Logo Search packages:      
Sourcecode: adanaxisgpl version File versions  Download package

st.c

//%Header {
/*****************************************************************************
 *
 * File: src/MushRuby/st.c (ruby)
 *
 * This file has been taken the ruby distribution and may have been modified.
 * For more information on the original see http://www.ruby-lang.org/.
 *
 * This file may contain original work and modifications by Andy Southgate.
 * In regard to these the author and his employer (Mushware Limited)
 * irrevocably waive all of their copyright rights vested in this particular
 * version of this file to the furthest extent permitted.  The author and
 * Mushware Limited also irrevocably waive any and all of their intellectual
 * property rights arising from said file and its modification and/or additions
 * that would otherwise restrict the rights of any party to use and/or
 * distribute the use of, the techniques and methods used herein.  A written
 * waiver can be obtained via http://www.mushware.com/.  This waiver does not
 * affect the rights of the original author or authors.
 *
 * This software carries NO WARRANTY of any kind from Andy Southgate or
 * Mushware Limited.
 *
 ****************************************************************************/
//%Header } oml9RcCIV5ukiYUbQpJjBw
/* This is a public domain general purpose hash table package written by Peter Moore @ UCB. */

/* static   char  sccsid[] = "@(#) st.c 5.1 89/12/14 Crucible"; */

#include "rubyconfig.h"
#include "defines.h"
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <string.h>
#include "st.h"

typedef struct st_table_entry st_table_entry;

struct st_table_entry {
    unsigned int hash;
    st_data_t key;
    st_data_t record;
    st_table_entry *next;
};

#define ST_DEFAULT_MAX_DENSITY 5
#define ST_DEFAULT_INIT_TABLE_SIZE 11

    /*
     * DEFAULT_MAX_DENSITY is the default for the largest we allow the
     * average number of items per bin before increasing the number of
     * bins
     *
     * DEFAULT_INIT_TABLE_SIZE is the default for the number of bins
     * allocated initially
     *
     */
static int numcmp(long, long);
static int numhash(long);
static struct st_hash_type type_numhash = {
    numcmp,
    numhash,
};

/* extern int strcmp(const char *, const char *); */
static int strhash(const char *);
static struct st_hash_type type_strhash = {
    strcmp,
    strhash,
};

static void rehash(st_table *);

#define alloc(type) (type*)malloc((unsigned)sizeof(type))
#define Calloc(n,s) (char*)calloc((n),(s))

#define EQUAL(table,x,y) ((x)==(y) || (*table->type->compare)((x),(y)) == 0)

#define do_hash(key,table) (unsigned int)(*(table)->type->hash)((key))
#define do_hash_bin(key,table) (do_hash(key, table)%(table)->num_bins)

/*
 * MINSIZE is the minimum size of a dictionary.
 */

#define MINSIZE 8

/*
Table of prime numbers 2^n+a, 2<=n<=30.
*/
static long primes[] = {
      8 + 3,
      16 + 3,
      32 + 5,
      64 + 3,
      128 + 3,
      256 + 27,
      512 + 9,
      1024 + 9,
      2048 + 5,
      4096 + 3,
      8192 + 27,
      16384 + 43,
      32768 + 3,
      65536 + 45,
      131072 + 29,
      262144 + 3,
      524288 + 21,
      1048576 + 7,
      2097152 + 17,
      4194304 + 15,
      8388608 + 9,
      16777216 + 43,
      33554432 + 35,
      67108864 + 15,
      134217728 + 29,
      268435456 + 3,
      536870912 + 11,
      1073741824 + 85,
      0
};

static int
new_size(size)
    int size;
{
    int i;

#if 0
    for (i=3; i<31; i++) {
      if ((1<<i) > size) return 1<<i;
    }
    return -1;
#else
    int newsize;

    for (i = 0, newsize = MINSIZE;
       i < sizeof(primes)/sizeof(primes[0]);
       i++, newsize <<= 1)
    {
      if (newsize > size) return primes[i];
    }
    /* Ran out of polynomials */
    return -1;                /* should raise exception */
#endif
}

#ifdef HASH_LOG
static int collision = 0;
static int init_st = 0;

static void
stat_col()
{
    FILE *f = fopen("/tmp/col", "w");
    fprintf(f, "collision: %d\n", collision);
    fclose(f);
}
#endif

st_table*
st_init_table_with_size(type, size)
    struct st_hash_type *type;
    int size;
{
    st_table *tbl;

