mirror of
https://github.com/ClickHouse/ClickHouse.git
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1141 lines
32 KiB
C++
1141 lines
32 KiB
C++
// Copyright 2007 The RE2 Authors. All Rights Reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Compile regular expression to Prog.
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//
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// Prog and Inst are defined in prog.h.
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// This file's external interface is just Regexp::CompileToProg.
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// The Compiler class defined in this file is private.
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#include "re2/prog.h"
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#include "re2/re2.h"
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#include "re2/regexp.h"
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#include "re2/walker-inl.h"
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namespace re2 {
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// List of pointers to Inst* that need to be filled in (patched).
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// Because the Inst* haven't been filled in yet,
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// we can use the Inst* word to hold the list's "next" pointer.
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// It's kind of sleazy, but it works well in practice.
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// See http://swtch.com/~rsc/regexp/regexp1.html for inspiration.
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//
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// Because the out and out1 fields in Inst are no longer pointers,
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// we can't use pointers directly here either. Instead, p refers
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// to inst_[p>>1].out (p&1 == 0) or inst_[p>>1].out1 (p&1 == 1).
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// p == 0 represents the NULL list. This is okay because instruction #0
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// is always the fail instruction, which never appears on a list.
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struct PatchList {
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uint32 p;
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// Returns patch list containing just p.
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static PatchList Mk(uint32 p);
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// Patches all the entries on l to have value v.
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// Caller must not ever use patch list again.
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static void Patch(Prog::Inst *inst0, PatchList l, uint32 v);
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// Deref returns the next pointer pointed at by p.
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static PatchList Deref(Prog::Inst *inst0, PatchList l);
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// Appends two patch lists and returns result.
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static PatchList Append(Prog::Inst *inst0, PatchList l1, PatchList l2);
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};
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static PatchList nullPatchList = { 0 };
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// Returns patch list containing just p.
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PatchList PatchList::Mk(uint32 p) {
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PatchList l;
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l.p = p;
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return l;
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}
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// Returns the next pointer pointed at by l.
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PatchList PatchList::Deref(Prog::Inst* inst0, PatchList l) {
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Prog::Inst* ip = &inst0[l.p>>1];
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if (l.p&1)
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l.p = ip->out1();
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else
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l.p = ip->out();
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return l;
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}
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// Patches all the entries on l to have value v.
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void PatchList::Patch(Prog::Inst *inst0, PatchList l, uint32 val) {
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while (l.p != 0) {
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Prog::Inst* ip = &inst0[l.p>>1];
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if (l.p&1) {
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l.p = ip->out1();
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ip->out1_ = val;
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} else {
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l.p = ip->out();
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ip->set_out(val);
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}
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}
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}
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// Appends two patch lists and returns result.
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PatchList PatchList::Append(Prog::Inst* inst0, PatchList l1, PatchList l2) {
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if (l1.p == 0)
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return l2;
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if (l2.p == 0)
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return l1;
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PatchList l = l1;
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for (;;) {
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PatchList next = PatchList::Deref(inst0, l);
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if (next.p == 0)
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break;
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l = next;
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}
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Prog::Inst* ip = &inst0[l.p>>1];
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if (l.p&1)
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ip->out1_ = l2.p;
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else
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ip->set_out(l2.p);
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return l1;
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}
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// Compiled program fragment.
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struct Frag {
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uint32 begin;
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PatchList end;
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Frag() : begin(0) { end.p = 0; } // needed so Frag can go in vector
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Frag(uint32 begin, PatchList end) : begin(begin), end(end) {}
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};
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// Input encodings.
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enum Encoding {
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kEncodingUTF8 = 1, // UTF-8 (0-10FFFF)
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kEncodingLatin1, // Latin1 (0-FF)
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};
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class Compiler : public Regexp::Walker<Frag> {
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public:
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explicit Compiler();
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~Compiler();
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// Compiles Regexp to a new Prog.
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// Caller is responsible for deleting Prog when finished with it.
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// If reversed is true, compiles for walking over the input
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// string backward (reverses all concatenations).
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static Prog *Compile(Regexp* re, bool reversed, int64 max_mem);
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// Compiles alternation of all the re to a new Prog.
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// Each re has a match with an id equal to its index in the vector.
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static Prog* CompileSet(const RE2::Options& options, RE2::Anchor anchor,
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Regexp* re);
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// Interface for Regexp::Walker, which helps traverse the Regexp.
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// The walk is purely post-recursive: given the machines for the
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// children, PostVisit combines them to create the machine for
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// the current node. The child_args are Frags.
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// The Compiler traverses the Regexp parse tree, visiting
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// each node in depth-first order. It invokes PreVisit before
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// visiting the node's children and PostVisit after visiting
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// the children.
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Frag PreVisit(Regexp* re, Frag parent_arg, bool* stop);
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Frag PostVisit(Regexp* re, Frag parent_arg, Frag pre_arg, Frag* child_args,
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int nchild_args);
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Frag ShortVisit(Regexp* re, Frag parent_arg);
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Frag Copy(Frag arg);
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// Given fragment a, returns a+ or a+?; a* or a*?; a? or a??
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Frag Plus(Frag a, bool nongreedy);
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Frag Star(Frag a, bool nongreedy);
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Frag Quest(Frag a, bool nongreedy);
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// Given fragment a, returns (a) capturing as \n.
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Frag Capture(Frag a, int n);
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// Given fragments a and b, returns ab; a|b
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Frag Cat(Frag a, Frag b);
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Frag Alt(Frag a, Frag b);
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// Returns a fragment that can't match anything.
