regexec.c

/**********************************************************************

  regexec.c -  Oniguruma (regular expression library)

  Copyright (C) 2002-2004  K.Kosako (kosako@sofnec.co.jp)

**********************************************************************/
#include "regint.h"

static void
region_list_clear(OnigRegion** list)
{
  int i;

  if (IS_NOT_NULL(list)) {
    for (i = 1; i <= ONIG_MAX_CAPTURE_HISTORY_GROUP; i++) {
      if (IS_NOT_NULL(list[i])) {
	xfree(list[i]);
	list[i] = (OnigRegion* )0;
      }
    }
  }
}

static void
region_list_free(OnigRegion* r)
{
  if (IS_NOT_NULL(r->list)) {
    region_list_clear(r->list);
    xfree(r->list);
    r->list = (OnigRegion** )0;
  }
}

static OnigRegion**
region_list_new()
{
  int i;
  OnigRegion** list;

  list = (OnigRegion** )xmalloc(sizeof(OnigRegion*)
			       * (ONIG_MAX_CAPTURE_HISTORY_GROUP + 1));
  CHECK_NULL_RETURN(list);
  for (i = 0; i <= ONIG_MAX_CAPTURE_HISTORY_GROUP; i++) {
    list[i] = (OnigRegion* )0;
  }

  return list;
}

extern void
onig_region_clear(OnigRegion* region)
{
  int i;

  for (i = 0; i < region->num_regs; i++) {
    region->beg[i] = region->end[i] = ONIG_REGION_NOTPOS;
  }
  region_list_clear(region->list);
}

extern int
onig_region_resize(OnigRegion* region, int n)
{
  int i;

  region->num_regs = n;

  if (n < ONIG_NREGION)
    n = ONIG_NREGION;

  if (region->allocated == 0) {
    region->beg = (int* )xmalloc(n * sizeof(int));
    region->end = (int* )xmalloc(n * sizeof(int));

    if (region->beg == 0 || region->end == 0)
      return ONIGERR_MEMORY;

    region->allocated = n;
  }
  else if (region->allocated < n) {
    region->beg = (int* )xrealloc(region->beg, n * sizeof(int));
    region->end = (int* )xrealloc(region->end, n * sizeof(int));

    if (region->beg == 0 || region->end == 0)
      return ONIGERR_MEMORY;

    region->allocated = n;
  }

  for (i = 0; i < region->num_regs; i++) {
    region->beg[i] = region->end[i] = ONIG_REGION_NOTPOS;
  }

  if (IS_NOT_NULL(region->list))
    region_list_clear(region->list);

  return 0;
}

static int
region_ensure_size(OnigRegion* region, int n)
{
  int i, new_size;

  if (region->allocated >= n)
    return 0;

  new_size = region->allocated;
  if (new_size == 0)
    new_size = ONIG_NREGION;
  while (new_size < n)
    new_size *= 2;

  if (region->allocated == 0) {
    region->beg = (int* )xmalloc(new_size * sizeof(int));
    region->end = (int* )xmalloc(new_size * sizeof(int));
    if (region->beg == 0 || region->end == 0)
      return ONIGERR_MEMORY;

    region->allocated = new_size;
  }
  else if (region->allocated < new_size) {
    region->beg = (int* )xrealloc(region->beg, new_size * sizeof(int));
    region->end = (int* )xrealloc(region->end, new_size * sizeof(int));
    if (region->beg == 0 || region->end == 0)
      return ONIGERR_MEMORY;

    region->allocated = new_size;
  }

  for (i = region->num_regs; i < n; i++) {
    region->beg[i] = region->end[i] = ONIG_REGION_NOTPOS;
  }
  return 0;
}

static int
region_list_add_entry(OnigRegion* region, int group, int start, int end)
{
  int r, pos;
  OnigRegion** list;

  if (group > ONIG_MAX_CAPTURE_HISTORY_GROUP)
    return ONIGERR_GROUP_NUMBER_OVER_FOR_CAPTURE_HISTORY;

  if (IS_NULL(region->list)) {
    region->list = region_list_new();
    CHECK_NULL_RETURN_VAL(region->list, ONIGERR_MEMORY);
  }

  list = region->list;
  if (IS_NULL(list[group])) {
    list[group] = onig_region_new();
    CHECK_NULL_RETURN_VAL(list[group], ONIGERR_MEMORY);
  }

  r = region_ensure_size(list[group], list[group]->num_regs + 1);
  if (r != 0) return r;

  pos = list[group]->num_regs;
  list[group]->beg[pos] = start;
  list[group]->end[pos] = end;
  list[group]->num_regs++;

  return 0;
}

static void
onig_region_init(OnigRegion* region)
{
  region->num_regs  = 0;
  region->allocated = 0;
  region->beg       = (int* )0;
  region->end       = (int* )0;
  region->list      = (OnigRegion** )0;
}

extern OnigRegion*
onig_region_new()
{
  OnigRegion* r;

  r = (OnigRegion* )xmalloc(sizeof(OnigRegion));
  onig_region_init(r);
  return r;
}

extern void
onig_region_free(OnigRegion* r, int free_self)
{
  if (r) {
    if (r->allocated > 0) {
      if (r->beg) xfree(r->beg);
      if (r->end) xfree(r->end);
      r->allocated = 0;
    }
    region_list_free(r);
    if (free_self) xfree(r);
  }
}

extern void
onig_region_copy(OnigRegion* to, OnigRegion* from)
{
#define RREGC_SIZE   (sizeof(int) * from->num_regs)
  int i;

  if (to == from) return;

  if (to->allocated == 0) {
    if (from->num_regs > 0) {
      to->beg = (int* )xmalloc(RREGC_SIZE);
      to->end = (int* )xmalloc(RREGC_SIZE);
      to->allocated = from->num_regs;
    }
  }
  else if (to->allocated < from->num_regs) {
    to->beg = (int* )xrealloc(to->beg, RREGC_SIZE);
    to->end = (int* )xrealloc(to->end, RREGC_SIZE);
    to->allocated = from->num_regs;
  }

  for (i = 0; i < from->num_regs; i++) {
    to->beg[i] = from->beg[i];
    to->end[i] = from->end[i];
  }
  to->num_regs = from->num_regs;

  if (IS_NOT_NULL(from->list)) {
    if (IS_NULL(to->list)) {
      to->list = region_list_new();
    }

    for (i = 1; i <= ONIG_MAX_CAPTURE_HISTORY_GROUP; i++) {
      if (IS_NOT_NULL(from->list[i])) {
	if (IS_NULL(to->list[i]))
	  to->list[i] = onig_region_new();

	onig_region_copy(to->list[i], from->list[i]);
      }
      else {
	if (IS_NOT_NULL(to->list[i])) {
	  xfree(to->list[i]);
	  to->list[i] = (OnigRegion* )0;
	}
      }
    }
  }
  else
    region_list_free(to);
}


/** stack **/
#define INVALID_STACK_INDEX   -1
typedef int  StackIndex;

typedef struct _StackType {
  unsigned int type;
  union {
    struct {
      UChar *pcode;      /* byte code position */
      UChar *pstr;       /* string position */
      UChar *pstr_prev;  /* previous char position of pstr */
    } state;
    struct {
      int   count;       /* for OP_REPEAT_INC, OP_REPEAT_INC_NG */
      UChar *pcode;      /* byte code position (head of repeated target) */
      int   num;         /* repeat id */
    } repeat;
    struct {
      StackIndex si;     /* index of stack */
    } repeat_inc;
    struct {
      int num;           /* memory num */
      UChar *pstr;       /* start/end position */
      /* Following information is setted, if this stack type is MEM-START */
      StackIndex start;  /* prev. info (for backtrack  "(...)*" ) */
      StackIndex end;    /* prev. info (for backtrack  "(...)*" ) */
    } mem;
    struct {
      int num;           /* null check id */
      UChar *pstr;       /* start position */
    } null_check;
#ifdef USE_SUBEXP_CALL
    struct {
      UChar *ret_addr;   /* byte code position */
      int    num;        /* null check id */
      UChar *pstr;       /* string position */
    } call_frame;
#endif
  } u;
} StackType;

/* stack type */
/* used by normal-POP */
#define STK_ALT                    0x0001
#define STK_LOOK_BEHIND_NOT        0x0003
#define STK_POS_NOT                0x0005
/* avoided by normal-POP, but value should be small */
#define STK_NULL_CHECK_START       0x0100
/* handled by normal-POP */
#define STK_MEM_START              0x0200
#define STK_MEM_END                0x0300
#define STK_REPEAT_INC             0x0400
/* avoided by normal-POP */
#define STK_POS                    0x0500  /* used when POP-POS */
#define STK_STOP_BT                0x0600  /* mark for "(?>...)" */
#define STK_REPEAT                 0x0700
#define STK_CALL_FRAME             0x0800
#define STK_RETURN                 0x0900
#define STK_MEM_END_MARK           0x0a00
#define STK_VOID                   0x0b00  /* for fill a blank */
#define STK_NULL_CHECK_END         0x0c00  /* for recursive call */

/* stack type check mask */
#define STK_MASK_POP_USED     0x00ff
#define IS_TO_VOID_TARGET(stk) \
     (((stk)->type & STK_MASK_POP_USED) || (stk)->type == STK_NULL_CHECK_START)

typedef struct {
  void* stack_p;
  int   stack_n;
  OnigOptionType options;
  OnigRegion*    region;
  UChar* start;   /* search start position (for \G: BEGIN_POSITION) */
} MatchArg;

#define MATCH_ARG_INIT(msa, arg_option, arg_region, arg_start) do {\
  (msa).stack_p = (void* )0;\
  (msa).options = (arg_option);\
  (msa).region  = (arg_region);\
  (msa).start   = (arg_start);\
} while (0)

#define MATCH_ARG_FREE(msa)   if ((msa).stack_p) xfree((msa).stack_p)


#define STACK_INIT(alloc_addr, ptr_num, stack_num)  do {\
  if (msa->stack_p) {\
    alloc_addr = (char* )xalloca(sizeof(char*) * (ptr_num));\
    stk_alloc  = (StackType* )(msa->stack_p);\
    stk_base   = stk_alloc;\
    stk        = stk_base;\
    stk_end    = stk_base + msa->stack_n;\
  }\
  else {\
    alloc_addr = (char* )xalloca(sizeof(char*) * (ptr_num)\
		       + sizeof(StackType) * (stack_num));\
    stk_alloc  = (StackType* )(alloc_addr + sizeof(char*) * (ptr_num));\
    stk_base   = stk_alloc;\
    stk        = stk_base;\
    stk_end    = stk_base + (stack_num);\
  }\
} while(0)

#define STACK_SAVE do{\
  if (stk_base != stk_alloc) {\
    msa->stack_p = stk_base;\
    msa->stack_n = stk_end - stk_base;\
  };\
} while(0)

static unsigned int MatchStackLimitSize = DEFAULT_MATCH_STACK_LIMIT_SIZE;

extern unsigned int
onig_get_match_stack_limit_size(void)
{
  return MatchStackLimitSize;
}

extern int
onig_set_match_stack_limit_size(unsigned int size)
{
  MatchStackLimitSize = size;
  return 0;
}

static int
stack_double(StackType** arg_stk_base, StackType** arg_stk_end,
	     StackType** arg_stk, StackType* stk_alloc, MatchArg* msa)
{
  unsigned int n;
  StackType *x, *stk_base, *stk_end, *stk;

  stk_base = *arg_stk_base;
  stk_end  = *arg_stk_end;
  stk      = *arg_stk;

  n = stk_end - stk_base;
  if (stk_base == stk_alloc && IS_NULL(msa->stack_p)) {
    x = (StackType* )xmalloc(sizeof(StackType) * n * 2);
    if (IS_NULL(x)) {
      STACK_SAVE;
      return ONIGERR_MEMORY;
    }
    xmemcpy(x, stk_base, n * sizeof(StackType));
    n *= 2;
  }
  else {
    n *= 2;
    if (MatchStackLimitSize != 0 && n > MatchStackLimitSize) {
      if ((unsigned int )(stk_end - stk_base) == MatchStackLimitSize)
        return ONIGERR_MATCH_STACK_LIMIT_OVER;
      else
        n = MatchStackLimitSize;
    }
    x = (StackType* )xrealloc(stk_base, sizeof(StackType) * n);
    if (IS_NULL(x)) {
      STACK_SAVE;
      return ONIGERR_MEMORY;
    }
  }
  *arg_stk      = x + (stk - stk_base);
  *arg_stk_base = x;
  *arg_stk_end  = x + n;
  return 0;
}

#define STACK_ENSURE(n)	do {\
  if (stk_end - stk < (n)) {\
    int r = stack_double(&stk_base, &stk_end, &stk, stk_alloc, msa);\
    if (r != 0) { STACK_SAVE; return r; } \
  }\
} while(0)

#define STACK_AT(index)        (stk_base + (index))
#define GET_STACK_INDEX(stk)   ((stk) - stk_base)

