Class: SDBM

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
init.c,
init.c

Overview

SDBM provides a simple file-based key-value store, which can only store String keys and values.

Note that Ruby comes with the source code for SDBM, while the DBM and GDBM standard libraries rely on external libraries and headers.

Examples

Insert values:

require 'sdbm'

SDBM.open 'my_database' do |db|
  db['apple'] = 'fruit'
  db['pear'] = 'fruit'
  db['carrot'] = 'vegetable'
  db['tomato'] = 'vegetable'
end

Bulk update:

require 'sdbm'

SDBM.open 'my_database' do |db|
  db.update('peach' => 'fruit', 'tomato' => 'fruit')
end

Retrieve values:

require 'sdbm'

SDBM.open 'my_database' do |db|
  db.each do |key, value|
    puts "Key: #{key}, Value: #{value}"
  end
end

Outputs:

Key: apple, Value: fruit
Key: pear, Value: fruit
Key: carrot, Value: vegetable
Key: peach, Value: fruit
Key: tomato, Value: fruit

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#new(filename, mode = 0666) ⇒ Object

Creates a new database handle by opening the given filename. SDBM actually uses two physical files, with extensions '.dir' and '.pag'. These extensions will automatically be appended to the filename.

If the file does not exist, a new file will be created using the given mode, unless mode is explicitly set to nil. In the latter case, no database will be created.

If the file exists, it will be opened in read/write mode. If this fails, it will be opened in read-only mode.


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# File 'init.c', line 178

static VALUE
fsdbm_initialize(int argc, VALUE *argv, VALUE obj)
{
    VALUE file, vmode;
    DBM *dbm;
    struct dbmdata *dbmp;
    int mode;

    TypedData_Get_Struct(obj, struct dbmdata, &sdbm_type, dbmp);
    if (rb_scan_args(argc, argv, "11", &file, &vmode) == 1) {
	mode = 0666;		/* default value */
    }
    else if (NIL_P(vmode)) {
	mode = -1;		/* return nil if DB not exist */
    }
    else {
	mode = NUM2INT(vmode);
    }
    FilePathValue(file);

    dbm = 0;
    if (mode >= 0)
	dbm = sdbm_open(RSTRING_PTR(file), O_RDWR|O_CREAT, mode);
    if (!dbm)
	dbm = sdbm_open(RSTRING_PTR(file), O_RDWR, 0);
    if (!dbm)
	dbm = sdbm_open(RSTRING_PTR(file), O_RDONLY, 0);

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

    if (dbmp->di_dbm)
	sdbm_close(dbmp->di_dbm);
    dbmp->di_dbm = dbm;
    dbmp->di_size = -1;

    return obj;
}

Class Method Details

.open(filename, mode = 0666) ⇒ Object .open(filename, mode = 0666) {|sdbm| ... } ⇒ Object

If called without a block, this is the same as SDBM.new.

If a block is given, the new database will be passed to the block and will be safely closed after the block has executed.

Example:

require 'sdbm'

SDBM.open('my_database') do |db|
  db['hello'] = 'world'
end

Overloads:

  • .open(filename, mode = 0666) {|sdbm| ... } ⇒ Object

    Yields:

    • (sdbm)

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# File 'init.c', line 237

static VALUE
fsdbm_s_open(int argc, VALUE *argv, VALUE klass)
{
    VALUE obj = fsdbm_alloc(klass);

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

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

    return obj;
}

Instance Method Details

#[](key) ⇒ nil

Returns the value in the database associated with the given key string.

If no value is found, returns nil.

Returns:

  • (nil)

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# File 'init.c', line 282

static VALUE
fsdbm_aref(VALUE obj, VALUE keystr)
{
    return fsdbm_fetch(obj, keystr, Qnil);
}

#[]=(key) ⇒ Object #store(key, value) ⇒ Object

Stores a new value in the database with the given key as an index.

If the key already exists, this will update the value associated with the key.

Returns the given value.