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Frag NoMatch();
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// Returns a fragment that matches the empty string.
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Frag Match(int32 id);
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// Returns a no-op fragment.
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Frag Nop();
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// Returns a fragment matching the byte range lo-hi.
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Frag ByteRange(int lo, int hi, bool foldcase);
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// Returns a fragment matching an empty-width special op.
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Frag EmptyWidth(EmptyOp op);
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// Adds n instructions to the program.
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// Returns the index of the first one.
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// Returns -1 if no more instructions are available.
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int AllocInst(int n);
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// Deletes unused instructions.
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void Trim();
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// Rune range compiler.
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// Begins a new alternation.
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void BeginRange();
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// Adds a fragment matching the rune range lo-hi.
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void AddRuneRange(Rune lo, Rune hi, bool foldcase);
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void AddRuneRangeLatin1(Rune lo, Rune hi, bool foldcase);
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void AddRuneRangeUTF8(Rune lo, Rune hi, bool foldcase);
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void Add_80_10ffff();
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// New suffix that matches the byte range lo-hi, then goes to next.
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int RuneByteSuffix(uint8 lo, uint8 hi, bool foldcase, int next);
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int UncachedRuneByteSuffix(uint8 lo, uint8 hi, bool foldcase, int next);
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// Adds a suffix to alternation.
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void AddSuffix(int id);
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// Returns the alternation of all the added suffixes.
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Frag EndRange();
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// Single rune.
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Frag Literal(Rune r, bool foldcase);
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void Setup(Regexp::ParseFlags, int64, RE2::Anchor);
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Prog* Finish();
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// Returns .* where dot = any byte
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Frag DotStar();
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private:
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Prog* prog_; // Program being built.
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bool failed_; // Did we give up compiling?
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Encoding encoding_; // Input encoding
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bool reversed_; // Should program run backward over text?
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int max_inst_; // Maximum number of instructions.
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Prog::Inst* inst_; // Pointer to first instruction.
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int inst_len_; // Number of instructions used.
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int inst_cap_; // Number of instructions allocated.
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int64 max_mem_; // Total memory budget.
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map<uint64, int> rune_cache_;
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Frag rune_range_;
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RE2::Anchor anchor_; // anchor mode for RE2::Set
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DISALLOW_EVIL_CONSTRUCTORS(Compiler);
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};
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Compiler::Compiler() {
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prog_ = new Prog();
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failed_ = false;
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encoding_ = kEncodingUTF8;
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reversed_ = false;
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inst_ = NULL;
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inst_len_ = 0;
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inst_cap_ = 0;
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max_inst_ = 1; // make AllocInst for fail instruction okay
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max_mem_ = 0;
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int fail = AllocInst(1);
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inst_[fail].InitFail();
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max_inst_ = 0; // Caller must change
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}
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Compiler::~Compiler() {
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delete prog_;
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delete[] inst_;
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}
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int Compiler::AllocInst(int n) {
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if (failed_ || inst_len_ + n > max_inst_) {
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failed_ = true;
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return -1;
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}
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if (inst_len_ + n > inst_cap_) {
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if (inst_cap_ == 0)
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inst_cap_ = 8;
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while (inst_len_ + n > inst_cap_)
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inst_cap_ *= 2;
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Prog::Inst* ip = new Prog::Inst[inst_cap_];
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memmove(ip, inst_, inst_len_ * sizeof ip[0]);
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memset(ip + inst_len_, 0, (inst_cap_ - inst_len_) * sizeof ip[0]);
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delete[] inst_;
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inst_ = ip;
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}
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int id = inst_len_;
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inst_len_ += n;
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return id;
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}
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void Compiler::Trim() {
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if (inst_len_ < inst_cap_) {
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Prog::Inst* ip = new Prog::Inst[inst_len_];
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memmove(ip, inst_, inst_len_ * sizeof ip[0]);
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delete[] inst_;
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inst_ = ip;
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inst_cap_ = inst_len_;
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}
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}
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// These routines are somewhat hard to visualize in text --
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// see http://swtch.com/~rsc/regexp/regexp1.html for
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// pictures explaining what is going on here.
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// Returns an unmatchable fragment.
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Frag Compiler::NoMatch() {
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return Frag(0, nullPatchList);
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}
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// Is a an unmatchable fragment?
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static bool IsNoMatch(Frag a) {
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return a.begin == 0;
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}
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// Given fragments a and b, returns fragment for ab.
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Frag Compiler::Cat(Frag a, Frag b) {
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if (IsNoMatch(a) || IsNoMatch(b))
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return NoMatch();
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// Elide no-op.
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Prog::Inst* begin = &inst_[a.begin];
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if (begin->opcode() == kInstNop &&
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a.end.p == (a.begin << 1) &&
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begin->out() == 0) {
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PatchList::Patch(inst_, a.end, b.begin); // in case refs to a somewhere
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return b;
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}
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// To run backward over string, reverse all concatenations.
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if (reversed_) {
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PatchList::Patch(inst_, b.end, a.begin);
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return Frag(b.begin, a.end);
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}
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PatchList::Patch(inst_, a.end, b.begin);
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return Frag(a.begin, b.end);
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}
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// Given fragments for a and b, returns fragment for a|b.
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Frag Compiler::Alt(Frag a, Frag b) {
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// Special case for convenience in loops.
