/js/lib/Socket.IO-node/support/expresso/deps/jscoverage/js/jsregexp.cpp

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set sw=4 ts=8 et tw=78:
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/*
 * JS regular expressions, after Perl.
 */
#include "jsstddef.h"
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include "jstypes.h"
#include "jsarena.h" /* Added by JSIFY */
#include "jsutil.h" /* Added by JSIFY */
#include "jsapi.h"
#include "jsarray.h"
#include "jsatom.h"
#include "jsbuiltins.h"
#include "jscntxt.h"
#include "jsversion.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jsinterp.h"
#include "jslock.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsregexp.h"
#include "jsscan.h"
#include "jsscope.h"
#include "jsstr.h"

#ifdef JS_TRACER
#include "jstracer.h"
using namespace avmplus;
using namespace nanojit;

/* 
 * FIXME  Duplicated with jstracer.cpp, doing it this way for now
 *        to keep it private to files that need it. 
 */
#ifdef JS_JIT_SPEW
static bool verbose_debug = getenv("TRACEMONKEY") && strstr(getenv("TRACEMONKEY"), "verbose");
#define debug_only_v(x) if (verbose_debug) { x; }
#else
#define debug_only_v(x)
#endif
#endif

typedef enum REOp {
#define REOP_DEF(opcode, name) opcode,
#include "jsreops.tbl"
#undef REOP_DEF
    REOP_LIMIT /* META: no operator >= to this */
} REOp;

#define REOP_IS_SIMPLE(op)  ((op) <= REOP_NCLASS)

#ifdef REGEXP_DEBUG
const char *reop_names[] = {
#define REOP_DEF(opcode, name) name,
#include "jsreops.tbl"
#undef REOP_DEF
    NULL
};
#endif

#ifdef __GNUC__
static int
re_debug(const char *fmt, ...) __attribute__ ((format(printf, 1, 2)));
#endif

#ifdef REGEXP_DEBUG
static int
re_debug(const char *fmt, ...)
{
    va_list ap;
    int retval;

    va_start(ap, fmt);
    retval = vprintf(fmt, ap);
    va_end(ap);
    return retval;
}

static void
re_debug_chars(const jschar *chrs, size_t length)
{
    int i = 0;

    printf(" \"");
    while (*chrs && i++ < length) {
        putchar((char)*chrs++);
    }
    printf("\"");
}
#else  /* !REGEXP_DEBUG */
/* This should be optimized to a no-op by our tier-1 compilers. */
static int
re_debug(const char *fmt, ...)
{
    return 0;
}

static void
re_debug_chars(const jschar *chrs, size_t length)
{
}
#endif /* !REGEXP_DEBUG */

struct RENode {
    REOp            op;         /* r.e. op bytecode */
    RENode          *next;      /* next in concatenation order */
    void            *kid;       /* first operand */
    union {
        void        *kid2;      /* second operand */
        jsint       num;        /* could be a number */
        size_t      parenIndex; /* or a parenthesis index */
        struct {                /* or a quantifier range */
            uintN  min;
            uintN  max;
            JSPackedBool greedy;
        } range;
        struct {                /* or a character class */
            size_t  startIndex;
            size_t  kidlen;     /* length of string at kid, in jschars */
            size_t  index;      /* index into class list */
            uint16  bmsize;     /* bitmap size, based on max char code */
            JSPackedBool sense;
        } ucclass;
        struct {                /* or a literal sequence */
            jschar  chr;        /* of one character */
            size_t  length;     /* or many (via the kid) */
        } flat;
        struct {
            RENode  *kid2;      /* second operand from ALT */
            jschar  ch1;        /* match char for ALTPREREQ */
            jschar  ch2;        /* ditto, or class index for ALTPREREQ2 */
        } altprereq;
    } u;
};

#define RE_IS_LETTER(c)     (((c >= 'A') && (c <= 'Z')) ||                    \
                             ((c >= 'a') && (c <= 'z')) )
#define RE_IS_LINE_TERM(c)  ((c == '\n') || (c == '\r') ||                    \
                             (c == LINE_SEPARATOR) || (c == PARA_SEPARATOR))

#define CLASS_CACHE_SIZE    4

typedef struct CompilerState {
    JSContext       *context;
    JSTokenStream   *tokenStream; /* For reporting errors */
    const jschar    *cpbegin;
    const jschar    *cpend;
    const jschar    *cp;
    size_t          parenCount;
    size_t          classCount;   /* number of [] encountered */
    size_t          treeDepth;    /* maximum depth of parse tree */
    size_t          progLength;   /* estimated bytecode length */
    RENode          *result;
    size_t          classBitmapsMem; /* memory to hold all class bitmaps */
    struct {
        const jschar *start;        /* small cache of class strings */
        size_t length;              /* since they're often the same */
        size_t index;
    } classCache[CLASS_CACHE_SIZE];
    uint16          flags;
} CompilerState;

typedef struct EmitStateStackEntry {
    jsbytecode      *altHead;       /* start of REOP_ALT* opcode */
    jsbytecode      *nextAltFixup;  /* fixup pointer to next-alt offset */
    jsbytecode      *nextTermFixup; /* fixup ptr. to REOP_JUMP offset */
    jsbytecode      *endTermFixup;  /* fixup ptr. to REOPT_ALTPREREQ* offset */
    RENode          *continueNode;  /* original REOP_ALT* node being stacked */
    jsbytecode      continueOp;     /* REOP_JUMP or REOP_ENDALT continuation */
    JSPackedBool    jumpToJumpFlag; /* true if we've patched jump-to-jump to
                                       avoid 16-bit unsigned offset overflow */
} EmitStateStackEntry;

/*
 * Immediate operand sizes and getter/setters.  Unlike the ones in jsopcode.h,
 * the getters and setters take the pc of the offset, not of the opcode before
 * the offset.
 */
#define ARG_LEN             2
#define GET_ARG(pc)         ((uint16)(((pc)[0] << 8) | (pc)[1]))
#define SET_ARG(pc, arg)    ((pc)[0] = (jsbytecode) ((arg) >> 8),       \
                             (pc)[1] = (jsbytecode) (arg))

#define OFFSET_LEN          ARG_LEN
#define OFFSET_MAX          (JS_BIT(ARG_LEN * 8) - 1)
#define GET_OFFSET(pc)      GET_ARG(pc)

/*
 * Maximum supported tree depth is maximum size of EmitStateStackEntry stack.
 * For sanity, we limit it to 2^24 bytes.
 */
#define TREE_DEPTH_MAX  (JS_BIT(24) / sizeof(EmitStateStackEntry))

/*
 * The maximum memory that can be allocated for class bitmaps.
 * For sanity, we limit it to 2^24 bytes.
 */
#define CLASS_BITMAPS_MEM_LIMIT JS_BIT(24)