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# File 'init.c', line 619

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

    if (valstr == Qnil) {
	fsdbm_delete(obj, keystr);
	return Qnil;
    }

    fdbm_modify(obj);
    ExportStringValue(keystr);
    ExportStringValue(valstr);

    key.dptr = RSTRING_PTR(keystr);
    key.dsize = RSTRING_LENINT(keystr);

    val.dptr = RSTRING_PTR(valstr);
    val.dsize = RSTRING_LENINT(valstr);

    GetDBM2(obj, dbmp, dbm);
    dbmp->di_size = -1;
    if (sdbm_store(dbm, key, val, DBM_REPLACE)) {
#ifdef HAVE_DBM_CLAERERR
	sdbm_clearerr(dbm);
#endif
	if (errno == EPERM) rb_sys_fail(0);
	rb_raise(rb_eDBMError, "sdbm_store failed");
    }

    return valstr;
}

#clearself

Deletes all data from the database.

Returns:

  • (self)

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# File 'init.c', line 552

static VALUE
fsdbm_clear(VALUE obj)
{
    datum key;
    struct dbmdata *dbmp;
    DBM *dbm;

    fdbm_modify(obj);
    GetDBM2(obj, dbmp, dbm);
    dbmp->di_size = -1;
    while (key = sdbm_firstkey(dbm), key.dptr) {
	if (sdbm_delete(dbm, key)) {
	    rb_raise(rb_eDBMError, "sdbm_delete failed");
	}
    }
    dbmp->di_size = 0;

    return obj;
}

#closenil

Closes the database file.

Raises SDBMError if the database is already closed.

Returns:

  • (nil)

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# File 'init.c', line 126

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

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

    return Qnil;
}

#closed?Boolean

Returns true if the database is closed.

Returns:

  • (Boolean)

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# File 'init.c', line 144

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

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

    return Qfalse;
}

#delete(key) ⇒ nil #delete(key) {|key, value| ... } ⇒ Object

Deletes the key-value pair corresponding to the given key. If the key exists, the deleted value will be returned, otherwise nil.

If a block is provided, the deleted key and value will be passed to the block as arguments. If the key does not exist in the database, the value will be nil.

Overloads:

  • #delete(key) ⇒ nil

    Returns:

    • (nil)
  • #delete(key) {|key, value| ... } ⇒ Object

    Yields:


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# File 'init.c', line 433

static VALUE
fsdbm_delete(VALUE obj, VALUE keystr)
{
    datum key, value;
    struct dbmdata *dbmp;
    DBM *dbm;
    VALUE valstr;

    fdbm_modify(obj);
    ExportStringValue(keystr);
    key.dptr = RSTRING_PTR(keystr);
    key.dsize = RSTRING_LENINT(keystr);

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

    value = sdbm_fetch(dbm, key);
    if (value.dptr == 0) {
	if (rb_block_given_p()) return rb_yield(keystr);
	return Qnil;
    }

    /* need to save value before sdbm_delete() */
    valstr = rb_external_str_new(value.dptr, value.dsize);

    if (sdbm_delete(dbm, key)) {
	dbmp->di_size = -1;
	rb_raise(rb_eDBMError, "dbm_delete failed");
    }
    else if (dbmp->di_size >= 0) {
	dbmp->di_size--;
    }
    return valstr;
}

#delete_if {|key, value| ... } ⇒ self #reject! {|key, value| ... } ⇒ self

Iterates over the key-value pairs in the database, deleting those for which the block returns true.

