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Aegisub/src/lpeg.cpp

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/*
** $Id: lpeg.c,v 1.112 2010/11/03 17:07:50 roberto Exp $
** LPeg - PEG pattern matching for Lua
** Copyright 2007, Lua.org & PUC-Rio (see 'lpeg.html' for license)
** written by Roberto Ierusalimschy
*/
#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include "lua.h"
#include "lauxlib.h"
#include "lpeg.h"
#define VERSION "0.10"
#define PATTERN_T "lpeg-pattern"
#define MAXSTACKIDX "lpeg-maxstack"
/*
** compatibility with Lua 5.2
*/
#if (LUA_VERSION_NUM == 502)
#undef lua_equal
#define lua_equal(L,idx1,idx2) lua_compare(L,(idx1),(idx2),LUA_OPEQ)
#undef lua_getfenv
#define lua_getfenv lua_getuservalue
#undef lua_setfenv
#define lua_setfenv lua_setuservalue
#undef lua_objlen
#define lua_objlen lua_rawlen
#undef luaL_register
#define luaL_register(L,n,f) \
{ if ((n) == NULL) luaL_setfuncs(L,f,0); else luaL_newlib(L,f); }
#endif
/* initial size for call/backtrack stack */
#define INITBACK 100
/* default maximum size for call/backtrack stack */
#define MAXBACK INITBACK
/* size for call/backtrack stack for verifier */
#define MAXBACKVER 200
/* initial size for capture's list */
#define INITCAPSIZE 32
/* index, on Lua stack, for subject */
#define SUBJIDX 2
/* number of fixed arguments to 'match' (before capture arguments) */
#define FIXEDARGS 3
/* index, on Lua stack, for substitution value cache */
#define subscache(cs) ((cs)->ptop + 1)
/* index, on Lua stack, for capture list */
#define caplistidx(ptop) ((ptop) + 2)
/* index, on Lua stack, for pattern's fenv */
#define penvidx(ptop) ((ptop) + 3)
/* index, on Lua stack, for backtracking stack */
#define stackidx(ptop) ((ptop) + 4)
typedef unsigned char byte;
#define CHARSETSIZE ((UCHAR_MAX/CHAR_BIT) + 1)
typedef byte Charset[CHARSETSIZE];
/* Virtual Machine's instructions */
typedef enum Opcode {
IAny, IChar, ISet, ISpan,
IBack,
IRet, IEnd,
IChoice, IJmp, ICall, IOpenCall,
ICommit, IPartialCommit, IBackCommit, IFailTwice, IFail, IGiveup,
IFunc,
IFullCapture, IEmptyCapture, IEmptyCaptureIdx,
IOpenCapture, ICloseCapture, ICloseRunTime
} Opcode;
#define ISJMP 0x1
#define ISCHECK 0x2
#define ISFIXCHECK 0x4
#define ISNOFAIL 0x8
#define ISCAPTURE 0x10
#define ISMOVABLE 0x20
#define ISFENVOFF 0x40
static const int opproperties[] = {
/* IAny */ ISCHECK | ISFIXCHECK | ISJMP,
/* IChar */ ISCHECK | ISFIXCHECK | ISJMP,
/* ISet */ ISCHECK | ISFIXCHECK | ISJMP,
/* ISpan */ ISNOFAIL,
/* IBack */ 0,
/* IRet */ 0,
/* IEnd */ 0,
/* IChoice */ ISJMP,
/* IJmp */ ISJMP | ISNOFAIL,
/* ICall */ ISJMP,
/* IOpenCall */ ISFENVOFF,
/* ICommit */ ISJMP,
/* IPartialCommit */ ISJMP,
/* IBackCommit */ ISJMP,
/* IFailTwice */ 0,
/* IFail */ 0,
/* IGiveup */ 0,
/* IFunc */ ISCHECK | ISJMP,
/* IFullCapture */ ISCAPTURE | ISNOFAIL | ISFENVOFF,
/* IEmptyCapture */ ISCAPTURE | ISNOFAIL | ISMOVABLE,
/* IEmptyCaptureIdx */ISCAPTURE | ISNOFAIL | ISMOVABLE | ISFENVOFF,
/* IOpenCapture */ ISCAPTURE | ISNOFAIL | ISMOVABLE | ISFENVOFF,
/* ICloseCapture */ ISCAPTURE | ISNOFAIL | ISMOVABLE | ISFENVOFF,
/* ICloseRunTime */ ISCAPTURE | ISFENVOFF
};
typedef union Instruction {
struct Inst {
byte code;
byte aux;
short offset;
} i;
PattFunc f;
int iv;
byte buff[1];
} Instruction;
static const Instruction giveup = {{IGiveup, 0, 0}};
#define getkind(op) ((op)->i.aux & 0xF)
#define getoff(op) (((op)->i.aux >> 4) & 0xF)
#define dest(p,x) ((x) + ((p)+(x))->i.offset)
#define MAXOFF 0xF
#define MAXAUX 0xFF
/* maximum size (in elements) for a pattern */
#define MAXPATTSIZE (SHRT_MAX - 10)
#define isprop(op,p) (opproperties[(op)->i.code] & (p))
#define isjmp(op) (isprop(op, ISJMP) && (op)->i.offset != 0)
#define iscapture(op) isprop(op, ISCAPTURE)
#define ischeck(op) (isprop(op, ISCHECK) && (op)->i.offset == 0)
#define isfixcheck(op) (isprop(op, ISFIXCHECK) && (op)->i.offset == 0)
#define istest(op) (isprop(op, ISCHECK) && (op)->i.offset != 0)
#define isnofail(op) isprop(op, ISNOFAIL)
#define ismovable(op) isprop(op, ISMOVABLE)
#define isfenvoff(op) isprop(op, ISFENVOFF)
/* kinds of captures */
typedef enum CapKind {
Cclose, Cposition, Cconst, Cbackref, Carg, Csimple, Ctable, Cfunction,
Cquery, Cstring, Csubst, Cfold, Cruntime, Cgroup
} CapKind;
#define iscapnosize(k) ((k) == Cposition || (k) == Cconst)
typedef struct Capture {
const char *s; /* position */
short idx;
byte kind;
byte siz;
} Capture;
/* size (in elements) for an instruction plus extra l bytes */
#define instsize(l) (((l) + sizeof(Instruction) - 1)/sizeof(Instruction) + 1)
/* size (in elements) for a ISet instruction */
#define CHARSETINSTSIZE instsize(CHARSETSIZE)
/* size (in elements) for a IFunc instruction */
#define funcinstsize(p) ((p)->i.aux + 2)
#define loopset(v,b) { int v; for (v = 0; v < CHARSETSIZE; v++) b; }
#define testchar(st,c) (((int)(st)[((c) >> 3)] & (1 << ((c) & 7))))
#define setchar(st,c) ((st)[(c) >> 3] |= (1 << ((c) & 7)))
static int sizei (const Instruction *i) {
switch((Opcode)i->i.code) {
case ISet: case ISpan: return CHARSETINSTSIZE;
case IFunc: return funcinstsize(i);
default: return 1;
}
}
static const char *val2str (lua_State *L, int idx) {
const char *k = lua_tostring(L, idx);
if (k != NULL)
return lua_pushfstring(L, "rule '%s'", k);
else
return lua_pushfstring(L, "rule <a %s>", luaL_typename(L, idx));
}
static int getposition (lua_State *L, int t, int i) {
int res;
lua_getfenv(L, -1);
lua_rawgeti(L, -1, i); /* get key from pattern's environment */
lua_gettable(L, t); /* get position from positions table */
res = lua_tointeger(L, -1);
if (res == 0) { /* key has no registered position? */
lua_rawgeti(L, -2, i); /* get key again */
return luaL_error(L, "%s is not defined in given grammar", val2str(L, -1));
}
lua_pop(L, 2); /* remove environment and position */
return res;
}
/*
** {======================================================
** Printing patterns
** =======================================================
*/
static void printcharset (const Charset st) {
int i;
printf("[");
for (i = 0; i <= UCHAR_MAX; i++) {
int first = i;
while (testchar(st, i) && i <= UCHAR_MAX) i++;
if (i - 1 == first) /* unary range? */
printf("(%02x)", first);
else if (i - 1 > first) /* non-empty range? */
printf("(%02x-%02x)", first, i - 1);
}
printf("]");
}
static void printcapkind (int kind) {
const char *const modes[] = {
"close", "position", "constant", "backref",
"argument", "simple", "table", "function",
"query", "string", "substitution", "fold",
"runtime", "group"};
printf("%s", modes[kind]);
}
static void printjmp (const Instruction *op, const Instruction *p) {
printf("-> ");
if (p->i.offset == 0) printf("FAIL");
else printf("%d", (int)(dest(0, p) - op));
}
static void printinst (const Instruction *op, const Instruction *p) {
const char *const names[] = {
"any", "char", "set", "span", "back",
"ret", "end",
"choice", "jmp", "call", "open_call",
"commit", "partial_commit", "back_commit", "failtwice", "fail", "giveup",
"func",
"fullcapture", "emptycapture", "emptycaptureidx", "opencapture",
"closecapture", "closeruntime"
};
printf("%02ld: %s ", (long)(p - op), names[p->i.code]);
switch ((Opcode)p->i.code) {
case IChar: {
printf("'%c'", p->i.aux);
printjmp(op, p);
break;
}
case IAny: {
printf("* %d", p->i.aux);
printjmp(op, p);
break;
}
case IFullCapture: case IOpenCapture:
case IEmptyCapture: case IEmptyCaptureIdx:
case ICloseCapture: case ICloseRunTime: {
printcapkind(getkind(p));
