Class: Zlib::GzipReader
- Includes:
- Enumerable
- Defined in:
- ext/zlib/zlib.c,
ext/zlib/zlib.c
Overview
Zlib::GzipReader is the class for reading a gzipped file. GzipReader should be used as an IO, or -IO-like, object.
Zlib::GzipReader.open('hoge.gz') {|gz|
print gz.read
}
File.open('hoge.gz') do |f|
gz = Zlib::GzipReader.new(f)
print gz.read
gz.close
end
Method Catalogue
The following methods in Zlib::GzipReader are just like their counterparts in IO, but they raise Zlib::Error or Zlib::GzipFile::Error exception if an error was found in the gzip file.
-
#each
-
#each_line
-
#each_byte
-
#gets
-
#getc
-
#lineno
-
#lineno=
-
#read
-
#readchar
-
#readline
-
#readlines
-
#ungetc
Be careful of the footer of the gzip file. A gzip file has the checksum of pre-compressed data in its footer. GzipReader checks all uncompressed data against that checksum at the following cases, and if it fails, raises Zlib::GzipFile::NoFooter
, Zlib::GzipFile::CRCError
, or Zlib::GzipFile::LengthError
exception.
-
When an reading request is received beyond the end of file (the end of compressed data). That is, when Zlib::GzipReader#read, Zlib::GzipReader#gets, or some other methods for reading returns nil.
-
When Zlib::GzipFile#close method is called after the object reaches the end of file.
-
When Zlib::GzipReader#unused method is called after the object reaches the end of file.
The rest of the methods are adequately described in their own documentation.
Class Method Summary collapse
-
.open(*args) ⇒ Object
call-seq: Zlib::GzipReader.open(filename) {|gz| … }.
-
.zcat(*args) ⇒ Object
call-seq: Zlib::GzipReader.zcat(io, options = {}, &block) => nil Zlib::GzipReader.zcat(io, options = {}) => string.
Instance Method Summary collapse
-
#each(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#each_byte ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#each_char ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#each_line(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#eof ⇒ Object
Returns
true
orfalse
whether the stream has reached the end. -
#eof? ⇒ Boolean
Returns
true
orfalse
whether the stream has reached the end. -
#external_encoding ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#getbyte ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#getc ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#gets(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#initialize(*args) ⇒ Object
constructor
call-seq: Zlib::GzipReader.new(io, options = {}).
-
#lineno ⇒ Object
The line number of the last row read from this file.
-
#lineno=(lineno) ⇒ Object
Specify line number of the last row read from this file.
-
#pos ⇒ Object
Total number of output bytes output so far.
-
#read(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#readbyte ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#readchar ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#readline(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#readlines(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#readpartial(*args) ⇒ Object
call-seq: gzipreader.readpartial(maxlen [, outbuf]) => string, outbuf.
-
#rewind ⇒ Object
Resets the position of the file pointer to the point created the GzipReader object.
-
#tell ⇒ Object
Total number of output bytes output so far.
-
#ungetbyte(ch) ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#ungetc(s) ⇒ Object
See Zlib::GzipReader documentation for a description.
-
#unused ⇒ Object
Returns the rest of the data which had read for parsing gzip format, or
nil
if the whole gzip file is not parsed yet.
Methods inherited from GzipFile
#close, #closed?, #comment, #crc, #finish, #level, #mtime, #orig_name, #os_code, #sync, #sync=, #to_io, wrap
Constructor Details
#initialize(*args) ⇒ Object
call-seq:
Zlib::GzipReader.new(io, = {})
Creates a GzipReader object associated with io
. The GzipReader object reads gzipped data from io
, and parses/decompresses it. The io
must have a read
method that behaves same as the IO#read.
The options
hash may be used to set the encoding of the data. :external_encoding
, :internal_encoding
and :encoding
may be set as in IO::new.
If the gzip file header is incorrect, raises an Zlib::GzipFile::Error exception.
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# File 'ext/zlib/zlib.c', line 3946
static VALUE
rb_gzreader_initialize(int argc, VALUE *argv, VALUE obj)
{
VALUE io, opt = Qnil;
struct gzfile *gz;
int err;
TypedData_Get_Struct(obj, struct gzfile, &gzfile_data_type, gz);
rb_scan_args(argc, argv, "1:", &io, &opt);
/* this is undocumented feature of zlib */
err = inflateInit2(&gz->z.stream, -MAX_WBITS);
if (err != Z_OK) {
raise_zlib_error(err, gz->z.stream.msg);
}
gz->io = io;
ZSTREAM_READY(&gz->z);
gzfile_read_header(gz, Qnil);
rb_gzfile_ecopts(gz, opt);
if (rb_respond_to(io, id_path)) {
/* File#path may raise IOError in case when a path is unavailable */
rb_rescue2(gzfile_initialize_path_partial, obj, NULL, Qnil, rb_eIOError, (VALUE)0);
}
return obj;
}
|
Class Method Details
.open(*args) ⇒ Object
call-seq: Zlib::GzipReader.open(filename) {|gz| … }
Opens a file specified by filename
as a gzipped file, and returns a GzipReader object associated with that file. Further details of this method are in Zlib::GzipReader.new and ZLib::GzipFile.wrap.