#define STACK_PUSH(stack_type,pat,s,sprev) do {\
  STACK_ENSURE(1);\
  stk->type = (stack_type);\
  stk->u.state.pcode     = (pat);\
  stk->u.state.pstr      = (s);\
  stk->u.state.pstr_prev = (sprev);\
  STACK_INC;\
} while(0)

#define STACK_PUSH_ENSURED(stack_type,pat) do {\
  stk->type = (stack_type);\
  stk->u.state.pcode = (pat);\
  STACK_INC;\
} while(0)

#define STACK_PUSH_TYPE(stack_type) do {\
  STACK_ENSURE(1);\
  stk->type = (stack_type);\
  STACK_INC;\
} while(0)

#define STACK_PUSH_ALT(pat,s,sprev)     STACK_PUSH(STK_ALT,pat,s,sprev)
#define STACK_PUSH_POS(s,sprev)         STACK_PUSH(STK_POS,NULL_UCHARP,s,sprev)
#define STACK_PUSH_POS_NOT(pat,s,sprev) STACK_PUSH(STK_POS_NOT,pat,s,sprev)
#define STACK_PUSH_STOP_BT              STACK_PUSH_TYPE(STK_STOP_BT)
#define STACK_PUSH_LOOK_BEHIND_NOT(pat,s,sprev) \
        STACK_PUSH(STK_LOOK_BEHIND_NOT,pat,s,sprev)

#define STACK_PUSH_REPEAT(id, pat) do {\
  STACK_ENSURE(1);\
  stk->type = STK_REPEAT;\
  stk->u.repeat.num    = (id);\
  stk->u.repeat.pcode  = (pat);\
  stk->u.repeat.count  = 0;\
  STACK_INC;\
} while(0)

#define STACK_PUSH_REPEAT_INC(sindex) do {\
  STACK_ENSURE(1);\
  stk->type = STK_REPEAT_INC;\
  stk->u.repeat_inc.si  = (sindex);\
  STACK_INC;\
} while(0)

#define STACK_PUSH_MEM_START(mnum, s) do {\
  STACK_ENSURE(1);\
  stk->type = STK_MEM_START;\
  stk->u.mem.num      = (mnum);\
  stk->u.mem.pstr     = (s);\
  stk->u.mem.start    = mem_start_stk[mnum];\
  stk->u.mem.end      = mem_end_stk[mnum];\
  mem_start_stk[mnum] = GET_STACK_INDEX(stk);\
  mem_end_stk[mnum]   = INVALID_STACK_INDEX;\
  STACK_INC;\
} while(0)

#define STACK_PUSH_MEM_END(mnum, s) do {\
  STACK_ENSURE(1);\
  stk->type = STK_MEM_END;\
  stk->u.mem.num    = (mnum);\
  stk->u.mem.pstr   = (s);\
  stk->u.mem.start  = mem_start_stk[mnum];\
  stk->u.mem.end    = mem_end_stk[mnum];\
  mem_end_stk[mnum] = GET_STACK_INDEX(stk);\
  STACK_INC;\
} while(0)

#define STACK_PUSH_MEM_END_MARK(mnum) do {\
  STACK_ENSURE(1);\
  stk->type = STK_MEM_END_MARK;\
  stk->u.mem.num = (mnum);\
  STACK_INC;\
} while(0)

#define STACK_GET_MEM_START(mnum, k) do {\
  int level = 0;\
  k = stk;\
  while (k > stk_base) {\
    k--;\
    if ((k->type == STK_MEM_END_MARK || k->type == STK_MEM_END) \
      && k->u.mem.num == (mnum)) {\
      level++;\
    }\
    else if (k->type == STK_MEM_START && k->u.mem.num == (mnum)) {\
      if (level == 0) break;\
      level--;\
    }\
  }\
} while (0)

#define STACK_GET_MEM_RANGE(k, mnum, start, end) do {\
  int level = 0;\
  while (k < stk) {\
    if (k->type == STK_MEM_START && k->u.mem.num == (mnum)) {\
      if (level == 0) (start) = k->u.mem.pstr;\
      level++;\
    }\
    else if (k->type == STK_MEM_END && k->u.mem.num == (mnum)) {\
      level--;\
      if (level == 0) {\
        (end) = k->u.mem.pstr;\
        break;\
      }\
    }\
    k++;\
  }\
} while (0)

#define STACK_PUSH_NULL_CHECK_START(cnum, s) do {\
  STACK_ENSURE(1);\
  stk->type = STK_NULL_CHECK_START;\
  stk->u.null_check.num  = (cnum);\
  stk->u.null_check.pstr = (s);\
  STACK_INC;\
} while(0)

#define STACK_PUSH_NULL_CHECK_END(cnum) do {\
  STACK_ENSURE(1);\
  stk->type = STK_NULL_CHECK_END;\
  stk->u.null_check.num  = (cnum);\
  STACK_INC;\
} while(0)

#define STACK_PUSH_CALL_FRAME(pat) do {\
  STACK_ENSURE(1);\
  stk->type = STK_CALL_FRAME;\
  stk->u.call_frame.ret_addr = (pat);\
  STACK_INC;\
} while(0)

#define STACK_PUSH_RETURN do {\
  STACK_ENSURE(1);\
  stk->type = STK_RETURN;\
  STACK_INC;\
} while(0)


#ifdef ONIG_DEBUG
#define STACK_BASE_CHECK(p) \
  if ((p) < stk_base)  goto stack_error;
#else
#define STACK_BASE_CHECK(p)
#endif

#define STACK_POP_ONE do {\
  stk--;\
  STACK_BASE_CHECK(stk); \
} while(0)

#define STACK_POP  do {\
  switch (pop_level) {\
  case STACK_POP_LEVEL_FREE:\
    while (1) {\
      stk--;\
      STACK_BASE_CHECK(stk); \
      if ((stk->type & STK_MASK_POP_USED) != 0)  break;\
    }\
    break;\
  case STACK_POP_LEVEL_MEM_START:\
    while (1) {\
      stk--;\
      STACK_BASE_CHECK(stk); \
      if ((stk->type & STK_MASK_POP_USED) != 0)  break;\
      else if (stk->type == STK_MEM_START) {\
        mem_start_stk[stk->u.mem.num] = stk->u.mem.start;\
        mem_end_stk[stk->u.mem.num]   = stk->u.mem.end;\
      }\
    }\
    break;\
  default:\
    while (1) {\
      stk--;\
      STACK_BASE_CHECK(stk); \
      if ((stk->type & STK_MASK_POP_USED) != 0)  break;\
      else if (stk->type == STK_MEM_START) {\
        mem_start_stk[stk->u.mem.num] = stk->u.mem.start;\
        mem_end_stk[stk->u.mem.num]   = stk->u.mem.end;\
      }\
      else if (stk->type == STK_REPEAT_INC) {\
        STACK_AT(stk->u.repeat_inc.si)->u.repeat.count--;\
      }\
      else if (stk->type == STK_MEM_END) {\
        mem_start_stk[stk->u.mem.num] = stk->u.mem.start;\
        mem_end_stk[stk->u.mem.num]   = stk->u.mem.end;\
      }\
    }\
    break;\
  }\
} while(0)

#define STACK_POP_TIL_POS_NOT  do {\
  while (1) {\
    stk--;\
    STACK_BASE_CHECK(stk); \
    if (stk->type == STK_POS_NOT) break;\
    else if (stk->type == STK_MEM_START) {\
      mem_start_stk[stk->u.mem.num] = stk->u.mem.start;\
      mem_end_stk[stk->u.mem.num]   = stk->u.mem.end;\
    }\
    else if (stk->type == STK_REPEAT_INC) {\
      STACK_AT(stk->u.repeat_inc.si)->u.repeat.count--;\
    }\
    else if (stk->type == STK_MEM_END) {\
      mem_start_stk[stk->u.mem.num] = stk->u.mem.start;\
      mem_end_stk[stk->u.mem.num]   = stk->u.mem.end;\
    }\
  }\
} while(0)

#define STACK_POP_TIL_LOOK_BEHIND_NOT  do {\
  while (1) {\
    stk--;\
    STACK_BASE_CHECK(stk); \
    if (stk->type == STK_LOOK_BEHIND_NOT) break;\
    else if (stk->type == STK_MEM_START) {\
      mem_start_stk[stk->u.mem.num] = stk->u.mem.start;\
      mem_end_stk[stk->u.mem.num]   = stk->u.mem.end;\
    }\
    else if (stk->type == STK_REPEAT_INC) {\
      STACK_AT(stk->u.repeat_inc.si)->u.repeat.count--;\
    }\
    else if (stk->type == STK_MEM_END) {\
      mem_start_stk[stk->u.mem.num] = stk->u.mem.start;\
      mem_end_stk[stk->u.mem.num]   = stk->u.mem.end;\
    }\
  }\
} while(0)

#define STACK_POS_END(k) do {\
  k = stk;\
  while (1) {\
    k--;\
    STACK_BASE_CHECK(k); \
    if (IS_TO_VOID_TARGET(k)) {\
      k->type = STK_VOID;\
    }\
    else if (k->type == STK_POS) {\
      k->type = STK_VOID;\
      break;\
    }\
  }\
} while(0)

#define STACK_STOP_BT_END do {\
  StackType *k = stk;\
  while (1) {\
    k--;\
    STACK_BASE_CHECK(k); \
    if (IS_TO_VOID_TARGET(k)) {\
      k->type = STK_VOID;\
    }\
    else if (k->type == STK_STOP_BT) {\
      k->type = STK_VOID;\
      break;\
    }\
  }\
} while(0)

#define STACK_NULL_CHECK(isnull,id,s) do {\
  StackType* k = stk;\
  while (1) {\
    k--;\
    STACK_BASE_CHECK(k); \
    if (k->type == STK_NULL_CHECK_START) {\
      if (k->u.null_check.num == (id)) {\
        (isnull) = (k->u.null_check.pstr == (s));\
        break;\
      }\
    }\
  }\
} while(0)

#define STACK_NULL_CHECK_REC(isnull,id,s) do {\
  int level = 0;\
  StackType* k = stk;\
  while (1) {\
    k--;\
    STACK_BASE_CHECK(k); \
    if (k->type == STK_NULL_CHECK_START) {\
      if (k->u.null_check.num == (id)) {\
        if (level == 0) {\
          (isnull) = (k->u.null_check.pstr == (s));\
          break;\
        }\
        else level--;\
      }\
    }\
    else if (k->type == STK_NULL_CHECK_END) {\
      level++;\
    }\
  }\
} while(0)

#define STACK_NULL_CHECK_MEMST(isnull,id,s,reg) do {\
  StackType* k = stk;\
  while (1) {\
    k--;\
    STACK_BASE_CHECK(k); \
    if (k->type == STK_NULL_CHECK_START) {\
      if (k->u.null_check.num == (id)) {\
        if (k->u.null_check.pstr != (s)) {\
          (isnull) = 0;\
          break;\
        }\
        else {\
          UChar* endp;\
          (isnull) = 1;\
          while (k < stk) {\
            if (k->type == STK_MEM_START) {\
              if (k->u.mem.end == INVALID_STACK_INDEX) {\
                (isnull) = 0; break;\
              }\
              if (BIT_STATUS_AT(reg->bt_mem_end, k->u.mem.num))\
                endp = STACK_AT(k->u.mem.end)->u.mem.pstr;\
              else\
                endp = (UChar* )k->u.mem.end;\
              if (STACK_AT(k->u.mem.start)->u.mem.pstr != endp) {\
                (isnull) = 0; break;\
              }\
              else if (endp != s) {\
                (isnull) = -1; /* empty, but position changed */ \
              }\
            }\
            k++;\
          }\
  	  break;\
        }\
      }\
    }\
  }\
} while(0)

#define STACK_NULL_CHECK_MEMST_REC(isnull,id,s,reg) do {\
  int level = 0;\
  StackType* k = stk;\
  while (1) {\
    k--;\
    STACK_BASE_CHECK(k); \
    if (k->type == STK_NULL_CHECK_START) {\
      if (k->u.null_check.num == (id)) {\
        if (level == 0) {\
          if (k->u.null_check.pstr != (s)) {\
            (isnull) = 0;\
            break;\
          }\
          else {\
            UChar* endp;\
            (isnull) = 1;\
            while (k < stk) {\
              if (k->type == STK_MEM_START) {\
                if (k->u.mem.end == INVALID_STACK_INDEX) {\
                  (isnull) = 0; break;\
                }\
                if (BIT_STATUS_AT(reg->bt_mem_end, k->u.mem.num))\
                  endp = STACK_AT(k->u.mem.end)->u.mem.pstr;\
                else\
                  endp = (UChar* )k->u.mem.end;\
                if (STACK_AT(k->u.mem.start)->u.mem.pstr != endp) {\
                  (isnull) = 0; break;\
                }\
                else if (endp != s) {\
                  (isnull) = -1; /* empty, but position changed */ \
                }\
              }\
              k++;\
            }\
  	    break;\
          }\
        }\
        else {\
          level--;\
        }\
      }\
    }\
    else if (k->type == STK_NULL_CHECK_END) {\
      if (k->u.null_check.num == (id)) level++;\
    }\
  }\
} while(0)

