ruby/ext/gdbm/gdbm.c

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

  gdbm.c -

  $Author$
  $Date$
  modified at: Mon Jan 24 15:59:52 JST 1994

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

#include "ruby.h"

#include <gdbm.h>
#include <fcntl.h>
#include <errno.h>

static VALUE rb_cGDBM, rb_eGDBMError, rb_eGDBMFatalError;

#define RUBY_GDBM_RW_BIT 0x20000000

#define MY_BLOCK_SIZE (2048)
#define MY_FATAL_FUNC rb_gdbm_fatal
static void
rb_gdbm_fatal(char *msg)
{
    rb_raise(rb_eGDBMFatalError, msg);
}

struct dbmdata {
    int  di_size;
    GDBM_FILE di_dbm;
};

static void
closed_dbm(void)
{
    rb_raise(rb_eRuntimeError, "closed GDBM file");
}

#define GetDBM(obj, dbmp) do {\
    Data_Get_Struct(obj, struct dbmdata, dbmp);\
    if (dbmp == 0) closed_dbm();\
    if (dbmp->di_dbm == 0) closed_dbm();\
} while (0)

#define GetDBM2(obj, data, dbm) {\
    GetDBM(obj, data);\
    (dbm) = dbmp->di_dbm;\
}

static void
free_dbm(struct dbmdata *dbmp)
{
    if (dbmp) {
	if (dbmp->di_dbm) gdbm_close(dbmp->di_dbm);
	free(dbmp);
    }
}

static VALUE
fgdbm_close(VALUE obj)
{
    struct dbmdata *dbmp;

    GetDBM(obj, dbmp);
    gdbm_close(dbmp->di_dbm);
    dbmp->di_dbm = 0;

    return Qnil;
}

static VALUE
fgdbm_closed(VALUE obj)
{
    struct dbmdata *dbmp;

    Data_Get_Struct(obj, struct dbmdata, dbmp);
    if (dbmp == 0)
	return Qtrue;
    if (dbmp->di_dbm == 0)
	return Qtrue;

    return Qfalse;
}

static VALUE
fgdbm_s_alloc(VALUE klass)
{
    return Data_Wrap_Struct(klass, 0, free_dbm, 0);
}

static VALUE
fgdbm_initialize(int argc, VALUE *argv, VALUE obj)
{
    VALUE file, vmode, vflags;
    GDBM_FILE dbm;
    struct dbmdata *dbmp;
    int mode, flags = 0;

    if (rb_scan_args(argc, argv, "12", &file, &vmode, &vflags) == 1) {
	mode = 0666;		/* default value */
    }
    else if (NIL_P(vmode)) {
	mode = -1;		/* return nil if DB not exist */
    }
    else {
	mode = NUM2INT(vmode);
    }

    if (!NIL_P(vflags))
        flags = NUM2INT(vflags);

    SafeStringValue(file);

    if (flags & RUBY_GDBM_RW_BIT) {
        flags &= ~RUBY_GDBM_RW_BIT;
	dbm = gdbm_open(RSTRING(file)->ptr, MY_BLOCK_SIZE, 
			flags, mode, MY_FATAL_FUNC);
    }
    else {
        dbm = 0;
        if (mode >= 0)
            dbm = gdbm_open(RSTRING(file)->ptr, MY_BLOCK_SIZE, 
                            GDBM_WRCREAT|flags, mode, MY_FATAL_FUNC);
        if (!dbm)
            dbm = gdbm_open(RSTRING(file)->ptr, MY_BLOCK_SIZE, 
                            GDBM_WRITER|flags, 0, MY_FATAL_FUNC);
        if (!dbm)
            dbm = gdbm_open(RSTRING(file)->ptr, MY_BLOCK_SIZE, 
                            GDBM_READER|flags, 0, MY_FATAL_FUNC);
    }

    if (!dbm) {
	if (mode == -1) return Qnil;