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if (IsNoMatch(a))
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return b;
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if (IsNoMatch(b))
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return a;
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int id = AllocInst(1);
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if (id < 0)
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return NoMatch();
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inst_[id].InitAlt(a.begin, b.begin);
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return Frag(id, PatchList::Append(inst_, a.end, b.end));
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}
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// When capturing submatches in like-Perl mode, a kOpAlt Inst
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// treats out_ as the first choice, out1_ as the second.
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//
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// For *, +, and ?, if out_ causes another repetition,
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// then the operator is greedy. If out1_ is the repetition
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// (and out_ moves forward), then the operator is non-greedy.
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// Given a fragment a, returns a fragment for a* or a*? (if nongreedy)
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Frag Compiler::Star(Frag a, bool nongreedy) {
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int id = AllocInst(1);
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if (id < 0)
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return NoMatch();
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inst_[id].InitAlt(0, 0);
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PatchList::Patch(inst_, a.end, id);
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if (nongreedy) {
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inst_[id].out1_ = a.begin;
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return Frag(id, PatchList::Mk(id << 1));
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} else {
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inst_[id].set_out(a.begin);
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return Frag(id, PatchList::Mk((id << 1) | 1));
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}
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}
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// Given a fragment for a, returns a fragment for a+ or a+? (if nongreedy)
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Frag Compiler::Plus(Frag a, bool nongreedy) {
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// a+ is just a* with a different entry point.
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Frag f = Star(a, nongreedy);
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return Frag(a.begin, f.end);
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}
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// Given a fragment for a, returns a fragment for a? or a?? (if nongreedy)
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Frag Compiler::Quest(Frag a, bool nongreedy) {
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if (IsNoMatch(a))
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return Nop();
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int id = AllocInst(1);
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if (id < 0)
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return NoMatch();
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PatchList pl;
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if (nongreedy) {
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inst_[id].InitAlt(0, a.begin);
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pl = PatchList::Mk(id << 1);
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} else {
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inst_[id].InitAlt(a.begin, 0);
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pl = PatchList::Mk((id << 1) | 1);
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}
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return Frag(id, PatchList::Append(inst_, pl, a.end));
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}
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// Returns a fragment for the byte range lo-hi.
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Frag Compiler::ByteRange(int lo, int hi, bool foldcase) {
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int id = AllocInst(1);
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if (id < 0)
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return NoMatch();
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inst_[id].InitByteRange(lo, hi, foldcase, 0);
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prog_->byte_inst_count_++;
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prog_->MarkByteRange(lo, hi);
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if (foldcase && lo <= 'z' && hi >= 'a') {
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if (lo < 'a')
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lo = 'a';
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if (hi > 'z')
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hi = 'z';
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if (lo <= hi)
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prog_->MarkByteRange(lo + 'A' - 'a', hi + 'A' - 'a');
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}
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return Frag(id, PatchList::Mk(id << 1));
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}
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// Returns a no-op fragment. Sometimes unavoidable.
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Frag Compiler::Nop() {
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int id = AllocInst(1);
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if (id < 0)
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return NoMatch();
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inst_[id].InitNop(0);
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return Frag(id, PatchList::Mk(id << 1));
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}
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// Returns a fragment that signals a match.
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Frag Compiler::Match(int32 match_id) {
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int id = AllocInst(1);
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if (id < 0)
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return NoMatch();
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inst_[id].InitMatch(match_id);
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return Frag(id, nullPatchList);
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}
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// Returns a fragment matching a particular empty-width op (like ^ or $)
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Frag Compiler::EmptyWidth(EmptyOp empty) {
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int id = AllocInst(1);
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if (id < 0)
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return NoMatch();
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inst_[id].InitEmptyWidth(empty, 0);
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if (empty & (kEmptyBeginLine|kEmptyEndLine))
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prog_->MarkByteRange('\n', '\n');
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if (empty & (kEmptyWordBoundary|kEmptyNonWordBoundary)) {
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int j;
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for (int i = 0; i < 256; i = j) {
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for (j = i+1; j < 256 && Prog::IsWordChar(i) == Prog::IsWordChar(j); j++)
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;
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prog_->MarkByteRange(i, j-1);
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}
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}
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return Frag(id, PatchList::Mk(id << 1));
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}
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// Given a fragment a, returns a fragment with capturing parens around a.
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Frag Compiler::Capture(Frag a, int n) {
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if (IsNoMatch(a))
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return NoMatch();
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int id = AllocInst(2);
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if (id < 0)
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return NoMatch();
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inst_[id].InitCapture(2*n, a.begin);
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inst_[id+1].InitCapture(2*n+1, 0);
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PatchList::Patch(inst_, a.end, id+1);
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return Frag(id, PatchList::Mk((id+1) << 1));
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}
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// A Rune is a name for a Unicode code point.
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// Returns maximum rune encoded by UTF-8 sequence of length len.
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static int MaxRune(int len) {
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int b; // number of Rune bits in len-byte UTF-8 sequence (len < UTFmax)
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if (len == 1)
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b = 7;
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else
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b = 8-(len+1) + 6*(len-1);
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return (1<<b) - 1; // maximum Rune for b bits.
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}
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// The rune range compiler caches common suffix fragments,
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// which are very common in UTF-8 (e.g., [80-bf]).
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// The fragment suffixes are identified by their start
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// instructions. NULL denotes the eventual end match.
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// The Frag accumulates in rune_range_. Caching common
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// suffixes reduces the UTF-8 "." from 32 to 24 instructions,
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// and it reduces the corresponding one-pass NFA from 16 nodes to 8.