Overloads:

  • #delete_if {|key, value| ... } ⇒ self

    Yields:

    Returns:

    • (self)
  • #reject! {|key, value| ... } ⇒ self

    Yields:

    Returns:

    • (self)

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# File 'init.c', line 506

static VALUE
fsdbm_delete_if(VALUE obj)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;
    VALUE keystr, valstr;
    VALUE ret, ary = rb_ary_new();
    long i;
    int status = 0, n;

    fdbm_modify(obj);
    GetDBM2(obj, dbmp, dbm);
    n = dbmp->di_size;
    dbmp->di_size = -1;
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	keystr = rb_external_str_new(key.dptr, key.dsize);
	valstr = rb_external_str_new(val.dptr, val.dsize);
        ret = rb_protect(rb_yield, rb_assoc_new(rb_str_dup(keystr), valstr), &status);
        if (status != 0) break;
	if (RTEST(ret)) rb_ary_push(ary, keystr);
	GetDBM2(obj, dbmp, dbm);
    }

    for (i = 0; i < RARRAY_LEN(ary); i++) {
	keystr = RARRAY_AREF(ary, i);
	ExportStringValue(keystr);
	key.dptr = RSTRING_PTR(keystr);
	key.dsize = RSTRING_LENINT(keystr);
	if (sdbm_delete(dbm, key)) {
	    rb_raise(rb_eDBMError, "sdbm_delete failed");
	}
    }
    if (status) rb_jump_tag(status);
    if (n > 0) dbmp->di_size = n - RARRAY_LENINT(ary);

    return obj;
}

#eachObject #each {|key, value| ... } ⇒ Object #each_pairObject #each_pair {|key, value| ... } ⇒ Object

Iterates over each key-value pair in the database.

If no block is given, returns an Enumerator.

Overloads:

  • #each {|key, value| ... } ⇒ Object

    Yields:

  • #each_pair {|key, value| ... } ⇒ Object

    Yields:


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# File 'init.c', line 818

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

    RETURN_ENUMERATOR(obj, 0, 0);

    GetDBM2(obj, dbmp, dbm);
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	keystr = rb_external_str_new(key.dptr, key.dsize);
	valstr = rb_external_str_new(val.dptr, val.dsize);
	rb_yield(rb_assoc_new(keystr, valstr));
	GetDBM2(obj, dbmp, dbm);
    }

    return obj;
}

#each_keyObject #each_key {|key| ... } ⇒ Object

Iterates over each key in the database.

If no block is given, returns an Enumerator.

Overloads:

  • #each_key {|key| ... } ⇒ Object

    Yields:


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# File 'init.c', line 790

static VALUE
fsdbm_each_key(VALUE obj)
{
    datum key;
    struct dbmdata *dbmp;
    DBM *dbm;

    RETURN_ENUMERATOR(obj, 0, 0);

    GetDBM2(obj, dbmp, dbm);
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	rb_yield(rb_external_str_new(key.dptr, key.dsize));
	GetDBM2(obj, dbmp, dbm);
    }
    return obj;
}

#eachObject #each {|key, value| ... } ⇒ Object #each_pairObject #each_pair {|key, value| ... } ⇒ Object

Iterates over each key-value pair in the database.

If no block is given, returns an Enumerator.

Overloads:

  • #each {|key, value| ... } ⇒ Object

    Yields:

  • #each_pair {|key, value| ... } ⇒ Object

    Yields:


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# File 'init.c', line 818

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

    RETURN_ENUMERATOR(obj, 0, 0);

    GetDBM2(obj, dbmp, dbm);
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	keystr = rb_external_str_new(key.dptr, key.dsize);
	valstr = rb_external_str_new(val.dptr, val.dsize);
	rb_yield(rb_assoc_new(keystr, valstr));
	GetDBM2(obj, dbmp, dbm);
    }

    return obj;
}

#each_valueObject #each_value {|value| ... } ⇒ Object

Iterates over each value in the database.

If no block is given, returns an Enumerator.

Overloads:

  • #each_value {|value| ... } ⇒ Object

    Yields:

    • (value)

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# File 'init.c', line 763

static VALUE
fsdbm_each_value(VALUE obj)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;

    RETURN_ENUMERATOR(obj, 0, 0);

    GetDBM2(obj, dbmp, dbm);
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	rb_yield(rb_external_str_new(val.dptr, val.dsize));
	GetDBM2(obj, dbmp, dbm);
    }
    return obj;
}

#empty?Boolean

Returns true if the database is empty.