	if (gdbm_errno == GDBM_FILE_OPEN_ERROR ||
	    gdbm_errno == GDBM_CANT_BE_READER ||
	    gdbm_errno == GDBM_CANT_BE_WRITER)
	    rb_sys_fail(RSTRING(file)->ptr);
	else
	    rb_raise(rb_eGDBMError, "%s", gdbm_strerror(gdbm_errno));
    }

    dbmp = ALLOC(struct dbmdata);
    free_dbm(DATA_PTR(obj));
    DATA_PTR(obj) = dbmp;
    dbmp->di_dbm = dbm;
    dbmp->di_size = -1;

    return obj;
}

static VALUE
fgdbm_s_open(int argc, VALUE *argv, VALUE klass)
{
    VALUE obj = Data_Wrap_Struct(klass, 0, free_dbm, 0);

    if (NIL_P(fgdbm_initialize(argc, argv, obj))) {
	return Qnil;
    }

    if (rb_block_given_p()) {
        return rb_ensure(rb_yield, obj, fgdbm_close, obj);
    }

    return obj;
}

static VALUE
rb_gdbm_fetch(GDBM_FILE dbm, datum key)
{
    datum val;
    VALUE str;

    val = gdbm_fetch(dbm, key);
    if (val.dptr == 0)
        return Qnil;

    str = rb_obj_alloc(rb_cString);
    RSTRING(str)->len = val.dsize;
    RSTRING(str)->aux.capa = val.dsize;
    RSTRING(str)->ptr = REALLOC_N(val.dptr,char,val.dsize+1);
    RSTRING(str)->ptr[val.dsize] = '\0';

    OBJ_TAINT(str);
    return (VALUE)str;
}

static VALUE
rb_gdbm_fetch2(GDBM_FILE dbm, VALUE keystr)
{
    datum key;

    StringValue(keystr);
    key.dptr = RSTRING(keystr)->ptr;
    key.dsize = RSTRING(keystr)->len;

    return rb_gdbm_fetch(dbm, key);
}

static VALUE
rb_gdbm_fetch3(VALUE obj, VALUE keystr)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;

    GetDBM2(obj, dbmp, dbm);
    return rb_gdbm_fetch2(dbm, keystr);
}

static VALUE
rb_gdbm_firstkey(GDBM_FILE dbm)
{
    datum key;
    VALUE str;

    key = gdbm_firstkey(dbm);
    if (key.dptr == 0)
        return Qnil;

    str = rb_obj_alloc(rb_cString);
    RSTRING(str)->len = key.dsize;
    RSTRING(str)->aux.capa = key.dsize;
    RSTRING(str)->ptr = REALLOC_N(key.dptr,char,key.dsize+1);
    RSTRING(str)->ptr[RSTRING(str)->len] = '\0';

    OBJ_TAINT(str);
    return str;
}

static VALUE
rb_gdbm_nextkey(GDBM_FILE dbm, VALUE keystr)
{
    datum key, key2;
    VALUE str;

    key.dptr = RSTRING(keystr)->ptr;
    key.dsize = RSTRING(keystr)->len;
    key2 = gdbm_nextkey(dbm, key);
    if (key2.dptr == 0)
        return Qnil;

    str = rb_obj_alloc(rb_cString);
    RSTRING(str)->len = key2.dsize;
    RSTRING(str)->aux.capa = key2.dsize;
    RSTRING(str)->ptr = REALLOC_N(key2.dptr,char,key2.dsize+1);
    RSTRING(str)->ptr[RSTRING(str)->len] = '\0';

