Class: Zlib::ZStream
- Inherits:
-
Object
- Object
- Zlib::ZStream
- Defined in:
- ext/zlib/zlib.c,
ext/zlib/zlib.c
Overview
Zlib::ZStream is the abstract class for the stream which handles the compressed data. The operations are defined in the subclasses: Zlib::Deflate for compression, and Zlib::Inflate for decompression.
An instance of Zlib::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 Zlib::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 Zlib::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 Zlib::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 Zlib::Inflate and Zlib::Deflate.
The higher level methods are listed below.
-
#total_in
-
#total_out
-
#data_type
-
#adler
-
#reset
-
#finish
-
#finished?
-
#close
-
#closed?
Instance Method Summary collapse
-
#adler ⇒ Object
Returns the adler-32 checksum.
-
#avail_in ⇒ Object
Returns bytes of data in the input buffer.
-
#avail_out ⇒ Object
Returns number of bytes of free spaces in output buffer.
-
#avail_out=(size) ⇒ Object
Allocates
size
bytes of free space in the output buffer. -
#close ⇒ Object
Closes the stream.
-
#closed? ⇒ Boolean
Returns true if the stream is closed.
-
#data_type ⇒ Object
Guesses the type of the data which have been inputed into the stream.
-
#end ⇒ Object
Closes the stream.
-
#ended? ⇒ Boolean
Returns true if the stream is closed.
-
#finish ⇒ Object
Finishes the stream and flushes output buffer.
-
#finished? ⇒ Boolean
Returns true if the stream is finished.
- #flush_next_in ⇒ Object
-
#flush_next_out ⇒ Object
Flushes output buffer and returns all data in that buffer.
-
#reset ⇒ Object
Resets and initializes the stream.
-
#stream_end? ⇒ Boolean
Returns true if the stream is finished.
-
#total_in ⇒ Object
Returns the total bytes of the input data to the stream.
-
#total_out ⇒ Object
Returns the total bytes of the output data from the stream.
Instance Method Details
#adler ⇒ Object
Returns the adler-32 checksum.
1412 1413 1414 1415 1416 |
# File 'ext/zlib/zlib.c', line 1412
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.
1372 1373 1374 1375 1376 1377 1378 |
# File 'ext/zlib/zlib.c', line 1372
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.
1346 1347 1348 1349 1350 1351 1352 |
# File 'ext/zlib/zlib.c', line 1346
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.
1360 1361 1362 1363 1364 1365 1366 1367 |
# File 'ext/zlib/zlib.c', line 1360
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.
1269 1270 1271 1272 1273 1274 |
# File 'ext/zlib/zlib.c', line 1269
static VALUE
rb_zstream_end(VALUE obj)
{
zstream_end(get_zstream(obj));
return Qnil;
}
|
#closed? ⇒ Boolean
Returns true if the stream is closed.
1430 1431 1432 1433 1434 1435 1436 |
# File 'ext/zlib/zlib.c', line 1430
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
.
1403 1404 1405 1406 1407 |
# File 'ext/zlib/zlib.c', line 1403
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.
1269 1270 1271 1272 1273 1274 |
# File 'ext/zlib/zlib.c', line 1269
static VALUE
rb_zstream_end(VALUE obj)
{
zstream_end(get_zstream(obj));
return Qnil;
}
|
#ended? ⇒ Boolean
Returns true if the stream is closed.
1430 1431 1432 1433 1434 1435 1436 |
# File 'ext/zlib/zlib.c', line 1430
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.
1296 1297 1298 1299 1300 1301 1302 1303 1304 |
# File 'ext/zlib/zlib.c', line 1296
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.
1421 1422 1423 1424 1425 |
# File 'ext/zlib/zlib.c', line 1421
static VALUE
rb_zstream_finished_p(VALUE obj)
{
return ZSTREAM_IS_FINISHED(get_zstream(obj)) ? Qtrue : Qfalse;
}
|
#flush_next_in ⇒ Object
1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 |
# File 'ext/zlib/zlib.c', line 1311
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);
OBJ_INFECT(dst, obj);
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.
1332 1333 1334 1335 1336 1337 1338 1339 1340 |
# File 'ext/zlib/zlib.c', line 1332
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.
1280 1281 1282 1283 1284 1285 |
# File 'ext/zlib/zlib.c', line 1280
static VALUE
rb_zstream_reset(VALUE obj)
{
zstream_reset(get_zstream(obj));
return Qnil;
}
|
#stream_end? ⇒ Boolean
Returns true if the stream is finished.
1421 1422 1423 1424 1425 |
# File 'ext/zlib/zlib.c', line 1421
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
1383 1384 1385 1386 1387 |
# File 'ext/zlib/zlib.c', line 1383
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
1392 1393 1394 1395 1396 |
# File 'ext/zlib/zlib.c', line 1392
static VALUE
rb_zstream_total_out(VALUE obj)
{
return rb_uint2inum(get_zstream(obj)->stream.total_out);
}
|