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+/* Provides high-level routines to manipulate the keywork list
+ structures the code generation output.
+ Copyright (C) 1989-1998, 2000 Free Software Foundation, Inc.
+ written by Douglas C. Schmidt (schmidt@ics.uci.edu)
+
+This file is part of GNU GPERF.
+
+GNU GPERF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 1, or (at your option)
+any later version.
+
+GNU GPERF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU GPERF; see the file COPYING. If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
+
+#include <stdio.h>
+#include <stdlib.h> /* declares rand(), srand() */
+#include <time.h> /* declares time() */
+#include "options.h"
+#include "gen-perf.h"
+#include "trace.h"
+
+/* Efficiently returns the least power of two greater than or equal to X! */
+#define POW(X) ((!X)?1:(X-=1,X|=X>>1,X|=X>>2,X|=X>>4,X|=X>>8,X|=X>>16,(++X)))
+
+/* Reads input keys, possibly applies the reordering heuristic, sets the
+ maximum associated value size (rounded up to the nearest power of 2),
+ may initialize the associated values array, and determines the maximum
+ hash table size. Note: using the random numbers is often helpful,
+ though not as deterministic, of course! */
+
+Gen_Perf::Gen_Perf (void)
+{
+ T (Trace t ("Gen_Perf::Gen_Perf");)
+ int asso_value_max;
+ int non_linked_length;
+
+ Key_List::read_keys ();
+ if (option[ORDER])
+ reorder ();
+ asso_value_max = option.get_asso_max ();
+ non_linked_length = Key_List::keyword_list_length ();
+ num_done = 1;
+ fewest_collisions = 0;
+ if (asso_value_max == 0)
+ asso_value_max = non_linked_length;
+ else if (asso_value_max > 0)
+ asso_value_max *= non_linked_length;
+ else /* if (asso_value_max < 0) */
+ asso_value_max = non_linked_length / -asso_value_max;
+ option.set_asso_max (POW (asso_value_max));
+
+ if (option[RANDOM])
+ {
+ srand ((long) time (0));
+
+ for (int i = 0; i < ALPHA_SIZE; i++)
+ asso_values[i] = (rand () & asso_value_max - 1);
+ }
+ else
+ {
+ int asso_value = option.initial_value ();
+
+ if (asso_value) /* Initialize array if user requests non-zero default. */
+ for (int i = ALPHA_SIZE - 1; i >= 0; i--)
+ asso_values[i] = asso_value & option.get_asso_max () - 1;
+ }
+ max_hash_value = Key_List::max_key_length () + option.get_asso_max () *
+ option.get_max_keysig_size ();
+
+ if (option[DEBUG])
+ fprintf (stderr, "total non-linked keys = %d\nmaximum associated value is %d"
+ "\nmaximum size of generated hash table is %d\n",
+ non_linked_length, asso_value_max, max_hash_value);
+}
+
+/* Merge two disjoint hash key multisets to form the ordered disjoint union of the sets.
+ (In a multiset, an element can occur multiple times.)
+ Precondition: both set_1 and set_2 must be ordered. Returns the length
+ of the combined set. */
+
+inline int
+Gen_Perf::compute_disjoint_union (const char *set_1, int size_1, const char *set_2, int size_2, char *set_3)
+{
+ T (Trace t ("Gen_Perf::compute_disjoint_union");)
+ char *base = set_3;
+
+ while (size_1 > 0 && size_2 > 0)
+ if (*set_1 == *set_2)
+ set_1++, size_1--, set_2++, size_2--;
+ else
+ {
+ char next;
+ if (*set_1 < *set_2)
+ next = *set_1++, size_1--;
+ else
+ next = *set_2++, size_2--;
+ if (set_3 == base || next != set_3[-1])
+ *set_3++ = next;
+ }
+
+ while (size_1 > 0)
+ {
+ char next;
+ next = *set_1++, size_1--;
+ if (set_3 == base || next != set_3[-1])
+ *set_3++ = next;
+ }
+
+ while (size_2 > 0)
+ {
+ char next;
+ next = *set_2++, size_2--;
+ if (set_3 == base || next != set_3[-1])
+ *set_3++ = next;
+ }
+ return set_3 - base;
+}
+
+/* Sort the UNION_SET in increasing frequency of occurrence.