/*
 * Functions to get size and write/read bytecode that represent small indexes
 * compactly.
 * Each byte in the code represent 7-bit chunk of the index. 8th bit when set
 * indicates that the following byte brings more bits to the index. Otherwise
 * this is the last byte in the index bytecode representing highest index bits.
 */
static size_t
GetCompactIndexWidth(size_t index)
{
    size_t width;

    for (width = 1; (index >>= 7) != 0; ++width) { }
    return width;
}

static JS_ALWAYS_INLINE jsbytecode *
WriteCompactIndex(jsbytecode *pc, size_t index)
{
    size_t next;

    while ((next = index >> 7) != 0) {
        *pc++ = (jsbytecode)(index | 0x80);
        index = next;
    }
    *pc++ = (jsbytecode)index;
    return pc;
}

static JS_ALWAYS_INLINE jsbytecode *
ReadCompactIndex(jsbytecode *pc, size_t *result)
{
    size_t nextByte;

    nextByte = *pc++;
    if ((nextByte & 0x80) == 0) {
        /*
         * Short-circuit the most common case when compact index <= 127.
         */
        *result = nextByte;
    } else {
        size_t shift = 7;
        *result = 0x7F & nextByte;
        do {
            nextByte = *pc++;
            *result |= (nextByte & 0x7F) << shift;
            shift += 7;
        } while ((nextByte & 0x80) != 0);
    }
    return pc;
}

typedef struct RECapture {
    ptrdiff_t index;           /* start of contents, -1 for empty  */
    size_t length;             /* length of capture */
} RECapture;

typedef struct REMatchState {
    const jschar *cp;
    RECapture parens[1];      /* first of 're->parenCount' captures,
                                 allocated at end of this struct */
} REMatchState;

struct REBackTrackData;

typedef struct REProgState {
    jsbytecode *continue_pc;        /* current continuation data */
    jsbytecode continue_op;
    ptrdiff_t index;                /* progress in text */
    size_t parenSoFar;              /* highest indexed paren started */
    union {
        struct {
            uintN min;             /* current quantifier limits */
            uintN max;
        } quantifier;
        struct {
            size_t top;             /* backtrack stack state */
            size_t sz;
        } assertion;
    } u;
} REProgState;

typedef struct REBackTrackData {
    size_t sz;                      /* size of previous stack entry */
    jsbytecode *backtrack_pc;       /* where to backtrack to */
    jsbytecode backtrack_op;
    const jschar *cp;               /* index in text of match at backtrack */
    size_t parenIndex;              /* start index of saved paren contents */
    size_t parenCount;              /* # of saved paren contents */
    size_t saveStateStackTop;       /* number of parent states */
    /* saved parent states follow */
    /* saved paren contents follow */
} REBackTrackData;

#define INITIAL_STATESTACK  100
#define INITIAL_BACKTRACK   8000

typedef struct REGlobalData {
    JSContext *cx;
    JSRegExp *regexp;               /* the RE in execution */
    JSBool ok;                      /* runtime error (out_of_memory only?) */
    size_t start;                   /* offset to start at */
    ptrdiff_t skipped;              /* chars skipped anchoring this r.e. */
    const jschar    *cpbegin;       /* text base address */
    const jschar    *cpend;         /* text limit address */

    REProgState *stateStack;        /* stack of state of current parents */
    size_t stateStackTop;
    size_t stateStackLimit;

    REBackTrackData *backTrackStack;/* stack of matched-so-far positions */
    REBackTrackData *backTrackSP;
    size_t backTrackStackSize;
    size_t cursz;                   /* size of current stack entry */
    size_t backTrackCount;          /* how many times we've backtracked */
    size_t backTrackLimit;          /* upper limit on backtrack states */
} REGlobalData;

/*
 * 1. If IgnoreCase is false, return ch.
 * 2. Let u be ch converted to upper case as if by calling
 *    String.prototype.toUpperCase on the one-character string ch.
 * 3. If u does not consist of a single character, return ch.
 * 4. Let cu be u's character.
 * 5. If ch's code point value is greater than or equal to decimal 128 and cu's
 *    code point value is less than decimal 128, then return ch.
 * 6. Return cu.
 */
static JS_ALWAYS_INLINE uintN
upcase(uintN ch)
{
    uintN cu;

    JS_ASSERT((uintN) (jschar) ch == ch);
    if (ch < 128) {
        if (ch - (uintN) 'a' <= (uintN) ('z' - 'a'))
            ch -= (uintN) ('a' - 'A');
        return ch;
    }

    cu = JS_TOUPPER(ch);
    return (cu < 128) ? ch : cu;
}

static JS_ALWAYS_INLINE uintN
downcase(uintN ch)
{
    JS_ASSERT((uintN) (jschar) ch == ch);
    if (ch < 128) {
        if (ch - (uintN) 'A' <= (uintN) ('Z' - 'A'))
            ch += (uintN) ('a' - 'A');
        return ch;
    }

    return JS_TOLOWER(ch);
}

/* Construct and initialize an RENode, returning NULL for out-of-memory */
static RENode *
NewRENode(CompilerState *state, REOp op)
{
    JSContext *cx;
    RENode *ren;

    cx = state->context;
    JS_ARENA_ALLOCATE_CAST(ren, RENode *, &cx->tempPool, sizeof *ren);
    if (!ren) {
        js_ReportOutOfScriptQuota(cx);
        return NULL;
    }
    ren->op = op;
    ren->next = NULL;
    ren->kid = NULL;
    return ren;
}

/*
 * Validates and converts hex ascii value.
 */
static JSBool
isASCIIHexDigit(jschar c, uintN *digit)
{
    uintN cv = c;

    if (cv < '0')
        return JS_FALSE;
    if (cv <= '9') {
        *digit = cv - '0';
        return JS_TRUE;
    }
    cv |= 0x20;
    if (cv >= 'a' && cv <= 'f') {
        *digit = cv - 'a' + 10;
        return JS_TRUE;
    }
    return JS_FALSE;
}


typedef struct {
    REOp op;
    const jschar *errPos;
    size_t parenIndex;
} REOpData;

static JSBool
ReportRegExpErrorHelper(CompilerState *state, uintN flags, uintN errorNumber,
                        const jschar *arg)
{
    if (state->tokenStream) {
        return js_ReportCompileErrorNumber(state->context, state->tokenStream,
                                           NULL, JSREPORT_UC | flags,
                                           errorNumber, arg);
    }
    return JS_ReportErrorFlagsAndNumberUC(state->context, flags,
                                          js_GetErrorMessage, NULL,
                                          errorNumber, arg);
}

static JSBool
ReportRegExpError(CompilerState *state, uintN flags, uintN errorNumber)
{
    return ReportRegExpErrorHelper(state, flags, errorNumber, NULL);
}

/*
 * Process the op against the two top operands, reducing them to a single
 * operand in the penultimate slot. Update progLength and treeDepth.
 */
static JSBool
ProcessOp(CompilerState *state, REOpData *opData, RENode **operandStack,
          intN operandSP)
{
    RENode *result;

    switch (opData->op) {
      case REOP_ALT:
        result = NewRENode(state, REOP_ALT);
        if (!result)
            return JS_FALSE;
        result->kid = operandStack[operandSP - 2];
        result->u.kid2 = operandStack[operandSP - 1];
        operandStack[operandSP - 2] = result;

        if (state->treeDepth == TREE_DEPTH_MAX) {
            ReportRegExpError(state, JSREPORT_ERROR, JSMSG_REGEXP_TOO_COMPLEX);
            return JS_FALSE;
        }
        ++state->treeDepth;