printf("(n = %d) (off = %d)", getoff(p), p->i.offset);
break;
}
case ISet: {
printcharset((p+1)->buff);
printjmp(op, p);
break;
}
case ISpan: {
printcharset((p+1)->buff);
break;
}
case IOpenCall: {
printf("-> %d", p->i.offset);
break;
}
case IChoice: {
printjmp(op, p);
printf(" (%d)", p->i.aux);
break;
}
case IJmp: case ICall: case ICommit:
case IPartialCommit: case IBackCommit: {
printjmp(op, p);
break;
}
default: break;
}
printf("\n");
}
static void printpatt (Instruction *p) {
Instruction *op = p;
for (;;) {
printinst(op, p);
if ((Opcode)p->i.code == IEnd) break;
p += sizei(p);
}
}
static void printcap (Capture *cap) {
printcapkind(cap->kind);
printf(" (idx: %d - size: %d) -> %p\n", cap->idx, cap->siz, cap->s);
}
static void printcaplist (Capture *cap) {
for (; cap->s; cap++) printcap(cap);
}
/* }====================================================== */
/*
** {======================================================
** Virtual Machine
** =======================================================
*/
typedef struct Stack {
const char *s;
const Instruction *p;
int caplevel;
} Stack;
#define getstackbase(L, ptop) ((Stack *)lua_touserdata(L, stackidx(ptop)))
static int runtimecap (lua_State *L, Capture *close, Capture *ocap,
const char *o, const char *s, int ptop);
static Capture *doublecap (lua_State *L, Capture *cap, int captop, int ptop) {
Capture *newc;
if (captop >= INT_MAX/((int)sizeof(Capture) * 2))
luaL_error(L, "too many captures");
newc = (Capture *)lua_newuserdata(L, captop * 2 * sizeof(Capture));
memcpy(newc, cap, captop * sizeof(Capture));
lua_replace(L, caplistidx(ptop));
return newc;
}
static Stack *doublestack (lua_State *L, Stack **stacklimit, int ptop) {
Stack *stack = getstackbase(L, ptop);
Stack *newstack;
int n = *stacklimit - stack;
int max, newn;
lua_getfield(L, LUA_REGISTRYINDEX, MAXSTACKIDX);
max = lua_tointeger(L, -1);
lua_pop(L, 1);
if (n >= max)
luaL_error(L, "too many pending calls/choices");
newn = 2*n; if (newn > max) newn = max;
newstack = (Stack *)lua_newuserdata(L, newn * sizeof(Stack));
memcpy(newstack, stack, n * sizeof(Stack));
lua_replace(L, stackidx(ptop));
*stacklimit = newstack + newn;
return newstack + n;
}
static void adddyncaptures (const char *s, Capture *base, int n, int fd) {
int i;
assert(base[0].kind == Cruntime && base[0].siz == 0);
base[0].idx = fd; /* first returned capture */
for (i = 1; i < n; i++) { /* add extra captures */
base[i].siz = 1; /* mark it as closed */
base[i].s = s;
base[i].kind = Cruntime;
base[i].idx = fd + i; /* stack index */
}
base[n].kind = Cclose; /* add closing entry */
base[n].siz = 1;
base[n].s = s;
}
#define condfailed(p) { int f = p->i.offset; if (f) p+=f; else goto fail; }
static const char *match (lua_State *L,
const char *o, const char *s, const char *e,
Instruction *op, Capture *capture, int ptop) {
Stack stackbase[INITBACK];
Stack *stacklimit = stackbase + INITBACK;
Stack *stack = stackbase; /* point to first empty slot in stack */
int capsize = INITCAPSIZE;
int captop = 0; /* point to first empty slot in captures */
const Instruction *p = op;
stack->p = &giveup; stack->s = s; stack->caplevel = 0; stack++;
lua_pushlightuserdata(L, stackbase);
for (;;) {
#if defined(DEBUG)
printf("s: |%s| stck: %d c: %d ",
s, stack - getstackbase(L, ptop), captop);
printinst(op, p);
#endif
switch ((Opcode)p->i.code) {
case IEnd: {
assert(stack == getstackbase(L, ptop) + 1);
capture[captop].kind = Cclose;
capture[captop].s = NULL;
return s;
}
case IGiveup: {
assert(stack == getstackbase(L, ptop));
return NULL;
}
case IRet: {
assert(stack > getstackbase(L, ptop) && (stack - 1)->s == NULL);
p = (--stack)->p;
continue;
}
case IAny: {
int n = p->i.aux;
if (n <= e - s) { p++; s += n; }
else condfailed(p);
continue;
}
case IChar: {
if ((byte)*s == p->i.aux && s < e) { p++; s++; }
else condfailed(p);
continue;
}
case ISet: {
int c = (byte)*s;
if (testchar((p+1)->buff, c) && s < e)
{ p += CHARSETINSTSIZE; s++; }
else condfailed(p);
continue;
}
case IBack: {
int n = p->i.aux;
if (n > s - o) goto fail;
s -= n; p++;
continue;
}
case ISpan: {
for (; s < e; s++) {
int c = (byte)*s;
if (!testchar((p+1)->buff, c)) break;
}
p += CHARSETINSTSIZE;
continue;
}
case IFunc: {
const char *r = (p+1)->f(s, e, o, (p+2)->buff);
if (r != NULL) { s = r; p += funcinstsize(p); }
else condfailed(p);
continue;
}
case IJmp: {
p += p->i.offset;
continue;
}
case IChoice: {
if (stack == stacklimit)
stack = doublestack(L, &stacklimit, ptop);
stack->p = dest(0, p);
stack->s = s - p->i.aux;
stack->caplevel = captop;
stack++;
p++;
continue;
}
case ICall: {
if (stack == stacklimit)
stack = doublestack(L, &stacklimit, ptop);
stack->s = NULL;
stack->p = p + 1; /* save return address */
stack++;
p += p->i.offset;
continue;
}
case ICommit: {
assert(stack > getstackbase(L, ptop) && (stack - 1)->s != NULL);
stack--;
p += p->i.offset;
continue;
}
case IPartialCommit: {
assert(stack > getstackbase(L, ptop) && (stack - 1)->s != NULL);
(stack - 1)->s = s;
(stack - 1)->caplevel = captop;
p += p->i.offset;
continue;
}
case IBackCommit: {
assert(stack > getstackbase(L, ptop) && (stack - 1)->s != NULL);
s = (--stack)->s;
captop = stack->caplevel;
p += p->i.offset;
continue;
}
case IFailTwice:
assert(stack > getstackbase(L, ptop));
stack--;
/* go through */
case IFail:
fail: { /* pattern failed: try to backtrack */
do { /* remove pending calls */
assert(stack > getstackbase(L, ptop));
s = (--stack)->s;
} while (s == NULL);
captop = stack->caplevel;
p = stack->p;
continue;
}
case ICloseRunTime: {
int fr = lua_gettop(L) + 1; /* stack index of first result */
int ncap = runtimecap(L, capture + captop, capture, o, s, ptop);
lua_Integer res = lua_tointeger(L, fr) - 1; /* offset */
int n = lua_gettop(L) - fr; /* number of new captures */
if (res == -1) { /* may not be a number */
if (!lua_toboolean(L, fr)) { /* false value? */
lua_settop(L, fr - 1); /* remove results */
goto fail; /* and fail */
}
else if (lua_isboolean(L, fr)) /* true? */
res = s - o; /* keep current position */
}
if (res < s - o || res > e - o)
luaL_error(L, "invalid position returned by match-time capture");
s = o + res; /* update current position */
captop -= ncap; /* remove nested captures */
lua_remove(L, fr); /* remove first result (offset) */
if (n > 0) { /* captures? */
if ((captop += n + 1) >= capsize) {
capture = doublecap(L, capture, captop, ptop);
capsize = 2 * captop;
}
adddyncaptures(s, capture + captop - n - 1, n, fr);
}
p++;
continue;
}
case ICloseCapture: {
const char *s1 = s - getoff(p);
assert(captop > 0);
if (capture[captop - 1].siz == 0 &&
s1 - capture[captop - 1].s < UCHAR_MAX) {
capture[captop - 1].siz = s1 - capture[captop - 1].s + 1;
p++;
continue;
}
else {
capture[captop].siz = 1; /* mark entry as closed */
goto capture;
}
}
case IEmptyCapture: case IEmptyCaptureIdx:
capture[captop].siz = 1; /* mark entry as closed */
goto capture;
case IOpenCapture:
capture[captop].siz = 0; /* mark entry as open */
goto capture;
case IFullCapture:
capture[captop].siz = getoff(p) + 1; /* save capture size */
capture: {
capture[captop].s = s - getoff(p);
capture[captop].idx = p->i.offset;
capture[captop].kind = getkind(p);
if (++captop >= capsize) {
capture = doublecap(L, capture, captop, ptop);
capsize = 2 * captop;
}
p++;
continue;
}
case IOpenCall: {
lua_rawgeti(L, penvidx(ptop), p->i.offset);
luaL_error(L, "reference to %s outside a grammar", val2str(L, -1));
}
default: assert(0); return NULL;