#define STACK_GET_REPEAT(id, k) do {\
  int level = 0;\
  k = stk;\
  while (1) {\
    k--;\
    STACK_BASE_CHECK(k); \
    if (k->type == STK_REPEAT) {\
      if (level == 0) {\
        if (k->u.repeat.num == (id)) {\
          break;\
        }\
      }\
    }\
    else if (k->type == STK_CALL_FRAME) level--;\
    else if (k->type == STK_RETURN)     level++;\
  }\
} while (0)

#define STACK_RETURN(addr)  do {\
  int level = 0;\
  StackType* k = stk;\
  while (1) {\
    k--;\
    STACK_BASE_CHECK(k); \
    if (k->type == STK_CALL_FRAME) {\
      if (level == 0) {\
        (addr) = k->u.call_frame.ret_addr;\
        break;\
      }\
      else level--;\
    }\
    else if (k->type == STK_RETURN)\
      level++;\
  }\
} while(0)


#define STRING_CMP(s1,s2,len) do {\
  while (len-- > 0) {\
    if (*s1++ != *s2++) goto fail;\
  }\
} while(0)

#define STRING_CMP_IC(s1,ps2,len) do {\
  if (string_cmp_ic(encode, s1, ps2, len) == 0) \
    goto fail; \
} while(0)

static int string_cmp_ic(OnigEncoding enc,
			 UChar* s1, UChar** ps2, int mblen)
{
  UChar buf1[ONIGENC_MBC_TO_LOWER_MAXLEN];
  UChar buf2[ONIGENC_MBC_TO_LOWER_MAXLEN];
  UChar *p1, *p2, *end, *s2;
  int len1, len2;

  s2  = *ps2;
  end = s1 + mblen;
  while (s1 < end) {
    len1 = ONIGENC_MBC_TO_LOWER(enc, s1, buf1);
    len2 = ONIGENC_MBC_TO_LOWER(enc, s2, buf2);
    if (len1 != len2) return 0;
    p1 = buf1;
    p2 = buf2;
    while (len1-- > 0) {
      if (*p1 != *p2) return 0;
      p1++;
      p2++;
    }

    s1 += enc_len(enc, *s1);
    s2 += enc_len(enc, *s2);
  }

  *ps2 = s2;
  return 1;
}

#define STRING_CMP_VALUE(s1,s2,len,is_fail) do {\
  is_fail = 0;\
  while (len-- > 0) {\
    if (*s1++ != *s2++) {\
      is_fail = 1; break;\
    }\
  }\
} while(0)

#define STRING_CMP_VALUE_IC(s1,ps2,len,is_fail) do {\
  if (string_cmp_ic(encode, s1, ps2, len) == 0) \
    is_fail = 1; \
  else \
    is_fail = 0; \
} while(0)

#define ON_STR_BEGIN(s)  ((s) == str)
#define ON_STR_END(s)    ((s) == end)
#define IS_EMPTY_STR     (str == end)

#define DATA_ENSURE(n) \
  if (s + (n) > end) goto fail

#define DATA_ENSURE_CHECK(n)   (s + (n) <= end)

#ifdef ONIG_DEBUG_STATISTICS

#define USE_TIMEOFDAY

#ifdef USE_TIMEOFDAY
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
static struct timeval ts, te;
#define GETTIME(t)        gettimeofday(&(t), (struct timezone* )0)
#define TIMEDIFF(te,ts)   (((te).tv_usec - (ts).tv_usec) + \
                           (((te).tv_sec - (ts).tv_sec)*1000000))
#else
#ifdef HAVE_SYS_TIMES_H
#include <sys/times.h>
#endif
static struct tms ts, te;
#define GETTIME(t)         times(&(t))
#define TIMEDIFF(te,ts)   ((te).tms_utime - (ts).tms_utime)
#endif

static int OpCounter[256];
static int OpPrevCounter[256];
static unsigned long OpTime[256];
static int OpCurr = OP_FINISH;
static int OpPrevTarget = OP_FAIL;
static int MaxStackDepth = 0;

#define STAT_OP_IN(opcode) do {\
  if (opcode == OpPrevTarget) OpPrevCounter[OpCurr]++;\
  OpCurr = opcode;\
  OpCounter[opcode]++;\
  GETTIME(ts);\
} while (0)

#define STAT_OP_OUT do {\
  GETTIME(te);\
  OpTime[OpCurr] += TIMEDIFF(te, ts);\
} while (0)

#ifdef RUBY_PLATFORM
/*
 * :nodoc:
 */
static VALUE onig_stat_print()
{
  onig_print_statistics(stderr);
  return Qnil;
}
#endif

extern void onig_statistics_init()
{
  int i;
  for (i = 0; i < 256; i++) {
    OpCounter[i] = OpPrevCounter[i] = 0; OpTime[i] = 0;
  }
  MaxStackDepth = 0;

#ifdef RUBY_PLATFORM
  rb_define_global_function("onig_stat_print", onig_stat_print, 0);
#endif
}

extern void
onig_print_statistics(FILE* f)
{
  int i;
  fprintf(f, "   count      prev        time\n");
  for (i = 0; OnigOpInfo[i].opcode >= 0; i++) {
    fprintf(f, "%8d: %8d: %10ld: %s\n",
	    OpCounter[i], OpPrevCounter[i], OpTime[i], OnigOpInfo[i].name);
  }
  fprintf(f, "\nmax stack depth: %d\n", MaxStackDepth);
}

#define STACK_INC do {\
  stk++;\
  if (stk - stk_base > MaxStackDepth) \
    MaxStackDepth = stk - stk_base;\
} while (0)

#else
#define STACK_INC     stk++

#define STAT_OP_IN(opcode)
#define STAT_OP_OUT
#endif

extern int
onig_is_in_code_range(UChar* p, OnigCodePoint code)
{
  OnigCodePoint n, *data;
  OnigCodePoint low, high, x;

  GET_CODE_POINT(n, p);
  data = (OnigCodePoint* )p;
  data++;

  for (low = 0, high = n; low < high; ) {
    x = (low + high) >> 1;
    if (code > data[x * 2 + 1])
      low = x + 1;
    else
      high = x;
  }

  return ((low < n && code >= data[low * 2]) ? 1 : 0);
}


/* matching region of POSIX API */
typedef int regoff_t;

typedef struct {
  regoff_t  rm_so;
  regoff_t  rm_eo;
} posix_regmatch_t;

/* match data(str - end) from position (sstart). */
/* if sstart == str then set sprev to NULL. */
static int
match_at(regex_t* reg, UChar* str, UChar* end, UChar* sstart,
	 UChar* sprev, MatchArg* msa)
{
  static UChar FinishCode[] = { OP_FINISH };

  int i, n, num_mem, best_len, pop_level;
  LengthType tlen, tlen2;
  MemNumType mem;
  RelAddrType addr;
  OnigOptionType option = reg->options;
  OnigEncoding encode = reg->enc;
  int ignore_case;
  UChar *s, *q, *sbegin;
  UChar *p = reg->p;
  char *alloca_base;
  StackType *stk_alloc, *stk_base, *stk, *stk_end;
  StackType *stkp; /* used as any purpose. */
  StackIndex *repeat_stk;
  StackIndex *mem_start_stk, *mem_end_stk;
  n = reg->num_repeat + reg->num_mem * 2;

  STACK_INIT(alloca_base, n, INIT_MATCH_STACK_SIZE);
  ignore_case = IS_IGNORECASE(option);
  pop_level = reg->stack_pop_level;
  num_mem = reg->num_mem;
  repeat_stk = (StackIndex* )alloca_base;

  mem_start_stk = (StackIndex* )(repeat_stk + reg->num_repeat);
  mem_end_stk   = mem_start_stk + num_mem;
  mem_start_stk--; /* for index start from 1,
		      mem_start_stk[1]..mem_start_stk[num_mem] */
  mem_end_stk--;   /* for index start from 1,
		      mem_end_stk[1]..mem_end_stk[num_mem] */
  for (i = 1; i <= num_mem; i++) {
    mem_start_stk[i] = mem_end_stk[i] = INVALID_STACK_INDEX;
  }

#ifdef ONIG_DEBUG_MATCH
  fprintf(stderr, "match_at: str: %d, end: %d, start: %d, sprev: %d\n",
	  (int )str, (int )end, (int )sstart, (int )sprev);
  fprintf(stderr, "size: %d, start offset: %d\n",
	  (int )(end - str), (int )(sstart - str));
#endif

  STACK_PUSH_ENSURED(STK_ALT, FinishCode);  /* bottom stack */
  best_len = ONIG_MISMATCH;
  s = sstart;
  while (1) {
#ifdef ONIG_DEBUG_MATCH
    {
      UChar *q, *bp, buf[50];
      int len;
      fprintf(stderr, "%4d> \"", (int )(s - str));
      bp = buf;
      for (i = 0, q = s; i < 7 && q < end; i++) {
	len = enc_len(encode, *q);
	while (len-- > 0) *bp++ = *q++;
      }
      if (q < end) { xmemcpy(bp, "...\"", 4); bp += 4; }
      else         { xmemcpy(bp, "\"",    1); bp += 1; }
      *bp = 0;
      fputs(buf, stderr);
      for (i = 0; i < 20 - (bp - buf); i++) fputc(' ', stderr);
      onig_print_compiled_byte_code(stderr, p, NULL);
      fprintf(stderr, "\n");
    }
#endif

    sbegin = s;
    switch (*p++) {
    case OP_END:  STAT_OP_IN(OP_END);
      n = s - sstart;
      if (n > best_len) {
	OnigRegion* region = msa->region;
	best_len = n;
	if (region) {
#ifdef USE_POSIX_REGION_OPTION
	  if (IS_POSIX_REGION(msa->options)) {
	    posix_regmatch_t* rmt = (posix_regmatch_t* )region;

	    rmt[0].rm_so = sstart - str;
	    rmt[0].rm_eo = s      - str;
	    for (i = 1; i <= num_mem; i++) {
	      if (mem_end_stk[i] != INVALID_STACK_INDEX) {
		if (BIT_STATUS_AT(reg->bt_mem_start, i))
		  rmt[i].rm_so = STACK_AT(mem_start_stk[i])->u.mem.pstr - str;
		else
		  rmt[i].rm_so = (UChar* )((void* )(mem_start_stk[i])) - str;

		rmt[i].rm_eo = (BIT_STATUS_AT(reg->bt_mem_end, i)
				? STACK_AT(mem_end_stk[i])->u.mem.pstr
				: (UChar* )((void* )mem_end_stk[i])) - str;
	      }
	      else {
		rmt[i].rm_so = rmt[i].rm_eo = ONIG_REGION_NOTPOS;
	      }
	    }
	  }
	  else {
#endif /* USE_POSIX_REGION_OPTION */
	    region->beg[0] = sstart - str;
	    region->end[0] = s      - str;
	    for (i = 1; i <= num_mem; i++) {
	      if (mem_end_stk[i] != INVALID_STACK_INDEX) {
		if (BIT_STATUS_AT(reg->bt_mem_start, i))
		  region->beg[i] = STACK_AT(mem_start_stk[i])->u.mem.pstr - str;
		else
		  region->beg[i] = (UChar* )((void* )mem_start_stk[i]) - str;

		region->end[i] = (BIT_STATUS_AT(reg->bt_mem_end, i)
				  ? STACK_AT(mem_end_stk[i])->u.mem.pstr
				  : (UChar* )((void* )mem_end_stk[i])) - str;
	      }
	      else {
		region->beg[i] = region->end[i] = ONIG_REGION_NOTPOS;
	      }
	    }

	    if (reg->capture_history != 0) {
	      UChar *pstart, *pend;
	      for (i = 1; i <= ONIG_MAX_CAPTURE_HISTORY_GROUP; i++) {
		if (BIT_STATUS_AT(reg->capture_history, i) != 0) {
		  stkp = stk_base;
		  do {
		    STACK_GET_MEM_RANGE(stkp, i, pstart, pend);
		    if (stkp < stk) {
		      int r;
		      r = region_list_add_entry(region, i,
						pstart - str, pend - str);
		      if (r) {
			STACK_SAVE;
			return r;
		      }
		    }
		    stkp++;
		  } while (stkp < stk);
		}
	      }
	    } /* list of captures */
#ifdef USE_POSIX_REGION_OPTION
	  } /* else IS_POSIX_REGION() */
#endif
	} /* if (region) */
      } /* n > best_len */
      STAT_OP_OUT;

      if (IS_FIND_CONDITION(option)) {
	if (IS_FIND_NOT_EMPTY(option) && s == sstart) {
	  best_len = ONIG_MISMATCH;
	  goto fail; /* for retry */
	}
	if (IS_FIND_LONGEST(option) && s < end) {
	  goto fail; /* for retry */
	}
      }