        /*
         * Look at both alternates to see if there's a FLAT or a CLASS at
         * the start of each. If so, use a prerequisite match.
         */
        if (((RENode *) result->kid)->op == REOP_FLAT &&
            ((RENode *) result->u.kid2)->op == REOP_FLAT &&
            (state->flags & JSREG_FOLD) == 0) {
            result->op = REOP_ALTPREREQ;
            result->u.altprereq.ch1 = ((RENode *) result->kid)->u.flat.chr;
            result->u.altprereq.ch2 = ((RENode *) result->u.kid2)->u.flat.chr;
            /* ALTPREREQ, <end>, uch1, uch2, <next>, ...,
                                            JUMP, <end> ... ENDALT */
            state->progLength += 13;
        }
        else
        if (((RENode *) result->kid)->op == REOP_CLASS &&
            ((RENode *) result->kid)->u.ucclass.index < 256 &&
            ((RENode *) result->u.kid2)->op == REOP_FLAT &&
            (state->flags & JSREG_FOLD) == 0) {
            result->op = REOP_ALTPREREQ2;
            result->u.altprereq.ch1 = ((RENode *) result->u.kid2)->u.flat.chr;
            result->u.altprereq.ch2 = ((RENode *) result->kid)->u.ucclass.index;
            /* ALTPREREQ2, <end>, uch1, uch2, <next>, ...,
                                            JUMP, <end> ... ENDALT */
            state->progLength += 13;
        }
        else
        if (((RENode *) result->kid)->op == REOP_FLAT &&
            ((RENode *) result->u.kid2)->op == REOP_CLASS &&
            ((RENode *) result->u.kid2)->u.ucclass.index < 256 &&
            (state->flags & JSREG_FOLD) == 0) {
            result->op = REOP_ALTPREREQ2;
            result->u.altprereq.ch1 = ((RENode *) result->kid)->u.flat.chr;
            result->u.altprereq.ch2 =
                ((RENode *) result->u.kid2)->u.ucclass.index;
            /* ALTPREREQ2, <end>, uch1, uch2, <next>, ...,
                                          JUMP, <end> ... ENDALT */
            state->progLength += 13;
        }
        else {
            /* ALT, <next>, ..., JUMP, <end> ... ENDALT */
            state->progLength += 7;
        }
        break;

      case REOP_CONCAT:
        result = operandStack[operandSP - 2];
        while (result->next)
            result = result->next;
        result->next = operandStack[operandSP - 1];
        break;

      case REOP_ASSERT:
      case REOP_ASSERT_NOT:
      case REOP_LPARENNON:
      case REOP_LPAREN:
        /* These should have been processed by a close paren. */
        ReportRegExpErrorHelper(state, JSREPORT_ERROR, JSMSG_MISSING_PAREN,
                                opData->errPos);
        return JS_FALSE;

      default:;
    }
    return JS_TRUE;
}

/*
 * Parser forward declarations.
 */
static JSBool ParseTerm(CompilerState *state);
static JSBool ParseQuantifier(CompilerState *state);
static intN ParseMinMaxQuantifier(CompilerState *state, JSBool ignoreValues);

/*
 * Top-down regular expression grammar, based closely on Perl4.
 *
 *  regexp:     altern                  A regular expression is one or more
 *              altern '|' regexp       alternatives separated by vertical bar.
 */
#define INITIAL_STACK_SIZE  128

static JSBool
ParseRegExp(CompilerState *state)
{
    size_t parenIndex;
    RENode *operand;
    REOpData *operatorStack;
    RENode **operandStack;
    REOp op;
    intN i;
    JSBool result = JS_FALSE;

    intN operatorSP = 0, operatorStackSize = INITIAL_STACK_SIZE;
    intN operandSP = 0, operandStackSize = INITIAL_STACK_SIZE;

    /* Watch out for empty regexp */
    if (state->cp == state->cpend) {
        state->result = NewRENode(state, REOP_EMPTY);
        return (state->result != NULL);
    }

    operatorStack = (REOpData *)
        JS_malloc(state->context, sizeof(REOpData) * operatorStackSize);
    if (!operatorStack)
        return JS_FALSE;

    operandStack = (RENode **)
        JS_malloc(state->context, sizeof(RENode *) * operandStackSize);
    if (!operandStack)
        goto out;

    for (;;) {
        parenIndex = state->parenCount;
        if (state->cp == state->cpend) {
            /*
             * If we are at the end of the regexp and we're short one or more
             * operands, the regexp must have the form /x|/ or some such, with
             * left parentheses making us short more than one operand.
             */
            if (operatorSP >= operandSP) {
                operand = NewRENode(state, REOP_EMPTY);
                if (!operand)
                    goto out;
                goto pushOperand;
            }
        } else {
            switch (*state->cp) {
              case '(':
                ++state->cp;
                if (state->cp + 1 < state->cpend &&
                    *state->cp == '?' &&
                    (state->cp[1] == '=' ||
                     state->cp[1] == '!' ||
                     state->cp[1] == ':')) {
                    switch (state->cp[1]) {
                      case '=':
                        op = REOP_ASSERT;
                        /* ASSERT, <next>, ... ASSERTTEST */
                        state->progLength += 4;
                        break;
                      case '!':
                        op = REOP_ASSERT_NOT;
                        /* ASSERTNOT, <next>, ... ASSERTNOTTEST */
                        state->progLength += 4;
                        break;
                      default:
                        op = REOP_LPARENNON;
                        break;
                    }
                    state->cp += 2;
                } else {
                    op = REOP_LPAREN;
                    /* LPAREN, <index>, ... RPAREN, <index> */
                    state->progLength
                        += 2 * (1 + GetCompactIndexWidth(parenIndex));
                    state->parenCount++;
                    if (state->parenCount == 65535) {
                        ReportRegExpError(state, JSREPORT_ERROR,
                                          JSMSG_TOO_MANY_PARENS);
                        goto out;
                    }
                }
                goto pushOperator;

              case ')':
                /*
                 * If there's no stacked open parenthesis, throw syntax error.
                 */
                for (i = operatorSP - 1; ; i--) {
                    if (i < 0) {
                        ReportRegExpError(state, JSREPORT_ERROR,
                                          JSMSG_UNMATCHED_RIGHT_PAREN);
                        goto out;
                    }
                    if (operatorStack[i].op == REOP_ASSERT ||
                        operatorStack[i].op == REOP_ASSERT_NOT ||
                        operatorStack[i].op == REOP_LPARENNON ||
                        operatorStack[i].op == REOP_LPAREN) {
                        break;
                    }
                }
                /* FALL THROUGH */

              case '|':
                /* Expected an operand before these, so make an empty one */
                operand = NewRENode(state, REOP_EMPTY);
                if (!operand)
                    goto out;
                goto pushOperand;

              default:
                if (!ParseTerm(state))
                    goto out;
                operand = state->result;
pushOperand:
                if (operandSP == operandStackSize) {
                    RENode **tmp;
                    operandStackSize += operandStackSize;
                    tmp = (RENode **)
                        JS_realloc(state->context, operandStack,
                                   sizeof(RENode *) * operandStackSize);
                    if (!tmp)
                        goto out;
                    operandStack = tmp;
                }
                operandStack[operandSP++] = operand;
                break;
            }
        }

        /* At the end; process remaining operators. */
restartOperator:
        if (state->cp == state->cpend) {
            while (operatorSP) {
                --operatorSP;
                if (!ProcessOp(state, &operatorStack[operatorSP],
                               operandStack, operandSP))
                    goto out;
                --operandSP;
            }
            JS_ASSERT(operandSP == 1);
            state->result = operandStack[0];
            result = JS_TRUE;
            goto out;
        }

        switch (*state->cp) {
          case '|':
            /* Process any stacked 'concat' operators */
            ++state->cp;
            while (operatorSP &&
                   operatorStack[operatorSP - 1].op == REOP_CONCAT) {
                --operatorSP;
                if (!ProcessOp(state, &operatorStack[operatorSP],
                               operandStack, operandSP)) {
                    goto out;
                }
                --operandSP;
            }
            op = REOP_ALT;
            goto pushOperator;

          case ')':
            /*
             * If there's no stacked open parenthesis, throw syntax error.
             */
            for (i = operatorSP - 1; ; i--) {
                if (i < 0) {
                    ReportRegExpError(state, JSREPORT_ERROR,
                                      JSMSG_UNMATCHED_RIGHT_PAREN);
                    goto out;
                }
                if (operatorStack[i].op == REOP_ASSERT ||
                    operatorStack[i].op == REOP_ASSERT_NOT ||
                    operatorStack[i].op == REOP_LPARENNON ||
                    operatorStack[i].op == REOP_LPAREN) {
                    break;
                }
            }
            ++state->cp;