    OBJ_TAINT(str);
    return str;
}

static VALUE
fgdbm_fetch(VALUE obj, VALUE keystr, VALUE ifnone)
{
    VALUE valstr;

    valstr = rb_gdbm_fetch3(obj, keystr);
    if (NIL_P(valstr)) {
	if (ifnone == Qnil && rb_block_given_p())
	    return rb_yield(keystr);
	return ifnone;
    }
    return valstr;
}

static VALUE
fgdbm_aref(VALUE obj, VALUE keystr)
{
    return rb_gdbm_fetch3(obj, keystr);
}

static VALUE
fgdbm_fetch_m(int argc, VALUE *argv, VALUE obj)
{
    VALUE keystr, valstr, ifnone;

    rb_scan_args(argc, argv, "11", &keystr, &ifnone);
    valstr = fgdbm_fetch(obj, keystr, ifnone);
    if (argc == 1 && !rb_block_given_p() && NIL_P(valstr))
	rb_raise(rb_eIndexError, "key not found");

    return valstr;
}

static VALUE
fgdbm_index(VALUE obj, VALUE valstr)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr, valstr2;

    StringValue(valstr);
    GetDBM2(obj, dbmp, dbm);
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {

	valstr2 = rb_gdbm_fetch2(dbm, keystr);
        if (!NIL_P(valstr2) &&
            RSTRING(valstr)->len == RSTRING(valstr2)->len &&
            memcmp(RSTRING(valstr)->ptr, RSTRING(valstr2)->ptr,
                   RSTRING(valstr)->len) == 0) {
	    return keystr;
        }
    }
    return Qnil;
}

static VALUE
fgdbm_select(VALUE obj)
{
    VALUE new = rb_ary_new();
    GDBM_FILE dbm;
    struct dbmdata *dbmp;
    VALUE keystr;

    GetDBM2(obj, dbmp, dbm);
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
	 keystr = rb_gdbm_nextkey(dbm, keystr)) {
	VALUE assoc = rb_assoc_new(keystr, rb_gdbm_fetch2(dbm, keystr));
	VALUE v = rb_yield(assoc);

	if (RTEST(v)) {
	    rb_ary_push(new, assoc);
	}
	GetDBM2(obj, dbmp, dbm);
    }

    return new;
}

static VALUE
fgdbm_values_at(int argc, VALUE *argv, VALUE obj)
{
    VALUE new = rb_ary_new2(argc);
    int i;

    for (i=0; i<argc; i++) {
        rb_ary_push(new, rb_gdbm_fetch3(obj, argv[i]));
    }

    return new;
}

static void
rb_gdbm_modify(VALUE obj)
{
    rb_secure(4);
    if (OBJ_FROZEN(obj)) rb_error_frozen("GDBM");
}

static VALUE
rb_gdbm_delete(VALUE obj, VALUE keystr)
{
    datum key;
    struct dbmdata *dbmp;
    GDBM_FILE dbm;

    rb_gdbm_modify(obj);
    StringValue(keystr);
    key.dptr = RSTRING(keystr)->ptr;
    key.dsize = RSTRING(keystr)->len;

    GetDBM2(obj, dbmp, dbm);
    if (!gdbm_exists(dbm, key)) {
	return Qnil;
    }

    if (gdbm_delete(dbm, key)) {
	dbmp->di_size = -1;
	rb_raise(rb_eGDBMError, "%s", gdbm_strerror(gdbm_errno));
    }
    else if (dbmp->di_size >= 0) {
	dbmp->di_size--;
    }
    return obj;
}

static VALUE
fgdbm_delete(VALUE obj, VALUE keystr)
{
    VALUE valstr;

    valstr = fgdbm_fetch(obj, keystr, Qnil);
    rb_gdbm_delete(obj, keystr);
    return valstr;
}

static VALUE
fgdbm_shift(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr, valstr;

    rb_gdbm_modify(obj);
    GetDBM2(obj, dbmp, dbm);
    keystr = rb_gdbm_firstkey(dbm);
    if (NIL_P(keystr)) return Qnil;
    valstr = rb_gdbm_fetch2(dbm, keystr);
    rb_gdbm_delete(obj, keystr);

    return rb_assoc_new(keystr, valstr);
}

static VALUE
fgdbm_delete_if(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr, valstr;
    VALUE ret, ary = rb_ary_new();
    int i, status = 0, n;

    rb_gdbm_modify(obj);
    GetDBM2(obj, dbmp, dbm);
    n = dbmp->di_size;
    dbmp->di_size = -1;