Returns:

  • (Boolean)

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# File 'init.c', line 732

static VALUE
fsdbm_empty_p(VALUE obj)
{
    datum key;
    struct dbmdata *dbmp;
    DBM *dbm;

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

	for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	    return Qfalse;
	}
    }
    else {
	if (dbmp->di_size)
	    return Qfalse;
    }
    return Qtrue;
}

#fetch(key) ⇒ nil #fetch(key) {|key| ... } ⇒ Object

Returns the value in the database associated with the given key string.

If a block is provided, the block will be called when there is no value associated with the given key. The key will be passed in as an argument to the block.

If no block is provided and no value is associated with the given key, then an IndexError will be raised.

Overloads:

  • #fetch(key) ⇒ nil

    Returns:

    • (nil)
  • #fetch(key) {|key| ... } ⇒ Object

    Yields:


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# File 'init.c', line 302

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

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

    return valstr;
}

#include?(key) ⇒ Boolean #key?(key) ⇒ Boolean #member?(key) ⇒ Boolean #has_key?(key) ⇒ Boolean

Returns true if the database contains the given key.

Overloads:

  • #include?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #member?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #has_key?(key) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'init.c', line 896

static VALUE
fsdbm_has_key(VALUE obj, VALUE keystr)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;

    ExportStringValue(keystr);
    key.dptr = RSTRING_PTR(keystr);
    key.dsize = RSTRING_LENINT(keystr);

    GetDBM2(obj, dbmp, dbm);
    val = sdbm_fetch(dbm, key);
    if (val.dptr) return Qtrue;
    return Qfalse;
}

#value?(key) ⇒ Boolean #has_value?(key) ⇒ Boolean

Returns true if the database contains the given value.

Overloads:

  • #value?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #has_value?(key) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'init.c', line 920

static VALUE
fsdbm_has_value(VALUE obj, VALUE valstr)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;

    ExportStringValue(valstr);
    val.dptr = RSTRING_PTR(valstr);
    val.dsize = RSTRING_LENINT(valstr);

    GetDBM2(obj, dbmp, dbm);
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	if (val.dsize == RSTRING_LENINT(valstr) &&
	    memcmp(val.dptr, RSTRING_PTR(valstr), val.dsize) == 0)
	    return Qtrue;
    }
    return Qfalse;
}

#include?(key) ⇒ Boolean #key?(key) ⇒ Boolean #member?(key) ⇒ Boolean #has_key?(key) ⇒ Boolean

Returns true if the database contains the given key.

Overloads:

  • #include?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #member?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #has_key?(key) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'init.c', line 896

static VALUE
fsdbm_has_key(VALUE obj, VALUE keystr)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;

    ExportStringValue(keystr);
    key.dptr = RSTRING_PTR(keystr);
    key.dsize = RSTRING_LENINT(keystr);

    GetDBM2(obj, dbmp, dbm);
    val = sdbm_fetch(dbm, key);
    if (val.dptr) return Qtrue;
    return Qfalse;
}

#index(value) ⇒ Object

:nodoc:


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# File 'init.c', line 347

static VALUE
fsdbm_index(VALUE hash, VALUE value)
{
    rb_warn("SDBM#index is deprecated; use SDBM#key");
    return fsdbm_key(hash, value);
}

#invertHash

Returns a Hash in which the key-value pairs have been inverted.

Example:

require 'sdbm'

SDBM.open 'my_database' do |db|
  db.update('apple' => 'fruit', 'spinach' => 'vegetable')

  db.invert  #=> {"fruit" => "apple", "vegetable" => "spinach"}
end

Returns:

  • (Hash)

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# File 'init.c', line 588

static VALUE
fsdbm_invert(VALUE obj)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;
    VALUE keystr, valstr;
    VALUE hash = rb_hash_new();

    GetDBM2(obj, dbmp, dbm);
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	keystr = rb_external_str_new(key.dptr, key.dsize);
	valstr = rb_external_str_new(val.dptr, val.dsize);
	rb_hash_aset(hash, valstr, keystr);
    }
    return hash;
}

#key(value) ⇒ Object

Returns the key associated with the given value. If more than one key corresponds to the given value, then the first key to be found will be returned. If no keys are found, nil will be returned.