}
}
}
/* }====================================================== */
/*
** {======================================================
** Verifier
** =======================================================
*/
/*
** check whether pattern may go from 'p' to 'e' without consuming any
** input. Raises an error if it detects a left recursion. 'op' points
** the beginning of the pattern. If pattern belongs to a grammar,
** 'rule' is the stack index where is its corresponding key (only for
** error messages) and 'posttable' is the stack index with a table
** mapping rule keys to the position of their code in the pattern.
*/
static int verify (lua_State *L, Instruction *op, const Instruction *p,
Instruction *e, int postable, int rule) {
static const char dummy[] = "";
Stack back[MAXBACKVER];
int backtop = 0; /* point to first empty slot in back */
while (p != e) {
switch ((Opcode)p->i.code) {
case IRet: {
p = back[--backtop].p;
continue;
}
case IChoice: {
if (backtop >= MAXBACKVER)
return luaL_error(L, "too many pending calls/choices");
back[backtop].p = dest(0, p);
back[backtop++].s = dummy;
p++;
continue;
}
case ICall: {
assert((p + 1)->i.code != IRet); /* no tail call */
if (backtop >= MAXBACKVER)
return luaL_error(L, "too many pending calls/choices");
back[backtop].s = NULL;
back[backtop++].p = p + 1;
goto dojmp;
}
case IOpenCall: {
int i;
if (postable == 0) /* grammar still not fixed? */
goto fail; /* to be verified later */
for (i = 0; i < backtop; i++) {
if (back[i].s == NULL && back[i].p == p + 1)
return luaL_error(L, "%s is left recursive", val2str(L, rule));
}
if (backtop >= MAXBACKVER)
return luaL_error(L, "too many pending calls/choices");
back[backtop].s = NULL;
back[backtop++].p = p + 1;
p = op + getposition(L, postable, p->i.offset);
continue;
}
case IBackCommit:
case ICommit: {
assert(backtop > 0 && p->i.offset > 0);
backtop--;
goto dojmp;
}
case IPartialCommit: {
assert(backtop > 0);
if (p->i.offset > 0) goto dojmp; /* forward jump */
else { /* loop will be detected when checking corresponding rule */
assert(postable != 0);
backtop--;
p++; /* just go on now */
continue;
}
}
case IBack: {
if (p->i.aux == 1 && isfixcheck(p + 1)) { /* char test? */
p++; /* skip back instruction */
p += sizei(p); /* skip char test */
}
else { /* standard lookbehind code */
assert((Opcode)(p - 1)->i.code == IChoice); /* look behind */
backtop--;
p += (p - 1)->i.offset;
assert((Opcode)(p - 1)->i.code == IFail); /* look behind */
}
continue;
}
case IAny:
case IChar:
case ISet: {
const Instruction *next = p + sizei(p);
if ((Opcode)next->i.code == IBack)
p = next + 1; /* continue after the back instruction */
else if (p->i.offset == 0) goto fail;
else /* jump */
p += p->i.offset;
continue;
}
case IJmp:
dojmp: {
p += p->i.offset;
continue;
}
case IFailTwice: /* 'not' predicate */
goto fail; /* body could have failed; try to backtrack it */
case IFail: {
if (p > op && (p - 1)->i.code == IBackCommit) { /* 'and' predicate? */
p++; /* pretend it succeeded and go ahead */
continue;
}
/* else failed: go through */
}
fail: { /* pattern failed: try to backtrack */
do {
if (backtop-- == 0)
return 1; /* no more backtracking */
} while (back[backtop].s == NULL);
p = back[backtop].p;
continue;
}
case ISpan:
case IOpenCapture: case ICloseCapture:
case IEmptyCapture: case IEmptyCaptureIdx:
case IFullCapture: {
p += sizei(p);
continue;
}
case ICloseRunTime: {
goto fail; /* be liberal in this case */
}
case IFunc: {
const char *r = (p+1)->f(dummy, dummy, dummy, (p+2)->buff);
if (r != NULL) { p += funcinstsize(p); }
else condfailed(p);
continue;
}
case IEnd: /* cannot happen (should stop before it) */
default: assert(0); return 0;
}
}
assert(backtop == 0);
return 0;
}
static void checkrule (lua_State *L, Instruction *op, int from, int to,
int postable, int rule) {
int i;
int lastopen = 0; /* more recent OpenCall seen in the code */
for (i = from; i < to; i += sizei(op + i)) {
if (op[i].i.code == IPartialCommit && op[i].i.offset < 0) { /* loop? */
int start = dest(op, i);
assert(op[start - 1].i.code == IChoice && dest(op, start - 1) == i + 1);
if (start <= lastopen) { /* loop does contain an open call? */
if (!verify(L, op, op + start, op + i, postable, rule)) /* check body */
luaL_error(L, "possible infinite loop in %s", val2str(L, rule));
}
}
else if (op[i].i.code == IOpenCall)
lastopen = i;
}
assert(op[i - 1].i.code == IRet);
verify(L, op, op + from, op + to - 1, postable, rule);
}
/* }====================================================== */
/*
** {======================================================
** Building Patterns
** =======================================================
*/
enum charsetanswer { NOINFO, ISCHARSET, VALIDSTARTS };
typedef struct CharsetTag {
enum charsetanswer tag;
Charset cs;
} CharsetTag;
static Instruction *getpatt (lua_State *L, int idx, int *size);
static void check2test (Instruction *p, int n) {
assert(ischeck(p) && n != 0);
p->i.offset = n;
}
/*
** invert array slice p[0]-p[e] (both inclusive)
*/
static void invert (Instruction *p, int e) {
int i;
for (i = 0; i < e; i++, e--) {
Instruction temp = p[i];
p[i] = p[e];
p[e] = temp;
}
}
/*
** rotate array slice p[0]-p[e] (both inclusive) 'n' steps
** to the 'left'
*/
static void rotate (Instruction *p, int e, int n) {
invert(p, n - 1);
invert(p + n, e - n);
invert(p, e);
}
#define op_step(p) ((p)->i.code == IAny ? (p)->i.aux : 1)
static int skipchecks (Instruction *p, int up, int *pn) {
int i, n = 0;
for (i = 0; isfixcheck(p + i); i += sizei(p + i)) {
int st = op_step(p + i);
if (n + st > MAXOFF - up) break;
n += st;
}
*pn = n;
return i;
}
#define ismovablecap(op) (ismovable(op) && getoff(op) < MAXOFF)
static void optimizecaptures (Instruction *p) {
int i;
int limit = 0;
for (i = 0; p[i].i.code != IEnd; i += sizei(p + i)) {
if (isjmp(p + i) && dest(p, i) >= limit)
limit = dest(p, i) + 1; /* do not optimize jump targets */
else if (i >= limit && ismovablecap(p + i) && isfixcheck(p + i + 1)) {
int end, n, j; /* found a border capture|check */
int maxoff = getoff(p + i);
int start = i;
/* find first capture in the group */
while (start > limit && ismovablecap(p + start - 1)) {
start--;
if (getoff(p + start) > maxoff) maxoff = getoff(p + start);
}
end = skipchecks(p + i + 1, maxoff, &n) + i; /* find last check */
if (n == 0) continue; /* first check is too big to move across */
assert(n <= MAXOFF && start <= i && i < end);
for (j = start; j <= i; j++)
p[j].i.aux += (n << 4); /* correct offset of captures to be moved */
rotate(p + start, end - start, i - start + 1); /* move them up */
i = end;
assert(isfixcheck(p + start) && iscapture(p + i));
}
}
}
static int target (Instruction *p, int i) {
while (p[i].i.code == IJmp) i += p[i].i.offset;
return i;
}
static void optimizejumps (Instruction *p) {
int i;
for (i = 0; p[i].i.code != IEnd; i += sizei(p + i)) {
if (isjmp(p + i))
p[i].i.offset = target(p, dest(p, i)) - i;
}
}
static void optimizechoice (Instruction *p) {
assert(p->i.code == IChoice);
if (isfixcheck(p + 1)) {
int lc = sizei(p + 1);
rotate(p, lc, 1);
assert(isfixcheck(p) && (p + lc)->i.code == IChoice);
(p + lc)->i.aux = op_step(p);
check2test(p, (p + lc)->i.offset);
(p + lc)->i.offset -= lc;
}
}
/*
** A 'headfail' pattern is a pattern that can only fails in its first
** instruction, which must be a check.
*/
static int isheadfail (Instruction *p) {
if (!ischeck(p)) return 0;
/* check that other operations cannot fail */
for (p += sizei(p); p->i.code != IEnd; p += sizei(p))
if (!isnofail(p)) return 0;
return 1;
}
#define checkpattern(L, idx) ((Instruction *)luaL_checkudata(L, idx, PATTERN_T))