    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {

	valstr = rb_gdbm_fetch2(dbm, keystr);
        ret = rb_protect(rb_yield, rb_assoc_new(keystr, valstr), &status);
        if (status != 0) break;
	if (RTEST(ret)) rb_ary_push(ary, keystr);
	GetDBM2(obj, dbmp, dbm);
    }

    for (i = 0; i < RARRAY(ary)->len; i++)
        rb_gdbm_delete(obj, RARRAY(ary)->ptr[i]);
    if (status) rb_jump_tag(status);
    if (n > 0) dbmp->di_size = n - RARRAY(ary)->len;

    return obj;
}

static VALUE
fgdbm_clear(VALUE obj)
{
    datum key, nextkey;
    struct dbmdata *dbmp;
    GDBM_FILE dbm;

    rb_gdbm_modify(obj);
    GetDBM2(obj, dbmp, dbm);
    dbmp->di_size = -1;

#if 0
    while (key = gdbm_firstkey(dbm), key.dptr) {
	if (gdbm_delete(dbm, key)) {
	    free(key.dptr);
	    rb_raise(rb_eGDBMError, "%s", gdbm_strerror(gdbm_errno));
	}
	free(key.dptr); 
    }
#else
    while (key = gdbm_firstkey(dbm), key.dptr) {
        for (; key.dptr; key = nextkey) {
            nextkey = gdbm_nextkey(dbm, key);
            if (gdbm_delete(dbm, key)) {
                free(key.dptr);
                if (nextkey.dptr) free(nextkey.dptr);
                rb_raise(rb_eGDBMError, "%s", gdbm_strerror(gdbm_errno));
            }
            free(key.dptr);
        }
    }
#endif
    dbmp->di_size = 0;

    return obj;
}

static VALUE
fgdbm_invert(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr, valstr;
    VALUE hash = rb_hash_new();

    GetDBM2(obj, dbmp, dbm);
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {
	valstr = rb_gdbm_fetch2(dbm, keystr);

	rb_hash_aset(hash, valstr, keystr);
    }
    return hash;
}

static VALUE
fgdbm_store(VALUE obj, VALUE keystr, VALUE valstr)
{
    datum key, val;
    struct dbmdata *dbmp;
    GDBM_FILE dbm;

    rb_gdbm_modify(obj);
    StringValue(keystr);
    StringValue(valstr);

    key.dptr = RSTRING(keystr)->ptr;
    key.dsize = RSTRING(keystr)->len;

    val.dptr = RSTRING(valstr)->ptr;
    val.dsize = RSTRING(valstr)->len;

    GetDBM2(obj, dbmp, dbm);
    dbmp->di_size = -1;
    if (gdbm_store(dbm, key, val, GDBM_REPLACE)) {
	if (errno == EPERM) rb_sys_fail(0);
	rb_raise(rb_eGDBMError, "%s", gdbm_strerror(gdbm_errno));
    }

    return valstr;
}

static VALUE
update_i(VALUE pair, VALUE dbm)
{
    Check_Type(pair, T_ARRAY);
    if (RARRAY(pair)->len < 2) {
	rb_raise(rb_eArgError, "pair must be [key, value]");
    }
    fgdbm_store(dbm, RARRAY(pair)->ptr[0], RARRAY(pair)->ptr[1]);
    return Qnil;
}

static VALUE
fgdbm_update(VALUE obj, VALUE other)
{
    rb_block_call(other, rb_intern("each_pair"), 0, 0, update_i, obj);
    return obj;
}

static VALUE
fgdbm_replace(VALUE obj, VALUE other)
{
    fgdbm_clear(obj);
    rb_block_call(other, rb_intern("each_pair"), 0, 0, update_i, obj);
    return obj;
}

static VALUE
fgdbm_length(VALUE obj)
{
    datum key, nextkey;
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    int i = 0;