            /* Process everything on the stack until the open parenthesis. */
            for (;;) {
                JS_ASSERT(operatorSP);
                --operatorSP;
                switch (operatorStack[operatorSP].op) {
                  case REOP_ASSERT:
                  case REOP_ASSERT_NOT:
                  case REOP_LPAREN:
                    operand = NewRENode(state, operatorStack[operatorSP].op);
                    if (!operand)
                        goto out;
                    operand->u.parenIndex =
                        operatorStack[operatorSP].parenIndex;
                    JS_ASSERT(operandSP);
                    operand->kid = operandStack[operandSP - 1];
                    operandStack[operandSP - 1] = operand;
                    if (state->treeDepth == TREE_DEPTH_MAX) {
                        ReportRegExpError(state, JSREPORT_ERROR,
                                          JSMSG_REGEXP_TOO_COMPLEX);
                        goto out;
                    }
                    ++state->treeDepth;
                    /* FALL THROUGH */

                  case REOP_LPARENNON:
                    state->result = operandStack[operandSP - 1];
                    if (!ParseQuantifier(state))
                        goto out;
                    operandStack[operandSP - 1] = state->result;
                    goto restartOperator;
                  default:
                    if (!ProcessOp(state, &operatorStack[operatorSP],
                                   operandStack, operandSP))
                        goto out;
                    --operandSP;
                    break;
                }
            }
            break;

          case '{':
          {
            const jschar *errp = state->cp;

            if (ParseMinMaxQuantifier(state, JS_TRUE) < 0) {
                /*
                 * This didn't even scan correctly as a quantifier, so we should
                 * treat it as flat.
                 */
                op = REOP_CONCAT;
                goto pushOperator;
            }

            state->cp = errp;
            /* FALL THROUGH */
          }

          case '+':
          case '*':
          case '?':
            ReportRegExpErrorHelper(state, JSREPORT_ERROR, JSMSG_BAD_QUANTIFIER,
                                    state->cp);
            result = JS_FALSE;
            goto out;

          default:
            /* Anything else is the start of the next term. */
            op = REOP_CONCAT;
pushOperator:
            if (operatorSP == operatorStackSize) {
                REOpData *tmp;
                operatorStackSize += operatorStackSize;
                tmp = (REOpData *)
                    JS_realloc(state->context, operatorStack,
                               sizeof(REOpData) * operatorStackSize);
                if (!tmp)
                    goto out;
                operatorStack = tmp;
            }
            operatorStack[operatorSP].op = op;
            operatorStack[operatorSP].errPos = state->cp;
            operatorStack[operatorSP++].parenIndex = parenIndex;
            break;
        }
    }
out:
    if (operatorStack)
        JS_free(state->context, operatorStack);
    if (operandStack)
        JS_free(state->context, operandStack);
    return result;
}

/*
 * Hack two bits in CompilerState.flags, for use within FindParenCount to flag
 * its being on the stack, and to propagate errors to its callers.
 */
#define JSREG_FIND_PAREN_COUNT  0x8000
#define JSREG_FIND_PAREN_ERROR  0x4000

/*
 * Magic return value from FindParenCount and GetDecimalValue, to indicate
 * overflow beyond GetDecimalValue's max parameter, or a computed maximum if
 * its findMax parameter is non-null.
 */
#define OVERFLOW_VALUE          ((uintN)-1)

static uintN
FindParenCount(CompilerState *state)
{
    CompilerState temp;
    int i;

    if (state->flags & JSREG_FIND_PAREN_COUNT)
        return OVERFLOW_VALUE;

    /*
     * Copy state into temp, flag it so we never report an invalid backref,
     * and reset its members to parse the entire regexp.  This is obviously
     * suboptimal, but GetDecimalValue calls us only if a backref appears to
     * refer to a forward parenthetical, which is rare.
     */
    temp = *state;
    temp.flags |= JSREG_FIND_PAREN_COUNT;
    temp.cp = temp.cpbegin;
    temp.parenCount = 0;
    temp.classCount = 0;
    temp.progLength = 0;
    temp.treeDepth = 0;
    temp.classBitmapsMem = 0;
    for (i = 0; i < CLASS_CACHE_SIZE; i++)
        temp.classCache[i].start = NULL;

    if (!ParseRegExp(&temp)) {
        state->flags |= JSREG_FIND_PAREN_ERROR;
        return OVERFLOW_VALUE;
    }
    return temp.parenCount;
}

/*
 * Extract and return a decimal value at state->cp.  The initial character c
 * has already been read.  Return OVERFLOW_VALUE if the result exceeds max.
 * Callers who pass a non-null findMax should test JSREG_FIND_PAREN_ERROR in
 * state->flags to discover whether an error occurred under findMax.
 */
static uintN
GetDecimalValue(jschar c, uintN max, uintN (*findMax)(CompilerState *state),
                CompilerState *state)
{
    uintN value = JS7_UNDEC(c);
    JSBool overflow = (value > max && (!findMax || value > findMax(state)));

    /* The following restriction allows simpler overflow checks. */
    JS_ASSERT(max <= ((uintN)-1 - 9) / 10);
    while (state->cp < state->cpend) {
        c = *state->cp;
        if (!JS7_ISDEC(c))
            break;
        value = 10 * value + JS7_UNDEC(c);
        if (!overflow && value > max && (!findMax || value > findMax(state)))
            overflow = JS_TRUE;
        ++state->cp;
    }
    return overflow ? OVERFLOW_VALUE : value;
}

/*
 * Calculate the total size of the bitmap required for a class expression.
 */
static JSBool
CalculateBitmapSize(CompilerState *state, RENode *target, const jschar *src,
                    const jschar *end)
{
    uintN max = 0;
    JSBool inRange = JS_FALSE;
    jschar c, rangeStart = 0;
    uintN n, digit, nDigits, i;

    target->u.ucclass.bmsize = 0;
    target->u.ucclass.sense = JS_TRUE;

    if (src == end)
        return JS_TRUE;

    if (*src == '^') {
        ++src;
        target->u.ucclass.sense = JS_FALSE;
    }

    while (src != end) {
        JSBool canStartRange = JS_TRUE;
        uintN localMax = 0;

        switch (*src) {
          case '\\':
            ++src;
            c = *src++;
            switch (c) {
              case 'b':
                localMax = 0x8;
                break;
              case 'f':
                localMax = 0xC;
                break;
              case 'n':
                localMax = 0xA;
                break;
              case 'r':
                localMax = 0xD;
                break;
              case 't':
                localMax = 0x9;
                break;
              case 'v':
                localMax = 0xB;
                break;
              case 'c':
                if (src < end && RE_IS_LETTER(*src)) {
                    localMax = (uintN) (*src++) & 0x1F;
                } else {
                    --src;
                    localMax = '\\';
                }
                break;
              case 'x':
                nDigits = 2;
                goto lexHex;
              case 'u':
                nDigits = 4;
lexHex:
                n = 0;
                for (i = 0; (i < nDigits) && (src < end); i++) {
                    c = *src++;
                    if (!isASCIIHexDigit(c, &digit)) {
                        /*
                         * Back off to accepting the original
                         *'\' as a literal.
                         */
                        src -= i + 1;
                        n = '\\';
                        break;
                    }
                    n = (n << 4) | digit;
                }
                localMax = n;
                break;
              case 'd':
                canStartRange = JS_FALSE;
                if (inRange) {
                    JS_ReportErrorNumber(state->context,
                                         js_GetErrorMessage, NULL,
                                         JSMSG_BAD_CLASS_RANGE);
                    return JS_FALSE;
                }
                localMax = '9';
                break;
              case 'D':
              case 's':
              case 'S':
              case 'w':
              case 'W':
                canStartRange = JS_FALSE;
                if (inRange) {
                    JS_ReportErrorNumber(state->context,
                                         js_GetErrorMessage, NULL,
                                         JSMSG_BAD_CLASS_RANGE);
                    return JS_FALSE;
                }
                max = 65535;