/*
** Return the number of elements in the ktable of a pattern.
** in Lua 5.2, default "environment" for patterns is nil, not
** a table. Treat it as an empty table.
*/
static int ktablelen (lua_State *L, int idx) {
if (!lua_istable(L, idx)) return 0;
else return lua_objlen(L, idx);
}
/*
** join the elements of the ktable from pattern 'p1' into the ktable of
** the pattern at the top of the stack ('p'). If 'p1' has no elements,
** 'p' keeps its original ktable. If 'p' has no elements, it shares
** 'p1' ktable. Otherwise, this function creates a new ktable for 'p'.
** Return the offset of original 'p' elements in the new ktable.
*/
static int jointable (lua_State *L, int p1) {
int n, n1, i;
lua_getfenv(L, p1);
n1 = ktablelen(L, -1); /* number of elements in p1's env */
lua_getfenv(L, -2);
if (n1 == 0 || lua_equal(L, -2, -1)) {
lua_pop(L, 2);
return 0; /* no need to change anything */
}
n = ktablelen(L, -1); /* number of elements in p's env */
if (n == 0) {
lua_pop(L, 1); /* removes p env */
lua_setfenv(L, -2); /* p now shares p1's env */
return 0; /* no need to correct anything */
}
lua_createtable(L, n + n1, 0);
/* stack: p; p1 env; p env; new p env */
for (i = 1; i <= n; i++) {
lua_rawgeti(L, -2, i);
lua_rawseti(L, -2, i);
}
for (i = 1; i <= n1; i++) {
lua_rawgeti(L, -3, i);
lua_rawseti(L, -2, n + i);
}
lua_setfenv(L, -4); /* new table becomes p env */
lua_pop(L, 2); /* remove p1 env and old p env */
return n;
}
#define copypatt(p1,p2,sz) memcpy(p1, p2, (sz) * sizeof(Instruction));
#define pattsize(L,idx) (lua_objlen(L, idx)/sizeof(Instruction) - 1)
static int addpatt (lua_State *L, Instruction *p, int p1idx) {
Instruction *p1 = (Instruction *)lua_touserdata(L, p1idx);
int sz = pattsize(L, p1idx);
int corr = jointable(L, p1idx);
copypatt(p, p1, sz + 1);
if (corr != 0) {
Instruction *px;
for (px = p; px < p + sz; px += sizei(px)) {
if (isfenvoff(px) && px->i.offset != 0)
px->i.offset += corr;
}
}
return sz;
}
static void setinstaux (Instruction *i, Opcode op, int offset, int aux) {
assert(aux <= MAXAUX);
i->i.code = op;
i->i.offset = offset;
i->i.aux = aux;
}
#define setinst(i,op,off) setinstaux(i,op,off,0)
#define setinstcap(i,op,idx,k,n) setinstaux(i,op,idx,((k) | ((n) << 4)))
/*
** create a new ktable for pattern at the stack top, mapping
** '1' to the value at stack position 'vidx'.
*/
static int value2fenv (lua_State *L, int vidx) {
lua_createtable(L, 1, 0);
lua_pushvalue(L, vidx);
lua_rawseti(L, -2, 1);
lua_setfenv(L, -2);
return 1;
}
static Instruction *newpatt (lua_State *L, size_t n) {
Instruction *p;
if (n >= MAXPATTSIZE - 1)
luaL_error(L, "pattern too big");
p = (Instruction *)lua_newuserdata(L, (n + 1) * sizeof(Instruction));
luaL_getmetatable(L, PATTERN_T);
lua_setmetatable(L, -2);
setinst(p + n, IEnd, 0);
return p;
}
static void fillcharset (Instruction *p, Charset cs) {
switch (p[0].i.code) {
case ISet: {
loopset(i, cs[i] = p[1].buff[i]);
break;
}
case IChar: {
loopset(i, cs[i] = 0);
setchar(cs, p[0].i.aux);
break;
}
default: { /* any char may start unhandled instructions */
loopset(i, cs[i] = 0xff);
break;
}
}
}
/*
** Function 'tocharset' gets information about which chars may be a
** valid start for a pattern.
*/
static enum charsetanswer tocharset (Instruction *p, CharsetTag *c) {
if (isfixcheck(p)) {
fillcharset(p, c->cs);
if ((p + sizei(p))->i.code == IEnd && op_step(p) == 1)
c->tag = ISCHARSET;
else
c->tag = VALIDSTARTS;
}
else
c->tag = NOINFO;
return c->tag;
}
static int exclusiveset (Charset c1, Charset c2) {
/* non-empty intersection? */
loopset(i, {if ((c1[i] & c2[i]) != 0) return 0;});
return 1; /* no intersection */
}
static int exclusive (CharsetTag *c1, CharsetTag *c2) {
if (c1->tag == NOINFO || c2->tag == NOINFO)
return 0; /* one of them is not filled */
else return exclusiveset(c1->cs, c2->cs);
}
static Instruction *newcharset (lua_State *L) {
Instruction *p = newpatt(L, CHARSETINSTSIZE);
p[0].i.code = ISet;
p[0].i.offset = 0;
loopset(i, p[1].buff[i] = 0);
return p;
}
static int set_l (lua_State *L) {
size_t l;
const char *s = luaL_checklstring(L, 1, &l);
if (l == 1)
getpatt(L, 1, NULL); /* a unit set is equivalent to a literal */
else {
Instruction *p = newcharset(L);
while (l--) {
setchar(p[1].buff, (byte)(*s));
s++;
}
}
return 1;
}
static int range_l (lua_State *L) {
int arg;
int top = lua_gettop(L);
Instruction *p = newcharset(L);
for (arg = 1; arg <= top; arg++) {
int c;
size_t l;
const char *r = luaL_checklstring(L, arg, &l);
luaL_argcheck(L, l == 2, arg, "range must have two characters");
for (c = (byte)r[0]; c <= (byte)r[1]; c++)
setchar(p[1].buff, c);
}
return 1;
}
static int nter_l (lua_State *L) {
Instruction *p;
luaL_argcheck(L, !lua_isnoneornil(L, 1), 1, "non-nil value expected");
p = newpatt(L, 1);
setinst(p, IOpenCall, value2fenv(L, 1));
return 1;
}
static int testpattern (lua_State *L, int idx) {
if (lua_touserdata(L, idx)) { /* value is a userdata? */
if (lua_getmetatable(L, idx)) { /* does it have a metatable? */
luaL_getmetatable(L, PATTERN_T);
if (lua_rawequal(L, -1, -2)) { /* does it have the correct mt? */
lua_pop(L, 2); /* remove both metatables */
return 1;
}
}
}
return 0;
}
static Instruction *fix_l (lua_State *L, int t) {
Instruction *p;
int i;
int totalsize = 2; /* include initial call and jump */
int n = 0; /* number of rules */
int base = lua_gettop(L);
lua_newtable(L); /* to store relative positions of each rule */
lua_pushinteger(L, 1); /* default initial rule */
/* collect patterns and compute sizes */
lua_pushnil(L);
while (lua_next(L, t) != 0) {
int l;
if (lua_tonumber(L, -2) == 1 && lua_isstring(L, -1)) {
lua_replace(L, base + 2); /* use this value as initial rule */
continue;
}
if (!testpattern(L, -1))
luaL_error(L, "%s is not a pattern", val2str(L, -2));
l = pattsize(L, -1) + 1; /* space for pattern + ret */
if (totalsize >= MAXPATTSIZE - l)
luaL_error(L, "grammar too large");
luaL_checkstack(L, LUA_MINSTACK, "grammar has too many rules");
lua_insert(L, -2); /* put key on top */
lua_pushvalue(L, -1); /* duplicate key (for lua_next) */
lua_pushvalue(L, -1); /* duplicate key (to index positions table)) */
lua_pushinteger(L, totalsize); /* position for this rule */
lua_settable(L, base + 1); /* store key=>position in positions table */
totalsize += l;
n++;
}
luaL_argcheck(L, n > 0, t, "empty grammar");
p = newpatt(L, totalsize); /* create new pattern */
p++; /* save space for call */
setinst(p++, IJmp, totalsize - 1); /* after call, jumps to the end */
for (i = 1; i <= n; i++) { /* copy all rules into new pattern */
p += addpatt(L, p, base + 1 + i*2);
setinst(p++, IRet, 0);
}
p -= totalsize; /* back to first position */
totalsize = 2; /* go through each rule's position */
for (i = 1; i <= n; i++) { /* check all rules */
int l = pattsize(L, base + 1 + i*2) + 1;
checkrule(L, p, totalsize, totalsize + l, base + 1, base + 2 + i*2);
totalsize += l;
}
lua_pushvalue(L, base + 2); /* get initial rule */
lua_gettable(L, base + 1); /* get its position in postions table */