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void Compiler::BeginRange() {
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rune_cache_.clear();
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rune_range_.begin = 0;
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rune_range_.end = nullPatchList;
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}
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int Compiler::UncachedRuneByteSuffix(uint8 lo, uint8 hi, bool foldcase,
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int next) {
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Frag f = ByteRange(lo, hi, foldcase);
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if (next != 0) {
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PatchList::Patch(inst_, f.end, next);
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} else {
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rune_range_.end = PatchList::Append(inst_, rune_range_.end, f.end);
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}
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return f.begin;
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}
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int Compiler::RuneByteSuffix(uint8 lo, uint8 hi, bool foldcase, int next) {
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// In Latin1 mode, there's no point in caching.
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// In forward UTF-8 mode, only need to cache continuation bytes.
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if (encoding_ == kEncodingLatin1 ||
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(encoding_ == kEncodingUTF8 &&
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!reversed_ &&
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!(0x80 <= lo && hi <= 0xbf))) {
|
|
return UncachedRuneByteSuffix(lo, hi, foldcase, next);
|
|
}
|
|
|
|
uint64 key = ((uint64)next << 17) | (lo<<9) | (hi<<1) | foldcase;
|
|
map<uint64, int>::iterator it = rune_cache_.find(key);
|
|
if (it != rune_cache_.end())
|
|
return it->second;
|
|
int id = UncachedRuneByteSuffix(lo, hi, foldcase, next);
|
|
rune_cache_[key] = id;
|
|
return id;
|
|
}
|
|
|
|
void Compiler::AddSuffix(int id) {
|
|
if (rune_range_.begin == 0) {
|
|
rune_range_.begin = id;
|
|
return;
|
|
}
|
|
|
|
int alt = AllocInst(1);
|
|
if (alt < 0) {
|
|
rune_range_.begin = 0;
|
|
return;
|
|
}
|
|
inst_[alt].InitAlt(rune_range_.begin, id);
|
|
rune_range_.begin = alt;
|
|
}
|
|
|
|
Frag Compiler::EndRange() {
|
|
return rune_range_;
|
|
}
|
|
|
|
// Converts rune range lo-hi into a fragment that recognizes
|
|
// the bytes that would make up those runes in the current
|
|
// encoding (Latin 1 or UTF-8).
|
|
// This lets the machine work byte-by-byte even when
|
|
// using multibyte encodings.
|
|
|
|
void Compiler::AddRuneRange(Rune lo, Rune hi, bool foldcase) {
|
|
switch (encoding_) {
|
|
default:
|
|
case kEncodingUTF8:
|
|
AddRuneRangeUTF8(lo, hi, foldcase);
|
|
break;
|
|
case kEncodingLatin1:
|
|
AddRuneRangeLatin1(lo, hi, foldcase);
|
|
break;
|
|
}
|
|
}
|
|
|
|
void Compiler::AddRuneRangeLatin1(Rune lo, Rune hi, bool foldcase) {
|
|
// Latin1 is easy: runes *are* bytes.
|
|
if (lo > hi || lo > 0xFF)
|
|
return;
|
|
if (hi > 0xFF)
|
|
hi = 0xFF;
|
|
AddSuffix(RuneByteSuffix(lo, hi, foldcase, 0));
|
|
}
|
|
|
|
// 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]/)
|
|
// and the rune_cache_ map is slow enough that this is worth
|
|
// special handling. Makes compilation of a small expression
|
|
// with a dot in it about 10% faster.
|
|
// The * in the comments below mark whole sequences.
|
|
static struct ByteRangeProg {
|
|
int next;
|
|
int lo;
|
|
int hi;
|
|
} prog_80_10ffff[] = {
|
|
// Two-byte
|
|
{ -1, 0x80, 0xBF, }, // 0: 80-BF
|
|
{ 0, 0xC2, 0xDF, }, // 1: C2-DF 80-BF*
|
|
|
|
// Three-byte
|
|
{ 0, 0xA0, 0xBF, }, // 2: A0-BF 80-BF
|
|
{ 2, 0xE0, 0xE0, }, // 3: E0 A0-BF 80-BF*
|
|
{ 0, 0x80, 0xBF, }, // 4: 80-BF 80-BF
|
|
{ 4, 0xE1, 0xEF, }, // 5: E1-EF 80-BF 80-BF*
|
|
|
|
// Four-byte
|
|
{ 4, 0x90, 0xBF, }, // 6: 90-BF 80-BF 80-BF
|
|
{ 6, 0xF0, 0xF0, }, // 7: F0 90-BF 80-BF 80-BF*
|
|
{ 4, 0x80, 0xBF, }, // 8: 80-BF 80-BF 80-BF
|
|
{ 8, 0xF1, 0xF3, }, // 9: F1-F3 80-BF 80-BF 80-BF*
|
|
{ 4, 0x80, 0x8F, }, // 10: 80-8F 80-BF 80-BF
|
|
{ 10, 0xF4, 0xF4, }, // 11: F4 80-8F 80-BF 80-BF*
|
|
};
|
|
|
|
void Compiler::Add_80_10ffff() {
|
|
int inst[arraysize(prog_80_10ffff)] = { 0 }; // does not need to be initialized; silences gcc warning
|
|
for (size_t i = 0; i < arraysize(prog_80_10ffff); i++) {
|
|
const ByteRangeProg& p = prog_80_10ffff[i];
|
|
int next = 0;
|
|
if (p.next >= 0)
|
|
next = inst[p.next];
|
|
inst[i] = UncachedRuneByteSuffix(p.lo, p.hi, false, next);
|
|
if ((p.lo & 0xC0) != 0x80)
|
|
AddSuffix(inst[i]);
|
|
}
|
|
}
|
|
|
|
void Compiler::AddRuneRangeUTF8(Rune lo, Rune hi, bool foldcase) {
|
|
if (lo > hi)
|
|
return;
|
|
|
|
// Pick off 80-10FFFF as a common special case
|
|
// that can bypass the slow rune_cache_.
