mirror of
https://github.com/dlang/phobos.git
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582 lines
20 KiB
D
582 lines
20 KiB
D
/*
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ShiftOr is a kickstart engine, a coarse-grained "filter" engine that finds
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potential matches to be verified by a full-blown matcher.
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*/
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module std.regex.internal.shiftor;
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package(std.regex):
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import std.regex.internal.ir;
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import std.range.primitives, std.utf;
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//utility for shiftOr, returns a minimum number of bytes to test in a Char
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uint effectiveSize(Char)()
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{
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static if (is(Char == char))
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return 1;
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else static if (is(Char == wchar))
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return 2;
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else static if (is(Char == dchar))
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return 3;
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else
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static assert(0);
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}
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/*
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Kickstart engine using ShiftOr algorithm,
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a bit parallel technique for inexact string searching.
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*/
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class ShiftOr(Char) : Kickstart!Char
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{
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private:
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pure:
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uint[] table;
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uint fChar;
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uint n_length;
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enum charSize = effectiveSize!Char();
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//maximum number of chars in CodepointSet to process
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enum uint charsetThreshold = 32_000;
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static struct ShiftThread
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{
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uint[] tab;
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uint mask;
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uint idx;
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uint pc, counter, hops;
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this(uint newPc, uint newCounter, uint[] table)
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{
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pc = newPc;
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counter = newCounter;
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mask = 1;
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idx = 0;
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hops = 0;
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tab = table;
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}
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void setMask(uint idx, uint mask)
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{
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tab[idx] |= mask;
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}
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void setInvMask(uint idx, uint mask)
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{
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tab[idx] &= ~mask;
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}
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void set(alias setBits = setInvMask)(dchar ch)
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{
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static if (charSize == 3)
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{
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uint val = ch, tmask = mask;
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setBits(val&0xFF, tmask);
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tmask <<= 1;
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val >>= 8;
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setBits(val&0xFF, tmask);
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tmask <<= 1;
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val >>= 8;
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assert(val <= 0x10);
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setBits(val, tmask);
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tmask <<= 1;
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}
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else
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{
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Char[dchar.sizeof/Char.sizeof] buf;
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uint tmask = mask;
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size_t total = encode(buf, ch);
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for (size_t i = 0; i < total; i++, tmask<<=1)
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{
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static if (charSize == 1)
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setBits(buf[i], tmask);
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else static if (charSize == 2)
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{
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setBits(buf[i]&0xFF, tmask);
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tmask <<= 1;
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setBits(buf[i]>>8, tmask);
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}
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}
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}
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}
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void add(dchar ch){ return set!setInvMask(ch); }
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void advance(uint s)
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{
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mask <<= s;
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idx += s;
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}
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@property bool full(){ return !mask; }
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}
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static ShiftThread fork(ShiftThread t, uint newPc, uint newCounter)
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{
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ShiftThread nt = t;
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nt.pc = newPc;
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nt.counter = newCounter;
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return nt;
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}
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@trusted static ShiftThread fetch(ref ShiftThread[] worklist)
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{
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auto t = worklist[$-1];
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worklist.length -= 1;
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//if (!__ctfe)
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// cast(void)worklist.assumeSafeAppend();
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return t;
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}
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static uint charLen(uint ch)
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{
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assert(ch <= 0x10FFFF);
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return codeLength!Char(cast(dchar)ch)*charSize;
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}
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public:
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@trusted this(ref Regex!Char re)
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{
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static import std.algorithm.comparison;
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import std.algorithm.searching : countUntil;
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import std.conv : text;
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import std.range : assumeSorted;
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uint[] memory = new uint[256];
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fChar = uint.max;
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// FNV-1a flavored hash (uses 32bits at a time)
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ulong hash(uint[] tab)
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{
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ulong h = 0xcbf29ce484222325;
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foreach (v; tab)
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{
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h ^= v;
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h *= 0x100000001b3;
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}