    GetDBM2(obj, dbmp, dbm);
    if (dbmp->di_size > 0) return INT2FIX(dbmp->di_size);

    for (key = gdbm_firstkey(dbm); key.dptr; key = nextkey) {
        nextkey = gdbm_nextkey(dbm, key);
        free(key.dptr);
	i++;
    }
    dbmp->di_size = i;

    return INT2FIX(i);
}

static VALUE
fgdbm_empty_p(VALUE obj)
{
    datum key;
    struct dbmdata *dbmp;
    GDBM_FILE dbm;

    GetDBM(obj, dbmp);
    if (dbmp->di_size < 0) {
	dbm = dbmp->di_dbm;

	key = gdbm_firstkey(dbm);
        if (key.dptr) {
            free(key.dptr);
            return Qfalse;
	}
        return Qtrue;
    }

    if (dbmp->di_size == 0) return Qtrue;
    return Qfalse;
}

static VALUE
fgdbm_each_value(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr;

    GetDBM2(obj, dbmp, dbm);
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {

        rb_yield(rb_gdbm_fetch2(dbm, keystr));
	GetDBM2(obj, dbmp, dbm);
    }
    return obj;
}

static VALUE
fgdbm_each_key(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr;

    GetDBM2(obj, dbmp, dbm);
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {

        rb_yield(keystr);
	GetDBM2(obj, dbmp, dbm);
    }
    return obj;
}

static VALUE
fgdbm_each_pair(VALUE obj)
{
    GDBM_FILE dbm;
    struct dbmdata *dbmp;
    VALUE keystr;

    GetDBM2(obj, dbmp, dbm);
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {

        rb_yield(rb_assoc_new(keystr, rb_gdbm_fetch2(dbm, keystr)));
	GetDBM2(obj, dbmp, dbm);
    }

    return obj;
}

static VALUE
fgdbm_keys(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr, ary;

    GetDBM2(obj, dbmp, dbm);
    ary = rb_ary_new();
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {

        rb_ary_push(ary, keystr);
    }

    return ary;
}

static VALUE
fgdbm_values(VALUE obj)
{
    datum key, nextkey;
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE valstr, ary;

    GetDBM2(obj, dbmp, dbm);
    ary = rb_ary_new();
    for (key = gdbm_firstkey(dbm); key.dptr; key = nextkey) {
        nextkey = gdbm_nextkey(dbm, key);
	valstr = rb_gdbm_fetch(dbm, key);
        free(key.dptr);
	rb_ary_push(ary, valstr);
    }

    return ary;
}

static VALUE
fgdbm_has_key(VALUE obj, VALUE keystr)
{
    datum key;
    struct dbmdata *dbmp;
    GDBM_FILE dbm;

    StringValue(keystr);
    key.dptr = RSTRING(keystr)->ptr;
    key.dsize = RSTRING(keystr)->len;

    GetDBM2(obj, dbmp, dbm);
    if (gdbm_exists(dbm, key))
        return Qtrue;
    return Qfalse;
}

static VALUE
fgdbm_has_value(VALUE obj, VALUE valstr)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr, valstr2;

    StringValue(valstr);
    GetDBM2(obj, dbmp, dbm);
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {

	valstr2 = rb_gdbm_fetch2(dbm, keystr);

        if (!NIL_P(valstr2) &&
            RSTRING(valstr)->len == RSTRING(valstr2)->len &&
            memcmp(RSTRING(valstr)->ptr, RSTRING(valstr2)->ptr,
                   RSTRING(valstr)->len) == 0) {
	    return Qtrue;
        }
    }
    return Qfalse;
}

static VALUE
fgdbm_to_a(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr, ary;

    GetDBM2(obj, dbmp, dbm);
    ary = rb_ary_new();
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {

        rb_ary_push(ary, rb_assoc_new(keystr, rb_gdbm_fetch2(dbm, keystr)));
    }

    return ary;
}

static VALUE
fgdbm_reorganize(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;

    rb_gdbm_modify(obj);
    GetDBM2(obj, dbmp, dbm);
    gdbm_reorganize(dbm);
    return obj;
}

static VALUE
fgdbm_sync(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;

    rb_gdbm_modify(obj);
    GetDBM2(obj, dbmp, dbm);
    gdbm_sync(dbm);
    return obj;
}

static VALUE
fgdbm_set_cachesize(VALUE obj, VALUE val)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    int optval;