                /*
                 * If this is the start of a range, ensure that it's less than
                 * the end.
                 */
                localMax = 0;
                break;
              case '0':
              case '1':
              case '2':
              case '3':
              case '4':
              case '5':
              case '6':
              case '7':
                /*
                 *  This is a non-ECMA extension - decimal escapes (in this
                 *  case, octal!) are supposed to be an error inside class
                 *  ranges, but supported here for backwards compatibility.
                 *
                 */
                n = JS7_UNDEC(c);
                c = *src;
                if ('0' <= c && c <= '7') {
                    src++;
                    n = 8 * n + JS7_UNDEC(c);
                    c = *src;
                    if ('0' <= c && c <= '7') {
                        src++;
                        i = 8 * n + JS7_UNDEC(c);
                        if (i <= 0377)
                            n = i;
                        else
                            src--;
                    }
                }
                localMax = n;
                break;

              default:
                localMax = c;
                break;
            }
            break;
          default:
            localMax = *src++;
            break;
        }

        if (inRange) {
            /* Throw a SyntaxError here, per ECMA-262, 15.10.2.15. */
            if (rangeStart > localMax) {
                JS_ReportErrorNumber(state->context,
                                     js_GetErrorMessage, NULL,
                                     JSMSG_BAD_CLASS_RANGE);
                return JS_FALSE;
            }
            inRange = JS_FALSE;
        } else {
            if (canStartRange && src < end - 1) {
                if (*src == '-') {
                    ++src;
                    inRange = JS_TRUE;
                    rangeStart = (jschar)localMax;
                    continue;
                }
            }
            if (state->flags & JSREG_FOLD)
                rangeStart = localMax;   /* one run of the uc/dc loop below */
        }

        if (state->flags & JSREG_FOLD) {
            jschar maxch = localMax;

            for (i = rangeStart; i <= localMax; i++) {
                jschar uch, dch;

                uch = upcase(i);
                dch = downcase(i);
                maxch = JS_MAX(maxch, uch);
                maxch = JS_MAX(maxch, dch);
            }
            localMax = maxch;
        }

        if (localMax > max)
            max = localMax;
    }
    target->u.ucclass.bmsize = max;
    return JS_TRUE;
}

/*
 *  item:       assertion               An item is either an assertion or
 *              quantatom               a quantified atom.
 *
 *  assertion:  '^'                     Assertions match beginning of string
 *                                      (or line if the class static property
 *                                      RegExp.multiline is true).
 *              '$'                     End of string (or line if the class
 *                                      static property RegExp.multiline is
 *                                      true).
 *              '\b'                    Word boundary (between \w and \W).
 *              '\B'                    Word non-boundary.
 *
 *  quantatom:  atom                    An unquantified atom.
 *              quantatom '{' n ',' m '}'
 *                                      Atom must occur between n and m times.
 *              quantatom '{' n ',' '}' Atom must occur at least n times.
 *              quantatom '{' n '}'     Atom must occur exactly n times.
 *              quantatom '*'           Zero or more times (same as {0,}).
 *              quantatom '+'           One or more times (same as {1,}).
 *              quantatom '?'           Zero or one time (same as {0,1}).
 *
 *              any of which can be optionally followed by '?' for ungreedy
 *
 *  atom:       '(' regexp ')'          A parenthesized regexp (what matched
 *                                      can be addressed using a backreference,
 *                                      see '\' n below).
 *              '.'                     Matches any char except '\n'.
 *              '[' classlist ']'       A character class.
 *              '[' '^' classlist ']'   A negated character class.
 *              '\f'                    Form Feed.
 *              '\n'                    Newline (Line Feed).
 *              '\r'                    Carriage Return.
 *              '\t'                    Horizontal Tab.
 *              '\v'                    Vertical Tab.
 *              '\d'                    A digit (same as [0-9]).
 *              '\D'                    A non-digit.
 *              '\w'                    A word character, [0-9a-z_A-Z].
 *              '\W'                    A non-word character.
 *              '\s'                    A whitespace character, [ \b\f\n\r\t\v].
 *              '\S'                    A non-whitespace character.
 *              '\' n                   A backreference to the nth (n decimal
 *                                      and positive) parenthesized expression.
 *              '\' octal               An octal escape sequence (octal must be
 *                                      two or three digits long, unless it is
 *                                      0 for the null character).
 *              '\x' hex                A hex escape (hex must be two digits).
 *              '\u' unicode            A unicode escape (must be four digits).
 *              '\c' ctrl               A control character, ctrl is a letter.
 *              '\' literalatomchar     Any character except one of the above
 *                                      that follow '\' in an atom.
 *              otheratomchar           Any character not first among the other
 *                                      atom right-hand sides.
 */
static JSBool
ParseTerm(CompilerState *state)
{
    jschar c = *state->cp++;
    uintN nDigits;
    uintN num, tmp, n, i;
    const jschar *termStart;

    switch (c) {
    /* assertions and atoms */
      case '^':
        state->result = NewRENode(state, REOP_BOL);
        if (!state->result)
            return JS_FALSE;
        state->progLength++;
        return JS_TRUE;
      case '$':
        state->result = NewRENode(state, REOP_EOL);
        if (!state->result)
            return JS_FALSE;
        state->progLength++;
        return JS_TRUE;
      case '\\':
        if (state->cp >= state->cpend) {
            /* a trailing '\' is an error */
            ReportRegExpError(state, JSREPORT_ERROR, JSMSG_TRAILING_SLASH);
            return JS_FALSE;
        }
        c = *state->cp++;
        switch (c) {
        /* assertion escapes */
          case 'b' :
            state->result = NewRENode(state, REOP_WBDRY);
            if (!state->result)
                return JS_FALSE;
            state->progLength++;
            return JS_TRUE;
          case 'B':
            state->result = NewRENode(state, REOP_WNONBDRY);
            if (!state->result)
                return JS_FALSE;
            state->progLength++;
            return JS_TRUE;
          /* Decimal escape */
          case '0':
            /* Give a strict warning. See also the note below. */
            if (!ReportRegExpError(state, JSREPORT_WARNING | JSREPORT_STRICT,
                                   JSMSG_INVALID_BACKREF)) {
                return JS_FALSE;
            }
     doOctal:
            num = 0;
            while (state->cp < state->cpend) {
                c = *state->cp;
                if (c < '0' || '7' < c)
                    break;
                state->cp++;
                tmp = 8 * num + (uintN)JS7_UNDEC(c);
                if (tmp > 0377)
                    break;
                num = tmp;
            }
            c = (jschar)num;
    doFlat:
            state->result = NewRENode(state, REOP_FLAT);
            if (!state->result)
                return JS_FALSE;
            state->result->u.flat.chr = c;
            state->result->u.flat.length = 1;
            state->progLength += 3;
            break;
          case '1':
          case '2':
          case '3':
          case '4':
          case '5':
          case '6':
          case '7':
          case '8':
          case '9':
            termStart = state->cp - 1;
            num = GetDecimalValue(c, state->parenCount, FindParenCount, state);
            if (state->flags & JSREG_FIND_PAREN_ERROR)
                return JS_FALSE;
            if (num == OVERFLOW_VALUE) {
                /* Give a strict mode warning. */
                if (!ReportRegExpError(state,
                                       JSREPORT_WARNING | JSREPORT_STRICT,
                                       (c >= '8')
                                       ? JSMSG_INVALID_BACKREF
                                       : JSMSG_BAD_BACKREF)) {
                    return JS_FALSE;
                }