|
|
if (lo == 0x80 && hi == 0x10ffff && !reversed_) {
|
|
Add_80_10ffff();
|
|
return;
|
|
}
|
|
|
|
// Split range into same-length sized ranges.
|
|
for (int i = 1; i < UTFmax; i++) {
|
|
Rune max = MaxRune(i);
|
|
if (lo <= max && max < hi) {
|
|
AddRuneRangeUTF8(lo, max, foldcase);
|
|
AddRuneRangeUTF8(max+1, hi, foldcase);
|
|
return;
|
|
}
|
|
}
|
|
|
|
// ASCII range is always a special case.
|
|
if (hi < Runeself) {
|
|
AddSuffix(RuneByteSuffix(lo, hi, foldcase, 0));
|
|
return;
|
|
}
|
|
|
|
// Split range into sections that agree on leading bytes.
|
|
for (int i = 1; i < UTFmax; i++) {
|
|
uint m = (1<<(6*i)) - 1; // last i bytes of a UTF-8 sequence
|
|
if ((lo & ~m) != (hi & ~m)) {
|
|
if ((lo & m) != 0) {
|
|
AddRuneRangeUTF8(lo, lo|m, foldcase);
|
|
AddRuneRangeUTF8((lo|m)+1, hi, foldcase);
|
|
return;
|
|
}
|
|
if ((hi & m) != m) {
|
|
AddRuneRangeUTF8(lo, (hi&~m)-1, foldcase);
|
|
AddRuneRangeUTF8(hi&~m, hi, foldcase);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Finally. Generate byte matching equivalent for lo-hi.
|
|
uint8 ulo[UTFmax], uhi[UTFmax];
|
|
int n = runetochar(reinterpret_cast<char*>(ulo), &lo);
|
|
int m = runetochar(reinterpret_cast<char*>(uhi), &hi);
|
|
(void)m; // USED(m)
|
|
DCHECK_EQ(n, m);
|
|
|
|
int id = 0;
|
|
if (reversed_) {
|
|
for (int i = 0; i < n; i++)
|
|
id = RuneByteSuffix(ulo[i], uhi[i], false, id);
|
|
} else {
|
|
for (int i = n-1; i >= 0; i--)
|
|
id = RuneByteSuffix(ulo[i], uhi[i], false, id);
|
|
}
|
|
AddSuffix(id);
|
|
}
|
|
|
|
// Should not be called.
|
|
Frag Compiler::Copy(Frag arg) {
|
|
// We're using WalkExponential; there should be no copying.
|
|
LOG(DFATAL) << "Compiler::Copy called!";
|
|
failed_ = true;
|
|
return NoMatch();
|
|
}
|
|
|
|
// Visits a node quickly; called once WalkExponential has
|
|
// decided to cut this walk short.
|
|
Frag Compiler::ShortVisit(Regexp* re, Frag) {
|
|
failed_ = true;
|
|
return NoMatch();
|
|
}
|
|
|
|
// Called before traversing a node's children during the walk.
|
|
Frag Compiler::PreVisit(Regexp* re, Frag, bool* stop) {
|
|
// Cut off walk if we've already failed.
|
|
if (failed_)
|
|
*stop = true;
|
|
|
|
return Frag(); // not used by caller
|
|
}
|
|
|
|
Frag Compiler::Literal(Rune r, bool foldcase) {
|
|
switch (encoding_) {
|
|
default:
|
|
return Frag();
|
|
|
|
case kEncodingLatin1:
|
|
return ByteRange(r, r, foldcase);
|
|
|
|
case kEncodingUTF8: {
|
|
if (r < Runeself) // Make common case fast.
|
|
return ByteRange(r, r, foldcase);
|
|
uint8 buf[UTFmax];
|
|
int n = runetochar(reinterpret_cast<char*>(buf), &r);
|
|
Frag f = ByteRange((uint8)buf[0], buf[0], false);
|
|
for (int i = 1; i < n; i++)
|
|
f = Cat(f, ByteRange((uint8)buf[i], buf[i], false));
|
|
return f;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Called after traversing the node's children during the walk.
|
|
// Given their frags, build and return the frag for this re.
|
|
Frag Compiler::PostVisit(Regexp* re, Frag, Frag, Frag* child_frags,
|
|
int nchild_frags) {
|
|
// If a child failed, don't bother going forward, especially
|
|
// since the child_frags might contain Frags with NULLs in them.
|
|
if (failed_)
|
|
return NoMatch();
|
|
|
|
// Given the child fragments, return the fragment for this node.
|
|
switch (re->op()) {
|
|
case kRegexpRepeat:
|
|
// Should not see; code at bottom of function will print error
|
|
break;
|
|
|
|
case kRegexpNoMatch:
|
|
return NoMatch();
|
|
|
|
case kRegexpEmptyMatch:
|
|
return Nop();
|
|
|
|
case kRegexpHaveMatch: {
|
|
Frag f = Match(re->match_id());
|
|
// Remember unanchored match to end of string.