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return h;
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}
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L_FindChar:
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for (size_t i = 0;;)
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{
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switch (re.ir[i].code)
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{
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case IR.Char:
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fChar = re.ir[i].data;
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static if (charSize != 3)
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{
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Char[dchar.sizeof/Char.sizeof] buf;
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encode(buf, fChar);
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fChar = buf[0];
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}
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fChar = fChar & 0xFF;
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break L_FindChar;
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case IR.GroupStart, IR.GroupEnd:
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i += IRL!(IR.GroupStart);
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break;
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case IR.Bof, IR.Bol, IR.Wordboundary, IR.Notwordboundary:
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i += IRL!(IR.Bol);
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break;
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default:
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break L_FindChar;
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}
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}
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table = memory;
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table[] = uint.max;
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alias MergeTab = bool[ulong];
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// use reasonably complex hash to identify equivalent tables
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auto merge = new MergeTab[re.hotspotTableSize];
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ShiftThread[] trs;
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ShiftThread t = ShiftThread(0, 0, table);
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//locate first fixed char if any
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n_length = 32;
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for (;;)
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{
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L_Eval_Thread:
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for (;;)
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{
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switch (re.ir[t.pc].code)
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{
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case IR.Char:
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uint s = charLen(re.ir[t.pc].data);
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if (t.idx+s > n_length)
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goto L_StopThread;
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t.add(re.ir[t.pc].data);
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t.advance(s);
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t.pc += IRL!(IR.Char);
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break;
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case IR.OrChar://assumes IRL!(OrChar) == 1
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uint len = re.ir[t.pc].sequence;
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uint end = t.pc + len;
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uint[Bytecode.maxSequence] s;
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uint numS;
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for (uint i = 0; i < len; i++)
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{
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auto x = charLen(re.ir[t.pc+i].data);
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if (countUntil(s[0..numS], x) < 0)
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s[numS++] = x;
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}
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for (uint i = t.pc; i < end; i++)
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{
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t.add(re.ir[i].data);
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}
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for (uint i = 0; i < numS; i++)
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{
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auto tx = fork(t, t.pc + len, t.counter);
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if (tx.idx + s[i] <= n_length)
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{
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tx.advance(s[i]);
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trs ~= tx;
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}
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}
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if (!trs.empty)
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t = fetch(trs);
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else
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goto L_StopThread;
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break;
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case IR.CodepointSet:
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case IR.Trie:
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auto set = re.charsets[re.ir[t.pc].data];
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uint[4] s;
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uint numS;
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static if (charSize == 3)
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{
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s[0] = charSize;
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numS = 1;
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}
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else
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{
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static if (charSize == 1)
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static immutable codeBounds = [0x0, 0x7F, 0x80, 0x7FF, 0x800, 0xFFFF, 0x10000, 0x10FFFF];
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else //== 2
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static immutable codeBounds = [0x0, 0xFFFF, 0x10000, 0x10FFFF];
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uint[] arr = new uint[set.length * 2];
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size_t ofs = 0;
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foreach (ival; set)
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{
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arr[ofs++] = ival.a;
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arr[ofs++] = ival.b;
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}
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auto srange = assumeSorted!"a <= b"(arr);
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for (uint i = 0; i < codeBounds.length/2; i++)
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{
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auto start = srange.lowerBound(codeBounds[2*i]).length;
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auto end = srange.lowerBound(codeBounds[2*i+1]).length;
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if (end > start || (end == start && (end & 1)))
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s[numS++] = (i+1)*charSize;
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}
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}
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if (numS == 0 || t.idx + s[numS-1] > n_length)
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goto L_StopThread;
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auto chars = set.length;
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if (chars > charsetThreshold)
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goto L_StopThread;
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foreach (ival; set)
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foreach (ch; ival.a..ival.b)
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{
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//avoid surrogate pairs
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if (0xD800 <= ch && ch <= 0xDFFF)
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continue;
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t.add(ch);
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}
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for (uint i = 0; i < numS; i++)
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{
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auto tx = fork(t, t.pc + IRL!(IR.CodepointSet), t.counter);
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tx.advance(s[i]);
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trs ~= tx;
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}
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if (!trs.empty)
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t = fetch(trs);
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else
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goto L_StopThread;
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break;
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case IR.Any:
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goto L_StopThread;
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case IR.GotoEndOr:
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t.pc += IRL!(IR.GotoEndOr)+re.ir[t.pc].data;
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assert(re.ir[t.pc].code == IR.OrEnd);
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goto case;
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case IR.OrEnd:
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auto slot = re.ir[t.pc+1].raw+t.counter;
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auto val = hash(t.tab);
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if (val in merge[slot])
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goto L_StopThread; // merge equivalent
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merge[slot][val] = true;
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t.pc += IRL!(IR.OrEnd);
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break;
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case IR.OrStart:
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t.pc += IRL!(IR.OrStart);
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goto case;
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case IR.Option:
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uint next = t.pc + re.ir[t.pc].data + IRL!(IR.Option);
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//queue next Option
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if (re.ir[next].code == IR.Option)
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{
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trs ~= fork(t, next, t.counter);
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}
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t.pc += IRL!(IR.Option);
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break;
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case IR.RepeatStart:case IR.RepeatQStart:
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t.pc += IRL!(IR.RepeatStart)+re.ir[t.pc].data;
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goto case IR.RepeatEnd;
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case IR.RepeatEnd:
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case IR.RepeatQEnd:
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auto slot = re.ir[t.pc+1].raw+t.counter;
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auto val = hash(t.tab);
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if (val in merge[slot])
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goto L_StopThread; // merge equivalent
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merge[slot][val] = true;
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uint len = re.ir[t.pc].data;
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uint step = re.ir[t.pc+2].raw;
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uint min = re.ir[t.pc+3].raw;
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if (t.counter < min)
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{
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t.counter += step;
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t.pc -= len;
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break;
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}
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uint max = re.ir[t.pc+4].raw;
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if (t.counter < max)
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{
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trs ~= fork(t, t.pc - len, t.counter + step);
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t.counter = t.counter%step;
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t.pc += IRL!(IR.RepeatEnd);
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}
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else
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{
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t.counter = t.counter%step;
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t.pc += IRL!(IR.RepeatEnd);
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}
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break;
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case IR.GroupStart, IR.GroupEnd:
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t.pc += IRL!(IR.GroupStart);
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break;
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case IR.Bof, IR.Bol, IR.Wordboundary, IR.Notwordboundary:
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t.pc += IRL!(IR.Bol);
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break;
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case IR.LookaheadStart, IR.NeglookaheadStart, IR.LookbehindStart, IR.NeglookbehindStart:
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t.pc += IRL!(IR.LookaheadStart) + IRL!(IR.LookaheadEnd) + re.ir[t.pc].data;
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break;
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default:
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L_StopThread:
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assert(re.ir[t.pc].code >= 0x80, text(re.ir[t.pc].code));
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n_length = std.algorithm.comparison.min(t.idx, n_length);
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break L_Eval_Thread;
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}
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}
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if (trs.empty)
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break;
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t = fetch(trs);
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}
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debug(std_regex_search)
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{
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writeln("Min length: ", n_length);
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}
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}
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final @property bool empty() const { return n_length < 3 && fChar == uint.max; }
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final @property uint length() const{ return n_length/charSize; }
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// lookup compatible bit pattern in haystack, return starting index
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// has a useful trait: if supplied with valid UTF indexes,
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// returns only valid UTF indexes
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// (that given the haystack in question is valid UTF string)
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final @trusted bool search(ref Input!Char s) const
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{//@BUG: apparently assumes little endian machines
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import std.conv : text;
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import core.stdc.string : memchr;
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assert(!empty);
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auto haystack = s._origin;
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uint state = uint.max;
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uint limit = 1u<<(n_length - 1u);
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auto p = cast(const(ubyte)*)(haystack.ptr+s._index);
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debug(std_regex_search) writefln("Limit: %32b",limit);
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if (fChar != uint.max)
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{
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const(ubyte)* end = cast(ubyte*)(haystack.ptr + haystack.length);
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const orginalAlign = cast(size_t)p & (Char.sizeof-1);
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while (p != end)
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{
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if (!~state)
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{//speed up seeking first matching place
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for (;;)
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{
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assert(p <= end, text(p," vs ", end));
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p = cast(ubyte*)memchr(p, fChar, end - p);
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if (!p)
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{
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s._index = haystack.length;
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return false;
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}
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if ((cast(size_t)p & (Char.sizeof-1)) == orginalAlign)
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break;
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if (++p == end)
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{
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s._index = haystack.length;
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return false;
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}
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}
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state = ~1u;
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assert((cast(size_t)p & (Char.sizeof-1)) == orginalAlign);
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static if (charSize == 3)
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{