                /*
                 * Note: ECMA 262, 15.10.2.9 says that we should throw a syntax
                 * error here. However, for compatibility with IE, we treat the
                 * whole backref as flat if the first character in it is not a
                 * valid octal character, and as an octal escape otherwise.
                 */
                state->cp = termStart;
                if (c >= '8') {
                    /* Treat this as flat. termStart - 1 is the \. */
                    c = '\\';
                    goto asFlat;
                }

                /* Treat this as an octal escape. */
                goto doOctal;
            }
            JS_ASSERT(1 <= num && num <= 0x10000);
            state->result = NewRENode(state, REOP_BACKREF);
            if (!state->result)
                return JS_FALSE;
            state->result->u.parenIndex = num - 1;
            state->progLength
                += 1 + GetCompactIndexWidth(state->result->u.parenIndex);
            break;
          /* Control escape */
          case 'f':
            c = 0xC;
            goto doFlat;
          case 'n':
            c = 0xA;
            goto doFlat;
          case 'r':
            c = 0xD;
            goto doFlat;
          case 't':
            c = 0x9;
            goto doFlat;
          case 'v':
            c = 0xB;
            goto doFlat;
          /* Control letter */
          case 'c':
            if (state->cp < state->cpend && RE_IS_LETTER(*state->cp)) {
                c = (jschar) (*state->cp++ & 0x1F);
            } else {
                /* back off to accepting the original '\' as a literal */
                --state->cp;
                c = '\\';
            }
            goto doFlat;
          /* HexEscapeSequence */
          case 'x':
            nDigits = 2;
            goto lexHex;
          /* UnicodeEscapeSequence */
          case 'u':
            nDigits = 4;
lexHex:
            n = 0;
            for (i = 0; i < nDigits && state->cp < state->cpend; i++) {
                uintN digit;
                c = *state->cp++;
                if (!isASCIIHexDigit(c, &digit)) {
                    /*
                     * Back off to accepting the original 'u' or 'x' as a
                     * literal.
                     */
                    state->cp -= i + 2;
                    n = *state->cp++;
                    break;
                }
                n = (n << 4) | digit;
            }
            c = (jschar) n;
            goto doFlat;
          /* Character class escapes */
          case 'd':
            state->result = NewRENode(state, REOP_DIGIT);
doSimple:
            if (!state->result)
                return JS_FALSE;
            state->progLength++;
            break;
          case 'D':
            state->result = NewRENode(state, REOP_NONDIGIT);
            goto doSimple;
          case 's':
            state->result = NewRENode(state, REOP_SPACE);
            goto doSimple;
          case 'S':
            state->result = NewRENode(state, REOP_NONSPACE);
            goto doSimple;
          case 'w':
            state->result = NewRENode(state, REOP_ALNUM);
            goto doSimple;
          case 'W':
            state->result = NewRENode(state, REOP_NONALNUM);
            goto doSimple;
          /* IdentityEscape */
          default:
            state->result = NewRENode(state, REOP_FLAT);
            if (!state->result)
                return JS_FALSE;
            state->result->u.flat.chr = c;
            state->result->u.flat.length = 1;
            state->result->kid = (void *) (state->cp - 1);
            state->progLength += 3;
            break;
        }
        break;
      case '[':
        state->result = NewRENode(state, REOP_CLASS);
        if (!state->result)
            return JS_FALSE;
        termStart = state->cp;
        state->result->u.ucclass.startIndex = termStart - state->cpbegin;
        for (;;) {
            if (state->cp == state->cpend) {
                ReportRegExpErrorHelper(state, JSREPORT_ERROR,
                                        JSMSG_UNTERM_CLASS, termStart);

                return JS_FALSE;
            }
            if (*state->cp == '\\') {
                state->cp++;
                if (state->cp != state->cpend)
                    state->cp++;
                continue;
            }
            if (*state->cp == ']') {
                state->result->u.ucclass.kidlen = state->cp - termStart;
                break;
            }
            state->cp++;
        }
        for (i = 0; i < CLASS_CACHE_SIZE; i++) {
            if (!state->classCache[i].start) {
                state->classCache[i].start = termStart;
                state->classCache[i].length = state->result->u.ucclass.kidlen;
                state->classCache[i].index = state->classCount;
                break;
            }
            if (state->classCache[i].length ==
                state->result->u.ucclass.kidlen) {
                for (n = 0; ; n++) {
                    if (n == state->classCache[i].length) {
                        state->result->u.ucclass.index
                            = state->classCache[i].index;
                        goto claim;
                    }
                    if (state->classCache[i].start[n] != termStart[n])
                        break;
                }
            }
        }
        state->result->u.ucclass.index = state->classCount++;

    claim:
        /*
         * Call CalculateBitmapSize now as we want any errors it finds
         * to be reported during the parse phase, not at execution.
         */
        if (!CalculateBitmapSize(state, state->result, termStart, state->cp++))
            return JS_FALSE;
        /*
         * Update classBitmapsMem with number of bytes to hold bmsize bits,
         * which is (bitsCount + 7) / 8 or (highest_bit + 1 + 7) / 8
         * or highest_bit / 8 + 1 where highest_bit is u.ucclass.bmsize.
         */
        n = (state->result->u.ucclass.bmsize >> 3) + 1;
        if (n > CLASS_BITMAPS_MEM_LIMIT - state->classBitmapsMem) {
            ReportRegExpError(state, JSREPORT_ERROR, JSMSG_REGEXP_TOO_COMPLEX);
            return JS_FALSE;
        }
        state->classBitmapsMem += n;
        /* CLASS, <index> */
        state->progLength
            += 1 + GetCompactIndexWidth(state->result->u.ucclass.index);
        break;

      case '.':
        state->result = NewRENode(state, REOP_DOT);
        goto doSimple;

      case '{':
      {
        const jschar *errp = state->cp--;
        intN err;

        err = ParseMinMaxQuantifier(state, JS_TRUE);
        state->cp = errp;

        if (err < 0)
            goto asFlat;

        /* FALL THROUGH */
      }
      case '*':
      case '+':
      case '?':
        ReportRegExpErrorHelper(state, JSREPORT_ERROR,
                                JSMSG_BAD_QUANTIFIER, state->cp - 1);
        return JS_FALSE;
      default:
asFlat:
        state->result = NewRENode(state, REOP_FLAT);
        if (!state->result)
            return JS_FALSE;
        state->result->u.flat.chr = c;
        state->result->u.flat.length = 1;
        state->result->kid = (void *) (state->cp - 1);
        state->progLength += 3;
        break;
    }
    return ParseQuantifier(state);
}

static JSBool
ParseQuantifier(CompilerState *state)
{
    RENode *term;
    term = state->result;
    if (state->cp < state->cpend) {
        switch (*state->cp) {
          case '+':
            state->result = NewRENode(state, REOP_QUANT);
            if (!state->result)
                return JS_FALSE;
            state->result->u.range.min = 1;
            state->result->u.range.max = (uintN)-1;
            /* <PLUS>, <next> ... <ENDCHILD> */
            state->progLength += 4;
            goto quantifier;
          case '*':
            state->result = NewRENode(state, REOP_QUANT);
            if (!state->result)
                return JS_FALSE;
            state->result->u.range.min = 0;
            state->result->u.range.max = (uintN)-1;
            /* <STAR>, <next> ... <ENDCHILD> */
            state->progLength += 4;
            goto quantifier;
          case '?':
            state->result = NewRENode(state, REOP_QUANT);
            if (!state->result)
                return JS_FALSE;
            state->result->u.range.min = 0;
            state->result->u.range.max = 1;
            /* <OPT>, <next> ... <ENDCHILD> */
            state->progLength += 4;
            goto quantifier;
          case '{':       /* balance '}' */
          {
            intN err;
            const jschar *errp = state->cp;

            err = ParseMinMaxQuantifier(state, JS_FALSE);
            if (err == 0)
                goto quantifier;
            if (err == -1)
                return JS_TRUE;

