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Class: GDBM

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

Overview

Summary

Ruby extension for GNU dbm (gdbm) – a simple database engine for storing key-value pairs on disk.

Description

GNU dbm is a library for simple databases. A database is a file that stores key-value pairs. Gdbm allows the user to store, retrieve, and delete data by key. It furthermore allows a non-sorted traversal of all key-value pairs. A gdbm database thus provides the same functionality as a hash. As with objects of the Hash class, elements can be accessed with #[]. Furthermore, GDBM mixes in the Enumerable module, thus providing convenient methods such as #find, #collect, #map, etc.

A process is allowed to open several different databases at the same time. A process can open a database as a “reader” or a “writer”. Whereas a reader has only read-access to the database, a writer has read- and write-access. A database can be accessed either by any number of readers or by exactly one writer at the same time.

Examples

  1. Opening/creating a database, and filling it with some entries:

    require 'gdbm'
    
    gdbm = GDBM.new("fruitstore.db")
    gdbm["ananas"]    = "3"
    gdbm["banana"]    = "8"
    gdbm["cranberry"] = "4909"
    gdbm.close
  2. Reading out a database:

    require 'gdbm'
    
    gdbm = GDBM.new("fruitstore.db")
    gdbm.each_pair do |key, value|
      print "#{key}: #{value}\n"
    end
    gdbm.close

    produces

    banana: 8
    ananas: 3
    cranberry: 4909

Constant Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(filename, mode = 0666, flags = nil)

Creates a new GDBM instance by opening a gdbm file named filename. If the file does not exist, a new file with file mode mode will be created. flags may be one of the following:

  • READER - open as a reader

  • WRITER - open as a writer

  • WRCREAT - open as a writer; if the database does not exist, create a new one

  • NEWDB - open as a writer; overwrite any existing databases

The values WRITER, WRCREAT and NEWDB may be combined with the following values by bitwise or:

  • SYNC - cause all database operations to be synchronized to the disk

  • NOLOCK - do not lock the database file

If no flags are specified, the GDBM object will try to open the database file as a writer and will create it if it does not already exist (cf. flag WRCREAT). If this fails (for instance, if another process has already opened the database as a reader), it will try to open the database file as a reader (cf. flag READER).

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 210

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

    TypedData_Get_Struct(obj, struct dbmdata, &dbm_type, dbmp);
    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 does not exist */
    }
    else {
        mode = NUM2INT(vmode);
    }

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

    FilePathValue(file);

#ifdef GDBM_CLOEXEC
    /* GDBM_CLOEXEC is available since gdbm 1.10. */
    flags |= GDBM_CLOEXEC;
#endif

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

    if (dbm) {
        rb_fd_fix_cloexec(gdbm_fdesc(dbm));
    }

    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_str(file);
        else
            rb_raise(rb_eGDBMError, "%s", gdbm_strerror(gdbm_errno));
    }

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

    return obj;
}

Class Method Details

.open(filename, mode = 0666, flags = nil) .open(filename, mode = 0666, flags = nil) {|gdbm| ... }

If called without a block, this is synonymous to .new. If a block is given, the new GDBM instance will be passed to the block as a parameter, and the corresponding database file will be closed after the execution of the block code has been finished.

Example for an open call with a block:

require 'gdbm'
GDBM.open("fruitstore.db") do |gdbm|
  gdbm.each_pair do |key, value|
    print "#{key}: #{value}\n"
  end
end
[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 299

static VALUE
fgdbm_s_open(int argc, VALUE *argv, VALUE klass)
{
    VALUE obj = fgdbm_s_alloc(klass);

    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;
}

Instance Attribute Details

#cachesize=(size) ⇒ size (writeonly)

Sets the size of the internal bucket cache to size.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 1108

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;
}

#closed?Boolean (readonly)

Returns true if the associated database file has been closed.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 167

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

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

    return Qfalse;
}

#empty?Boolean (readonly)

Returns true if the database is empty.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 821

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;
}

#fastmode=(boolean) ⇒ Boolean (writeonly)

Turns the database's fast mode on or off. If fast mode is turned on, gdbm does not wait for writes to be flushed to the disk before continuing.

This option is obsolete for gdbm >= 1.8 since fast mode is turned on by default. See also: #syncmode=

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 1133

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;
}

#syncmode=(boolean) ⇒ Boolean (writeonly)

Turns the database's synchronization mode on or off. If the synchronization mode is turned on, the database's in-memory state will be synchronized to disk after every database modification operation. If the synchronization mode is turned off, GDBM does not wait for writes to be flushed to the disk before continuing.

This option is only available for gdbm >= 1.8 where syncmode is turned off by default. See also: #fastmode=

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 1164

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
}

Instance Method Details

#[](key) ⇒ value

Retrieves the value corresponding to key.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 410

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

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

Associates the value value with the specified key.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 717

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

    rb_gdbm_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 (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;
}

#clearGDBM

Removes all the key-value pairs within gdbm.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 648

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;
}

#close

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 149

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

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

    return Qnil;
}

#delete(key) ⇒ value?