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# File 'init.c', line 323

static VALUE
fsdbm_key(VALUE obj, VALUE valstr)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;

    ExportStringValue(valstr);
    val.dptr = RSTRING_PTR(valstr);
    val.dsize = RSTRING_LENINT(valstr);

    GetDBM2(obj, dbmp, dbm);
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	if (val.dsize == RSTRING_LEN(valstr) &&
	    memcmp(val.dptr, RSTRING_PTR(valstr), val.dsize) == 0)
	    return rb_external_str_new(key.dptr, key.dsize);
    }
    return Qnil;
}

#include?(key) ⇒ Boolean #key?(key) ⇒ Boolean #member?(key) ⇒ Boolean #has_key?(key) ⇒ Boolean

Returns true if the database contains the given key.

Overloads:

  • #include?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #member?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #has_key?(key) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'init.c', line 896

static VALUE
fsdbm_has_key(VALUE obj, VALUE keystr)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;

    ExportStringValue(keystr);
    key.dptr = RSTRING_PTR(keystr);
    key.dsize = RSTRING_LENINT(keystr);

    GetDBM2(obj, dbmp, dbm);
    val = sdbm_fetch(dbm, key);
    if (val.dptr) return Qtrue;
    return Qfalse;
}

#keysArray

Returns a new Array containing the keys in the database.

Returns:

  • (Array)

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# File 'init.c', line 846

static VALUE
fsdbm_keys(VALUE obj)
{
    datum key;
    struct dbmdata *dbmp;
    DBM *dbm;
    VALUE ary;

    GetDBM2(obj, dbmp, dbm);
    ary = rb_ary_new();
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	rb_ary_push(ary, rb_external_str_new(key.dptr, key.dsize));
    }

    return ary;
}

#lengthInteger #sizeInteger

Returns the number of keys in the database.

Overloads:

  • #lengthInteger

    Returns:

    • (Integer)
  • #sizeInteger

    Returns:

    • (Integer)

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# File 'init.c', line 707

static VALUE
fsdbm_length(VALUE obj)
{
    datum key;
    struct dbmdata *dbmp;
    DBM *dbm;
    int i = 0;

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

    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	i++;
    }
    dbmp->di_size = i;

    return INT2FIX(i);
}

#include?(key) ⇒ Boolean #key?(key) ⇒ Boolean #member?(key) ⇒ Boolean #has_key?(key) ⇒ Boolean

Returns true if the database contains the given key.

Overloads:

  • #include?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #member?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #has_key?(key) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'init.c', line 896

static VALUE
fsdbm_has_key(VALUE obj, VALUE keystr)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;

    ExportStringValue(keystr);
    key.dptr = RSTRING_PTR(keystr);
    key.dsize = RSTRING_LENINT(keystr);

    GetDBM2(obj, dbmp, dbm);
    val = sdbm_fetch(dbm, key);
    if (val.dptr) return Qtrue;
    return Qfalse;
}

#reject {|key, value| ... } ⇒ Hash

Creates a new Hash using the key-value pairs from the database, then calls Hash#reject with the given block, which returns a Hash with only the key-value pairs for which the block returns false.

Yields:

Returns:

  • (Hash)

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# File 'init.c', line 1009

static VALUE
fsdbm_reject(VALUE obj)
{
    return rb_hash_delete_if(fsdbm_to_hash(obj));
}

#delete_if {|key, value| ... } ⇒ self #reject! {|key, value| ... } ⇒ self

Iterates over the key-value pairs in the database, deleting those for which the block returns true.