i = lua_tonumber(L, -1); /* convert to number */
lua_pop(L, 1);
if (i == 0) /* is it defined? */
luaL_error(L, "initial rule not defined in given grammar");
setinst(p, ICall, i); /* first instruction calls initial rule */
/* correct calls */
for (i = 0; i < totalsize; i += sizei(p + i)) {
if (p[i].i.code == IOpenCall) {
int pos = getposition(L, base + 1, p[i].i.offset);
p[i].i.code = (p[target(p, i + 1)].i.code == IRet) ? IJmp : ICall;
p[i].i.offset = pos - i;
}
}
optimizejumps(p);
lua_replace(L, t); /* put new pattern in old's position */
lua_settop(L, base); /* remove rules and positions table */
return p;
}
static Instruction *any (lua_State *L, int n, int extra, int *offsetp) {
int offset = offsetp ? *offsetp : 0;
Instruction *p = newpatt(L, (n - 1)/UCHAR_MAX + extra + 1);
Instruction *p1 = p + offset;
for (; n > UCHAR_MAX; n -= UCHAR_MAX)
setinstaux(p1++, IAny, 0, UCHAR_MAX);
setinstaux(p1++, IAny, 0, n);
if (offsetp) *offsetp = p1 - p;
return p;
}
static Instruction *getpatt (lua_State *L, int idx, int *size) {
Instruction *p;
switch (lua_type(L, idx)) {
case LUA_TSTRING: {
size_t i, len;
const char *s = lua_tolstring(L, idx, &len);
p = newpatt(L, len);
for (i = 0; i < len; i++)
setinstaux(p + i, IChar, 0, (byte)s[i]);
lua_replace(L, idx);
break;
}
case LUA_TNUMBER: {
int n = lua_tointeger(L, idx);
if (n == 0) /* empty pattern? */
p = newpatt(L, 0);
else if (n > 0)
p = any(L, n, 0, NULL);
else if (-n <= UCHAR_MAX) {
p = newpatt(L, 2);
setinstaux(p, IAny, 2, -n);
setinst(p + 1, IFail, 0);
}
else {
int offset = 2; /* space for ITestAny & IChoice */
p = any(L, -n - UCHAR_MAX, 3, &offset);
setinstaux(p, IAny, offset + 1, UCHAR_MAX);
setinstaux(p + 1, IChoice, offset, UCHAR_MAX);
setinst(p + offset, IFailTwice, 0);
}
lua_replace(L, idx);
break;
}
case LUA_TBOOLEAN: {
if (lua_toboolean(L, idx)) /* true? */
p = newpatt(L, 0); /* empty pattern (always succeeds) */
else {
p = newpatt(L, 1);
setinst(p, IFail, 0);
}
lua_replace(L, idx);
break;
}
case LUA_TTABLE: {
p = fix_l(L, idx);
break;
}
case LUA_TFUNCTION: {
p = newpatt(L, 2);
setinstcap(p, IOpenCapture, value2fenv(L, idx), Cruntime, 0);
setinstcap(p + 1, ICloseRunTime, 0, Cclose, 0);
lua_replace(L, idx);
break;
}
default: {
p = checkpattern(L, idx);
break;
}
}
if (size) *size = pattsize(L, idx);
return p;
}
static int getpattl (lua_State *L, int idx) {
int size;
getpatt(L, idx, &size);
return size;
}
static int pattern_l (lua_State *L) {
lua_settop(L, 1);
getpatt(L, 1, NULL);
return 1;
}
#define isany(p) ((p)->i.code == IAny && ((p) + 1)->i.code == IEnd)
#define isfail(p) ((p)->i.code == IFail)
#define issucc(p) ((p)->i.code == IEnd)
static int concat_l (lua_State *L) {
/* p1; p2; */
int l1, l2;
Instruction *p1 = getpatt(L, 1, &l1);
Instruction *p2 = getpatt(L, 2, &l2);
if (isfail(p1) || issucc(p2))
lua_pushvalue(L, 1); /* fail * x == fail; x * true == x */
else if (isfail(p2) || issucc(p1))
lua_pushvalue(L, 2); /* x * fail == fail; true * x == x */
else if (isany(p1) && isany(p2))
any(L, p1->i.aux + p2->i.aux, 0, NULL);
else {
Instruction *op = newpatt(L, l1 + l2);
Instruction *p = op + addpatt(L, op, 1);
addpatt(L, p, 2);
optimizecaptures(op);
}
return 1;
}
static int diff_l (lua_State *L) {
int l1, l2;
Instruction *p1 = getpatt(L, 1, &l1);
Instruction *p2 = getpatt(L, 2, &l2);
CharsetTag st1, st2;
if (tocharset(p1, &st1) == ISCHARSET && tocharset(p2, &st2) == ISCHARSET) {
Instruction *p = newcharset(L);
loopset(i, p[1].buff[i] = st1.cs[i] & ~st2.cs[i]);
}
else if (isheadfail(p2)) {
Instruction *p = newpatt(L, l2 + 1 + l1);
p += addpatt(L, p, 2);
check2test(p - l2, l2 + 1);
setinst(p++, IFail, 0);
addpatt(L, p, 1);
}
else { /* !e2 . e1 */
/* !e -> choice L1; e; failtwice; L1: ... */
Instruction *p = newpatt(L, 1 + l2 + 1 + l1);
Instruction *pi = p;
setinst(p++, IChoice, 1 + l2 + 1);
p += addpatt(L, p, 2);
setinst(p++, IFailTwice, 0);
addpatt(L, p, 1);
optimizechoice(pi);
}
return 1;
}
static int unm_l (lua_State *L) {
Instruction *p = getpatt(L, 1, NULL);
if (isfail(p)) { /* -false? */
newpatt(L, 0); /* true */
return 1;
}
else if (issucc(p)) { /* -true? */
Instruction *p1 = newpatt(L, 1); /* false */
setinst(p1, IFail, 0);
return 1;
}
else { /* -A == '' - A */
lua_pushliteral(L, "");
lua_insert(L, 1);
return diff_l(L);
}
}
static int pattand_l (lua_State *L) {
int l1;
CharsetTag st1;
Instruction *p1 = getpatt(L, 1, &l1);
if (isfail(p1) || issucc(p1))
lua_pushvalue(L, 1); /* &fail == fail; &true == true */
else if (tocharset(p1, &st1) == ISCHARSET) {
Instruction *p = newpatt(L, l1 + 1);
copypatt(p, p1, l1); p += l1;
setinstaux(p, IBack, 0, 1);
}
else { /* Choice L1; p1; BackCommit L2; L1: Fail; L2: */
Instruction *p = newpatt(L, 1 + l1 + 2);
setinst(p++, IChoice, 1 + l1 + 1);
p += addpatt(L, p, 1);
setinst(p++, IBackCommit, 2);
setinst(p, IFail, 0);
}
return 1;
}
static int nocalls (const Instruction *p) {
for (; (Opcode)p->i.code != IEnd; p += sizei(p))
if ((Opcode)p->i.code == IOpenCall) return 0;
return 1;
}
static int pattbehind (lua_State *L) {
int l1;
CharsetTag st1;
Instruction *p1 = getpatt(L, 1, &l1);
int n = luaL_optint(L, 2, 1);
luaL_argcheck(L, n <= MAXAUX, 2, "lookbehind delta too large");
if (!nocalls(p1))
luaL_error(L, "lookbehind pattern cannot contain non terminals");
if (isfail(p1) || issucc(p1))
lua_pushvalue(L, 1); /* <fail == fail; <true == true */
else if (n == 1 && tocharset(p1, &st1) == ISCHARSET) {
Instruction *p = newpatt(L, 1 + l1);
setinstaux(p, IBack, 0, 1); p++;
copypatt(p, p1, l1);
}
else { /* Choice L1; Back; p1; BackCommit L2; L1: fail; L2: */
Instruction *p = newpatt(L, 2 + l1 + 2);
setinst(p++, IChoice, 2 + l1 + 1);
setinstaux(p++, IBack, 0, n);
p += addpatt(L, p, 1);
setinst(p++, IBackCommit, 2);
setinst(p, IFail, 0);
}
return 1;
}
static int firstpart (Instruction *p, int l) {
if (istest(p)) {
int e = p[0].i.offset - 1;
if ((p[e].i.code == IJmp || p[e].i.code == ICommit) &&
e + p[e].i.offset == l)
return e + 1;
}
else if (p[0].i.code == IChoice) {
int e = p[0].i.offset - 1;
if (p[e].i.code == ICommit && e + p[e].i.offset == l)
return e + 1;
}
return 0;
}
static Instruction *auxnew (lua_State *L, Instruction **op, int *size,
int extra) {
*op = newpatt(L, *size + extra);
jointable(L, 1);
*size += extra;
return *op + *size - extra;
}
static int nofail (Instruction *p, int l) {
int i;
for (i = 0; i < l; i += sizei(p + i)) {
if (!isnofail(p + i)) return 0;
}
return 1;
}
static int interfere (Instruction *p1, int l1, CharsetTag *st2) {
if (nofail(p1, l1)) /* p1 cannot fail? */
return 0; /* nothing can intefere with it */
if (st2->tag == NOINFO) return 1;
assert(p1->i.offset != 0);
switch (p1->i.code) {
case IChar: return testchar(st2->cs, p1->i.aux);
case ISet: return !exclusiveset(st2->cs, (p1 + 1)->buff);
default: assert(p1->i.code == IAny); return 1;
}
}
static Instruction *basicUnion (lua_State *L, Instruction *p1, int l1,
int l2, int *size, CharsetTag *st2) {
Instruction *op;