Removes the key-value-pair with the specified key from this database and returns the corresponding value. Returns nil if the database is empty.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 566

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

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

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

Alias for #reject!.

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

Executes block for each key in the database, passing the key and the corresponding value as a parameter.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 903

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

    RETURN_ENUMERATOR(obj, 0, 0);

    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;
}

#each_key {|key| ... } ⇒ GDBM

Executes block for each key in the database, passing the key as a parameter.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 877

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

    RETURN_ENUMERATOR(obj, 0, 0);

    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;
}

#each_pair {|key, value| ... } ⇒ GDBM #each_pair {|key, value| ... } ⇒ GDBM

Alias for #each.

#each_value {|value| ... } ⇒ GDBM

Executes block for each key in the database, passing the corresponding value as a parameter.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 851

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

    RETURN_ENUMERATOR(obj, 0, 0);

    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;
}

#fetch(key [, default]) ⇒ value

Retrieves the value corresponding to key. If there is no value associated with key, default will be returned instead.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 423

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;
}

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

Alias for #key?.

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

Alias for #value?.

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

Alias for #key?.

#index(value)

This method is for internal use only.
[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 467

static VALUE
fgdbm_index(VALUE obj, VALUE value)
{
    rb_warn("GDBM#index is deprecated; use GDBM#key");
    return fgdbm_key(obj, value);
}

#invertHash

Returns a hash created by using gdbm's values as keys, and the keys as values.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 692

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;
}

#key(value) ⇒ key

Returns the key for a given value. If several keys may map to the same value, the key that is found first will be returned.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 443

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

    ExportStringValue(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) &&
            (int)RSTRING_LEN(valstr) == (int)RSTRING_LEN(valstr2) &&
            memcmp(RSTRING_PTR(valstr), RSTRING_PTR(valstr2),
                   (int)RSTRING_LEN(valstr)) == 0) {
            return keystr;
        }
    }
    return Qnil;
}

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

Returns true if the given key k exists within the database. Returns false otherwise.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 983

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

    ExportStringValue(keystr);
    len = RSTRING_LENINT(keystr);
    if (TOO_LONG(len)) return Qfalse;
    key.dptr = RSTRING_PTR(keystr);
    key.dsize = (int)len;

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

#keysArray

Returns an array of all keys of this database.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 929

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;
}

#lengthFixnum #sizeFixnum
Also known as: #size

Returns the number of key-value pairs in this database.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 794

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);
}

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

Alias for #key?.

#reject {|key, value| ... } ⇒ Hash

Returns a hash copy of gdbm where all key-value pairs from gdbm for which block evaluates to true are removed. See also: #delete_if

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 1218

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

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

Deletes every key-value pair from gdbm for which block evaluates to true.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 607

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

	OBJ_FREEZE(keystr);
        valstr = rb_gdbm_fetch2(dbm, keystr);
        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++)
        rb_gdbm_delete(obj, RARRAY_AREF(ary, i));
    if (status) rb_jump_tag(status);
    if (n > 0) dbmp->di_size = n - (int)RARRAY_LEN(ary);
    rb_ary_clear(ary);

    return obj;
}

#reorganizeGDBM

Reorganizes the database file. This operation removes reserved space of elements that have already been deleted. It is only useful after a lot of deletions in the database.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 1067

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

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

#replace(other) ⇒ GDBM

Replaces the content of gdbm with the key-value pairs of other. other must have an each_pair method.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 779

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;
}

#select {|key, value| ... } ⇒ Array

Returns a new array of all key-value pairs of the database for which block evaluates to true.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 481

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;
}

#shift ⇒ (key, value)?

Removes a key-value-pair from this database and returns it as a two-item array [ key, value ]. Returns nil if the database is empty.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 583

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);
}

#lengthFixnum #sizeFixnum

Alias for #length.

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

Alias for #[]=.

#syncGDBM

Unless the gdbm object has been opened with the SYNC flag, it is not guaranteed that database modification operations are immediately applied to the database file. This method ensures that all recent modifications to the database are written to the file. Blocks until all writing operations to the disk have been finished.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 1090

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;
}

#to_aArray

Returns an array of all key-value pairs contained in the database.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 1041

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;
}

#to_hashHash

Returns a hash of all key-value pairs contained in the database.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 1193

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;
}

#update(other) ⇒ GDBM

Adds the key-value pairs of other to gdbm, overwriting entries with duplicate keys with those from other. other must have an each_pair method.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 765

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

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

Returns true if the given value v exists within the database. Returns false otherwise.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 1011

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

    ExportStringValue(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) &&
            (int)RSTRING_LEN(valstr) == (int)RSTRING_LEN(valstr2) &&
            memcmp(RSTRING_PTR(valstr), RSTRING_PTR(valstr2),
                   (int)RSTRING_LEN(valstr)) == 0) {
            return Qtrue;
        }
    }
    return Qfalse;
}

#valuesArray

Returns an array of all values of this database.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 953

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;
}

#values_at(key, ...) ⇒ Array

Returns an array of the values associated with each specified key.

[ GitHub ]

  
# File 'ext/gdbm/gdbm.c', line 510

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;
}