|
|
if (anchor_ != RE2::ANCHOR_BOTH)
|
|
f = Cat(DotStar(), Cat(EmptyWidth(kEmptyEndText), f));
|
|
return f;
|
|
}
|
|
|
|
case kRegexpConcat: {
|
|
Frag f = child_frags[0];
|
|
for (int i = 1; i < nchild_frags; i++)
|
|
f = Cat(f, child_frags[i]);
|
|
return f;
|
|
}
|
|
|
|
case kRegexpAlternate: {
|
|
Frag f = child_frags[0];
|
|
for (int i = 1; i < nchild_frags; i++)
|
|
f = Alt(f, child_frags[i]);
|
|
return f;
|
|
}
|
|
|
|
case kRegexpStar:
|
|
return Star(child_frags[0], re->parse_flags()&Regexp::NonGreedy);
|
|
|
|
case kRegexpPlus:
|
|
return Plus(child_frags[0], re->parse_flags()&Regexp::NonGreedy);
|
|
|
|
case kRegexpQuest:
|
|
return Quest(child_frags[0], re->parse_flags()&Regexp::NonGreedy);
|
|
|
|
case kRegexpLiteral:
|
|
return Literal(re->rune(), re->parse_flags()&Regexp::FoldCase);
|
|
|
|
case kRegexpLiteralString: {
|
|
// Concatenation of literals.
|
|
if (re->nrunes() == 0)
|
|
return Nop();
|
|
Frag f;
|
|
for (int i = 0; i < re->nrunes(); i++) {
|
|
Frag f1 = Literal(re->runes()[i], re->parse_flags()&Regexp::FoldCase);
|
|
if (i == 0)
|
|
f = f1;
|
|
else
|
|
f = Cat(f, f1);
|
|
}
|
|
return f;
|
|
}
|
|
|
|
case kRegexpAnyChar:
|
|
BeginRange();
|
|
AddRuneRange(0, Runemax, false);
|
|
return EndRange();
|
|
|
|
case kRegexpAnyByte:
|
|
return ByteRange(0x00, 0xFF, false);
|
|
|
|
case kRegexpCharClass: {
|
|
CharClass* cc = re->cc();
|
|
if (cc->empty()) {
|
|
// This can't happen.
|
|
LOG(DFATAL) << "No ranges in char class";
|
|
failed_ = true;
|
|
return NoMatch();
|
|
}
|
|
|
|
// ASCII case-folding optimization: if the char class
|
|
// behaves the same on A-Z as it does on a-z,
|
|
// discard any ranges wholly contained in A-Z
|
|
// and mark the other ranges as foldascii.
|
|
// This reduces the size of a program for
|
|
// (?i)abc from 3 insts per letter to 1 per letter.
|
|
bool foldascii = cc->FoldsASCII();
|
|
|
|
// Character class is just a big OR of the different
|
|
// character ranges in the class.
|
|
BeginRange();
|
|
for (CharClass::iterator i = cc->begin(); i != cc->end(); ++i) {
|
|
// ASCII case-folding optimization (see above).
|
|
if (foldascii && 'A' <= i->lo && i->hi <= 'Z')
|
|
continue;
|
|
|
|
// If this range contains all of A-Za-z or none of it,
|
|
// the fold flag is unnecessary; don't bother.
|
|
bool fold = foldascii;
|
|
if ((i->lo <= 'A' && 'z' <= i->hi) || i->hi < 'A' || 'z' < i->lo)
|
|
fold = false;
|
|
|
|
AddRuneRange(i->lo, i->hi, fold);
|
|
}
|
|
return EndRange();
|
|
}
|
|
|
|
case kRegexpCapture:
|
|
// If this is a non-capturing parenthesis -- (?:foo) --
|
|
// just use the inner expression.
|
|
if (re->cap() < 0)
|
|
return child_frags[0];
|
|
return Capture(child_frags[0], re->cap());
|
|
|
|
case kRegexpBeginLine:
|
|
return EmptyWidth(reversed_ ? kEmptyEndLine : kEmptyBeginLine);
|
|
|
|
case kRegexpEndLine:
|
|
return EmptyWidth(reversed_ ? kEmptyBeginLine : kEmptyEndLine);
|
|
|
|
case kRegexpBeginText:
|
|
return EmptyWidth(reversed_ ? kEmptyEndText : kEmptyBeginText);
|
|
|
|
case kRegexpEndText:
|
|
return EmptyWidth(reversed_ ? kEmptyBeginText : kEmptyEndText);
|
|
|
|
case kRegexpWordBoundary:
|
|
return EmptyWidth(kEmptyWordBoundary);
|
|
|
|
case kRegexpNoWordBoundary:
|
|
return EmptyWidth(kEmptyNonWordBoundary);
|
|
}
|
|
LOG(DFATAL) << "Missing case in Compiler: " << re->op();
|
|
failed_ = true;
|
|
return NoMatch();
|
|
}
|
|
|
|
// Is this regexp required to start at the beginning of the text?
|
|
// Only approximate; can return false for complicated regexps like (\Aa|\Ab),
|
|
// but handles (\A(a|b)). Could use the Walker to write a more exact one.
|
|
static bool IsAnchorStart(Regexp** pre, int depth) {
|
|
Regexp* re = *pre;
|
|
Regexp* sub;
|
|
// The depth limit makes sure that we don't overflow
|
|
// the stack on a deeply nested regexp. As the comment
|
|
// above says, IsAnchorStart is conservative, so returning
|
|
// a false negative is okay. The exact limit is somewhat arbitrary.