      /* default behavior: return first-matching result. */
      goto finish;
      break;

    case OP_EXACT1:  STAT_OP_IN(OP_EXACT1);
#if 0
      DATA_ENSURE(1);
      if (*p != *s) goto fail;
      p++; s++;
#endif
      if (*p != *s++) goto fail;
      DATA_ENSURE(0);
      p++;
      STAT_OP_OUT;
      break;

    case OP_EXACT1_IC:  STAT_OP_IN(OP_EXACT1_IC);
      {
	int len;
	UChar *q, lowbuf[ONIGENC_MBC_TO_LOWER_MAXLEN];

	len = ONIGENC_MBC_TO_LOWER(encode, s, lowbuf);
	DATA_ENSURE(len);
	q = lowbuf;
	s += enc_len(encode, *s);
	while (len-- > 0) {
	  if (*p != *q) goto fail;
	  p++; q++;
	}
      }
      STAT_OP_OUT;
      break;

    case OP_EXACT2:  STAT_OP_IN(OP_EXACT2);
      DATA_ENSURE(2);
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      sprev = s;
      p++; s++;
      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACT3:  STAT_OP_IN(OP_EXACT3);
      DATA_ENSURE(3);
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      sprev = s;
      p++; s++;
      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACT4:  STAT_OP_IN(OP_EXACT4);
      DATA_ENSURE(4);
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      sprev = s;
      p++; s++;
      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACT5:  STAT_OP_IN(OP_EXACT5);
      DATA_ENSURE(5);
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      sprev = s;
      p++; s++;
      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACTN:  STAT_OP_IN(OP_EXACTN);
      GET_LENGTH_INC(tlen, p);
      DATA_ENSURE(tlen);
      while (tlen-- > 0) {
	if (*p++ != *s++) goto fail;
      }
      sprev = s - 1;
      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACTN_IC:  STAT_OP_IN(OP_EXACTN_IC);
      {
	int len;
	UChar *q, *endp, lowbuf[ONIGENC_MBC_TO_LOWER_MAXLEN];

	GET_LENGTH_INC(tlen, p);
	endp = p + tlen;

	while (p < endp) {
	  len = ONIGENC_MBC_TO_LOWER(encode, s, lowbuf);
	  DATA_ENSURE(len);
	  sprev = s;
	  s += enc_len(encode, *s);
	  q = lowbuf;
	  while (len-- > 0) {
	    if (*p != *q) goto fail;
	    p++; q++;
	  }
	}
      }

      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACTMB2N1:  STAT_OP_IN(OP_EXACTMB2N1);
      DATA_ENSURE(2);
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      STAT_OP_OUT;
      break;

    case OP_EXACTMB2N2:  STAT_OP_IN(OP_EXACTMB2N2);
      DATA_ENSURE(4);
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      sprev = s;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACTMB2N3:  STAT_OP_IN(OP_EXACTMB2N3);
      DATA_ENSURE(6);
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      sprev = s;
      if (*p != *s) goto fail;
      p++; s++;
      if (*p != *s) goto fail;
      p++; s++;
      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACTMB2N:  STAT_OP_IN(OP_EXACTMB2N);
      GET_LENGTH_INC(tlen, p);
      DATA_ENSURE(tlen * 2);
      while (tlen-- > 0) {
	if (*p != *s) goto fail;
	p++; s++;
	if (*p != *s) goto fail;
	p++; s++;
      }
      sprev = s - 2;
      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACTMB3N:  STAT_OP_IN(OP_EXACTMB3N);
      GET_LENGTH_INC(tlen, p);
      DATA_ENSURE(tlen * 3);
      while (tlen-- > 0) {
	if (*p != *s) goto fail;
	p++; s++;
	if (*p != *s) goto fail;
	p++; s++;
	if (*p != *s) goto fail;
	p++; s++;
      }
      sprev = s - 3;
      STAT_OP_OUT;
      continue;
      break;

    case OP_EXACTMBN:  STAT_OP_IN(OP_EXACTMBN);
      GET_LENGTH_INC(tlen,  p);  /* mb-len */
      GET_LENGTH_INC(tlen2, p);  /* string len */
      tlen2 *= tlen;
      DATA_ENSURE(tlen2);
      while (tlen2-- > 0) {
	if (*p != *s) goto fail;
	p++; s++;
      }
      sprev = s - tlen;
      STAT_OP_OUT;
      continue;
      break;

    case OP_CCLASS:  STAT_OP_IN(OP_CCLASS);
      DATA_ENSURE(1);
      if (BITSET_AT(((BitSetRef )p), *s) == 0) goto fail;
      p += SIZE_BITSET;
      s += enc_len(encode, *s);   /* OP_CCLASS can match mb-code. \D, \S */
      STAT_OP_OUT;
      break;

    case OP_CCLASS_MB:  STAT_OP_IN(OP_CCLASS_MB);
      if (! ONIGENC_IS_MBC_HEAD(encode, *s)) goto fail;

    cclass_mb:
      GET_LENGTH_INC(tlen, p);
      {
	OnigCodePoint code;
	UChar *ss;
	int mb_len = enc_len(encode, *s);

	DATA_ENSURE(mb_len);
	ss = s;
	s += mb_len;
	code = ONIGENC_MBC_TO_CODE(encode, ss, s);

#ifdef PLATFORM_UNALIGNED_WORD_ACCESS
	if (! onig_is_in_code_range(p, code)) goto fail;
#else
	q = p;
	ALIGNMENT_RIGHT(q);
	if (! onig_is_in_code_range(q, code)) goto fail;
#endif
      }
      p += tlen;
      STAT_OP_OUT;
      break;

    case OP_CCLASS_MIX:  STAT_OP_IN(OP_CCLASS_MIX);
      DATA_ENSURE(1);
      if (ONIGENC_IS_MBC_HEAD(encode, *s)) {
	p += SIZE_BITSET;
	goto cclass_mb;
      }
      else {
	if (BITSET_AT(((BitSetRef )p), *s) == 0)
	  goto fail;

	p += SIZE_BITSET;
	GET_LENGTH_INC(tlen, p);
	p += tlen;
	s++;
      }
      STAT_OP_OUT;
      break;

    case OP_CCLASS_NOT:  STAT_OP_IN(OP_CCLASS_NOT);
      DATA_ENSURE(1);
      if (BITSET_AT(((BitSetRef )p), *s) != 0) goto fail;
      p += SIZE_BITSET;
      s += enc_len(encode, *s);
      STAT_OP_OUT;
      break;

    case OP_CCLASS_MB_NOT:  STAT_OP_IN(OP_CCLASS_MB_NOT);
      if (! ONIGENC_IS_MBC_HEAD(encode, *s)) {
	DATA_ENSURE(1);
	s++;
	GET_LENGTH_INC(tlen, p);
	p += tlen;
	goto cc_mb_not_success;
      }

    cclass_mb_not:
      GET_LENGTH_INC(tlen, p);
      {
	OnigCodePoint code;
	UChar *ss;
	int mb_len = enc_len(encode, *s);

	if (s + mb_len > end) {
          DATA_ENSURE(1);
	  s = end;
	  p += tlen;
	  goto cc_mb_not_success;
	}

	ss = s;
	s += mb_len;
	code = ONIGENC_MBC_TO_CODE(encode, ss, s);

#ifdef PLATFORM_UNALIGNED_WORD_ACCESS
	if (onig_is_in_code_range(p, code)) goto fail;
#else
	q = p;
	ALIGNMENT_RIGHT(q);
	if (onig_is_in_code_range(q, code)) goto fail;
#endif
      }
      p += tlen;

    cc_mb_not_success:
      STAT_OP_OUT;
      break;

    case OP_CCLASS_MIX_NOT:  STAT_OP_IN(OP_CCLASS_MIX_NOT);
      DATA_ENSURE(1);
      if (ONIGENC_IS_MBC_HEAD(encode, *s)) {
	p += SIZE_BITSET;
	goto cclass_mb_not;
      }
      else {
	if (BITSET_AT(((BitSetRef )p), *s) != 0)
	  goto fail;

	p += SIZE_BITSET;
	GET_LENGTH_INC(tlen, p);
	p += tlen;
	s++;
      }
      STAT_OP_OUT;
      break;

    case OP_ANYCHAR:  STAT_OP_IN(OP_ANYCHAR);
      n = enc_len(encode, *s);
      if (n > 1) {
	DATA_ENSURE(n);
	s += n;
      }
      else {
	DATA_ENSURE(1);
	if (ONIG_IS_NEWLINE(*s)) goto fail;
	s++;
      }
      STAT_OP_OUT;
      break;

    case OP_ANYCHAR_ML:  STAT_OP_IN(OP_ANYCHAR_ML);
      n = enc_len(encode, *s);
      DATA_ENSURE(n);
      s += n;
      STAT_OP_OUT;
      break;

    case OP_ANYCHAR_STAR:  STAT_OP_IN(OP_ANYCHAR_STAR);
      while (s < end) {
	STACK_PUSH_ALT(p, s, sprev);
	n = enc_len(encode, *s);
	if (n > 1) {
	  DATA_ENSURE(n);
	  sprev = s;
	  s += n;
	}
	else {
	  if (ONIG_IS_NEWLINE(*s))  goto fail;
	  sprev = s;
	  s++;
	}
      }
      STAT_OP_OUT;
      break;

    case OP_ANYCHAR_ML_STAR:  STAT_OP_IN(OP_ANYCHAR_ML_STAR);
      while (s < end) {
	STACK_PUSH_ALT(p, s, sprev);
	n = enc_len(encode, *s);
	if (n > 1) {
	  DATA_ENSURE(n);
	  sprev = s;
	  s += n;
	}
	else {
	  sprev = s;
	  s++;
	}
      }
      STAT_OP_OUT;
      break;

    case OP_ANYCHAR_STAR_PEEK_NEXT:  STAT_OP_IN(OP_ANYCHAR_STAR_PEEK_NEXT);
      while (s < end) {
	if (*p == *s) {
	  STACK_PUSH_ALT(p + 1, s, sprev);
	}
	n = enc_len(encode, *s);
	if (n > 1) {
	  DATA_ENSURE(n);
	  sprev = s;
	  s += n;
	}
	else {
	  if (ONIG_IS_NEWLINE(*s))  goto fail;
	  sprev = s;
	  s++;
	}
      }
      p++;
      STAT_OP_OUT;
      break;

    case OP_ANYCHAR_ML_STAR_PEEK_NEXT:STAT_OP_IN(OP_ANYCHAR_ML_STAR_PEEK_NEXT);
      while (s < end) {
	if (*p == *s) {
	  STACK_PUSH_ALT(p + 1, s, sprev);
	}
	n = enc_len(encode, *s);
	if (n >1) {
	  DATA_ENSURE(n);
	  sprev = s;
	  s += n;
	}
	else {
	  sprev = s;
	  s++;
	}
      }
      p++;
      STAT_OP_OUT;
      break;

    case OP_WORD:  STAT_OP_IN(OP_WORD);
      DATA_ENSURE(1);
      if (! ONIGENC_IS_MBC_WORD(encode, s, end))
	goto fail;

      s += enc_len(encode, *s);
      STAT_OP_OUT;
      break;

    case OP_NOT_WORD:  STAT_OP_IN(OP_NOT_WORD);
      DATA_ENSURE(1);
      if (ONIGENC_IS_MBC_WORD(encode, s, end))
	goto fail;

      s += enc_len(encode, *s);
      STAT_OP_OUT;
      break;

    case OP_WORD_BOUND:  STAT_OP_IN(OP_WORD_BOUND);
      if (ON_STR_BEGIN(s)) {
	DATA_ENSURE(1);
	if (! ONIGENC_IS_MBC_WORD(encode, s, end))
	  goto fail;
      }
      else if (ON_STR_END(s)) {
	if (! ONIGENC_IS_MBC_WORD(encode, sprev, end))
	  goto fail;
      }
      else {
	if (ONIGENC_IS_MBC_WORD(encode, s, end)
	    == ONIGENC_IS_MBC_WORD(encode, sprev, end))
	  goto fail;
      }
      STAT_OP_OUT;
      continue;
      break;

    case OP_NOT_WORD_BOUND:  STAT_OP_IN(OP_NOT_WORD_BOUND);
      if (ON_STR_BEGIN(s)) {
	if (DATA_ENSURE_CHECK(1) && ONIGENC_IS_MBC_WORD(encode, s, end))
	  goto fail;
      }
      else if (ON_STR_END(s)) {
	if (ONIGENC_IS_MBC_WORD(encode, sprev, end))
	  goto fail;
      }
      else {
	if (ONIGENC_IS_MBC_WORD(encode, s, end)
	    != ONIGENC_IS_MBC_WORD(encode, sprev, end))
	  goto fail;
      }
      STAT_OP_OUT;
      continue;
      break;