    GetDBM2(obj, dbmp, dbm);
    optval = FIX2INT(val);
    if (gdbm_setopt(dbm, GDBM_CACHESIZE, &optval, sizeof(optval)) == -1) {
	rb_raise(rb_eGDBMError, "%s", gdbm_strerror(gdbm_errno));
    }
    return val;
}

static VALUE
fgdbm_set_fastmode(VALUE obj, VALUE val)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    int optval;

    GetDBM2(obj, dbmp, dbm);
    optval = 0;
    if (RTEST(val))
        optval = 1;

    if (gdbm_setopt(dbm, GDBM_FASTMODE, &optval, sizeof(optval)) == -1) {
	rb_raise(rb_eGDBMError, "%s", gdbm_strerror(gdbm_errno));
    }
    return val;
}

static VALUE
fgdbm_set_syncmode(VALUE obj, VALUE val)
{
#if !defined(GDBM_SYNCMODE)
    fgdbm_set_fastmode(obj, RTEST(val) ? Qfalse : Qtrue);
    return val;
#else
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    int optval;

    GetDBM2(obj, dbmp, dbm);
    optval = 0;
    if (RTEST(val))
        optval = 1;

    if (gdbm_setopt(dbm, GDBM_FASTMODE, &optval, sizeof(optval)) == -1) {
	rb_raise(rb_eGDBMError, "%s", gdbm_strerror(gdbm_errno));
    }
    return val;
#endif
}

static VALUE
fgdbm_to_hash(VALUE obj)
{
    struct dbmdata *dbmp;
    GDBM_FILE dbm;
    VALUE keystr, hash;

    GetDBM2(obj, dbmp, dbm);
    hash = rb_hash_new();
    for (keystr = rb_gdbm_firstkey(dbm); RTEST(keystr);
         keystr = rb_gdbm_nextkey(dbm, keystr)) {

        rb_hash_aset(hash, keystr, rb_gdbm_fetch2(dbm, keystr));
    }

    return hash;
}

static VALUE
fgdbm_reject(VALUE obj)
{
    return rb_hash_delete_if(fgdbm_to_hash(obj));
}

void
Init_gdbm(void)
{
    rb_cGDBM = rb_define_class("GDBM", rb_cObject);
    rb_eGDBMError = rb_define_class("GDBMError", rb_eStandardError);
    rb_eGDBMFatalError = rb_define_class("GDBMFatalError", rb_eException);
    rb_include_module(rb_cGDBM, rb_mEnumerable);

    rb_define_alloc_func(rb_cGDBM, fgdbm_s_alloc);
    rb_define_singleton_method(rb_cGDBM, "open", fgdbm_s_open, -1);

