Class: SDBM

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, Enumerable
Inherits:	Object
Defined in:	ext/sdbm/init.c, ext/sdbm/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

.new(filename, mode = 0666) constructor

Creates a new database handle by opening the given filename.
.open(filename, mode = 0666)

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

Instance Attribute Summary

#closed? ⇒ Boolean readonly

Returns true if the database is closed.
#empty? ⇒ Boolean readonly

Returns true if the database is empty.

Instance Method Summary

#[](key) ⇒ value^?

Returns the value in the database associated with the given #key string.
#[]=(key, value) ⇒ value (also: #store)

Stores a new value in the database with the given #key as an index.
#clear ⇒ self

Deletes all data from the database.
#close
#delete(key) ⇒ value^?

Deletes the key-value pair corresponding to the given #key.
#delete_if {|key, value| ... } ⇒ self

Alias for #reject!.
#each (also: #each_pair)

Iterates over each key-value pair in the database.
#each_key

Iterates over each #key in the database.
#each_pair

Alias for #each.
#each_value

Iterates over each value in the database.
#fetch(key) ⇒ value^?

Returns the value in the database associated with the given #key string.
#has_key?(key) ⇒ Boolean

Alias for #key?.
#has_value?(key) ⇒ Boolean

Alias for #value?.
#include?(key) ⇒ Boolean

Alias for #key?.
#invert ⇒ Hash

Returns a Hash in which the key-value pairs have been inverted.
#key(value) ⇒ key

Returns the key associated with the given value.
#key?(key) ⇒ Boolean (also: #has_key?, #include?, #member?)

Returns true if the database contains the given #key.
#keys ⇒ Array

Returns a new Array containing the keys in the database.
#length ⇒ Integer (also: #size)

Returns the number of keys in the database.
#member?(key) ⇒ Boolean

Alias for #key?.
#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.
#reject! {|key, value| ... } ⇒ self (also: #delete_if)

Iterates over the key-value pairs in the database, deleting those for which the block returns true.
#replace(pairs) ⇒ self

Empties the database, then inserts the given key-value pairs.
#select {|key, value| ... } ⇒ Array

Returns a new Array of key-value pairs for which the block returns true.
#shift ⇒ Array^?

Removes a key-value pair from the database and returns them as an Array.
#size ⇒ Integer

Alias for #length.
#store(key, value) ⇒ value

Alias for #[]=.
#to_a ⇒ Array

Returns a new Array containing each key-value pair in the database.
#to_hash ⇒ Hash

Returns a new Hash containing each key-value pair in the database.
#update(pairs) ⇒ self

Insert or update key-value pairs.
#value?(key) ⇒ Boolean (also: #has_value?)

Returns true if the database contains the given value.
#values ⇒ Array

Returns a new Array containing the values in the database.
#values_at(key, ...) ⇒ Array

Returns an Array of values corresponding to the given keys.
#index(value) Internal use only

Constructor Details

.new(filename, mode = 0666)

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.

[ GitHub ]

# File 'ext/sdbm/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) .open(filename, mode = 0666) {|sdbm| ... }

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

[ GitHub ]

# File 'ext/sdbm/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 Attribute Details

#closed? ⇒ `Boolean` (readonly)

Returns true if the database is closed.

[ GitHub ]

# File 'ext/sdbm/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;
}

#empty? ⇒ `Boolean` (readonly)

Returns true if the database is empty.

[ GitHub ]

# File 'ext/sdbm/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;
}

Instance Method Details

#[](key) ⇒ `value`^?

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

If no value is found, returns nil.

[ GitHub ]

# File 'ext/sdbm/init.c', line 282


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

#[]=(key, value) ⇒ `value` #store(key, value) ⇒ `value`
Also known as: #store

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.

[ GitHub ]

# File 'ext/sdbm/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;
}

#clear ⇒ `self`

Deletes all data from the database.

[ GitHub ]

# File 'ext/sdbm/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;
}

#close

[ GitHub ]

# File 'ext/sdbm/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;
}

#delete(key) ⇒ `value`^? #delete(key) {|key, value| ... }

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.

[ GitHub ]

# File 'ext/sdbm/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`

Alias for #reject!.

#each #each {|key, value| ... } #each_pair #each_pair {|key, value| ... }
Also known as: #each_pair

Iterates over each key-value pair in the database.

If no block is given, returns an Enumerator.

[ GitHub ]

# File 'ext/sdbm/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_key #each_key {|key| ... }

Iterates over each #key in the database.

If no block is given, returns an Enumerator.

[ GitHub ]

# File 'ext/sdbm/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;
}

#each #each {|key, value| ... } #each_pair #each_pair {|key, value| ... }

Alias for #each.

#each_value #each_value {|value| ... }

Iterates over each value in the database.

If no block is given, returns an Enumerator.

[ GitHub ]

# File 'ext/sdbm/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;
}

#fetch(key) ⇒ `value`^? #fetch(key) {|key| ... }

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.

[ GitHub ]

# File 'ext/sdbm/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`

Alias for #key?.

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

Alias for #value?.

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

Alias for #key?.

#index(value)

This method is for internal use only.