#ifdef USE_WORD_BEGIN_END
    case OP_WORD_BEGIN:  STAT_OP_IN(OP_WORD_BEGIN);
      if (DATA_ENSURE_CHECK(1) && ONIGENC_IS_MBC_WORD(encode, s, end)) {
	if (ON_STR_BEGIN(s) || !ONIGENC_IS_MBC_WORD(encode, sprev, end)) {
	  STAT_OP_OUT;
	  continue;
	}
      }
      goto fail;
      break;

    case OP_WORD_END:  STAT_OP_IN(OP_WORD_END);
      if (!ON_STR_BEGIN(s) && ONIGENC_IS_MBC_WORD(encode, sprev, end)) {
	if (ON_STR_END(s) || !ONIGENC_IS_MBC_WORD(encode, s, end)) {
	  STAT_OP_OUT;
	  continue;
	}
      }
      goto fail;
      break;
#endif

    case OP_BEGIN_BUF:  STAT_OP_IN(OP_BEGIN_BUF);
      if (! ON_STR_BEGIN(s)) goto fail;

      STAT_OP_OUT;
      continue;
      break;

    case OP_END_BUF:  STAT_OP_IN(OP_END_BUF);
      if (! ON_STR_END(s)) goto fail;

      STAT_OP_OUT;
      continue;
      break;

    case OP_BEGIN_LINE:  STAT_OP_IN(OP_BEGIN_LINE);
      if (ON_STR_BEGIN(s)) {
	if (IS_NOTBOL(msa->options)) goto fail;
	STAT_OP_OUT;
	continue;
      }
      else if (ONIG_IS_NEWLINE(*sprev) && !ON_STR_END(s)) {
	STAT_OP_OUT;
	continue;
      }
      goto fail;
      break;

    case OP_END_LINE:  STAT_OP_IN(OP_END_LINE);
      if (ON_STR_END(s)) {
#ifndef USE_NEWLINE_AT_END_OF_STRING_HAS_EMPTY_LINE
	if (IS_EMPTY_STR || !ONIG_IS_NEWLINE(*sprev)) {
#endif
	  if (IS_NOTEOL(msa->options)) goto fail;
	  STAT_OP_OUT;
	  continue;
#ifndef USE_NEWLINE_AT_END_OF_STRING_HAS_EMPTY_LINE
	}
#endif
      }
      else if (ONIG_IS_NEWLINE(*s)) {
	STAT_OP_OUT;
	continue;
      }
      goto fail;
      break;

    case OP_SEMI_END_BUF:  STAT_OP_IN(OP_SEMI_END_BUF);
      if (ON_STR_END(s)) {
#ifndef USE_NEWLINE_AT_END_OF_STRING_HAS_EMPTY_LINE
	if (IS_EMPTY_STR || !ONIG_IS_NEWLINE(*sprev)) {
#endif
	  if (IS_NOTEOL(msa->options)) goto fail;   /* Is it needed? */
	  STAT_OP_OUT;
	  continue;
#ifndef USE_NEWLINE_AT_END_OF_STRING_HAS_EMPTY_LINE
	}
#endif
      }
      if (ONIG_IS_NEWLINE(*s) && ON_STR_END(s+1)) {
	STAT_OP_OUT;
	continue;
      }
      goto fail;
      break;

    case OP_BEGIN_POSITION:  STAT_OP_IN(OP_BEGIN_POSITION);
      if (s != msa->start)
	goto fail;

      STAT_OP_OUT;
      continue;
      break;

    case OP_MEMORY_START_PUSH:  STAT_OP_IN(OP_MEMORY_START_PUSH);
      GET_MEMNUM_INC(mem, p);
      STACK_PUSH_MEM_START(mem, s);
      STAT_OP_OUT;
      continue;
      break;

    case OP_MEMORY_START:  STAT_OP_IN(OP_MEMORY_START);
      GET_MEMNUM_INC(mem, p);
      mem_start_stk[mem] = (StackIndex )((void* )s);
      STAT_OP_OUT;
      continue;
      break;

    case OP_MEMORY_END_PUSH:  STAT_OP_IN(OP_MEMORY_END_PUSH);
      GET_MEMNUM_INC(mem, p);
      STACK_PUSH_MEM_END(mem, s);
      STAT_OP_OUT;
      continue;
      break;

    case OP_MEMORY_END:  STAT_OP_IN(OP_MEMORY_END);
      GET_MEMNUM_INC(mem, p);
      mem_end_stk[mem] = (StackIndex )((void* )s);
      STAT_OP_OUT;
      continue;
      break;

#ifdef USE_SUBEXP_CALL
    case OP_MEMORY_END_PUSH_REC:  STAT_OP_IN(OP_MEMORY_END_PUSH_REC);
      GET_MEMNUM_INC(mem, p);
      STACK_GET_MEM_START(mem, stkp); /* should be before push mem-end. */
      STACK_PUSH_MEM_END(mem, s);
      mem_start_stk[mem] = GET_STACK_INDEX(stkp);
      STAT_OP_OUT;
      continue;
      break;

    case OP_MEMORY_END_REC:  STAT_OP_IN(OP_MEMORY_END_REC);
      GET_MEMNUM_INC(mem, p);
      mem_end_stk[mem] = (StackIndex )((void* )s);
      STACK_GET_MEM_START(mem, stkp);

      if (BIT_STATUS_AT(reg->bt_mem_start, mem))
	mem_start_stk[mem] = GET_STACK_INDEX(stkp);
      else
	mem_start_stk[mem] = (StackIndex )((void* )stkp->u.mem.pstr);

      STACK_PUSH_MEM_END_MARK(mem);
      STAT_OP_OUT;
      continue;
      break;
#endif

    case OP_BACKREF1:  STAT_OP_IN(OP_BACKREF1);
      mem = 1;
      goto backref;
      break;

    case OP_BACKREF2:  STAT_OP_IN(OP_BACKREF2);
      mem = 2;
      goto backref;
      break;

    case OP_BACKREF3:  STAT_OP_IN(OP_BACKREF3);
      mem = 3;
      goto backref;
      break;

    case OP_BACKREFN:  STAT_OP_IN(OP_BACKREFN);
      GET_MEMNUM_INC(mem, p);
    backref:
      {
	int len;
	UChar *pstart, *pend;

	/* if you want to remove following line, 
	   you should check in parse and compile time. */
	if (mem > num_mem) goto fail;
	if (mem_end_stk[mem]   == INVALID_STACK_INDEX) goto fail;
	if (mem_start_stk[mem] == INVALID_STACK_INDEX) goto fail;

	if (BIT_STATUS_AT(reg->bt_mem_start, mem))
	  pstart = STACK_AT(mem_start_stk[mem])->u.mem.pstr;
	else
	  pstart = (UChar* )((void* )mem_start_stk[mem]);

	pend = (BIT_STATUS_AT(reg->bt_mem_end, mem)
		? STACK_AT(mem_end_stk[mem])->u.mem.pstr
		: (UChar* )((void* )mem_end_stk[mem]));
	n = pend - pstart;
	DATA_ENSURE(n);
	sprev = s;
	STRING_CMP(pstart, s, n);
	while (sprev + (len = enc_len(encode, *sprev)) < s)
	  sprev += len;

	STAT_OP_OUT;
	continue;
      }
      break;

    case OP_BACKREFN_IC:  STAT_OP_IN(OP_BACKREFN_IC);
      GET_MEMNUM_INC(mem, p);
      {
	int len;
	UChar *pstart, *pend;

	/* if you want to remove following line, 
	   you should check in parse and compile time. */
	if (mem > num_mem) goto fail;
	if (mem_end_stk[mem]   == INVALID_STACK_INDEX) goto fail;
	if (mem_start_stk[mem] == INVALID_STACK_INDEX) goto fail;

	if (BIT_STATUS_AT(reg->bt_mem_start, mem))
	  pstart = STACK_AT(mem_start_stk[mem])->u.mem.pstr;
	else
	  pstart = (UChar* )((void* )mem_start_stk[mem]);

	pend = (BIT_STATUS_AT(reg->bt_mem_end, mem)
		? STACK_AT(mem_end_stk[mem])->u.mem.pstr
		: (UChar* )((void* )mem_end_stk[mem]));
	n = pend - pstart;
	DATA_ENSURE(n);
	sprev = s;
	STRING_CMP_IC(pstart, &s, n);
	while (sprev + (len = enc_len(encode, *sprev)) < s)
	  sprev += len;

	STAT_OP_OUT;
	continue;
      }
      break;

    case OP_BACKREF_MULTI:  STAT_OP_IN(OP_BACKREF_MULTI);
      {
	int len, is_fail;
	UChar *pstart, *pend, *swork;

	GET_LENGTH_INC(tlen, p);
	for (i = 0; i < tlen; i++) {
	  GET_MEMNUM_INC(mem, p);

	  if (mem_end_stk[mem]   == INVALID_STACK_INDEX) continue;
	  if (mem_start_stk[mem] == INVALID_STACK_INDEX) continue;

	  if (BIT_STATUS_AT(reg->bt_mem_start, mem))
	    pstart = STACK_AT(mem_start_stk[mem])->u.mem.pstr;
	  else
	    pstart = (UChar* )((void* )mem_start_stk[mem]);

	  pend = (BIT_STATUS_AT(reg->bt_mem_end, mem)
		  ? STACK_AT(mem_end_stk[mem])->u.mem.pstr
		  : (UChar* )((void* )mem_end_stk[mem]));
	  n = pend - pstart;
	  DATA_ENSURE(n);
	  sprev = s;
	  swork = s;
	  STRING_CMP_VALUE(pstart, swork, n, is_fail);
	  if (is_fail) continue;
	  s = swork;
	  while (sprev + (len = enc_len(encode, *sprev)) < s)
	    sprev += len;

	  p += (SIZE_MEMNUM * (tlen - i - 1));
	  break; /* success */
	}
	if (i == tlen) goto fail;
	STAT_OP_OUT;
	continue;
      }
      break;

    case OP_BACKREF_MULTI_IC:  STAT_OP_IN(OP_BACKREF_MULTI_IC);
      {
	int len, is_fail;
	UChar *pstart, *pend, *swork;

	GET_LENGTH_INC(tlen, p);
	for (i = 0; i < tlen; i++) {
	  GET_MEMNUM_INC(mem, p);

	  if (mem_end_stk[mem]   == INVALID_STACK_INDEX) continue;
	  if (mem_start_stk[mem] == INVALID_STACK_INDEX) continue;

	  if (BIT_STATUS_AT(reg->bt_mem_start, mem))
	    pstart = STACK_AT(mem_start_stk[mem])->u.mem.pstr;
	  else
	    pstart = (UChar* )((void* )mem_start_stk[mem]);

	  pend = (BIT_STATUS_AT(reg->bt_mem_end, mem)
		  ? STACK_AT(mem_end_stk[mem])->u.mem.pstr
		  : (UChar* )((void* )mem_end_stk[mem]));
	  n = pend - pstart;
	  DATA_ENSURE(n);
	  sprev = s;
	  swork = s;
	  STRING_CMP_VALUE_IC(pstart, &swork, n, is_fail);
	  if (is_fail) continue;
	  s = swork;
	  while (sprev + (len = enc_len(encode, *sprev)) < s)
	    sprev += len;

	  p += (SIZE_MEMNUM * (tlen - i - 1));
	  break; /* success */
	}
	if (i == tlen) goto fail;
	STAT_OP_OUT;
	continue;
      }
      break;
    
    case OP_SET_OPTION_PUSH:  STAT_OP_IN(OP_SET_OPTION_PUSH);
      GET_OPTION_INC(option, p);
      ignore_case = IS_IGNORECASE(option);
      STACK_PUSH_ALT(p, s, sprev);
      p += SIZE_OP_SET_OPTION + SIZE_OP_FAIL;
      STAT_OP_OUT;
      continue;
      break;

    case OP_SET_OPTION:  STAT_OP_IN(OP_SET_OPTION);
      GET_OPTION_INC(option, p);
      ignore_case = IS_IGNORECASE(option);
      STAT_OP_OUT;
      continue;
      break;

    case OP_NULL_CHECK_START:  STAT_OP_IN(OP_NULL_CHECK_START);
      GET_MEMNUM_INC(mem, p);    /* mem: null check id */
      STACK_PUSH_NULL_CHECK_START(mem, s);
      STAT_OP_OUT;
      continue;
      break;

    case OP_NULL_CHECK_END:  STAT_OP_IN(OP_NULL_CHECK_END);
      {
	int isnull;

