Adwaith-Rajesh/gperf
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Make the backtracking look like a standard Prolog box.

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This commit is contained in:
Bruno Haible
2003-02-25 12:01:50 +00:00
parent ee424350d0
commit ea37cea17b
1 changed files with 51 additions and 32 deletions
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83
src/search.cc
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@@ -993,6 +993,16 @@ Search::find_asso_values ()
}
}
/* Backtracking according to the standard Prolog call pattern:
+------------------+
-------CALL------>| |-------RETURN------>
| |
<------FAIL-------| |<------REDO---------
+------------------+
A CALL and RETURN increase the stack pointer, FAIL and REDO decrease it.
*/
{
/* Current stack pointer. */
StackEntry *sp = &stack[0];
@@ -1014,7 +1024,8 @@ Search::find_asso_values ()
/* Remaining number of iterations. */
int iter;
STARTOUTERLOOP:
/* ==== CALL ==== */
CALL:
/* Next keyword from the list. */
curr = sp->_curr;
@@ -1092,7 +1103,7 @@ Search::find_asso_values ()
fflush (stderr);
}
goto RECURSE_COLLISION;
BACKTRACK_COLLISION: ;
BACKTRACK_COLLISION:
if (option[DEBUG])
{
fprintf (stderr, "back to collision on keyword #%d, prior = \"%.*s\", curr = \"%.*s\" hash = %d\n",
@@ -1126,36 +1137,43 @@ Search::find_asso_values ()
iterations);
fflush (stderr);
}
BACKTRACK_NO_COLLISION:
if (sp != stack)
{
sp--;
curr = sp->_curr;
prior = sp->_prior;
if (prior == NULL)
goto BACKTRACK_NO_COLLISION;
union_set = sp->_union_set;
union_set_length = sp->_union_set_length;
union_index = sp->_union_index;
c = sp->_c;
original_asso_value = sp->_original_asso_value;
iter = sp->_iter;
goto BACKTRACK_COLLISION;
}
/* No solution found after an exhaustive search!
We should ideally turn off option[FAST] and, if that doesn't help,
multiply _asso_value_max by 2. */
fprintf (stderr,
"\nBig failure, always got duplicate hash code values.\n");
if (option[POSITIONS])
fprintf (stderr, "try options -m or -r, or use new key positions.\n\n");
else
fprintf (stderr, "try options -m or -r.\n\n");
exit (1);
}
goto RECURSE_NO_COLLISION;
else
{
/* Nothing to do, just recurse. */
goto RECURSE_NO_COLLISION;
BACKTRACK_NO_COLLISION: ;
}
/* ==== FAIL ==== */
if (sp != stack)
{
sp--;
/* ==== REDO ==== */
curr = sp->_curr;
prior = sp->_prior;
if (prior == NULL)
goto BACKTRACK_NO_COLLISION;
union_set = sp->_union_set;
union_set_length = sp->_union_set_length;
union_index = sp->_union_index;
c = sp->_c;
original_asso_value = sp->_original_asso_value;
iter = sp->_iter;
goto BACKTRACK_COLLISION;
}
/* No solution found after an exhaustive search!
We should ideally turn off option[FAST] and, if that doesn't help,
multiply _asso_value_max by 2. */
fprintf (stderr,
"\nBig failure, always got duplicate hash code values.\n");
if (option[POSITIONS])
fprintf (stderr, "try options -m or -r, or use new key positions.\n\n");
else
fprintf (stderr, "try options -m or -r.\n\n");
exit (1);
RECURSE_COLLISION:
/*sp->_union_set = union_set;*/ // redundant
sp->_union_set_length = union_set_length;
@@ -1166,9 +1184,10 @@ Search::find_asso_values ()
RECURSE_NO_COLLISION:
/*sp->_curr = curr;*/ // redundant
sp->_prior = prior;
/* ==== RETURN ==== */
sp++;
if (sp - stack < _list_len)
goto STARTOUTERLOOP;
goto CALL;
}
/* Deallocate stack. */