Class: Zstdlib::ZStream

Inherits:
Object
  • Object
show all
Defined in:
ext/zstdlib/ruby/zlib-2.7/zstdlib.c,
ext/zstdlib/ruby/zlib-2.7/zstdlib.c,
ext/zstdlib/ruby/zlib-2.6/zstdlib.c,
ext/zstdlib/ruby/zlib-2.6/zstdlib.c,
ext/zstdlib/ruby/zlib-2.5/zstdlib.c,
ext/zstdlib/ruby/zlib-2.5/zstdlib.c,
ext/zstdlib/ruby/zlib-2.4/zstdlib.c,
ext/zstdlib/ruby/zlib-2.4/zstdlib.c,
ext/zstdlib/ruby/zlib-2.3/zstdlib.c,
ext/zstdlib/ruby/zlib-2.3/zstdlib.c,
ext/zstdlib/ruby/zlib-2.2/zstdlib.c,
ext/zstdlib/ruby/zlib-2.2/zstdlib.c

Overview

Zstdlib::ZStream is the abstract class for the stream which handles the compressed data. The operations are defined in the subclasses: Zstdlib::Deflate for compression, and Zstdlib::Inflate for decompression.

An instance of Zstdlib::ZStream has one stream (struct zstream in the source) and two variable-length buffers which associated to the input (next_in) of the stream and the output (next_out) of the stream. In this document, "input buffer" means the buffer for input, and "output buffer" means the buffer for output.

Data input into an instance of Zstdlib::ZStream are temporally stored into the end of input buffer, and then data in input buffer are processed from the beginning of the buffer until no more output from the stream is produced (i.e. until avail_out > 0 after processing). During processing, output buffer is allocated and expanded automatically to hold all output data.

Some particular instance methods consume the data in output buffer and return them as a String.

Here is an ascii art for describing above:

+================ an instance of Zstdlib::ZStream ================+ || || || +--------+ +-------+ +--------+ || || +--| output |<---------|zstream|<---------| input |<--+ || || | | buffer | next_out+-------+next_in | buffer | | || || | +--------+ +--------+ | || || | | || +===|======================================================|===+ | | v | "output data" "input data"

If an error occurs during processing input buffer, an exception which is a subclass of Zstdlib::Error is raised. At that time, both input and output buffer keep their conditions at the time when the error occurs.

== Method Catalogue

Many of the methods in this class are fairly low-level and unlikely to be of interest to users. In fact, users are unlikely to use this class directly; rather they will be interested in Zstdlib::Inflate and Zstdlib::Deflate.

The higher level methods are listed below.

  • #total_in
  • #total_out
  • #data_type
  • #adler
  • #reset
  • #finish
  • #finished?
  • #close
  • #closed?

Direct Known Subclasses

Deflate, Inflate

Instance Method Summary collapse

Instance Method Details

#adler ⇒ Object

Returns the adler-32 checksum.



1438
1439
1440
1441
1442
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1438

static VALUE
rb_zstream_adler(VALUE obj)
{
    return rb_uint2inum(get_zstream(obj)->stream.adler);
}

#avail_in ⇒ Object

Returns bytes of data in the input buffer. Normally, returns 0.



1398
1399
1400
1401
1402
1403
1404
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1398

static VALUE
rb_zstream_avail_in(VALUE obj)
{
    struct zstream *z;
    TypedData_Get_Struct(obj, struct zstream, &zstream_data_type, z);
    return INT2FIX(NIL_P(z->input) ? 0 : (int)(RSTRING_LEN(z->input)));
}

#avail_out ⇒ Object

Returns number of bytes of free spaces in output buffer. Because the free space is allocated automatically, this method returns 0 normally.



1372
1373
1374
1375
1376
1377
1378
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1372

static VALUE
rb_zstream_avail_out(VALUE obj)
{
    struct zstream *z;
    TypedData_Get_Struct(obj, struct zstream, &zstream_data_type, z);
    return rb_uint2inum(z->stream.avail_out);
}

#avail_out=(size) ⇒ Object

Allocates +size+ bytes of free space in the output buffer. If there are more than +size+ bytes already in the buffer, the buffer is truncated. Because free space is allocated automatically, you usually don't need to use this method.



1386
1387
1388
1389
1390
1391
1392
1393
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1386

static VALUE
rb_zstream_set_avail_out(VALUE obj, VALUE size)
{
    struct zstream *z = get_zstream(obj);

    zstream_expand_buffer_into(z, FIX2INT(size));
    return size;
}

#close ⇒ Object

Closes the stream. All operations on the closed stream will raise an exception.