CharsetTag st1;
tocharset(p1, &st1);
if (st1.tag == ISCHARSET && st2->tag == ISCHARSET) {
Instruction *p = auxnew(L, &op, size, CHARSETINSTSIZE);
setinst(p, ISet, 0);
loopset(i, p[1].buff[i] = st1.cs[i] | st2->cs[i]);
}
else if (exclusive(&st1, st2) || isheadfail(p1)) {
Instruction *p = auxnew(L, &op, size, l1 + 1 + l2);
copypatt(p, p1, l1);
check2test(p, l1 + 1);
p += l1;
setinst(p++, IJmp, l2 + 1);
addpatt(L, p, 2);
}
else {
/* choice L1; e1; commit L2; L1: e2; L2: ... */
Instruction *p = auxnew(L, &op, size, 1 + l1 + 1 + l2);
setinst(p++, IChoice, 1 + l1 + 1);
copypatt(p, p1, l1); p += l1;
setinst(p++, ICommit, 1 + l2);
addpatt(L, p, 2);
optimizechoice(p - (1 + l1 + 1));
}
return op;
}
static Instruction *separateparts (lua_State *L, Instruction *p1, int l1,
int l2, int *size, CharsetTag *st2) {
int sp = firstpart(p1, l1);
if (sp == 0) /* first part is entire p1? */
return basicUnion(L, p1, l1, l2, size, st2);
else if ((p1 + sp - 1)->i.code == ICommit || !interfere(p1, sp, st2)) {
Instruction *p;
int init = *size;
int end = init + sp;
*size = end;
p = separateparts(L, p1 + sp, l1 - sp, l2, size, st2);
copypatt(p + init, p1, sp);
(p + end - 1)->i.offset = *size - (end - 1);
return p;
}
else { /* must change back to non-optimized choice */
Instruction *p;
int init = *size;
int end = init + sp + 1; /* needs one extra instruction (choice) */
int sizefirst = sizei(p1); /* size of p1's first instruction (the test) */
*size = end;
p = separateparts(L, p1 + sp, l1 - sp, l2, size, st2);
copypatt(p + init, p1, sizefirst); /* copy the test */
(p + init)->i.offset++; /* correct jump (because of new instruction) */
init += sizefirst;
setinstaux(p + init, IChoice, sp - sizefirst + 1, 1); init++;
copypatt(p + init, p1 + sizefirst, sp - sizefirst - 1);
init += sp - sizefirst - 1;
setinst(p + init, ICommit, *size - (end - 1));
return p;
}
}
static int union_l (lua_State *L) {
int l1, l2;
int size = 0;
Instruction *p1 = getpatt(L, 1, &l1);
Instruction *p2 = getpatt(L, 2, &l2);
CharsetTag st2;
if (isfail(p1)) /* check for simple identities */
lua_pushvalue(L, 2); /* fail / a == a */
else if (isfail(p2) || issucc(p1))
lua_pushvalue(L, 1); /* a / fail == a; true / a == true */
else {
tocharset(p2, &st2);
separateparts(L, p1, l1, l2, &size, &st2);
}
return 1;
}
static int repeatcharset (lua_State *L, Charset cs, int l1, int n) {
/* e; ...; e; span; */
int i;
Instruction *p = newpatt(L, n*l1 + CHARSETINSTSIZE);
for (i = 0; i < n; i++) {
p += addpatt(L, p, 1);
}
setinst(p, ISpan, 0);
loopset(k, p[1].buff[k] = cs[k]);
return 1;
}
static Instruction *repeatheadfail (lua_State *L, int l1, int n) {
/* e; ...; e; L2: e'(L1); jump L2; L1: ... */
int i;
Instruction *p = newpatt(L, (n + 1)*l1 + 1);
Instruction *op = p;
for (i = 0; i < n; i++) {
p += addpatt(L, p, 1);
}
p += addpatt(L, p, 1);
check2test(p - l1, l1 + 1);
setinst(p, IJmp, -l1);
return op;
}
static Instruction *repeats (lua_State *L, Instruction *p1, int l1, int n) {
/* e; ...; e; choice L1; L2: e; partialcommit L2; L1: ... */
int i;
Instruction *op = newpatt(L, (n + 1)*l1 + 2);
Instruction *p = op;
if (!verify(L, p1, p1, p1 + l1, 0, 0))
luaL_error(L, "loop body may accept empty string");
for (i = 0; i < n; i++) {
p += addpatt(L, p, 1);
}
setinst(p++, IChoice, 1 + l1 + 1);
p += addpatt(L, p, 1);
setinst(p, IPartialCommit, -l1);
return op;
}
static void optionalheadfail (lua_State *L, int l1, int n) {
Instruction *op = newpatt(L, n * l1);
Instruction *p = op;
int i;
for (i = 0; i < n; i++) {
p += addpatt(L, p, 1);
check2test(p - l1, (n - i)*l1);
}
}
static void optionals (lua_State *L, int l1, int n) {
/* choice L1; e; partialcommit L2; L2: ... e; L1: commit L3; L3: ... */
int i;
Instruction *op = newpatt(L, n*(l1 + 1) + 1);
Instruction *p = op;
setinst(p++, IChoice, 1 + n*(l1 + 1));
for (i = 0; i < n; i++) {
p += addpatt(L, p, 1);
setinst(p++, IPartialCommit, 1);
}
setinst(p - 1, ICommit, 1); /* correct last commit */
optimizechoice(op);
}
static int star_l (lua_State *L) {
int l1;
int n = luaL_checkint(L, 2);
Instruction *p1 = getpatt(L, 1, &l1);
if (n >= 0) {
CharsetTag st;
Instruction *op;
if (tocharset(p1, &st) == ISCHARSET)
return repeatcharset(L, st.cs, l1, n);
if (isheadfail(p1))
op = repeatheadfail(L, l1, n);
else
op = repeats(L, p1, l1, n);
optimizecaptures(op);
optimizejumps(op);
}
else {
if (isheadfail(p1))
optionalheadfail(L, l1, -n);
else
optionals(L, l1, -n);
}
return 1;
}
static int getlabel (lua_State *L, int labelidx) {
if (labelidx == 0) return 0;
else return value2fenv(L, labelidx);
}
static int capture_aux (lua_State *L, int kind, int labelidx) {
int l1, n;
Instruction *p1 = getpatt(L, 1, &l1);
int lc = skipchecks(p1, 0, &n);
if (lc == l1) { /* got whole pattern? */
/* may use a IFullCapture instruction at its end */
Instruction *p = newpatt(L, l1 + 1);
int label = getlabel(L, labelidx);
p += addpatt(L, p, 1);
setinstcap(p, IFullCapture, label, kind, n);
}
else { /* must use open-close pair */
Instruction *op = newpatt(L, 1 + l1 + 1);
Instruction *p = op;
setinstcap(p++, IOpenCapture, getlabel(L, labelidx), kind, 0);
p += addpatt(L, p, 1);
setinstcap(p, ICloseCapture, 0, Cclose, 0);
optimizecaptures(op);
}
return 1;
}
static int capture_l (lua_State *L) { return capture_aux(L, Csimple, 0); }
static int tcapture_l (lua_State *L) { return capture_aux(L, Ctable, 0); }
static int capsubst_l (lua_State *L) { return capture_aux(L, Csubst, 0); }
static int rcapture_l (lua_State *L) {
switch (lua_type(L, 2)) {
case LUA_TFUNCTION: return capture_aux(L, Cfunction, 2);
case LUA_TTABLE: return capture_aux(L, Cquery, 2);
case LUA_TSTRING: return capture_aux(L, Cstring, 2);
default: return luaL_argerror(L, 2, "invalid replacement value");
}
}
static int fold_l (lua_State *L) {
luaL_checktype(L, 2, LUA_TFUNCTION);
return capture_aux(L, Cfold, 2);
}
static int group_l (lua_State *L) {
if (lua_isnoneornil(L, 2))
return capture_aux(L, Cgroup, 0);
else {
luaL_checkstring(L, 2);
return capture_aux(L, Cgroup, 2);
}
}
static int position_l (lua_State *L) {
Instruction *p = newpatt(L, 1);
setinstcap(p, IEmptyCapture, 0, Cposition, 0);
return 1;
}
static int backref_l (lua_State *L) {
Instruction *p = newpatt(L, 1);
int n = getlabel(L, 1);
setinstcap(p, IEmptyCaptureIdx, n, Cbackref, 0);
return 1;
}
static int argcap_l (lua_State *L) {
int n = luaL_checkint(L, 1);
Instruction *p = newpatt(L, 1);
luaL_argcheck(L, 0 < n && n <= SHRT_MAX, 1, "invalid argument index");
setinstcap(p, IEmptyCapture, n, Carg, 0);
return 1;
}
static int matchtime_l (lua_State *L) {
int l1 = getpattl(L, 1);
Instruction *op = newpatt(L, 1 + l1 + 1);
Instruction *p = op;
luaL_checktype(L, 2, LUA_TFUNCTION);
setinstcap(p++, IOpenCapture, value2fenv(L, 2), Cruntime, 0);
p += addpatt(L, p, 1);
setinstcap(p, ICloseRunTime, 0, Cclose, 0);
optimizecaptures(op);
return 1;
}
static int capconst_l (lua_State *L) {
int i, j;
int n = lua_gettop(L);
Instruction *p = newpatt(L, n > 1 ? n + 2 : n);