#ifdef HASH_LOG
    if (init_st == 0) {
      init_st = 1;
      atexit(stat_col);
    }
#endif

    size = new_size(size);    /* round up to prime number */

    tbl = alloc(st_table);
    tbl->type = type;
    tbl->num_entries = 0;
    tbl->num_bins = size;
    tbl->bins = (st_table_entry **)Calloc(size, sizeof(st_table_entry*));

    return tbl;
}

st_table*
st_init_table(type)
    struct st_hash_type *type;
{
    return st_init_table_with_size(type, 0);
}

st_table*
st_init_numtable(void)
{
    return st_init_table(&type_numhash);
}

st_table*
st_init_numtable_with_size(size)
    int size;
{
    return st_init_table_with_size(&type_numhash, size);
}

st_table*
st_init_strtable(void)
{
    return st_init_table(&type_strhash);
}

st_table*
st_init_strtable_with_size(size)
    int size;
{
    return st_init_table_with_size(&type_strhash, size);
}

void
st_free_table(table)
    st_table *table;
{
    register st_table_entry *ptr, *next;
    int i;

    for(i = 0; i < table->num_bins; i++) {
      ptr = table->bins[i];
      while (ptr != 0) {
          next = ptr->next;
          free(ptr);
          ptr = next;
      }
    }
    free(table->bins);
    free(table);
}

#define PTR_NOT_EQUAL(table, ptr, hash_val, key) \
((ptr) != 0 && (ptr->hash != (hash_val) || !EQUAL((table), (key), (ptr)->key)))

#ifdef HASH_LOG
#define COLLISION collision++
#else
#define COLLISION
#endif

#define FIND_ENTRY(table, ptr, hash_val, bin_pos) do {\
    bin_pos = hash_val%(table)->num_bins;\
    ptr = (table)->bins[bin_pos];\
    if (PTR_NOT_EQUAL(table, ptr, hash_val, key)) {\
      COLLISION;\
      while (PTR_NOT_EQUAL(table, ptr->next, hash_val, key)) {\
          ptr = ptr->next;\
      }\
      ptr = ptr->next;\
    }\
} while (0)

int
st_lookup(table, key, value)
    st_table *table;
    register st_data_t key;
    st_data_t *value;
{
    unsigned int hash_val, bin_pos;
    register st_table_entry *ptr;

    hash_val = do_hash(key, table);
    FIND_ENTRY(table, ptr, hash_val, bin_pos);

    if (ptr == 0) {
      return 0;
    }
    else {
      if (value != 0)  *value = ptr->record;
      return 1;
    }
}

#define ADD_DIRECT(table, key, value, hash_val, bin_pos)\
do {\
    st_table_entry *entry;\
    if (table->num_entries/(table->num_bins) > ST_DEFAULT_MAX_DENSITY) {\
      rehash(table);\
        bin_pos = hash_val % table->num_bins;\
    }\
    \
    entry = alloc(st_table_entry);\
    \
    entry->hash = hash_val;\
    entry->key = key;\
    entry->record = value;\
    entry->next = table->bins[bin_pos];\
    table->bins[bin_pos] = entry;\
    table->num_entries++;\
} while (0)

int
st_insert(table, key, value)
    register st_table *table;
    register st_data_t key;
    st_data_t value;
{
    unsigned int hash_val, bin_pos;
    register st_table_entry *ptr;

    hash_val = do_hash(key, table);
    FIND_ENTRY(table, ptr, hash_val, bin_pos);

    if (ptr == 0) {
      ADD_DIRECT(table, key, value, hash_val, bin_pos);
      return 0;
    }
    else {
      ptr->record = value;
      return 1;
    }
}

void
st_add_direct(table, key, value)
    st_table *table;
    st_data_t key;
    st_data_t value;
{
    unsigned int hash_val, bin_pos;

    hash_val = do_hash(key, table);
    bin_pos = hash_val % table->num_bins;
    ADD_DIRECT(table, key, value, hash_val, bin_pos);
}

static void
rehash(table)
    register st_table *table;
{
    register st_table_entry *ptr, *next, **new_bins;
    int i, old_num_bins = table->num_bins, new_num_bins;
    unsigned int hash_val;

    new_num_bins = new_size(old_num_bins+1);
    new_bins = (st_table_entry**)Calloc(new_num_bins, sizeof(st_table_entry*));

    for(i = 0; i < old_num_bins; i++) {
      ptr = table->bins[i];
      while (ptr != 0) {
          next = ptr->next;
          hash_val = ptr->hash % new_num_bins;
          ptr->next = new_bins[hash_val];
          new_bins[hash_val] = ptr;
          ptr = next;
      }
    }
    free(table->bins);
    table->num_bins = new_num_bins;
    table->bins = new_bins;
}

st_table*
st_copy(old_table)
    st_table *old_table;
{
    st_table *new_table;
    st_table_entry *ptr, *entry;
    int i, num_bins = old_table->num_bins;

    new_table = alloc(st_table);
    if (new_table == 0) {
      return 0;
    }

    *new_table = *old_table;
    new_table->bins = (st_table_entry**)
      Calloc((unsigned)num_bins, sizeof(st_table_entry*));