1296
1297
1298
1299
1300
1301
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1296

static VALUE
rb_zstream_end(VALUE obj)
{
    zstream_end(get_zstream(obj));
    return Qnil;
}

#closed? ⇒ Boolean

Returns true if the stream is closed.



1456
1457
1458
1459
1460
1461
1462
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1456

static VALUE
rb_zstream_closed_p(VALUE obj)
{
    struct zstream *z;
    TypedData_Get_Struct(obj, struct zstream, &zstream_data_type, z);
    return ZSTREAM_IS_READY(z) ? Qfalse : Qtrue;
}

#data_type ⇒ Object

Guesses the type of the data which have been inputed into the stream. The returned value is either BINARY, ASCII, or UNKNOWN.



1429
1430
1431
1432
1433
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1429

static VALUE
rb_zstream_data_type(VALUE obj)
{
    return INT2FIX(get_zstream(obj)->stream.data_type);
}

#end ⇒ Object

Closes the stream. All operations on the closed stream will raise an exception.



1296
1297
1298
1299
1300
1301
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1296

static VALUE
rb_zstream_end(VALUE obj)
{
    zstream_end(get_zstream(obj));
    return Qnil;
}

#ended? ⇒ Boolean

Returns true if the stream is closed.



1456
1457
1458
1459
1460
1461
1462
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1456

static VALUE
rb_zstream_closed_p(VALUE obj)
{
    struct zstream *z;
    TypedData_Get_Struct(obj, struct zstream, &zstream_data_type, z);
    return ZSTREAM_IS_READY(z) ? Qfalse : Qtrue;
}

#finish ⇒ String #finish {|chunk| ... } ⇒ nil

Finishes the stream and flushes output buffer. If a block is given each chunk is yielded to the block until the input buffer has been flushed to the output buffer.

Overloads:

  • #finish {|chunk| ... } ⇒ nil

    Yields:

    • (chunk) 


1323
1324
1325
1326
1327
1328
1329
1330
1331
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1323

static VALUE
rb_zstream_finish(VALUE obj)
{
    struct zstream *z = get_zstream(obj);

    zstream_run(z, (Bytef*)"", 0, Z_FINISH);

    return zstream_detach_buffer(z);
}

#finished? ⇒ Boolean

Returns true if the stream is finished.



1447
1448
1449
1450
1451
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1447

static VALUE
rb_zstream_finished_p(VALUE obj)
{
    return ZSTREAM_IS_FINISHED(get_zstream(obj)) ? Qtrue : Qfalse;
}

#flush_next_in ⇒ Object 



1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1338

static VALUE
rb_zstream_flush_next_in(VALUE obj)
{
    struct zstream *z;
    VALUE dst;

    TypedData_Get_Struct(obj, struct zstream, &zstream_data_type, z);
    dst = zstream_detach_input(z);
    return dst;
}

#flush_next_out ⇒ String #flush_next_out {|chunk| ... } ⇒ nil

Flushes output buffer and returns all data in that buffer. If a block is given each chunk is yielded to the block until the current output buffer has been flushed.

Overloads:

  • #flush_next_out {|chunk| ... } ⇒ nil

    Yields:

    • (chunk) 


1358
1359
1360
1361
1362
1363
1364
1365
1366
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1358

static VALUE
rb_zstream_flush_next_out(VALUE obj)
{
    struct zstream *z;

    TypedData_Get_Struct(obj, struct zstream, &zstream_data_type, z);

    return zstream_detach_buffer(z);
}

#reset ⇒ Object

Resets and initializes the stream. All data in both input and output buffer are discarded.



1307
1308
1309
1310
1311
1312
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1307

static VALUE
rb_zstream_reset(VALUE obj)
{
    zstream_reset(get_zstream(obj));
    return Qnil;
}

#stream_end? ⇒ Boolean

Returns true if the stream is finished.



1447
1448
1449
1450
1451
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1447

static VALUE
rb_zstream_finished_p(VALUE obj)
{
    return ZSTREAM_IS_FINISHED(get_zstream(obj)) ? Qtrue : Qfalse;
}

#total_in ⇒ Object

Returns the total bytes of the input data to the stream. FIXME



1409
1410
1411
1412
1413
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1409

static VALUE
rb_zstream_total_in(VALUE obj)
{
    return rb_uint2inum(get_zstream(obj)->stream.total_in);
}

#total_out ⇒ Object

Returns the total bytes of the output data from the stream. FIXME



1418
1419
1420
1421
1422
 
# File 'ext/zstdlib/ruby/zlib-2.7/zstdlib.c', line 1418

static VALUE
rb_zstream_total_out(VALUE obj)
{
    return rb_uint2inum(get_zstream(obj)->stream.total_out);
}