+ This speeds up later processing since we may assume the resulting
+ set (Set_3, in this case), is ordered. Uses insertion sort, since
+ the UNION_SET is typically short. */
+
+inline void
+Gen_Perf::sort_set (char *union_set, int len)
+{
+ T (Trace t ("Gen_Perf::sort_set");)
+ int i, j;
+
+ for (i = 0, j = len - 1; i < j; i++)
+ {
+ int curr;
+ char tmp;
+
+ for (curr = i + 1, tmp = union_set[curr];
+ curr > 0 && occurrences[(unsigned char)tmp] < occurrences[(unsigned char)(union_set[curr-1])];
+ curr--)
+ union_set[curr] = union_set[curr - 1];
+
+ union_set[curr] = tmp;
+ }
+}
+
+/* Generate a key set's hash value. */
+
+inline int
+Gen_Perf::hash (List_Node *key_node)
+{
+ T (Trace t ("Gen_Perf::hash");)
+ int sum = option[NOLENGTH] ? 0 : key_node->key_length;
+
+ const char *p = key_node->char_set;
+ int i = key_node->char_set_length;
+ for (; i > 0; p++, i--)
+ sum += asso_values[(unsigned char)(*p)];
+
+ return key_node->hash_value = sum;
+}
+
+/* Find out how character value change affects successfully hashed items.
+ Returns FALSE if no other hash values are affected, else returns TRUE.
+ Note that because Option.Get_Asso_Max is a power of two we can guarantee
+ that all legal Asso_Values are visited without repetition since
+ Option.Get_Jump was forced to be an odd value! */
+
+inline int
+Gen_Perf::affects_prev (char c, List_Node *curr)
+{
+ T (Trace t ("Gen_Perf::affects_prev");)
+ int original_char = asso_values[(unsigned char)c];
+ int total_iterations = !option[FAST]
+ ? option.get_asso_max () : option.get_iterations () ? option.get_iterations () : keyword_list_length ();
+
+ /* Try all legal associated values. */
+
+ for (int i = total_iterations - 1; i >= 0; i--)
+ {
+ int collisions = 0;
+
+ asso_values[(unsigned char)c] =
+ (asso_values[(unsigned char)c] + (option.get_jump () ? option.get_jump () : rand ()))
+ & (option.get_asso_max () - 1);
+
+ /* Iteration Number array is a win, O(1) intialization time! */
+ reset ();
+
+ /* See how this asso_value change affects previous keywords. If
+ it does better than before we'll take it! */
+
+ for (List_Node *ptr = head;
+ !Bool_Array::find (hash (ptr)) || ++collisions < fewest_collisions;
+ ptr = ptr->next)
+ if (ptr == curr)
+ {
+ fewest_collisions = collisions;
+ if (option[DEBUG])
+ fprintf (stderr, "- resolved after %d iterations", total_iterations - i);
+ return 0;
+ }
+ }
+
+ /* Restore original values, no more tries. */
+ asso_values[(unsigned char)c] = original_char;
+ /* If we're this far it's time to try the next character.... */
+ return 1;
+}
+
+/* Change a character value, try least-used characters first. */
+
+void
+Gen_Perf::change (List_Node *prior, List_Node *curr)
+{
+ T (Trace t ("Gen_Perf::change");)
+ static char *union_set;
+ int union_set_length;
+
+ if (!union_set)
+ union_set = new char [2 * option.get_max_keysig_size ()];
+
+ if (option[DEBUG])
+ {
+ fprintf (stderr, "collision on keyword #%d, prior = \"%.*s\", curr = \"%.*s\" hash = %d\n",
+ num_done,
+ prior->key_length, prior->key,
+ curr->key_length, curr->key,
+ curr->hash_value);
+ fflush (stderr);
+ }
+ union_set_length = compute_disjoint_union (prior->char_set, prior->char_set_length, curr->char_set, curr->char_set_length, union_set);
+ sort_set (union_set, union_set_length);
+
+ /* Try changing some values, if change doesn't alter other values continue normal action. */
+ fewest_collisions++;
+
+ const char *p = union_set;
+ int i = union_set_length;
+ for (; i > 0; p++, i--)
+ if (!affects_prev (*p, curr))
+ {
+ if (option[DEBUG])
+ {
+ fprintf (stderr, " by changing asso_value['%c'] (char #%d) to %d\n",
+ *p, p - union_set + 1, asso_values[(unsigned char)(*p)]);
+ fflush (stderr);
+ }
+ return; /* Good, doesn't affect previous hash values, we'll take it. */
+ }
+
+ for (List_Node *ptr = head; ptr != curr; ptr = ptr->next)
+ hash (ptr);
+
+ hash (curr);
+
+ if (option[DEBUG])
+ {
+ fprintf (stderr, "** collision not resolved after %d iterations, %d duplicates remain, continuing...\n",
+ !option[FAST] ? option.get_asso_max () : option.get_iterations () ? option.get_iterations () : keyword_list_length (),
+ fewest_collisions + total_duplicates);
+ fflush (stderr);
+ }
+}
+
+/* Does the hard stuff....