            ReportRegExpErrorHelper(state, JSREPORT_ERROR, err, errp);
            return JS_FALSE;
          }
          default:;
        }
    }
    return JS_TRUE;

quantifier:
    if (state->treeDepth == TREE_DEPTH_MAX) {
        ReportRegExpError(state, JSREPORT_ERROR, JSMSG_REGEXP_TOO_COMPLEX);
        return JS_FALSE;
    }

    ++state->treeDepth;
    ++state->cp;
    state->result->kid = term;
    if (state->cp < state->cpend && *state->cp == '?') {
        ++state->cp;
        state->result->u.range.greedy = JS_FALSE;
    } else {
        state->result->u.range.greedy = JS_TRUE;
    }
    return JS_TRUE;
}

static intN
ParseMinMaxQuantifier(CompilerState *state, JSBool ignoreValues)
{
    uintN min, max;
    jschar c;
    const jschar *errp = state->cp++;

    c = *state->cp;
    if (JS7_ISDEC(c)) {
        ++state->cp;
        min = GetDecimalValue(c, 0xFFFF, NULL, state);
        c = *state->cp;

        if (!ignoreValues && min == OVERFLOW_VALUE)
            return JSMSG_MIN_TOO_BIG;

        if (c == ',') {
            c = *++state->cp;
            if (JS7_ISDEC(c)) {
                ++state->cp;
                max = GetDecimalValue(c, 0xFFFF, NULL, state);
                c = *state->cp;
                if (!ignoreValues && max == OVERFLOW_VALUE)
                    return JSMSG_MAX_TOO_BIG;
                if (!ignoreValues && min > max)
                    return JSMSG_OUT_OF_ORDER;
            } else {
                max = (uintN)-1;
            }
        } else {
            max = min;
        }
        if (c == '}') {
            state->result = NewRENode(state, REOP_QUANT);
            if (!state->result)
                return JSMSG_OUT_OF_MEMORY;
            state->result->u.range.min = min;
            state->result->u.range.max = max;
            /*
             * QUANT, <min>, <max>, <next> ... <ENDCHILD>
             * where <max> is written as compact(max+1) to make
             * (uintN)-1 sentinel to occupy 1 byte, not width_of(max)+1.
             */
            state->progLength += (1 + GetCompactIndexWidth(min)
                                  + GetCompactIndexWidth(max + 1)
                                  +3);
            return 0;
        }
    }

    state->cp = errp;
    return -1;
}

static JSBool
SetForwardJumpOffset(jsbytecode *jump, jsbytecode *target)
{
    ptrdiff_t offset = target - jump;

    /* Check that target really points forward. */
    JS_ASSERT(offset >= 2);
    if ((size_t)offset > OFFSET_MAX)
        return JS_FALSE;

    jump[0] = JUMP_OFFSET_HI(offset);
    jump[1] = JUMP_OFFSET_LO(offset);
    return JS_TRUE;
}

/* Copy the charset data from a character class node to the charset list
 * in the regexp object. */
static JS_ALWAYS_INLINE RECharSet *
InitNodeCharSet(JSRegExp *re, RENode *node)
{
    RECharSet *charSet = &re->classList[node->u.ucclass.index];
    charSet->converted = JS_FALSE;
    charSet->length = node->u.ucclass.bmsize;
    charSet->u.src.startIndex = node->u.ucclass.startIndex;
    charSet->u.src.length = node->u.ucclass.kidlen;
    charSet->sense = node->u.ucclass.sense;
    return charSet;
}

/*
 * Generate bytecode for the tree rooted at t using an explicit stack instead
 * of recursion.
 */
static jsbytecode *
EmitREBytecode(CompilerState *state, JSRegExp *re, size_t treeDepth,
               jsbytecode *pc, RENode *t)
{
    EmitStateStackEntry *emitStateSP, *emitStateStack;
    REOp op;

    if (treeDepth == 0) {
        emitStateStack = NULL;
    } else {
        emitStateStack =
            (EmitStateStackEntry *)JS_malloc(state->context,
                                             sizeof(EmitStateStackEntry) *
                                             treeDepth);
        if (!emitStateStack)
            return NULL;
    }
    emitStateSP = emitStateStack;
    op = t->op;
    JS_ASSERT(op < REOP_LIMIT);

    for (;;) {
        *pc++ = op;
        switch (op) {
          case REOP_EMPTY:
            --pc;
            break;

          case REOP_ALTPREREQ2:
          case REOP_ALTPREREQ:
            JS_ASSERT(emitStateSP);
            emitStateSP->altHead = pc - 1;
            emitStateSP->endTermFixup = pc;
            pc += OFFSET_LEN;
            SET_ARG(pc, t->u.altprereq.ch1);
            pc += ARG_LEN;
            SET_ARG(pc, t->u.altprereq.ch2);
            pc += ARG_LEN;

            emitStateSP->nextAltFixup = pc;    /* offset to next alternate */
            pc += OFFSET_LEN;

            emitStateSP->continueNode = t;
            emitStateSP->continueOp = REOP_JUMP;
            emitStateSP->jumpToJumpFlag = JS_FALSE;
            ++emitStateSP;
            JS_ASSERT((size_t)(emitStateSP - emitStateStack) <= treeDepth);
            t = (RENode *) t->kid;
            op = t->op;
            JS_ASSERT(op < REOP_LIMIT);
            continue;

          case REOP_JUMP:
            emitStateSP->nextTermFixup = pc;    /* offset to following term */
            pc += OFFSET_LEN;
            if (!SetForwardJumpOffset(emitStateSP->nextAltFixup, pc))
                goto jump_too_big;
            emitStateSP->continueOp = REOP_ENDALT;
            ++emitStateSP;
            JS_ASSERT((size_t)(emitStateSP - emitStateStack) <= treeDepth);
            t = (RENode *) t->u.kid2;
            op = t->op;
            JS_ASSERT(op < REOP_LIMIT);
            continue;

          case REOP_ENDALT:
            /*
             * If we already patched emitStateSP->nextTermFixup to jump to
             * a nearer jump, to avoid 16-bit immediate offset overflow, we
             * are done here.
             */
            if (emitStateSP->jumpToJumpFlag)
                break;

            /*
             * Fix up the REOP_JUMP offset to go to the op after REOP_ENDALT.
             * REOP_ENDALT is executed only on successful match of the last
             * alternate in a group.
             */
            if (!SetForwardJumpOffset(emitStateSP->nextTermFixup, pc))
                goto jump_too_big;
            if (t->op != REOP_ALT) {
                if (!SetForwardJumpOffset(emitStateSP->endTermFixup, pc))
                    goto jump_too_big;
            }