|
|
if (re == NULL || depth >= 4)
|
|
return false;
|
|
switch (re->op()) {
|
|
default:
|
|
break;
|
|
case kRegexpConcat:
|
|
if (re->nsub() > 0) {
|
|
sub = re->sub()[0]->Incref();
|
|
if (IsAnchorStart(&sub, depth+1)) {
|
|
Regexp** subcopy = new Regexp*[re->nsub()];
|
|
subcopy[0] = sub; // already have reference
|
|
for (int i = 1; i < re->nsub(); i++)
|
|
subcopy[i] = re->sub()[i]->Incref();
|
|
*pre = Regexp::Concat(subcopy, re->nsub(), re->parse_flags());
|
|
delete[] subcopy;
|
|
re->Decref();
|
|
return true;
|
|
}
|
|
sub->Decref();
|
|
}
|
|
break;
|
|
case kRegexpCapture:
|
|
sub = re->sub()[0]->Incref();
|
|
if (IsAnchorStart(&sub, depth+1)) {
|
|
*pre = Regexp::Capture(sub, re->parse_flags(), re->cap());
|
|
re->Decref();
|
|
return true;
|
|
}
|
|
sub->Decref();
|
|
break;
|
|
case kRegexpBeginText:
|
|
*pre = Regexp::LiteralString(NULL, 0, re->parse_flags());
|
|
re->Decref();
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Is this regexp required to start at the end of the text?
|
|
// Only approximate; can return false for complicated regexps like (a\z|b\z),
|
|
// but handles ((a|b)\z). Could use the Walker to write a more exact one.
|
|
static bool IsAnchorEnd(Regexp** pre, int depth) {
|
|
Regexp* re = *pre;
|
|
Regexp* sub;
|
|
// The depth limit makes sure that we don't overflow
|
|
// the stack on a deeply nested regexp. As the comment
|
|
// above says, IsAnchorEnd is conservative, so returning
|
|
// a false negative is okay. The exact limit is somewhat arbitrary.
|
|
if (re == NULL || depth >= 4)
|
|
return false;
|
|
switch (re->op()) {
|
|
default:
|
|
break;
|
|
case kRegexpConcat:
|
|
if (re->nsub() > 0) {
|
|
sub = re->sub()[re->nsub() - 1]->Incref();
|
|
if (IsAnchorEnd(&sub, depth+1)) {
|
|
Regexp** subcopy = new Regexp*[re->nsub()];
|
|
subcopy[re->nsub() - 1] = sub; // already have reference
|
|
for (int i = 0; i < re->nsub() - 1; i++)
|
|
subcopy[i] = re->sub()[i]->Incref();
|
|
*pre = Regexp::Concat(subcopy, re->nsub(), re->parse_flags());
|
|
delete[] subcopy;
|
|
re->Decref();
|
|
return true;
|
|
}
|
|
sub->Decref();
|
|
}
|
|
break;
|
|
case kRegexpCapture:
|
|
sub = re->sub()[0]->Incref();
|
|
if (IsAnchorEnd(&sub, depth+1)) {
|
|
*pre = Regexp::Capture(sub, re->parse_flags(), re->cap());
|
|
re->Decref();
|
|
return true;
|
|
}
|
|
sub->Decref();
|
|
break;
|
|
case kRegexpEndText:
|
|
*pre = Regexp::LiteralString(NULL, 0, re->parse_flags());
|
|
re->Decref();
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void Compiler::Setup(Regexp::ParseFlags flags, int64 max_mem,
|
|
RE2::Anchor anchor) {
|
|
prog_->set_flags(flags);
|
|
|
|
if (flags & Regexp::Latin1)
|
|
encoding_ = kEncodingLatin1;
|
|
max_mem_ = max_mem;
|
|
if (max_mem <= 0) {
|
|
max_inst_ = 100000; // more than enough
|
|
} else if (max_mem <= static_cast<int64>(sizeof(Prog))) {
|
|
// No room for anything.
|
|
max_inst_ = 0;
|
|
} else {
|
|
int64 m = (max_mem - sizeof(Prog)) / sizeof(Prog::Inst);
|
|
// Limit instruction count so that inst->id() fits nicely in an int.
|
|
// SparseArray also assumes that the indices (inst->id()) are ints.
|
|
// The call to WalkExponential uses 2*max_inst_ below,
|
|
// and other places in the code use 2 or 3 * prog->size().
|
|
// Limiting to 2^24 should avoid overflow in those places.
|
|
// (The point of allowing more than 32 bits of memory is to
|
|
// have plenty of room for the DFA states, not to use it up
|
|
// on the program.)
|
|
if (m >= 1<<24)
|
|
m = 1<<24;
|
|
|
|
// Inst imposes its own limit (currently bigger than 2^24 but be safe).
|
|
if (m > Prog::Inst::kMaxInst)
|
|
m = Prog::Inst::kMaxInst;
|
|
|
|
max_inst_ = m;
|
|
}
|
|
|
|
anchor_ = anchor;
|
|
}
|
|
|
|
// Compiles re, returning program.
|
|
// Caller is responsible for deleting prog_.
|
|
// If reversed is true, compiles a program that expects
|
|
// to run over the input string backward (reverses all concatenations).
|
|
// The reversed flag is also recorded in the returned program.
|
|
Prog* Compiler::Compile(Regexp* re, bool reversed, int64 max_mem) {
|
|
Compiler c;
|
|
|
|
c.Setup(re->parse_flags(), max_mem, RE2::ANCHOR_BOTH /* unused */);
|
|
c.reversed_ = reversed;
|
|
|
|
// Simplify to remove things like counted repetitions
|
|
// and character classes like \d.