Overloads:

  • #delete_if {|key, value| ... } ⇒ self

    Yields:

    Returns:

    • (self)
  • #reject! {|key, value| ... } ⇒ self

    Yields:

    Returns:

    • (self)

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# File 'init.c', line 506

static VALUE
fsdbm_delete_if(VALUE obj)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;
    VALUE keystr, valstr;
    VALUE ret, ary = rb_ary_new();
    long i;
    int status = 0, n;

    fdbm_modify(obj);
    GetDBM2(obj, dbmp, dbm);
    n = dbmp->di_size;
    dbmp->di_size = -1;
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	keystr = rb_external_str_new(key.dptr, key.dsize);
	valstr = rb_external_str_new(val.dptr, val.dsize);
        ret = rb_protect(rb_yield, rb_assoc_new(rb_str_dup(keystr), valstr), &status);
        if (status != 0) break;
	if (RTEST(ret)) rb_ary_push(ary, keystr);
	GetDBM2(obj, dbmp, dbm);
    }

    for (i = 0; i < RARRAY_LEN(ary); i++) {
	keystr = RARRAY_AREF(ary, i);
	ExportStringValue(keystr);
	key.dptr = RSTRING_PTR(keystr);
	key.dsize = RSTRING_LENINT(keystr);
	if (sdbm_delete(dbm, key)) {
	    rb_raise(rb_eDBMError, "sdbm_delete failed");
	}
    }
    if (status) rb_jump_tag(status);
    if (n > 0) dbmp->di_size = n - RARRAY_LENINT(ary);

    return obj;
}

#replace(pairs) ⇒ self

Empties the database, then inserts the given key-value pairs.

This method will work with any object which implements an each_pair method, such as a Hash.

Returns:

  • (self)

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# File 'init.c', line 692

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

#select {|key, value| ... } ⇒ Array

Returns a new Array of key-value pairs for which the block returns true.

Example:

require 'sdbm'

SDBM.open 'my_database' do |db|
  db['apple'] = 'fruit'
  db['pear'] = 'fruit'
  db['spinach'] = 'vegetable'

  veggies = db.select do |key, value|
    value == 'vegetable'
  end #=> [["apple", "fruit"], ["pear", "fruit"]]
end

Yields:

Returns:

  • (Array)

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# File 'init.c', line 373

static VALUE
fsdbm_select(VALUE obj)
{
    VALUE new = rb_ary_new();
    datum key, val;
    DBM *dbm;
    struct dbmdata *dbmp;

    GetDBM2(obj, dbmp, dbm);
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	VALUE assoc, v;
	val = sdbm_fetch(dbm, key);
	assoc = rb_assoc_new(rb_external_str_new(key.dptr, key.dsize),
			     rb_external_str_new(val.dptr, val.dsize));
	v = rb_yield(assoc);
	if (RTEST(v)) {
	    rb_ary_push(new, assoc);
	}
	GetDBM2(obj, dbmp, dbm);
    }

    return new;
}

#shiftArray?

Removes a key-value pair from the database and returns them as an Array. If the database is empty, returns nil.

Returns:

  • (Array, nil)

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# File 'init.c', line 475

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

    fdbm_modify(obj);
    GetDBM2(obj, dbmp, dbm);
    key = sdbm_firstkey(dbm);
    if (!key.dptr) return Qnil;
    val = sdbm_fetch(dbm, key);
    keystr = rb_external_str_new(key.dptr, key.dsize);
    valstr = rb_external_str_new(val.dptr, val.dsize);
    sdbm_delete(dbm, key);
    if (dbmp->di_size >= 0) {
	dbmp->di_size--;
    }

    return rb_assoc_new(keystr, valstr);
}

#lengthInteger #sizeInteger

Returns the number of keys in the database.

Overloads:

  • #lengthInteger

    Returns:

    • (Integer)
  • #sizeInteger

    Returns:

    • (Integer)

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# File 'init.c', line 707

static VALUE
fsdbm_length(VALUE obj)
{
    datum key;
    struct dbmdata *dbmp;
    DBM *dbm;
    int i = 0;

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

    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	i++;
    }
    dbmp->di_size = i;

    return INT2FIX(i);
}

#[]=(key) ⇒ Object #store(key, value) ⇒ Object

Stores a new value in the database with the given key as an index.