            /*
             * If the program is bigger than the REOP_JUMP offset range, then
             * we must check for alternates before this one that are part of
             * the same group, and fix up their jump offsets to target jumps
             * close enough to fit in a 16-bit unsigned offset immediate.
             */
            if ((size_t)(pc - re->program) > OFFSET_MAX &&
                emitStateSP > emitStateStack) {
                EmitStateStackEntry *esp, *esp2;
                jsbytecode *alt, *jump;
                ptrdiff_t span, header;

                esp2 = emitStateSP;
                alt = esp2->altHead;
                for (esp = esp2 - 1; esp >= emitStateStack; --esp) {
                    if (esp->continueOp == REOP_ENDALT &&
                        !esp->jumpToJumpFlag &&
                        esp->nextTermFixup + OFFSET_LEN == alt &&
                        (size_t)(pc - ((esp->continueNode->op != REOP_ALT)
                                       ? esp->endTermFixup
                                       : esp->nextTermFixup)) > OFFSET_MAX) {
                        alt = esp->altHead;
                        jump = esp->nextTermFixup;

                        /*
                         * The span must be 1 less than the distance from
                         * jump offset to jump offset, so we actually jump
                         * to a REOP_JUMP bytecode, not to its offset!
                         */
                        for (;;) {
                            JS_ASSERT(jump < esp2->nextTermFixup);
                            span = esp2->nextTermFixup - jump - 1;
                            if ((size_t)span <= OFFSET_MAX)
                                break;
                            do {
                                if (--esp2 == esp)
                                    goto jump_too_big;
                            } while (esp2->continueOp != REOP_ENDALT);
                        }

                        jump[0] = JUMP_OFFSET_HI(span);
                        jump[1] = JUMP_OFFSET_LO(span);

                        if (esp->continueNode->op != REOP_ALT) {
                            /*
                             * We must patch the offset at esp->endTermFixup
                             * as well, for the REOP_ALTPREREQ{,2} opcodes.
                             * If we're unlucky and endTermFixup is more than
                             * OFFSET_MAX bytes from its target, we cheat by
                             * jumping 6 bytes to the jump whose offset is at
                             * esp->nextTermFixup, which has the same target.
                             */
                            jump = esp->endTermFixup;
                            header = esp->nextTermFixup - jump;
                            span += header;
                            if ((size_t)span > OFFSET_MAX)
                                span = header;

                            jump[0] = JUMP_OFFSET_HI(span);
                            jump[1] = JUMP_OFFSET_LO(span);
                        }

                        esp->jumpToJumpFlag = JS_TRUE;
                    }
                }
            }
            break;

          case REOP_ALT:
            JS_ASSERT(emitStateSP);
            emitStateSP->altHead = pc - 1;
            emitStateSP->nextAltFixup = pc;     /* offset to next alternate */
            pc += OFFSET_LEN;
            emitStateSP->continueNode = t;
            emitStateSP->continueOp = REOP_JUMP;
            emitStateSP->jumpToJumpFlag = JS_FALSE;
            ++emitStateSP;
            JS_ASSERT((size_t)(emitStateSP - emitStateStack) <= treeDepth);
            t = (RENode *) t->kid;
            op = t->op;
            JS_ASSERT(op < REOP_LIMIT);
            continue;

          case REOP_FLAT:
            /*
             * Coalesce FLATs if possible and if it would not increase bytecode
             * beyond preallocated limit. The latter happens only when bytecode
             * size for coalesced string with offset p and length 2 exceeds 6
             * bytes preallocated for 2 single char nodes, i.e. when
             * 1 + GetCompactIndexWidth(p) + GetCompactIndexWidth(2) > 6 or
             * GetCompactIndexWidth(p) > 4.
             * Since when GetCompactIndexWidth(p) <= 4 coalescing of 3 or more
             * nodes strictly decreases bytecode size, the check has to be
             * done only for the first coalescing.
             */
            if (t->kid &&
                GetCompactIndexWidth((jschar *)t->kid - state->cpbegin) <= 4)
            {
                while (t->next &&
                       t->next->op == REOP_FLAT &&
                       (jschar*)t->kid + t->u.flat.length ==
                       (jschar*)t->next->kid) {
                    t->u.flat.length += t->next->u.flat.length;
                    t->next = t->next->next;
                }
            }
            if (t->kid && t->u.flat.length > 1) {
                pc[-1] = (state->flags & JSREG_FOLD) ? REOP_FLATi : REOP_FLAT;
                pc = WriteCompactIndex(pc, (jschar *)t->kid - state->cpbegin);
                pc = WriteCompactIndex(pc, t->u.flat.length);
            } else if (t->u.flat.chr < 256) {
                pc[-1] = (state->flags & JSREG_FOLD) ? REOP_FLAT1i : REOP_FLAT1;
                *pc++ = (jsbytecode) t->u.flat.chr;
            } else {
                pc[-1] = (state->flags & JSREG_FOLD)
                         ? REOP_UCFLAT1i
                         : REOP_UCFLAT1;
                SET_ARG(pc, t->u.flat.chr);
                pc += ARG_LEN;
            }
            break;

          case REOP_LPAREN:
            JS_ASSERT(emitStateSP);
            pc = WriteCompactIndex(pc, t->u.parenIndex);
            emitStateSP->continueNode = t;
            emitStateSP->continueOp = REOP_RPAREN;
            ++emitStateSP;
            JS_ASSERT((size_t)(emitStateSP - emitStateStack) <= treeDepth);
            t = (RENode *) t->kid;
            op = t->op;
            continue;

          case REOP_RPAREN:
            pc = WriteCompactIndex(pc, t->u.parenIndex);
            break;

          case REOP_BACKREF:
            pc = WriteCompactIndex(pc, t->u.parenIndex);
            break;

          case REOP_ASSERT:
            JS_ASSERT(emitStateSP);
            emitStateSP->nextTermFixup = pc;
            pc += OFFSET_LEN;
            emitStateSP->continueNode = t;
            emitStateSP->continueOp = REOP_ASSERTTEST;
            ++emitStateSP;
            JS_ASSERT((size_t)(emitStateSP - emitStateStack) <= treeDepth);
            t = (RENode *) t->kid;
            op = t->op;
            continue;

          case REOP_ASSERTTEST:
          case REOP_ASSERTNOTTEST:
            if (!SetForwardJumpOffset(emitStateSP->nextTermFixup, pc))
                goto jump_too_big;
            break;

          case REOP_ASSERT_NOT:
            JS_ASSERT(emitStateSP);
            emitStateSP->nextTermFixup = pc;
            pc += OFFSET_LEN;
            emitStateSP->continueNode = t;
            emitStateSP->continueOp = REOP_ASSERTNOTTEST;
            ++emitStateSP;
            JS_ASSERT((size_t)(emitStateSP - emitStateStack) <= treeDepth);
            t = (RENode *) t->kid;
            op = t->op;
            continue;

          case REOP_QUANT:
            JS_ASSERT(emitStateSP);
            if (t->u.range.min == 0 && t->u.range.max == (uintN)-1) {
                pc[-1] = (t->u.range.greedy) ? REOP_STAR : REOP_MINIMALSTAR;
            } else if (t->u.range.min == 0 && t->u.range.max == 1) {
                pc[-1] = (t->u.range.greedy) ? REOP_OPT : REOP_MINIMALOPT;
            } else if (t->u.range.min == 1 && t->u.range.max == (uintN) -1) {
                pc[-1] = (t->u.range.greedy) ? REOP_PLUS : REOP_MINIMALPLUS;
            } else {
                if (!t->u.range.greedy)
                    pc[-1] = REOP_M