[ GitHub ]

# File 'ext/sdbm/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);
}

#invert ⇒ `Hash`

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

[ GitHub ]

# File 'ext/sdbm/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) ⇒ key

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.

[ GitHub ]

# File 'ext/sdbm/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`
Also known as: #has_key?, #include?, #member?

Returns true if the database contains the given #key.

[ GitHub ]

# File 'ext/sdbm/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;
}

#keys ⇒ `Array`

Returns a new Array containing the keys in the database.

[ GitHub ]

# File 'ext/sdbm/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;
}

#length ⇒ `Integer` #size ⇒ `Integer`
Also known as: #size

Returns the number of keys in the database.

[ GitHub ]

# File 'ext/sdbm/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`

Alias for #key?.

#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.

[ GitHub ]

# File 'ext/sdbm/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`
Also known as: #delete_if

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

[ GitHub ]

# File 'ext/sdbm/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.

[ GitHub ]

# File 'ext/sdbm/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

[ GitHub ]

# File 'ext/sdbm/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;
}

#shift ⇒ `Array`^?

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

[ GitHub ]

# File 'ext/sdbm/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);
}

#length ⇒ `Integer` #size ⇒ `Integer`

Alias for #length.

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

Alias for #[]=.

#to_a ⇒ `Array`

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

[ GitHub ]

# File 'ext/sdbm/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_hash ⇒ `Hash`

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

[ GitHub ]

# File 'ext/sdbm/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.

[ GitHub ]

# File 'ext/sdbm/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`
Also known as: #has_value?

Returns true if the database contains the given value.

[ GitHub ]

# File 'ext/sdbm/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;
}

#values ⇒ `Array`

Returns a new Array containing the values in the database.

[ GitHub ]

# File 'ext/sdbm/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.

[ GitHub ]

# File 'ext/sdbm/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;
}

Class: SDBM

Overview

Examples

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(filename, mode = 0666)

Class Method Details

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

Instance Attribute Details

#closed? ⇒ Boolean (readonly)

#empty? ⇒ Boolean (readonly)

Instance Method Details

#[](key) ⇒ value?

#[]=(key, value) ⇒ value #store(key, value) ⇒ value Also known as: #store

#clear ⇒ self

#close

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

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

#each #each {|key, value| ... } #each_pair #each_pair {|key, value| ... } Also known as: #each_pair

#each_key #each_key {|key| ... }

#each #each {|key, value| ... } #each_pair #each_pair {|key, value| ... }

#each_value #each_value {|value| ... }

#fetch(key) ⇒ value? #fetch(key) {|key| ... }

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

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

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

#index(value)

#invert ⇒ Hash

#key(value) ⇒ key

#include?(key) ⇒ Boolean #key?(key) ⇒ Boolean #member?(key) ⇒ Boolean #has_key?(key) ⇒ Boolean Also known as: #has_key?, #include?, #member?

#keys ⇒ Array

#length ⇒ Integer #size ⇒ Integer Also known as: #size

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

#reject {|key, value| ... } ⇒ Hash

#delete_if {|key, value| ... } ⇒ self #reject! {|key, value| ... } ⇒ self Also known as: #delete_if

#replace(pairs) ⇒ self

#select {|key, value| ... } ⇒ Array

#shift ⇒ Array?

#length ⇒ Integer #size ⇒ Integer

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

#to_a ⇒ Array

#to_hash ⇒ Hash

#update(pairs) ⇒ self

#value?(key) ⇒ Boolean #has_value?(key) ⇒ Boolean Also known as: #has_value?

#values ⇒ Array

#values_at(key, ...) ⇒ Array

#closed? ⇒ `Boolean` (readonly)

#empty? ⇒ `Boolean` (readonly)

#[](key) ⇒ `value`^?

#[]=(key, value) ⇒ `value` #store(key, value) ⇒ `value`
Also known as: #store

#clear ⇒ `self`

#delete(key) ⇒ `value`^? #delete(key) {|key, value| ... }

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

#each #each {|key, value| ... } #each_pair #each_pair {|key, value| ... }
Also known as: #each_pair

#fetch(key) ⇒ `value`^? #fetch(key) {|key| ... }

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

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

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

#invert ⇒ `Hash`

#include?(key) ⇒ `Boolean` #key?(key) ⇒ `Boolean` #member?(key) ⇒ `Boolean` #has_key?(key) ⇒ `Boolean`
Also known as: #has_key?, #include?, #member?

#keys ⇒ `Array`

#length ⇒ `Integer` #size ⇒ `Integer`
Also known as: #size

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

#reject {|key, value| ... } ⇒ `Hash`

#delete_if {|key, value| ... } ⇒ `self` #reject! {|key, value| ... } ⇒ `self`
Also known as: #delete_if

#replace(pairs) ⇒ `self`

#select {|key, value| ... } ⇒ `Array`

#shift ⇒ `Array`^?

#length ⇒ `Integer` #size ⇒ `Integer`

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

#to_a ⇒ `Array`

#to_hash ⇒ `Hash`

#update(pairs) ⇒ `self`

#value?(key) ⇒ `Boolean` #has_value?(key) ⇒ `Boolean`
Also known as: #has_value?

#values ⇒ `Array`

#values_at(key, ...) ⇒ `Array`