	GET_MEMNUM_INC(mem, p); /* mem: null check id */
	STACK_NULL_CHECK(isnull, mem, s);
	if (isnull) {
#ifdef ONIG_DEBUG_MATCH
	  fprintf(stderr, "NULL_CHECK_END: skip  id:%d, s:%d\n",
		  (int )mem, (int )s);
#endif
	null_check_found:
	  /* empty loop founded, skip next instruction */
	  switch (*p++) {
	  case OP_JUMP:
	  case OP_PUSH:
	    p += SIZE_RELADDR;
	    break;
	  case OP_REPEAT_INC:
	  case OP_REPEAT_INC_NG:
	    p += SIZE_MEMNUM;
	    break;
	  default:
	    goto unexpected_bytecode_error;
	    break;
	  }
	}
      }
      STAT_OP_OUT;
      continue;
      break;

#ifdef USE_INFINITE_REPEAT_MONOMANIAC_MEM_STATUS_CHECK
    case OP_NULL_CHECK_END_MEMST:  STAT_OP_IN(OP_NULL_CHECK_END_MEMST);
      {
	int isnull;

	GET_MEMNUM_INC(mem, p); /* mem: null check id */
	STACK_NULL_CHECK_MEMST(isnull, mem, s, reg);
	if (isnull) {
#ifdef ONIG_DEBUG_MATCH
	  fprintf(stderr, "NULL_CHECK_END_MEMST: skip  id:%d, s:%d\n",
		  (int )mem, (int )s);
#endif
	  if (isnull == -1) goto fail;
	  goto 	null_check_found;
	}
      }
      STAT_OP_OUT;
      continue;
      break;
#endif

#ifdef USE_SUBEXP_CALL
    case OP_NULL_CHECK_END_MEMST_PUSH:
      STAT_OP_IN(OP_NULL_CHECK_END_MEMST_PUSH);
      {
	int isnull;

	GET_MEMNUM_INC(mem, p); /* mem: null check id */
#ifdef USE_INFINITE_REPEAT_MONOMANIAC_MEM_STATUS_CHECK
	STACK_NULL_CHECK_MEMST_REC(isnull, mem, s, reg);
#else
	STACK_NULL_CHECK_REC(isnull, mem, s);
#endif
	if (isnull) {
#ifdef ONIG_DEBUG_MATCH
	  fprintf(stderr, "NULL_CHECK_END_MEMST_PUSH: skip  id:%d, s:%d\n",
		  (int )mem, (int )s);
#endif
	  if (isnull == -1) goto fail;
	  goto 	null_check_found;
	}
	else {
	  STACK_PUSH_NULL_CHECK_END(mem);
	}
      }
      STAT_OP_OUT;
      continue;
      break;
#endif

    case OP_JUMP:  STAT_OP_IN(OP_JUMP);
      GET_RELADDR_INC(addr, p);
      p += addr;
      STAT_OP_OUT;
      continue;
      break;

    case OP_PUSH:  STAT_OP_IN(OP_PUSH);
      GET_RELADDR_INC(addr, p);
      STACK_PUSH_ALT(p + addr, s, sprev);
      STAT_OP_OUT;
      continue;
      break;

    case OP_POP:  STAT_OP_IN(OP_POP);
      STACK_POP_ONE;
      STAT_OP_OUT;
      continue;
      break;

    case OP_PUSH_OR_JUMP_EXACT1:  STAT_OP_IN(OP_PUSH_OR_JUMP_EXACT1);
      GET_RELADDR_INC(addr, p);
      if (*p == *s && DATA_ENSURE_CHECK(1)) {
	p++;
	STACK_PUSH_ALT(p + addr, s, sprev);
	STAT_OP_OUT;
	continue;
      }
      p += (addr + 1);
      STAT_OP_OUT;
      continue;
      break;

    case OP_PUSH_IF_PEEK_NEXT:  STAT_OP_IN(OP_PUSH_IF_PEEK_NEXT);
      GET_RELADDR_INC(addr, p);
      if (*p == *s) {
	p++;
	STACK_PUSH_ALT(p + addr, s, sprev);
	STAT_OP_OUT;
	continue;
      }
      p++;
      STAT_OP_OUT;
      continue;
      break;

    case OP_REPEAT:  STAT_OP_IN(OP_REPEAT);
      {
	GET_MEMNUM_INC(mem, p);    /* mem: OP_REPEAT ID */
	GET_RELADDR_INC(addr, p);

	STACK_ENSURE(1);
	repeat_stk[mem] = GET_STACK_INDEX(stk);
	STACK_PUSH_REPEAT(mem, p);

	if (reg->repeat_range[mem].lower == 0) {
	  STACK_PUSH_ALT(p + addr, s, sprev);
	}
      }
      STAT_OP_OUT;
      continue;
      break;

    case OP_REPEAT_NG:  STAT_OP_IN(OP_REPEAT_NG);
      {
	GET_MEMNUM_INC(mem, p);    /* mem: OP_REPEAT ID */
	GET_RELADDR_INC(addr, p);

	STACK_ENSURE(1);
	repeat_stk[mem] = GET_STACK_INDEX(stk);
	STACK_PUSH_REPEAT(mem, p);

	if (reg->repeat_range[mem].lower == 0) {
	  STACK_PUSH_ALT(p, s, sprev);
	  p += addr;
	}
      }
      STAT_OP_OUT;
      continue;
      break;

    case OP_REPEAT_INC:  STAT_OP_IN(OP_REPEAT_INC);
      {
	StackIndex si;

	GET_MEMNUM_INC(mem, p); /* mem: OP_REPEAT ID */
#ifdef USE_SUBEXP_CALL
	if (reg->num_call > 0) {
	  STACK_GET_REPEAT(mem, stkp);
	  si = GET_STACK_INDEX(stkp);
	}
	else {
	  si = repeat_stk[mem];
	  stkp = STACK_AT(si);
	}
#else
	si = repeat_stk[mem];
	stkp = STACK_AT(si);
#endif
	stkp->u.repeat.count++;
	if (stkp->u.repeat.count == reg->repeat_range[mem].upper) {
	  /* end of repeat. Nothing to do. */
	}
	else if (stkp->u.repeat.count >= reg->repeat_range[mem].lower) {
	  STACK_PUSH_ALT(p, s, sprev);
	  p = stkp->u.repeat.pcode;
	}
	else {
	  p = stkp->u.repeat.pcode;
	}
	STACK_PUSH_REPEAT_INC(si);
      }
      STAT_OP_OUT;
      continue;
      break;

    case OP_REPEAT_INC_NG:  STAT_OP_IN(OP_REPEAT_INC_NG);
      {
	StackIndex si;

	GET_MEMNUM_INC(mem, p); /* mem: OP_REPEAT ID */
#ifdef USE_SUBEXP_CALL
	if (reg->num_call > 0) {
	  STACK_GET_REPEAT(mem, stkp);
	  si = GET_STACK_INDEX(stkp);
	}
	else {
	  si = repeat_stk[mem];
	  stkp = STACK_AT(si);
	}
#else
	si = repeat_stk[mem];
	stkp = STACK_AT(si);
#endif
	stkp->u.repeat.count++;
	if (stkp->u.repeat.count < reg->repeat_range[mem].upper) {
	  if (stkp->u.repeat.count >= reg->repeat_range[mem].lower) {
	    UChar* pcode = stkp->u.repeat.pcode;

	    STACK_PUSH_REPEAT_INC(si);
	    STACK_PUSH_ALT(pcode, s, sprev);
	  }
	  else {
	    p = stkp->u.repeat.pcode;
	    STACK_PUSH_REPEAT_INC(si);
	  }
	}
	else if (stkp->u.repeat.count == reg->repeat_range[mem].upper) {
	  STACK_PUSH_REPEAT_INC(si);
	}
      }
      STAT_OP_OUT;
      continue;
      break;

    case OP_PUSH_POS:  STAT_OP_IN(OP_PUSH_POS);
      STACK_PUSH_POS(s, sprev);
      STAT_OP_OUT;
      continue;
      break;

    case OP_POP_POS:  STAT_OP_IN(OP_POP_POS);
      {
	STACK_POS_END(stkp);
	s     = stkp->u.state.pstr;
	sprev = stkp->u.state.pstr_prev;
      }
      STAT_OP_OUT;
      continue;
      break;

    case OP_PUSH_POS_NOT:  STAT_OP_IN(OP_PUSH_POS_NOT);
      GET_RELADDR_INC(addr, p);
      STACK_PUSH_POS_NOT(p + addr, s, sprev);
      STAT_OP_OUT;
      continue;
      break;

    case OP_FAIL_POS:  STAT_OP_IN(OP_FAIL_POS);
      STACK_POP_TIL_POS_NOT;
      goto fail;
      break;

    case OP_PUSH_STOP_BT:  STAT_OP_IN(OP_PUSH_STOP_BT);
      STACK_PUSH_STOP_BT;
      STAT_OP_OUT;
      continue;
      break;

    case OP_POP_STOP_BT:  STAT_OP_IN(OP_POP_STOP_BT);
      STACK_STOP_BT_END;
      STAT_OP_OUT;
      continue;
      break;

    case OP_LOOK_BEHIND:  STAT_OP_IN(OP_LOOK_BEHIND);
      GET_LENGTH_INC(tlen, p);
      s = ONIGENC_STEP_BACK(encode, str, s, (int )tlen);
      if (IS_NULL(s)) goto fail;
      sprev = onigenc_get_prev_char_head(encode, str, s);
      STAT_OP_OUT;
      continue;
      break;

    case OP_PUSH_LOOK_BEHIND_NOT:  STAT_OP_IN(OP_PUSH_LOOK_BEHIND_NOT);
      GET_RELADDR_INC(addr, p);
      GET_LENGTH_INC(tlen, p);
      q = ONIGENC_STEP_BACK(encode, str, s, (int )tlen);
      if (IS_NULL(q)) {
	/* too short case -> success. ex. /(?<!XXX)a/.match("a")
	   If you want to change to fail, replace following line. */
	p += addr;
	/* goto fail; */
      }
      else {
	STACK_PUSH_LOOK_BEHIND_NOT(p + addr, s, sprev);
	s = q;
	sprev = onigenc_get_prev_char_head(encode, str, s);
      }
      STAT_OP_OUT;
      continue;
      break;

    case OP_FAIL_LOOK_BEHIND_NOT:  STAT_OP_IN(OP_FAIL_LOOK_BEHIND_NOT);
      STACK_POP_TIL_LOOK_BEHIND_NOT;
      goto fail;
      break;

#ifdef USE_SUBEXP_CALL
    case OP_CALL:  STAT_OP_IN(OP_CALL);
      GET_ABSADDR_INC(addr, p);
      STACK_PUSH_CALL_FRAME(p);
      p = reg->p + addr;
      STAT_OP_OUT;
      continue;
      break;

    case OP_RETURN:  STAT_OP_IN(OP_RETURN);
      STACK_RETURN(p);
      STACK_PUSH_RETURN;
      STAT_OP_OUT;
      continue;
      break;
#endif

    case OP_FINISH:
      goto finish;
      break;

    fail:
      STAT_OP_OUT;
      /* fall */
    case OP_FAIL:  STAT_OP_IN(OP_FAIL);
      STACK_POP;
      p     = stk->u.state.pcode;
      s     = stk->u.state.pstr;
      sprev = stk->u.state.pstr_prev;
      STAT_OP_OUT;
      continue;
      break;

    default:
      goto bytecode_error;

    } /* end of switch */
    sprev = sbegin;
  } /* end of while(1) */

 finish:
  STACK_SAVE;
  return best_len;