If the key already exists, this will update the value associated with the key.

Returns the given value.


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# File 'init.c', line 619

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

    if (valstr == Qnil) {
	fsdbm_delete(obj, keystr);
	return Qnil;
    }

    fdbm_modify(obj);
    ExportStringValue(keystr);
    ExportStringValue(valstr);

    key.dptr = RSTRING_PTR(keystr);
    key.dsize = RSTRING_LENINT(keystr);

    val.dptr = RSTRING_PTR(valstr);
    val.dsize = RSTRING_LENINT(valstr);

    GetDBM2(obj, dbmp, dbm);
    dbmp->di_size = -1;
    if (sdbm_store(dbm, key, val, DBM_REPLACE)) {
#ifdef HAVE_DBM_CLAERERR
	sdbm_clearerr(dbm);
#endif
	if (errno == EPERM) rb_sys_fail(0);
	rb_raise(rb_eDBMError, "sdbm_store failed");
    }

    return valstr;
}

#to_aArray

Returns a new Array containing each key-value pair in the database.

Example:

require 'sdbm'

SDBM.open 'my_database' do |db|
  db.update('apple' => 'fruit', 'spinach' => 'vegetable')

  db.to_a  #=> [["apple", "fruit"], ["spinach", "vegetable"]]
end

Returns:

  • (Array)

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# File 'init.c', line 957

static VALUE
fsdbm_to_a(VALUE obj)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;
    VALUE ary;

    GetDBM2(obj, dbmp, dbm);
    ary = rb_ary_new();
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	rb_ary_push(ary, rb_assoc_new(rb_external_str_new(key.dptr, key.dsize),
				      rb_external_str_new(val.dptr, val.dsize)));
    }

    return ary;
}

#to_hashHash

Returns a new Hash containing each key-value pair in the database.

Returns:

  • (Hash)

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# File 'init.c', line 982

static VALUE
fsdbm_to_hash(VALUE obj)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;
    VALUE hash;

    GetDBM2(obj, dbmp, dbm);
    hash = rb_hash_new();
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	rb_hash_aset(hash, rb_external_str_new(key.dptr, key.dsize),
		           rb_external_str_new(val.dptr, val.dsize));
    }

    return hash;
}

#update(pairs) ⇒ self

Insert or update key-value pairs.

This method will work with any object which implements an each_pair method, such as a Hash.

Returns:

  • (self)

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# File 'init.c', line 676

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

#value?(key) ⇒ Boolean #has_value?(key) ⇒ Boolean

Returns true if the database contains the given value.

Overloads:

  • #value?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #has_value?(key) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'init.c', line 920

static VALUE
fsdbm_has_value(VALUE obj, VALUE valstr)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;

    ExportStringValue(valstr);
    val.dptr = RSTRING_PTR(valstr);
    val.dsize = RSTRING_LENINT(valstr);

    GetDBM2(obj, dbmp, dbm);
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	if (val.dsize == RSTRING_LENINT(valstr) &&
	    memcmp(val.dptr, RSTRING_PTR(valstr), val.dsize) == 0)
	    return Qtrue;
    }
    return Qfalse;
}

#valuesArray

Returns a new Array containing the values in the database.

Returns:

  • (Array)

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# File 'init.c', line 869

static VALUE
fsdbm_values(VALUE obj)
{
    datum key, val;
    struct dbmdata *dbmp;
    DBM *dbm;
    VALUE ary;

    GetDBM2(obj, dbmp, dbm);
    ary = rb_ary_new();
    for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
	val = sdbm_fetch(dbm, key);
	rb_ary_push(ary, rb_external_str_new(val.dptr, val.dsize));
    }

    return ary;
}

#values_at(key, ...) ⇒ Array

Returns an Array of values corresponding to the given keys.

Returns:

  • (Array)

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# File 'init.c', line 402

static VALUE
fsdbm_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, fsdbm_fetch(obj, argv[i], Qnil));
    }

    return new;
}