/* 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 "config.h"
#include <stdio.h>
#include <stdlib.h>
#include "syck_st.h"

#ifdef NT
#include <malloc.h>
#endif

#define SIZE32 4
#if SIZEOF_LONG == SIZE32
typedef long I32;
typedef unsigned long U32;
#define NUM2I32(x) NUM2LONG(x)
#define NUM2U32(x) NUM2ULONG(x)
#elif SIZEOF_INT == SIZE32
typedef int I32;
typedef unsigned int U32;
#define NUM2I32(x) NUM2INT(x)
#define NUM2U32(x) NUM2UINT(x)
#endif

typedef struct st_table_entry st_table_entry;

struct st_table_entry {
    unsigned int hash;
    char *key;
    char *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();
static int numhash();
static struct st_hash_type type_numhash = {
    numcmp,
    numhash,
};

extern int strcmp();
static int strhash();
static struct st_hash_type type_strhash = {
    strcmp,
    strhash,
};

static void rehash();

#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()
{
    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()
{
    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 char *key;
    char **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 char *key;
    char *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;
    char *key;
    char *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 char **key;
    char **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 char **key;
    char **value;
    char *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)
    char *key, *value, *never;
{
    if (value == never) return ST_DELETE;
    return ST_CONTINUE;
}

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

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

void
st_foreach(table, func, arg)
    st_table *table;
    enum st_retval (*func)();
    char *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_CONTINUE:
        last = ptr;
        ptr = ptr->next;
        break;
        case ST_STOP:
        return;
        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--;
        }
    }
    }
}

static int
strhash(string)
    register 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 = val*33 + c;
    }

    return val + (val>>5);
#elif HASH_JENKINS
    register const unsigned char *s_PeRlHaSh = (const unsigned char *)string;
    register U32 hash_PeRlHaSh = 0;
    while ((c = *s_PeRlHaSh++) != '\0') {
        hash_PeRlHaSh += c;
        hash_PeRlHaSh += (hash_PeRlHaSh << 10);
        hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6);
    }
    hash_PeRlHaSh += (hash_PeRlHaSh << 3);
    hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11);
    return (hash_PeRlHaSh + (hash_PeRlHaSh << 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;
}