#ifdef ONIG_DEBUG
 stack_error:
  STACK_SAVE;
  return ONIGERR_STACK_BUG;
#endif

 bytecode_error:
  STACK_SAVE;
  return ONIGERR_UNDEFINED_BYTECODE;

 unexpected_bytecode_error:
  STACK_SAVE;
  return ONIGERR_UNEXPECTED_BYTECODE;
}


static UChar*
slow_search(OnigEncoding enc, UChar* target, UChar* target_end,
	    UChar* text, UChar* text_end, UChar* text_range)
{
  UChar *t, *p, *s, *end;

  end = text_end - (target_end - target) + 1;
  if (end > text_range)
    end = text_range;

  s = text;

  while (s < end) {
    if (*s == *target) {
      p = s + 1;
      t = target + 1;
      while (t < target_end) {
	if (*t != *p++)
	  break;
	t++;
      }
      if (t == target_end)
	return s;
    }
    s += enc_len(enc, *s);
  }

  return (UChar* )NULL;
}

#if 0
static int
str_trans_match_after_head_byte(OnigEncoding enc,
				int len, UChar* t, UChar* tend, UChar* p)
{
  while (--len > 0) {
    if (*t != *p) break;
    t++; p++;
  }

  if (len == 0) {
    int lowlen;
    UChar *q, lowbuf[ONIGENC_MBC_TO_LOWER_MAXLEN];

    while (t < tend) {
      len = enc_len(enc, *p);
      lowlen = ONIGENC_MBC_TO_LOWER(enc, p, lowbuf);
      q = lowbuf;
      while (lowlen > 0) {
	if (*t++ != *q++) break;
	lowlen--;
      }
      if (lowlen > 0) break;
      p += len;
    }
    if (t == tend)
      return 1;
  }

  return 0;
}
#endif

static int
str_lower_case_match(OnigEncoding enc, UChar* t, UChar* tend, UChar* p)
{
  int len, lowlen;
  UChar *q, lowbuf[ONIGENC_MBC_TO_LOWER_MAXLEN];

  while (t < tend) {
    len = enc_len(enc, *p);
    lowlen = ONIGENC_MBC_TO_LOWER(enc, p, lowbuf);
    q = lowbuf;
    while (lowlen > 0) {
      if (*t++ != *q++) return 0;
      lowlen--;
    }
    p += len;
  }

  return 1;
}

static UChar*
slow_search_ic(OnigEncoding enc,
	       UChar* target, UChar* target_end,
	       UChar* text, UChar* text_end, UChar* text_range)
{
  int len, lowlen;
  UChar *t, *p, *s, *end;
  UChar lowbuf[ONIGENC_MBC_TO_LOWER_MAXLEN];

  end = text_end - (target_end - target) + 1;
  if (end > text_range)
    end = text_range;

  s = text;

  while (s < end) {
    len = enc_len(enc, *s);
    lowlen = ONIGENC_MBC_TO_LOWER(enc, s, lowbuf);
    if (*target == *lowbuf) {
      p = lowbuf + 1;
      t = target + 1;
      while (--lowlen > 0) {
	if (*p != *t) break;
	p++; *t++;
      }
      if (lowlen == 0) {
	if (str_lower_case_match(enc, t, target_end, s + len))
	  return s;
      }
    }

    s += len;
  }

  return (UChar* )NULL;
}

static UChar*
slow_search_backward(OnigEncoding enc, UChar* target, UChar* target_end,
	     UChar* text, UChar* adjust_text, UChar* text_end, UChar* text_start)
{
  UChar *t, *p, *s;

  s = text_end - (target_end - target);
  if (s > text_start)
    s = text_start;
  else
    s = ONIGENC_LEFT_ADJUST_CHAR_HEAD(enc, adjust_text, s);

  while (s >= text) {
    if (*s == *target) {
      p = s + 1;
      t = target + 1;
      while (t < target_end) {
	if (*t != *p++)
	  break;
	t++;
      }
      if (t == target_end)
	return s;
    }
    s = onigenc_get_prev_char_head(enc, adjust_text, s);
  }

  return (UChar* )NULL;
}

static UChar*
slow_search_backward_ic(OnigEncoding enc,
			UChar* target,UChar* target_end,
			UChar* text, UChar* adjust_text,
			UChar* text_end, UChar* text_start)
{
  int len, lowlen;
  UChar *t, *p, *s;
  UChar lowbuf[ONIGENC_MBC_TO_LOWER_MAXLEN];

  s = text_end - (target_end - target);
  if (s > text_start)
    s = text_start;
  else
    s = ONIGENC_LEFT_ADJUST_CHAR_HEAD(enc, adjust_text, s);

  while (s >= text) {
    len = enc_len(enc, *s);
    lowlen = ONIGENC_MBC_TO_LOWER(enc, s, lowbuf);
    if (*target == *lowbuf) {
      p = lowbuf + 1;
      t = target + 1;
      while (--lowlen > 0) {
	if (*p != *t) break;
	p++; *t++;
      }
      if (lowlen == 0) {
	if (str_lower_case_match(enc, t, target_end, s + len))
	  return s;
      }
    }

    s = onigenc_get_prev_char_head(enc, adjust_text, s);
  }

  return (UChar* )NULL;
}

static UChar*
bm_search_notrev(regex_t* reg, UChar* target, UChar* target_end,
		 UChar* text, UChar* text_end, UChar* text_range)
{
  UChar *s, *t, *p, *end;
  UChar *tail;
  int skip;

  end = text_range + (target_end - target) - 1;
  if (end > text_end)
    end = text_end;

  tail = target_end - 1;
  s = text;
  while ((s - text) < target_end - target) {
    s += enc_len(reg->enc, *s);
  }
  s--; /* set to text check tail position. */

  if (IS_NULL(reg->int_map)) {
    while (s < end) {
      p = s;
      t = tail;
      while (t >= target && *p == *t) {
	p--; t--;
      }
      if (t < target) return p + 1;

      skip = reg->map[*s];
      p = s + 1;
      if (p >= text_end) return (UChar* )NULL;
      t = p;
      do {
	p += enc_len(reg->enc, *p);
      } while ((p - t) < skip && p < text_end);

      s += (p - t);
    }
  }
  else {
    while (s < end) {
      p = s;
      t = tail;
      while (t >= target && *p == *t) {
	p--; t--;
      }
      if (t < target) return p + 1;

      skip = reg->int_map[*s];
      p = s + 1;
      if (p >= text_end) return (UChar* )NULL;
      t = p;
      do {
	p += enc_len(reg->enc, *p);
      } while ((p - t) < skip && p < text_end);

      s += (p - t);
    }
  }
  return (UChar* )NULL;
}

static UChar*
bm_search(regex_t* reg, UChar* target, UChar* target_end,
	  UChar* text, UChar* text_end, UChar* text_range)
{
  UChar *s, *t, *p, *end;
  UChar *tail;

  end = text_range + (target_end - target) - 1;
  if (end > text_end)
    end = text_end;

  tail = target_end - 1;
  s = text + (target_end - target) - 1;
  if (IS_NULL(reg->int_map)) {
    while (s < end) {
      p = s;
      t = tail;
      while (t >= target && *p == *t) {
	p--; t--;
      }
      if (t < target) return p + 1;
      s += reg->map[*s];
    }
  }
  else { /* see int_map[] */
    while (s < end) {
      p = s;
      t = tail;
      while (t >= target && *p == *t) {
	p--; t--;
      }
      if (t < target) return p + 1;
      s += reg->int_map[*s];
    }
  }
  return (UChar* )NULL;
}

static int
set_bm_backward_skip(UChar* s, UChar* end, OnigEncoding enc,
		     int ignore_case, int** skip)
{
  int i, len;
  UChar lowbuf[ONIGENC_MBC_TO_LOWER_MAXLEN];

  if (IS_NULL(*skip)) {
    *skip = (int* )xmalloc(sizeof(int) * ONIG_CHAR_TABLE_SIZE);
    if (IS_NULL(*skip)) return ONIGERR_MEMORY;
  }

  len = end - s;
  for (i = 0; i < ONIG_CHAR_TABLE_SIZE; i++)
    (*skip)[i] = len;

  if (ignore_case) {
    for (i = len - 1; i > 0; i--) {
      ONIGENC_MBC_TO_LOWER(enc, &(s[i]), lowbuf);
      (*skip)[*lowbuf] = i;
    }
  }
  else {
    for (i = len - 1; i > 0; i--)
      (*skip)[s[i]] = i;
  }
  return 0;
}

static UChar*
bm_search_backward(regex_t* reg, UChar* target, UChar* target_end, UChar* text,
		   UChar* adjust_text, UChar* text_end, UChar* text_start)
{
  UChar *s, *t, *p;

  s = text_end - (target_end - target);
  if (text_start < s)
    s = text_start;
  else
    s = ONIGENC_LEFT_ADJUST_CHAR_HEAD(reg->enc, adjust_text, s);

  while (s >= text) {
    p = s;
    t = target;
    while (t < target_end && *p == *t) {
      p++; t++;
    }
    if (t == target_end)
      return s;

    s -= reg->int_map_backward[*s];
    s = ONIGENC_LEFT_ADJUST_CHAR_HEAD(reg->enc, adjust_text, s);
  }

  return (UChar* )NULL;
}

static UChar*
map_search(OnigEncoding enc, UChar map[], UChar* text, UChar* text_range)
{
  UChar *s = text;

  while (s < text_range) {
    if (map[*s]) return s;

    s += enc_len(enc, *s);
  }
  return (UChar* )NULL;
}

static UChar*
map_search_backward(OnigEncoding enc, UChar map[],
		    UChar* text, UChar* adjust_text, UChar* text_start)
{
  UChar *s = text_start;

  while (s >= text) {
    if (map[*s]) return s;

    s = onigenc_get_prev_char_head(enc, adjust_text, s);
  }
  return (UChar* )NULL;
}

extern int
onig_match(regex_t* reg, UChar* str, UChar* end, UChar* at, OnigRegion* region,
	    OnigOptionType option)
{
  int r;
  UChar *prev;
  MatchArg msa;

  MATCH_ARG_INIT(msa, option, region, at);

  if (region
#ifdef USE_POSIX_REGION_OPTION
      && !IS_POSIX_REGION(option)
#endif
      ) {
    r = onig_region_resize(region, reg->num_mem + 1);
  }
  else
    r = 0;

  if (r == 0) {
    prev = onigenc_get_prev_char_head(reg->enc, str, at);
    r = match_at(reg, str, end, at, prev, &msa);
  }
  MATCH_ARG_FREE(msa);
  return r;
}

static int
forward_search_range(regex_t* reg, UChar* str, UChar* end, UChar* s,
		     UChar* range, UChar** low, UChar** high, UChar** low_prev)
{
  UChar *p, *pprev = (UChar* )NULL;

#ifdef ONIG_DEBUG_SEARCH
  fprintf(stderr, "forward_search_range: str: %d, end: %d, s: %d, range: %d\n",
	  (int )str, (int )end, (int )s, (int )range);
#endif

  p = s;
  if (reg->dmin > 0) {
    if (ONIGENC_IS_SINGLEBYTE(reg->enc)) {
      p += reg->dmin;
    }
    else {
      UChar *q = p + reg->dmin;
      while (p < q) p += enc_len(reg->enc, *p);
    }
  }

 retry:
  switch (reg->optimize) {
  case ONIG_OPTIMIZE_EXACT:
    p = slow_search(reg->enc, reg->exact, reg->exact_end, p, end, range);
    break;
  case ONIG_OPTIMIZE_EXACT_IC:
    p = slow_search_ic(reg->enc, reg->exact, reg->exact_end, p, end, range);
    break;

  case ONIG_OPTIMIZE_EXACT_BM:
    p = bm_search(reg, reg->exact, reg->exact_end, p, end, range);
    break;

  case ONIG_OPTIMIZE_EXACT_BM_NOT_REV:
    p = bm_search_notrev(reg, reg->exact, reg->exact_end, p, end, range);
    break;

  case ONIG_OPTIMIZE_MAP:
    p = map_search(reg->enc, reg->map, p, range);
    break;
  }

  if (p && p < range) {
    if (p - reg->dmin < s) {
    retry_gate:
      pprev = p;
      p += enc_len(reg->enc, *p);
      goto retry;
    }

    if (reg->sub_anchor) {
      UChar* prev;

      switch (reg->sub_anchor) {
      case ANCHOR_BEGIN_LINE:
	if (!ON_STR_BEGIN(p)) {
	  prev = onigenc_get_prev_char_head(reg->enc,
					    (pprev ? pprev : str), p);
	  if (!ONIG_IS_NEWLINE(*prev))
	    goto retry_gate;
	}
	break;

      case ANCHOR_END_LINE:
	if (ON_STR_END(p)) {
	  prev = onigenc_get_prev_char_head(reg->enc,
					    (pprev ? pprev : str), p);
	  if (prev && ONIG_IS_NEWLINE(*prev))
	    goto retry_gate;
	}
	else if (!ONIG_IS_NEWLINE(*p))
	  goto retry_gate;
	break;
      }
    }

    if (reg->dmax == 0) {
      *low = p;
      if (low_prev) {
	if (*low > s)
	  *low_prev = onigenc_get_prev_char_head(reg->enc, s, p);
	else
	  *low_prev = onigenc_get_prev_char_head(reg->enc,
						 (pprev ? pprev : str), p);
      }
    }
    else {
      if (reg->dmax != ONIG_INFINITE_DISTANCE) {
	*low = p - reg->dmax;
	if (*low > s) {
	  *low = onigenc_get_right_adjust_char_head_with_prev(reg->enc, s,
							  *low, low_prev);
	  if (low_prev && IS_NULL(*low_prev))
	    *low_prev = onigenc_get_prev_char_head(reg->enc,
						   (pprev ? pprev : s), *low);
	}
	else {
	  if (low_prev)
	    *low_prev = onigenc_get_prev_char_head(reg->enc,
					       (pprev ? pprev : str), *low);
	}
      }
    }
    /* no needs to adjust *high, *high is used as range check only */
    *high = p - reg->dmin;

#ifdef ONIG_DEBUG_SEARCH
    fprintf(stderr,
    "forward_search_range success: low: %d, high: %d, dmin: %d, dmax: %d\n",
	    (int )(*low - str), (int )(*high - str), reg->dmin, reg->dmax);
#endif
    return 1; /* success */
  }

  return 0; /* fail */
}

static int set_bm_backward_skip P_((UChar* s, UChar* end, OnigEncoding enc,
				    int ignore_case, int** skip));