    rb_define_method(rb_cGDBM, "initialize", fgdbm_initialize, -1);
    rb_define_method(rb_cGDBM, "close", fgdbm_close, 0);
    rb_define_method(rb_cGDBM, "closed?", fgdbm_closed, 0);
    rb_define_method(rb_cGDBM, "[]", fgdbm_aref, 1);
    rb_define_method(rb_cGDBM, "fetch", fgdbm_fetch_m, -1);
    rb_define_method(rb_cGDBM, "[]=", fgdbm_store, 2);
    rb_define_method(rb_cGDBM, "store", fgdbm_store, 2);
    rb_define_method(rb_cGDBM, "index",  fgdbm_index, 1);
    rb_define_method(rb_cGDBM, "select",  fgdbm_select, 0);
    rb_define_method(rb_cGDBM, "values_at",  fgdbm_values_at, -1);
    rb_define_method(rb_cGDBM, "length", fgdbm_length, 0);
    rb_define_method(rb_cGDBM, "size", fgdbm_length, 0);
    rb_define_method(rb_cGDBM, "empty?", fgdbm_empty_p, 0);
    rb_define_method(rb_cGDBM, "each", fgdbm_each_pair, 0);
    rb_define_method(rb_cGDBM, "each_value", fgdbm_each_value, 0);
    rb_define_method(rb_cGDBM, "each_key", fgdbm_each_key, 0);
    rb_define_method(rb_cGDBM, "each_pair", fgdbm_each_pair, 0);
    rb_define_method(rb_cGDBM, "keys", fgdbm_keys, 0);
    rb_define_method(rb_cGDBM, "values", fgdbm_values, 0);
    rb_define_method(rb_cGDBM, "shift", fgdbm_shift, 0);
    rb_define_method(rb_cGDBM, "delete", fgdbm_delete, 1);
    rb_define_method(rb_cGDBM, "delete_if", fgdbm_delete_if, 0);
    rb_define_method(rb_cGDBM, "reject!", fgdbm_delete_if, 0);
    rb_define_method(rb_cGDBM, "reject", fgdbm_reject, 0);
    rb_define_method(rb_cGDBM, "clear", fgdbm_clear, 0);
    rb_define_method(rb_cGDBM,"invert", fgdbm_invert, 0);
    rb_define_method(rb_cGDBM,"update", fgdbm_update, 1);
    rb_define_method(rb_cGDBM,"replace", fgdbm_replace, 1);
    rb_define_method(rb_cGDBM,"reorganize", fgdbm_reorganize, 0);
    rb_define_method(rb_cGDBM,"sync", fgdbm_sync, 0);
    /* rb_define_method(rb_cGDBM,"setopt", fgdbm_setopt, 2); */
    rb_define_method(rb_cGDBM,"cachesize=", fgdbm_set_cachesize, 1);
    rb_define_method(rb_cGDBM,"fastmode=", fgdbm_set_fastmode, 1);
    rb_define_method(rb_cGDBM,"syncmode=", fgdbm_set_syncmode, 1);

    rb_define_method(rb_cGDBM, "include?", fgdbm_has_key, 1);
    rb_define_method(rb_cGDBM, "has_key?", fgdbm_has_key, 1);
    rb_define_method(rb_cGDBM, "member?", fgdbm_has_key, 1);
    rb_define_method(rb_cGDBM, "has_value?", fgdbm_has_value, 1);
    rb_define_method(rb_cGDBM, "key?", fgdbm_has_key, 1);
    rb_define_method(rb_cGDBM, "value?", fgdbm_has_value, 1);

    rb_define_method(rb_cGDBM, "to_a", fgdbm_to_a, 0);
    rb_define_method(rb_cGDBM, "to_hash", fgdbm_to_hash, 0);

    /* flags for gdbm_open() */
    rb_define_const(rb_cGDBM, "READER",  INT2FIX(GDBM_READER|RUBY_GDBM_RW_BIT));
    rb_define_const(rb_cGDBM, "WRITER",  INT2FIX(GDBM_WRITER|RUBY_GDBM_RW_BIT));
    rb_define_const(rb_cGDBM, "WRCREAT", INT2FIX(GDBM_WRCREAT|RUBY_GDBM_RW_BIT));
    rb_define_const(rb_cGDBM, "NEWDB",   INT2FIX(GDBM_NEWDB|RUBY_GDBM_RW_BIT));

    rb_define_const(rb_cGDBM, "FAST", INT2FIX(GDBM_FAST));
    /* this flag is obsolete in gdbm 1.8.
       On gdbm 1.8, fast mode is default behavior. */

    /* gdbm version 1.8 specific */
#if defined(GDBM_SYNC)
    rb_define_const(rb_cGDBM, "SYNC",    INT2FIX(GDBM_SYNC));
#endif
#if defined(GDBM_NOLOCK)
    rb_define_const(rb_cGDBM, "NOLOCK",  INT2FIX(GDBM_NOLOCK));
#endif
    rb_define_const(rb_cGDBM, "VERSION",  rb_str_new2(gdbm_version));
}