lua_createtable(L, n, 0); /* new environment for the new pattern */
if (n > 1) setinstcap(p++, IOpenCapture, 0, Cgroup, 0);
for (i = j = 1; i <= n; i++) {
if (lua_isnil(L, i))
setinstcap(p++, IEmptyCaptureIdx, 0, Cconst, 0);
else {
setinstcap(p++, IEmptyCaptureIdx, j, Cconst, 0);
lua_pushvalue(L, i);
lua_rawseti(L, -2, j++);
}
}
if (n > 1) setinstcap(p++, ICloseCapture, 0, Cclose, 0);
lua_setfenv(L, -2); /* set environment */
return 1;
}
/* }====================================================== */
/*
** {======================================================
** User-Defined Patterns
** =======================================================
*/
static void l_newpf (lua_State *L, PattFunc f, const void *ud, size_t l) {
int n = instsize(l) + 1;
Instruction *p = newpatt(L, n);
if (n > MAXAUX) luaL_error(L, "pattern data too long");
p[0].i.code = IFunc;
p[0].i.aux = n - 2;
p[0].i.offset = 0;
p[1].f = f;
memcpy(p[2].buff, ud, l);
}
/* }====================================================== */
/*
** {======================================================
** Captures
** =======================================================
*/
typedef struct CapState {
Capture *cap; /* current capture */
Capture *ocap; /* (original) capture list */
lua_State *L;
int ptop; /* index of last argument to 'match' */
const char *s; /* original string */
int valuecached; /* value stored in cache slot */
} CapState;
#define captype(cap) ((cap)->kind)
#define isclosecap(cap) (captype(cap) == Cclose)
#define closeaddr(c) ((c)->s + (c)->siz - 1)
#define isfullcap(cap) ((cap)->siz != 0)
#define getfromenv(cs,v) lua_rawgeti((cs)->L, penvidx((cs)->ptop), v)
#define pushluaval(cs) getfromenv(cs, (cs)->cap->idx)
#define pushsubject(cs, c) lua_pushlstring((cs)->L, (c)->s, (c)->siz - 1)
#define updatecache(cs,v) { if ((v) != (cs)->valuecached) updatecache_(cs,v); }
static void updatecache_ (CapState *cs, int v) {
getfromenv(cs, v);
lua_replace(cs->L, subscache(cs));
cs->valuecached = v;
}
static int pushcapture (CapState *cs);
static Capture *findopen (Capture *cap) {
int n = 0;
for (;;) {
cap--;
if (isclosecap(cap)) n++;
else if (!isfullcap(cap))
if (n-- == 0) return cap;
}
}
static Capture *nextcap (Capture *cap) {
if (isfullcap(cap)) return cap + 1;
else {
int n = 0;
for (;;) {
cap++;
if (isclosecap(cap)) {
if (n-- == 0) return cap + 1;
}
else if (!isfullcap(cap)) n++;
}
}
}
static int pushallvalues (CapState *cs, int addextra) {
Capture *co = cs->cap;
int n = 0;
if (isfullcap(cs->cap++)) {
pushsubject(cs, co); /* push whole match */
return 1;
}
while (!isclosecap(cs->cap))
n += pushcapture(cs);
if (addextra || n == 0) { /* need extra? */
lua_pushlstring(cs->L, co->s, cs->cap->s - co->s); /* push whole match */
n++;
}
cs->cap++; /* skip close entry */
return n;
}
static Capture *findback (CapState *cs, Capture *cap) {
lua_State *L = cs->L;
for (;;) {
if (cap == cs->ocap) { /* not found */
const char *s = lua_tostring(L, -1);
if (s == NULL) s = lua_pushfstring(L, "(a %s)", luaL_typename(L, -1));
luaL_error(L, "back reference '%s' not found", s);
}
cap--;
if (isclosecap(cap))
cap = findopen(cap);
else if (!isfullcap(cap))
continue; /* opening an enclosing capture: skip and get previous */
if (captype(cap) == Cgroup) {
getfromenv(cs, cap->idx); /* get group name */
if (lua_equal(L, -2, -1)) { /* right group? */
lua_pop(L, 2); /* remove reference name and group name */
return cap;
}
else lua_pop(L, 1); /* remove group name */
}
}
}
static int backrefcap (CapState *cs) {
int n;
Capture *curr = cs->cap;
pushluaval(cs); /* reference name */
cs->cap = findback(cs, curr);
n = pushallvalues(cs, 0);
cs->cap = curr + 1;
return n;
}
static int tablecap (CapState *cs) {
lua_State *L = cs->L;
int n = 0;
lua_newtable(L);
if (isfullcap(cs->cap++))
return 1; /* table is empty */
while (!isclosecap(cs->cap)) {
if (captype(cs->cap) == Cgroup && cs->cap->idx != 0) { /* named group? */
int k;
pushluaval(cs); /* push group name */
k = pushallvalues(cs, 0);
if (k == 0) { /* no value? */
lua_pop(L, 1); /* remove group name */
continue; /* and go on */
}
else if (k > 1)
lua_pop(L, k - 1); /* keep just one value */
lua_settable(L, -3);
}
else {
int i;
int k = pushcapture(cs);
for (i = k; i > 0; i--)
lua_rawseti(L, -(i + 1), n + i);
n += k;
}
}
cs->cap++; /* skip close entry */
return 1;
}
static int querycap (CapState *cs) {
int idx = cs->cap->idx;
int n = pushallvalues(cs, 0);
if (n > 1) /* extra captures? */
lua_pop(cs->L, n - 1); /* throw them away */
updatecache(cs, idx);
lua_gettable(cs->L, subscache(cs));
if (!lua_isnil(cs->L, -1))
return 1;
else {
lua_pop(cs->L, 1); /* remove value */
return 0;
}
}
static int foldcap (CapState *cs) {
int n;
lua_State *L = cs->L;
int idx = cs->cap->idx;
if (isfullcap(cs->cap++) || isclosecap(cs->cap) || (n = pushcapture(cs)) == 0)
return luaL_error(L, "no initial value for fold capture");
if (n > 1)
lua_pop(L, n - 1); /* leave only one result */
while (!isclosecap(cs->cap)) {
updatecache(cs, idx);
lua_pushvalue(L, subscache(cs)); /* get folding function */
lua_insert(L, -2); /* put it before accumulator */
n = pushcapture(cs); /* get other captures */
lua_call(L, n + 1, 1); /* call folding function */
}
cs->cap++; /* skip close entry */
return 1;
}
static int functioncap (CapState *cs) {
int n;
int top = lua_gettop(cs->L);
pushluaval(cs);
n = pushallvalues(cs, 0);
lua_call(cs->L, n, LUA_MULTRET);
return lua_gettop(cs->L) - top;
}
static int runtimecap (lua_State *L, Capture *close, Capture *ocap,
const char *o, const char *s, int ptop) {
CapState cs;
int n;
Capture *open = findopen(close);
assert(captype(open) == Cruntime);
close->kind = Cclose;
close->s = s;
cs.ocap = ocap; cs.cap = open; cs.L = L;
cs.s = o; cs.valuecached = 0; cs.ptop = ptop;
luaL_checkstack(L, 4, "too many runtime captures");
pushluaval(&cs);
lua_pushvalue(L, SUBJIDX); /* push original subject */
lua_pushinteger(L, s - o + 1); /* current position */
n = pushallvalues(&cs, 0);
lua_call(L, n + 2, LUA_MULTRET);
return close - open;
}
typedef struct StrAux {
int isstring;
union {
Capture *cp;
struct {
const char *s;
const char *e;
} s;
} u;
} StrAux;
#define MAXSTRCAPS 10
static int getstrcaps (CapState *cs, StrAux *cps, int n) {
int k = n++;
cps[k].isstring = 1;
cps[k].u.s.s = cs->cap->s;
if (!isfullcap(cs->cap++)) {
while (!isclosecap(cs->cap)) {
if (n >= MAXSTRCAPS) /* too many captures? */
cs->cap = nextcap(cs->cap); /* skip it */
else if (captype(cs->cap) == Csimple)
n = getstrcaps(cs, cps, n);
else {
cps[n].isstring = 0;
cps[n].u.cp = cs->cap;
cs->cap = nextcap(cs->cap);
n++;
}
}
cs->cap++; /* skip close */
}
cps[k].u.s.e = closeaddr(cs->cap - 1);
return n;
}
/*
** add next capture (which should be a string) to buffer
*/
static int addonestring (luaL_Buffer *b, CapState *cs, const char *what);
static void stringcap (luaL_Buffer *b, CapState *cs) {
StrAux cps[MAXSTRCAPS];
int n;
size_t len, i;
const char *c;
updatecache(cs, cs->cap->idx);