+ Initializes the Iteration Number array, and attempts to find a perfect
+ function that will hash all the key words without getting any
+ duplications. This is made much easier since we aren't attempting
+ to generate *minimum* functions, only perfect ones.
+ If we can't generate a perfect function in one pass *and* the user
+ hasn't enabled the DUP option, we'll inform the user to try the
+ randomization option, use -D, or choose alternative key positions.
+ The alternatives (e.g., back-tracking) are too time-consuming, i.e,
+ exponential in the number of keys. */
+
+int
+Gen_Perf::operator() (void)
+{
+ T (Trace t ("Gen_Perf::operator()");)
+#if LARGE_STACK_ARRAYS
+ STORAGE_TYPE buffer[max_hash_value + 1];
+#else
+ // Note: we don't use new, because that invokes a custom operator new.
+ STORAGE_TYPE *buffer
+ = (STORAGE_TYPE*) malloc (sizeof(STORAGE_TYPE) * (max_hash_value + 1));
+ if (buffer == NULL)
+ abort ();
+#endif
+
+ Bool_Array::init (buffer, max_hash_value + 1);
+
+ List_Node *curr;
+ for (curr = head; curr; curr = curr->next)
+ {
+ hash (curr);
+
+ for (List_Node *ptr = head; ptr != curr; ptr = ptr->next)
+ if (ptr->hash_value == curr->hash_value)
+ {
+ change (ptr, curr);
+ break;
+ }
+ num_done++;
+ }
+
+ /* Make one final check, just to make sure nothing weird happened.... */
+
+ Bool_Array::reset ();
+
+ for (curr = head; curr; curr = curr->next)
+ if (Bool_Array::find (hash (curr)))
+ if (option[DUP]) /* Keep track of this number... */
+ total_duplicates++;
+ else /* Yow, big problems. we're outta here! */
+ {
+ fprintf (stderr, "\nInternal error, duplicate value %d:\n"
+ "try options -D or -r, or use new key positions.\n\n", hash (curr));
+#if !LARGE_STACK_ARRAYS
+ free ((char *) buffer);
+#endif
+ return 1;
+ }
+
+ /* Sorts the key word list by hash value, and then outputs the list.
+ The generated hash table code is only output if the early stage of
+ processing turned out O.K. */
+
+ sort ();
+ output ();
+#if !LARGE_STACK_ARRAYS
+ free ((char *) buffer);
+#endif
+ return 0;
+}
+
+/* Prints out some diagnostics upon completion. */
+
+Gen_Perf::~Gen_Perf (void)
+{
+ T (Trace t ("Gen_Perf::~Gen_Perf");)
+ if (option[DEBUG])
+ {
+ fprintf (stderr, "\ndumping occurrence and associated values tables\n");
+
+ for (int i = 0; i < ALPHA_SIZE; i++)
+ if (occurrences[i])
+ fprintf (stderr, "asso_values[%c] = %6d, occurrences[%c] = %6d\n",
+ i, asso_values[i], i, occurrences[i]);
+
+ fprintf (stderr, "end table dumping\n");
+
+ }
+}
+