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state = (state<<1) | table[p[1]];
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state = (state<<1) | table[p[2]];
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p += 4;
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}
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else
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p++;
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//first char is tested, see if that's all
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if (!(state & limit))
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{
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s._index = (p-cast(ubyte*)haystack.ptr)/Char.sizeof-length;
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return true;
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}
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}
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else
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{//have some bits/states for possible matches,
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//use the usual shift-or cycle
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static if (charSize == 3)
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{
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state = (state<<1) | table[p[0]];
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state = (state<<1) | table[p[1]];
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state = (state<<1) | table[p[2]];
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p += 4;
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}
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else
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{
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state = (state<<1) | table[p[0]];
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p++;
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}
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if (!(state & limit))
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{
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s._index = (p-cast(ubyte*)haystack.ptr)/Char.sizeof-length;
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return true;
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}
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}
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debug(std_regex_search) writefln("State: %32b", state);
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}
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}
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else
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{
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//normal path, partially unrolled for char/wchar
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static if (charSize == 3)
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{
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const(ubyte)* end = cast(ubyte*)(haystack.ptr + haystack.length);
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while (p != end)
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{
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state = (state<<1) | table[p[0]];
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state = (state<<1) | table[p[1]];
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state = (state<<1) | table[p[2]];
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p += 4;
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if (!(state & limit))//division rounds down for dchar
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{
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s._index = (p-cast(ubyte*)haystack.ptr)/Char.sizeof-length;
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return true;
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}
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}
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}
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else
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{
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auto len = cast(ubyte*)(haystack.ptr + haystack.length) - p;
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size_t i = 0;
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if (len & 1)
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{
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state = (state<<1) | table[p[i++]];
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if (!(state & limit))
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{
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s._index += i/Char.sizeof-length;
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return true;
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}
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}
|
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while (i < len)
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{
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state = (state<<1) | table[p[i++]];
|
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if (!(state & limit))
|
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{
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s._index += i/Char.sizeof-length;
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return true;
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}
|
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state = (state<<1) | table[p[i++]];
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if (!(state & limit))
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{
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s._index += i/Char.sizeof-length;
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return true;
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}
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debug(std_regex_search) writefln("State: %32b", state);
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}
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}
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}
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s._index = haystack.length;
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return false;
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}
|
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|
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final @trusted bool match(ref Input!Char s) const
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{
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//TODO: stub
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return false;
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}
|
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|
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@system debug static void dump(uint[] table)
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{//@@@BUG@@@ writef(ln) is @system
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import std.stdio : writefln;
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for (size_t i = 0; i < table.length; i += 4)
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{
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debug writefln("%32b %32b %32b %32b",table[i], table[i+1], table[i+2], table[i+3]);
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}
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}
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}
|
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|
|
unittest
|
|
{
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import std.conv, std.regex;
|
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auto shiftOrLength(C)(const(C)[] pat, uint length)
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{
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auto r = regex(pat, "s");
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auto kick = new ShiftOr!C(r);
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assert(kick.length == length, text(C.stringof, " == ", kick.length));
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return kick;
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}
|
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void searches(C)(const (C)[] source, ShiftOr!C kick, uint[] results...)
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{
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auto inp = Input!C(source);
|
|
foreach (r; results)
|
|
{
|
|
kick.search(inp);
|
|
dchar ch;
|
|
size_t idx;
|
|
assert(inp._index == r, text(inp._index, " vs ", r));
|
|
inp.nextChar(ch, idx);
|
|
}
|
|
}
|
|
|
|
|
|
foreach (i, Char; AliasSeq!(char, wchar, dchar))
|
|
{
|
|
alias String = immutable(Char)[];
|
|
shiftOrLength(`abc`.to!String, 3);
|
|
shiftOrLength(`abc$`.to!String, 3);
|
|
shiftOrLength(`(abc){2}a+`.to!String, 7);
|
|
shiftOrLength(`\b(a{2}b{3}){2,4}`.to!String, 10);
|
|
shiftOrLength(`\ba{2}c\bxyz`.to!String, 6);
|
|
auto kick = shiftOrLength(`\ba{2}c\b`.to!String, 3);
|
|
auto inp = Input!Char("aabaacaa");
|
|
assert(kick.search(inp));
|
|
assert(inp._index == 3, text(Char.stringof," == ", kick.length));
|
|
dchar ch;
|
|
size_t idx;
|
|
inp.nextChar(ch, idx);
|
|
assert(!kick.search(inp));
|
|
assert(inp._index == 8, text(Char.stringof," == ", kick.length));
|
|
}
|
|
|
|
foreach (i, Char; AliasSeq!(char, wchar, dchar))
|
|
{
|
|
alias String = immutable(Char)[];
|
|
auto kick = shiftOrLength(`abc[a-z]`.to!String, 4);
|
|
searches("abbabca".to!String, kick, 3);
|
|
kick = shiftOrLength(`(axx|bdx|cdy)`.to!String, 3);
|
|
searches("abdcdxabax".to!String, kick, 3);
|
|
|
|
shiftOrLength(`...`.to!String, 0);
|
|
kick = shiftOrLength(`a(b{1,2}|c{1,2})x`.to!String, 3);
|
|
searches("ababx".to!String, kick, 2);
|
|
searches("abaacba".to!String, kick, 3); //expected inexact
|
|
}
|
|
|
|
}
|
|
|