#define BM_BACKWARD_SEARCH_LENGTH_THRESHOLD   100

static int
backward_search_range(regex_t* reg, UChar* str, UChar* end, UChar* s,
		      UChar* range, UChar* adjrange, UChar** low, UChar** high)
{
  int r;
  UChar *p;

  range += reg->dmin;
  p = s;

 retry:
  switch (reg->optimize) {
  case ONIG_OPTIMIZE_EXACT:
  exact_method:
    p = slow_search_backward(reg->enc, reg->exact, reg->exact_end,
			     range, adjrange, end, p);
    break;

  case ONIG_OPTIMIZE_EXACT_IC:
    p = slow_search_backward_ic(reg->enc, reg->exact,
				reg->exact_end, range, adjrange, end, p);
    break;

  case ONIG_OPTIMIZE_EXACT_BM:
  case ONIG_OPTIMIZE_EXACT_BM_NOT_REV:
    if (IS_NULL(reg->int_map_backward)) {
      if (s - range < BM_BACKWARD_SEARCH_LENGTH_THRESHOLD)
	goto exact_method;

      r = set_bm_backward_skip(reg->exact, reg->exact_end, reg->enc, 0,
			       &(reg->int_map_backward));
      if (r) return r;
    }
    p = bm_search_backward(reg, reg->exact, reg->exact_end, range, adjrange,
			   end, p);
    break;

  case ONIG_OPTIMIZE_MAP:
    p = map_search_backward(reg->enc, reg->map, range, adjrange, p);
    break;
  }

  if (p) {
    if (reg->sub_anchor) {
      UChar* prev;

      switch (reg->sub_anchor) {
      case ANCHOR_BEGIN_LINE:
	if (!ON_STR_BEGIN(p)) {
	  prev = onigenc_get_prev_char_head(reg->enc, adjrange, p);
	  if (!ONIG_IS_NEWLINE(*prev)) {
	    p = prev;
	    goto retry;
	  }
	}
	break;

      case ANCHOR_END_LINE:
	if (ON_STR_END(p)) {
	  prev = onigenc_get_prev_char_head(reg->enc, adjrange, p);
	  if (IS_NULL(prev)) goto fail;
	  if (ONIG_IS_NEWLINE(*prev)) {
	    p = prev;
	    goto retry;
	  }
	}
	else if (!ONIG_IS_NEWLINE(*p)) {
	  p = onigenc_get_prev_char_head(reg->enc, adjrange, p);
	  if (IS_NULL(p)) goto fail;
	  goto retry;
	}
	break;
      }
    }

    /* no needs to adjust *high, *high is used as range check only */
    if (reg->dmax != ONIG_INFINITE_DISTANCE) {
      *low  = p - reg->dmax;
      *high = p - reg->dmin;
      *high = onigenc_get_right_adjust_char_head(reg->enc, adjrange, *high);
    }

#ifdef ONIG_DEBUG_SEARCH
    fprintf(stderr, "backward_search_range: low: %d, high: %d\n",
	    (int )(*low - str), (int )(*high - str));
#endif
    return 1; /* success */
  }

 fail:
#ifdef ONIG_DEBUG_SEARCH
  fprintf(stderr, "backward_search_range: fail.\n");
#endif
  return 0; /* fail */
}


extern int
onig_search(regex_t* reg, UChar* str, UChar* end,
	     UChar* start, UChar* range, OnigRegion* region, OnigOptionType option)
{
  int r;
  UChar *s, *prev;
  MatchArg msa;

  if (ONIG_STATE(reg) == ONIG_STATE_NORMAL) {
    reg->state++;  /* increment as search counter */
    if (IS_NOT_NULL(reg->chain)) {
      onig_chain_reduce(reg);
      reg->state++;
    }
  }
  else {
    int n = 0;
    while (ONIG_STATE(reg) < ONIG_STATE_NORMAL) {
      if (++n > THREAD_PASS_LIMIT_COUNT)
	return ONIGERR_OVER_THREAD_PASS_LIMIT_COUNT;
      THREAD_PASS;
    }
    reg->state++;  /* increment as search counter */
  }

#ifdef ONIG_DEBUG_SEARCH
  fprintf(stderr, "onig_search (entry point): str: %d, end: %d, start: %d, range: %d\n",
	  (int )str, (int )(end - str), (int )(start - str), (int )(range - str));
#endif

  if (region
#ifdef USE_POSIX_REGION_OPTION
      && !IS_POSIX_REGION(option)
#endif
      ) {
    r = onig_region_resize(region, reg->num_mem + 1);
    if (r) goto finish_no_msa;
  }

  if (start > end || start < str) goto mismatch_no_msa;

#define MATCH_AND_RETURN_CHECK \
  r = match_at(reg, str, end, s, prev, &msa);\
  if (r != ONIG_MISMATCH) {\
    if (r >= 0) goto match;\
    goto finish; /* error */ \
  }

  /* anchor optimize: resume search range */
  if (reg->anchor != 0 && str < end) {
    UChar* semi_end;

    if (reg->anchor & ANCHOR_BEGIN_POSITION) {
      /* search start-position only */
    begin_position:
      if (range > start)
	range = start + 1;
      else
	range = start;
    }
    else if (reg->anchor & ANCHOR_BEGIN_BUF) {
      /* search str-position only */
      if (range > start) {
	if (start != str) goto mismatch_no_msa;
	range = str + 1;
      }
      else {
	if (range <= str) {
	  start = str;
	  range = str;
	}
	else
	  goto mismatch_no_msa;
      }
    }
    else if (reg->anchor & ANCHOR_END_BUF) {
      semi_end = end;

    end_buf:
      if ((OnigDistance )(semi_end - str) < reg->anchor_dmin)
	goto mismatch_no_msa;

      if (range > start) {
	if ((OnigDistance )(semi_end - start) > reg->anchor_dmax) {
	  start = semi_end - reg->anchor_dmax;
	  if (start < end)
	    start = onigenc_get_right_adjust_char_head(reg->enc, str, start);
	  else { /* match with empty at end */
	    start = onigenc_get_prev_char_head(reg->enc, str, end);
	  }
	}
	if ((OnigDistance )(semi_end - (range - 1)) < reg->anchor_dmin) {
	  range = semi_end - reg->anchor_dmin + 1;
	}

	if (start >= range) goto mismatch_no_msa;
      }
      else {
	if ((OnigDistance )(semi_end - range) > reg->anchor_dmax) {
	  range = semi_end - reg->anchor_dmax;
	}
	if ((OnigDistance )(semi_end - start) < reg->anchor_dmin) {
	  start = semi_end - reg->anchor_dmin;
	  start = ONIGENC_LEFT_ADJUST_CHAR_HEAD(reg->enc, str, start);
	  if (range > start) goto mismatch_no_msa;
	}
      }
    }
    else if (reg->anchor & ANCHOR_SEMI_END_BUF) {
      if (ONIG_IS_NEWLINE(end[-1])) {
	semi_end = end - 1;
	if (semi_end > str && start <= semi_end) {
	  goto end_buf;
	}
      }
      else {
	semi_end = end;
	goto end_buf;
      }
    }
    else if ((reg->anchor & ANCHOR_ANYCHAR_STAR_PL)) {
      goto begin_position;
    }
  }
  else if (str == end) { /* empty string */
    static UChar* address_for_empty_string = "";

#ifdef ONIG_DEBUG_SEARCH
    fprintf(stderr, "onig_search: empty string.\n");
#endif

    if (reg->threshold_len == 0) {
      s = start = end = str = address_for_empty_string;
      prev = (UChar* )NULL;

      MATCH_ARG_INIT(msa, option, region, start);
      MATCH_AND_RETURN_CHECK;
      goto mismatch;
    }
    goto mismatch_no_msa;
  }

#ifdef ONIG_DEBUG_SEARCH
  fprintf(stderr, "onig_search(apply anchor): end: %d, start: %d, range: %d\n",
	  (int )(end - str), (int )(start - str), (int )(range - str));
#endif

  MATCH_ARG_INIT(msa, option, region, start);

  s = start;
  if (range > start) {   /* forward search */
    if (s > str)
      prev = onigenc_get_prev_char_head(reg->enc, str, s);
    else
      prev = (UChar* )NULL;

    if (reg->optimize != ONIG_OPTIMIZE_NONE) {
      UChar *sch_range, *low, *high, *low_prev;

      sch_range = range;
      if (reg->dmax != 0) {
	if (reg->dmax == ONIG_INFINITE_DISTANCE)
	  sch_range = end;
	else {
	  sch_range += reg->dmax;
	  if (sch_range > end) sch_range = end;
	}
      }
      if (reg->dmax != ONIG_INFINITE_DISTANCE &&
	  (end - start) >= reg->threshold_len) {
	do {
	  if (! forward_search_range(reg, str, end, s, sch_range,
				     &low, &high, &low_prev)) goto mismatch;
	  if (s < low) {
	    s    = low;
	    prev = low_prev;
	  }
	  while (s <= high) {
	    MATCH_AND_RETURN_CHECK;
	    prev = s;
	    s += enc_len(reg->enc, *s);
	  }
	  if ((reg->anchor & ANCHOR_ANYCHAR_STAR) != 0) {
	    if (IS_NOT_NULL(prev)) {
	      while (!ONIG_IS_NEWLINE(*prev) && s < range) {
		prev = s;
		s += enc_len(reg->enc, *s);
	      }
	    }
	  }
	} while (s < range);
	goto mismatch;
      }
      else { /* check only. */
	if ((end - start) < reg->threshold_len ||
	    ! forward_search_range(reg, str, end, s, sch_range,
				   &low, &high, (UChar** )NULL)) goto mismatch;
      }
    }

    do {
      MATCH_AND_RETURN_CHECK;
      prev = s;
      s += enc_len(reg->enc, *s);
    } while (s <= range);   /* exec s == range, because empty match with /$/. */
  }
  else {  /* backward search */
    if (reg->optimize != ONIG_OPTIMIZE_NONE) {
      UChar *low, *high, *adjrange, *sch_start;

      adjrange = ONIGENC_LEFT_ADJUST_CHAR_HEAD(reg->enc, str, range);
      if (reg->dmax != ONIG_INFINITE_DISTANCE &&
	  (end - range) >= reg->threshold_len) {
	do {
	  sch_start = s + reg->dmax;
	  if (sch_start > end) sch_start = end;
	  if (backward_search_range(reg, str, end, sch_start, range, adjrange,
				    &low, &high) <= 0)
	    goto mismatch;

	  if (s > high)
	    s = high;

	  while (s >= low) {
	    prev = onigenc_get_prev_char_head(reg->enc, str, s);
	    MATCH_AND_RETURN_CHECK;
	    s = prev;
	  }
	} while (s >= range);
	goto mismatch;
      }
      else { /* check only. */
	if ((end - range) < reg->threshold_len) goto mismatch;

	sch_start = s;
	if (reg->dmax != 0) {
	  if (reg->dmax == ONIG_INFINITE_DISTANCE)
	    sch_start = end;
	  else {
	    sch_start += reg->dmax;
	    if (sch_start > end) sch_start = end;
	    else
	      sch_start = ONIGENC_LEFT_ADJUST_CHAR_HEAD(reg->enc,
						    start, sch_start);
	  }
	}
	if (backward_search_range(reg, str, end, sch_start, range, adjrange,
				  &low, &high) <= 0) goto mismatch;
      }
    }

    do {
      prev = onigenc_get_prev_char_head(reg->enc, str, s);
      MATCH_AND_RETURN_CHECK;
      s = prev;
    } while (s >= range);
  }

 mismatch:
  r = ONIG_MISMATCH;

 finish:
  MATCH_ARG_FREE(msa);
  reg->state--;  /* decrement as search counter */

  /* If result is mismatch and no FIND_NOT_EMPTY option,
     then the region is not setted in match_at(). */
  if (IS_FIND_NOT_EMPTY(reg->options) && region
#ifdef USE_POSIX_REGION_OPTION
      && !IS_POSIX_REGION(option)
#endif
      ) {
    onig_region_clear(region);
  }

#ifdef ONIG_DEBUG
  if (r != ONIG_MISMATCH)
    fprintf(stderr, "onig_search: error %d\n", r);
#endif
  return r;

 mismatch_no_msa:
  r = ONIG_MISMATCH;
 finish_no_msa:
  reg->state--;  /* decrement as search counter */
#ifdef ONIG_DEBUG
  if (r != ONIG_MISMATCH)
    fprintf(stderr, "onig_search: error %d\n", r);
#endif
  return r;

 match:
  reg->state--;  /* decrement as search counter */
  MATCH_ARG_FREE(msa);
  return s - str;
}

extern OnigEncoding
onig_get_encoding(regex_t* reg)
{
  return reg->enc;
}

extern OnigOptionType
onig_get_options(regex_t* reg)
{
  return reg->options;
}

extern OnigSyntaxType*
onig_get_syntax(regex_t* reg)
{
  return reg->syntax;
}