    if (new_table->bins == 0) {
      free(new_table);
      return 0;
    }

    for(i = 0; i < num_bins; i++) {
      new_table->bins[i] = 0;
      ptr = old_table->bins[i];
      while (ptr != 0) {
          entry = alloc(st_table_entry);
          if (entry == 0) {
            free(new_table->bins);
            free(new_table);
            return 0;
          }
          *entry = *ptr;
          entry->next = new_table->bins[i];
          new_table->bins[i] = entry;
          ptr = ptr->next;
      }
    }
    return new_table;
}

int
st_delete(table, key, value)
    register st_table *table;
    register st_data_t *key;
    st_data_t *value;
{
    unsigned int hash_val;
    st_table_entry *tmp;
    register st_table_entry *ptr;

    hash_val = do_hash_bin(*key, table);
    ptr = table->bins[hash_val];

    if (ptr == 0) {
      if (value != 0) *value = 0;
      return 0;
    }

    if (EQUAL(table, *key, ptr->key)) {
      table->bins[hash_val] = ptr->next;
      table->num_entries--;
      if (value != 0) *value = ptr->record;
      *key = ptr->key;
      free(ptr);
      return 1;
    }

    for(; ptr->next != 0; ptr = ptr->next) {
      if (EQUAL(table, ptr->next->key, *key)) {
          tmp = ptr->next;
          ptr->next = ptr->next->next;
          table->num_entries--;
          if (value != 0) *value = tmp->record;
          *key = tmp->key;
          free(tmp);
          return 1;
      }
    }

    return 0;
}

int
st_delete_safe(table, key, value, never)
    register st_table *table;
    register st_data_t *key;
    st_data_t *value;
    st_data_t never;
{
    unsigned int hash_val;
    register st_table_entry *ptr;

    hash_val = do_hash_bin(*key, table);
    ptr = table->bins[hash_val];

    if (ptr == 0) {
      if (value != 0) *value = 0;
      return 0;
    }

    for(; ptr != 0; ptr = ptr->next) {
      if ((ptr->key != never) && EQUAL(table, ptr->key, *key)) {
          table->num_entries--;
          *key = ptr->key;
          if (value != 0) *value = ptr->record;
          ptr->key = ptr->record = never;
          return 1;
      }
    }

    return 0;
}

static int
delete_never(key, value, never)
    st_data_t key, value, never;
{
    if (value == never) return ST_DELETE;
    return ST_CONTINUE;
}

void
st_cleanup_safe(table, never)
    st_table *table;
    st_data_t never;
{
    int num_entries = table->num_entries;

    st_foreach(table, delete_never, never);
    table->num_entries = num_entries;
}

int
st_foreach(table, func, arg)
    st_table *table;
    int (*func)();
    st_data_t arg;
{
    st_table_entry *ptr, *last, *tmp;
    enum st_retval retval;
    int i;

    for(i = 0; i < table->num_bins; i++) {
      last = 0;
      for(ptr = table->bins[i]; ptr != 0;) {
          retval = (*func)(ptr->key, ptr->record, arg);
          switch (retval) {
          case ST_CHECK:      /* check if hash is modified during iteration */
              tmp = 0;
            if (i < table->num_bins) {
                for (tmp = table->bins[i]; tmp; tmp=tmp->next) {
                  if (tmp == ptr) break;
                }
            }
            if (!tmp) {
                /* call func with error notice */
                return 1;
            }
            /* fall through */
          case ST_CONTINUE:
            last = ptr;
            ptr = ptr->next;
            break;
          case ST_STOP:
              return 0;
          case ST_DELETE:
            tmp = ptr;
            if (last == 0) {
                table->bins[i] = ptr->next;
            }
            else {
                last->next = ptr->next;
            }
            ptr = ptr->next;
            free(tmp);
            table->num_entries--;
          }
      }
    }
    return 0;
}

static int
strhash(string)
    register const char *string;
{
    register int c;

#ifdef HASH_ELFHASH
    register unsigned int h = 0, g;

    while ((c = *string++) != '\0') {
      h = ( h << 4 ) + c;
      if ( g = h & 0xF0000000 )
          h ^= g >> 24;
      h &= ~g;
    }
    return h;
#elif HASH_PERL
    register int val = 0;

    while ((c = *string++) != '\0') {
      val += c;
      val += (val << 10);
      val ^= (val >> 6);
    }
    val += (val << 3);
    val ^= (val >> 11);

    return val + (val << 15);
#else
    register int val = 0;

    while ((c = *string++) != '\0') {
      val = val*997 + c;
    }

    return val + (val>>5);
#endif
}

static int
numcmp(x, y)
    long x, y;
{
    return x != y;
}

static int
numhash(n)
    long n;
{
    return n;
}

Generated by  Doxygen 1.6.0   Back to index