8.begin());
- }
- *sp = StringPiece(spbegin, spend - spbegin);
- }
-
- // Rewrites *sp from begin a pointer into text16 (UCS-2)
- // to being a pointer into text8 (equivalent text but in UTF-8).
- static void AdjustUCS2ToUTF8(const StringPiece& text16, const StringPiece& text8,
- StringPiece* sp) {
- if (sp->begin() == NULL)
- return;
-
- int nrune = 0;
- int n;
- Rune r;
- const char* p = text8.begin();
- const char* ep = text8.end();
- const char* spbegin = NULL;
- const char* spend = NULL;
- for (;;) {
- if (nrune == (sp->begin() - text16.begin())/2)
- spbegin = p;
- if (nrune == (sp->end() - text16.begin())/2)
- spend = p;
- if (p >= ep)
- break;
- n = chartorune(&r, p);
- p += n;
- nrune++;
- }
- if (text8.begin() != NULL && (spbegin == NULL || spend == NULL)) {
- LOG(FATAL) << "Error in AdjustUCS2ToUTF8 "
- << CEscape(text16) << " "
- << (int)(sp->begin() - text16.begin()) << " "
- << (int)(sp->end() - text16.begin());
- }
- *sp = StringPiece(spbegin, spend - spbegin);
- }
-
// Runs a single search using the named engine type.
// This interface hides all the irregularities of the various
// engine interfaces from the rest of this file.
re2/testing/tester.cc#12:393,411 - re2/testing/tester.cc#13:294,300
StringPiece text = orig_text;
StringPiece context = orig_context;
- bool ucs2 = false;
- if ((flags() & Regexp::UCS2) && type != kEnginePCRE) {
- if (!ConvertUTF8ToUCS2(orig_context, &context)) {
- result->skipped = true;
- return;
- }
-
- // Rewrite context to refer to new text.
- AdjustUTF8ToUCS2(orig_context, context, &text);
- ucs2 = true;
- }
-
switch (type) {
default:
LOG(FATAL) << "Bad RunSearch type: " << (int)type;
re2/testing/tester.cc#12:557,577 - re2/testing/tester.cc#13:446,451
}
}
- // If we did UCS-2 matching, rewrite the matches to refer
- // to the original UTF-8 text.
- if (ucs2) {
- if (result->matched) {
- if (result->have_submatch0) {
- AdjustUCS2ToUTF8(context, orig_context, &result->submatch[0]);
- } else if (result->have_submatch) {
- for (int i = 0; i < nsubmatch; i++) {
- AdjustUCS2ToUTF8(context, orig_context, &result->submatch[i]);
- }
- }
- }
- delete[] context.begin();
- }
-
if (!result->matched)
memset(result->submatch, 0, sizeof result->submatch);
}
re2/testing/tester.cc#12:596,617 - re2/testing/tester.cc#13:470,475
return true;
}
- // Check whether text uses only Unicode points <= 0xFFFF
- // (in the BMP).
- static bool IsBMP(const StringPiece& text) {
- const char* p = text.begin();
- const char* ep = text.end();
- while (p < ep) {
- if (!fullrune(p, ep - p))
- return false;
- Rune r;
- p += chartorune(&r, p);
- if (r > 0xFFFF)
- return false;
- }
- return true;
- }
-
// Runs a single test.
bool TestInstance::RunCase(const StringPiece& text, const StringPiece& context,
Prog::Anchor anchor) {
re2/testing/tester.cc#12:619,625 - re2/testing/tester.cc#13:477,483
Result correct;
RunSearch(kEngineBacktrack, text, context, anchor, &correct);
if (correct.skipped) {
- if (regexp_ == NULL || !IsBMP(context)) // okay to skip in UCS-2 mode
+ if (regexp_ == NULL)
return true;
LOG(ERROR) << "Skipped backtracking! " << CEscape(regexp_str_)
<< " " << FormatMode(flags_);