c = lua_tolstring(cs->L, subscache(cs), &len);
n = getstrcaps(cs, cps, 0) - 1;
for (i = 0; i < len; i++) {
if (c[i] != '%' || c[++i] < '0' || c[i] > '9')
luaL_addchar(b, c[i]);
else {
int l = c[i] - '0';
if (l > n)
luaL_error(cs->L, "invalid capture index (%d)", l);
else if (cps[l].isstring)
luaL_addlstring(b, cps[l].u.s.s, cps[l].u.s.e - cps[l].u.s.s);
else {
Capture *curr = cs->cap;
cs->cap = cps[l].u.cp;
if (addonestring(b, cs, "capture") == 0)
luaL_error(cs->L, "no values in capture index %d", l);
cs->cap = curr;
}
}
}
}
static void substcap (luaL_Buffer *b, CapState *cs) {
const char *curr = cs->cap->s;
if (isfullcap(cs->cap)) /* no nested captures? */
luaL_addlstring(b, curr, cs->cap->siz - 1); /* keep original text */
else {
cs->cap++;
while (!isclosecap(cs->cap)) {
const char *next = cs->cap->s;
luaL_addlstring(b, curr, next - curr); /* add text up to capture */
if (addonestring(b, cs, "replacement") == 0) /* no capture value? */
curr = next; /* keep original text in final result */
else
curr = closeaddr(cs->cap - 1); /* continue after match */
}
luaL_addlstring(b, curr, cs->cap->s - curr); /* add last piece of text */
}
cs->cap++; /* go to next capture */
}
static int addonestring (luaL_Buffer *b, CapState *cs, const char *what) {
switch (captype(cs->cap)) {
case Cstring:
stringcap(b, cs); /* add capture directly to buffer */
return 1;
case Csubst:
substcap(b, cs); /* add capture directly to buffer */
return 1;
default: {
lua_State *L = cs->L;
int n = pushcapture(cs);
if (n > 0) {
if (n > 1) lua_pop(L, n - 1); /* only one result */
if (!lua_isstring(L, -1))
luaL_error(L, "invalid %s value (a %s)", what, luaL_typename(L, -1));
luaL_addvalue(b);
}
return n;
}
}
}
static int pushcapture (CapState *cs) {
luaL_checkstack(cs->L, 4, "too many captures");
switch (captype(cs->cap)) {
case Cposition: {
lua_pushinteger(cs->L, cs->cap->s - cs->s + 1);
cs->cap++;
return 1;
}
case Cconst: {
pushluaval(cs);
cs->cap++;
return 1;
}
case Carg: {
int arg = (cs->cap++)->idx;
if (arg + FIXEDARGS > cs->ptop)
return luaL_error(cs->L, "reference to absent argument #%d", arg);
lua_pushvalue(cs->L, arg + FIXEDARGS);
return 1;
}
case Csimple: {
int k = pushallvalues(cs, 1);
if (k > 1)
lua_insert(cs->L, -k); /* whole match is first result */
return k;
}
case Cruntime: {
int n = 0;
while (!isclosecap(cs->cap++)) {
luaL_checkstack(cs->L, 4, "too many captures");
lua_pushvalue(cs->L, (cs->cap - 1)->idx);
n++;
}
return n;
}
case Cstring: {
luaL_Buffer b;
luaL_buffinit(cs->L, &b);
stringcap(&b, cs);
luaL_pushresult(&b);
return 1;
}
case Csubst: {
luaL_Buffer b;
luaL_buffinit(cs->L, &b);
substcap(&b, cs);
luaL_pushresult(&b);
return 1;
}
case Cgroup: {
if (cs->cap->idx == 0) /* anonymous group? */
return pushallvalues(cs, 0); /* add all nested values */
else { /* named group: add no values */
cs->cap = nextcap(cs->cap); /* skip capture */
return 0;
}
}
case Cbackref: return backrefcap(cs);
case Ctable: return tablecap(cs);
case Cfunction: return functioncap(cs);
case Cquery: return querycap(cs);
case Cfold: return foldcap(cs);
default: assert(0); return 0;
}
}
static int getcaptures (lua_State *L, const char *s, const char *r, int ptop) {
Capture *capture = (Capture *)lua_touserdata(L, caplistidx(ptop));
int n = 0;
if (!isclosecap(capture)) { /* is there any capture? */
CapState cs;
cs.ocap = cs.cap = capture; cs.L = L;
cs.s = s; cs.valuecached = 0; cs.ptop = ptop;
do { /* collect their values */
n += pushcapture(&cs);
} while (!isclosecap(cs.cap));
}
if (n == 0) { /* no capture values? */
lua_pushinteger(L, r - s + 1); /* return only end position */
n = 1;
}
return n;
}
/* }====================================================== */
static int version_l (lua_State *L) {
lua_pushstring(L, VERSION);
return 1;
}
static int type_l (lua_State *L) {
if (testpattern(L, 1))
lua_pushliteral(L, "pattern");
else
lua_pushnil(L);
return 1;
}
static void createcat (lua_State *L, const char *catname, int (catf) (int)) {
Instruction *p = newcharset(L);
int i;
for (i = 0; i < CHAR_MAX; i++)
if (catf(i)) setchar(p[1].buff, i);
lua_setfield(L, -2, catname);
}
static int locale_l (lua_State *L) {
if (lua_isnoneornil(L, 1)) {
lua_settop(L, 0);
lua_createtable(L, 0, 12);
}
else {
luaL_checktype(L, 1, LUA_TTABLE);
lua_settop(L, 1);
}
createcat(L, "alnum", isalnum);
createcat(L, "alpha", isalpha);
createcat(L, "cntrl", iscntrl);
createcat(L, "digit", isdigit);
createcat(L, "graph", isgraph);
createcat(L, "lower", islower);
createcat(L, "print", isprint);
createcat(L, "punct", ispunct);
createcat(L, "space", isspace);
createcat(L, "upper", isupper);
createcat(L, "xdigit", isxdigit);
return 1;
}
static int setmax (lua_State *L) {
luaL_optinteger(L, 1, -1);
lua_settop(L, 1);
lua_setfield(L, LUA_REGISTRYINDEX, MAXSTACKIDX);
return 0;
}
static int printpat_l (lua_State *L) {
Instruction *p = getpatt(L, 1, NULL);
int n, i;
lua_getfenv(L, 1);
n = ktablelen(L, -1);
printf("[");
for (i = 1; i <= n; i++) {
printf("%d = ", i);
lua_rawgeti(L, -1, i);
if (lua_isstring(L, -1))
printf("%s ", lua_tostring(L, -1));
else
printf("%s ", lua_typename(L, lua_type(L, -1)));
lua_pop(L, 1);
}
printf("]\n");
printpatt(p);
return 0;
}
static int matchl (lua_State *L) {
Capture capture[INITCAPSIZE];
const char *r;
size_t l;
Instruction *p = getpatt(L, 1, NULL);
const char *s = luaL_checklstring(L, SUBJIDX, &l);
int ptop = lua_gettop(L);
lua_Integer ii = luaL_optinteger(L, 3, 1);
size_t i = (ii > 0) ?
(((size_t)ii <= l) ? (size_t)ii - 1 : l) :
(((size_t)-ii <= l) ? l - ((size_t)-ii) : 0);
lua_pushnil(L); /* subscache */
lua_pushlightuserdata(L, capture); /* caplistidx */
lua_getfenv(L, 1); /* penvidx */
r = match(L, s, s + i, s + l, p, capture, ptop);
if (r == NULL) {
lua_pushnil(L);
return 1;
}
return getcaptures(L, s, r, ptop);
}
static struct luaL_reg pattreg[] = {
{"match", matchl},
{"print", printpat_l},
{"locale", locale_l},
{"setmaxstack", setmax},
{"B", pattbehind},
{"C", capture_l},
{"Cf", fold_l},
{"Cc", capconst_l},
{"Cg", group_l},
{"Cp", position_l},
{"Cb", backref_l},
{"Carg", argcap_l},
{"Cmt", matchtime_l},
{"Cs", capsubst_l},
{"Ct", tcapture_l},
{"P", pattern_l},
{"R", range_l},
{"S", set_l},
{"V", nter_l},
{"type", type_l},
{"version", version_l},
{NULL, NULL}
};
static struct luaL_reg metapattreg[] = {
{"__add", union_l},
{"__pow", star_l},
{"__sub", diff_l},
{"__mul", concat_l},
{"__div", rcapture_l},
{"__unm", unm_l},
{"__len", pattand_l},
{NULL, NULL}
};
int luaopen_lpeg (lua_State *L);
int luaopen_lpeg (lua_State *L) {
lua_pushcfunction(L, (lua_CFunction)&l_newpf); /* new-pattern function */
lua_setfield(L, LUA_REGISTRYINDEX, KEYNEWPATT); /* register it */
luaL_newmetatable(L, PATTERN_T);
lua_pushnumber(L, MAXBACK);
lua_setfield(L, LUA_REGISTRYINDEX, MAXSTACKIDX);
luaL_register(L, NULL, metapattreg);
luaL_register(L, "lpeg", pattreg);
lua_pushliteral(L, "__index");
lua_pushvalue(L, -2);
lua_settable(L, -4);
return 1;
}
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