|
|
Regexp* sre = re->Simplify();
|
|
if (sre == NULL)
|
|
return NULL;
|
|
|
|
// Record whether prog is anchored, removing the anchors.
|
|
// (They get in the way of other optimizations.)
|
|
bool is_anchor_start = IsAnchorStart(&sre, 0);
|
|
bool is_anchor_end = IsAnchorEnd(&sre, 0);
|
|
|
|
// Generate fragment for entire regexp.
|
|
Frag f = c.WalkExponential(sre, Frag(), 2*c.max_inst_);
|
|
sre->Decref();
|
|
if (c.failed_)
|
|
return NULL;
|
|
|
|
// Success! Finish by putting Match node at end, and record start.
|
|
// Turn off c.reversed_ (if it is set) to force the remaining concatenations
|
|
// to behave normally.
|
|
c.reversed_ = false;
|
|
Frag all = c.Cat(f, c.Match(0));
|
|
c.prog_->set_start(all.begin);
|
|
|
|
if (reversed) {
|
|
c.prog_->set_anchor_start(is_anchor_end);
|
|
c.prog_->set_anchor_end(is_anchor_start);
|
|
} else {
|
|
c.prog_->set_anchor_start(is_anchor_start);
|
|
c.prog_->set_anchor_end(is_anchor_end);
|
|
}
|
|
|
|
// Also create unanchored version, which starts with a .*? loop.
|
|
if (c.prog_->anchor_start()) {
|
|
c.prog_->set_start_unanchored(c.prog_->start());
|
|
} else {
|
|
Frag unanchored = c.Cat(c.DotStar(), all);
|
|
c.prog_->set_start_unanchored(unanchored.begin);
|
|
}
|
|
|
|
c.prog_->set_reversed(reversed);
|
|
|
|
// Hand ownership of prog_ to caller.
|
|
return c.Finish();
|
|
}
|
|
|
|
Prog* Compiler::Finish() {
|
|
if (failed_)
|
|
return NULL;
|
|
|
|
if (prog_->start() == 0 && prog_->start_unanchored() == 0) {
|
|
// No possible matches; keep Fail instruction only.
|
|
inst_len_ = 1;
|
|
}
|
|
|
|
// Trim instruction to minimum array and transfer to Prog.
|
|
Trim();
|
|
prog_->inst_ = inst_;
|
|
prog_->size_ = inst_len_;
|
|
inst_ = NULL;
|
|
|
|
// Compute byte map.
|
|
prog_->ComputeByteMap();
|
|
|
|
prog_->Optimize();
|
|
|
|
// Record remaining memory for DFA.
|
|
if (max_mem_ <= 0) {
|
|
prog_->set_dfa_mem(1<<20);
|
|
} else {
|
|
int64 m = max_mem_ - sizeof(Prog) - inst_len_*sizeof(Prog::Inst);
|
|
if (m < 0)
|
|
m = 0;
|
|
prog_->set_dfa_mem(m);
|
|
}
|
|
|
|
Prog* p = prog_;
|
|
prog_ = NULL;
|
|
return p;
|
|
}
|
|
|
|
// Converts Regexp to Prog.
|
|
Prog* Regexp::CompileToProg(int64 max_mem) {
|
|
return Compiler::Compile(this, false, max_mem);
|
|
}
|
|
|
|
Prog* Regexp::CompileToReverseProg(int64 max_mem) {
|
|
return Compiler::Compile(this, true, max_mem);
|
|
}
|
|
|
|
Frag Compiler::DotStar() {
|
|
return Star(ByteRange(0x00, 0xff, false), true);
|
|
}
|
|
|
|
// Compiles RE set to Prog.
|
|
Prog* Compiler::CompileSet(const RE2::Options& options, RE2::Anchor anchor,
|
|
Regexp* re) {
|
|
Compiler c;
|
|
|
|
Regexp::ParseFlags pf = static_cast<Regexp::ParseFlags>(options.ParseFlags());
|
|
c.Setup(pf, options.max_mem(), anchor);
|
|
|
|
// Compile alternation of fragments.
|
|
Frag all = c.WalkExponential(re, Frag(), 2*c.max_inst_);
|
|
re->Decref();
|
|
if (c.failed_)
|
|
return NULL;
|
|
|
|
if (anchor == RE2::UNANCHORED) {
|
|
// The trailing .* was added while handling kRegexpHaveMatch.
|
|
// We just have to add the leading one.
|
|
all = c.Cat(c.DotStar(), all);
|
|
}
|
|
|
|
c.prog_->set_start(all.begin);
|
|
c.prog_->set_start_unanchored(all.begin);
|
|
c.prog_->set_anchor_start(true);
|
|
c.prog_->set_anchor_end(true);
|
|
|
|
Prog* prog = c.Finish();
|
|
if (prog == NULL)
|
|
return NULL;
|
|
|
|
// Make sure DFA has enough memory to operate,
|
|
// since we're not going to fall back to the NFA.
|
|
bool failed;
|
|
StringPiece sp = "hello, world";
|
|
prog->SearchDFA(sp, sp, Prog::kAnchored, Prog::kManyMatch,
|
|
NULL, &failed, NULL);
|
|
if (failed) {
|
|
delete prog;
|
|
return NULL;
|
|
}
|
|
|
|
return prog;
|
|
}
|
|
|
|
Prog* Prog::CompileSet(const RE2::Options& options, RE2::Anchor anchor,
|
|
Regexp* re) {
|
|
return Compiler::CompileSet(options, anchor, re);
|
|
}
|
|
|
|
} // namespace re2
|