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# File 'ext/zlib/zlib.c', line 3869
static VALUE
rb_gzreader_s_open(int argc, VALUE *argv, VALUE klass)
{
return gzfile_s_open(argc, argv, klass, "rb");
}
|
.zcat(*args) ⇒ Object
call-seq:
Zlib::GzipReader.zcat(io, = {}, &block) => nil
Zlib::GzipReader.zcat(io, = {}) => string
Decompresses all gzip data in the io
, handling multiple gzip streams until the end of the io
. There should not be any non-gzip data after the gzip streams.
If a block is given, it is yielded strings of uncompressed data, and the method returns nil
. If a block is not given, the method returns the concatenation of all uncompressed data in all gzip streams.
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# File 'ext/zlib/zlib.c', line 3891
static VALUE
rb_gzreader_s_zcat(int argc, VALUE *argv, VALUE klass)
{
VALUE io, unused, obj, buf=0, tmpbuf;
long pos;
rb_check_arity(argc, 1, 2);
io = argv[0];
do {
obj = rb_funcallv(klass, rb_intern("new"), argc, argv);
if (rb_block_given_p()) {
rb_gzreader_each(0, 0, obj);
}
else {
if (!buf) {
buf = rb_str_new(0, 0);
}
tmpbuf = gzfile_read_all(get_gzfile(obj));
rb_str_cat(buf, RSTRING_PTR(tmpbuf), RSTRING_LEN(tmpbuf));
}
rb_gzreader_read(0, 0, obj);
pos = NUM2LONG(rb_funcall(io, rb_intern("pos"), 0));
unused = rb_gzreader_unused(obj);
rb_gzfile_finish(obj);
if (!NIL_P(unused)) {
pos -= NUM2LONG(rb_funcall(unused, rb_intern("length"), 0));
rb_funcall(io, rb_intern("pos="), 1, LONG2NUM(pos));
}
} while (pos < NUM2LONG(rb_funcall(io, rb_intern("size"), 0)));
if (rb_block_given_p()) {
return Qnil;
}
return buf;
}
|
Instance Method Details
#each(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4416
static VALUE
rb_gzreader_each(int argc, VALUE *argv, VALUE obj)
{
VALUE str;
RETURN_ENUMERATOR(obj, 0, 0);
while (!NIL_P(str = gzreader_gets(argc, argv, obj))) {
rb_yield(str);
}
return obj;
}
|
#each_byte ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4142
static VALUE
rb_gzreader_each_byte(VALUE obj)
{
VALUE c;
RETURN_ENUMERATOR(obj, 0, 0);
while (!NIL_P(c = rb_gzreader_getbyte(obj))) {
rb_yield(c);
}
return Qnil;
}
|
#each_char ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4124
static VALUE
rb_gzreader_each_char(VALUE obj)
{
VALUE c;
RETURN_ENUMERATOR(obj, 0, 0);
while (!NIL_P(c = rb_gzreader_getc(obj))) {
rb_yield(c);
}
return Qnil;
}
|
#each_line(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4416
static VALUE
rb_gzreader_each(int argc, VALUE *argv, VALUE obj)
{
VALUE str;
RETURN_ENUMERATOR(obj, 0, 0);
while (!NIL_P(str = gzreader_gets(argc, argv, obj))) {
rb_yield(str);
}
return obj;
}
|
#eof ⇒ Object
Returns true
or false
whether the stream has reached the end.
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# File 'ext/zlib/zlib.c', line 3499
static VALUE
rb_gzfile_eof_p(VALUE obj)
{
struct gzfile *gz = get_gzfile(obj);
return GZFILE_IS_FINISHED(gz) ? Qtrue : Qfalse;
}
|
#eof? ⇒ Boolean
Returns true
or false
whether the stream has reached the end.
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# File 'ext/zlib/zlib.c', line 3499
static VALUE
rb_gzfile_eof_p(VALUE obj)
{
struct gzfile *gz = get_gzfile(obj);
return GZFILE_IS_FINISHED(gz) ? Qtrue : Qfalse;
}
|
#external_encoding ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4450
static VALUE
rb_gzreader_external_encoding(VALUE self)
{
return rb_enc_from_encoding(get_gzfile(self)->enc);
}
|
#getbyte ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4090
static VALUE
rb_gzreader_getbyte(VALUE obj)
{
struct gzfile *gz = get_gzfile(obj);
VALUE dst;
dst = gzfile_read(gz, 1);
if (!NIL_P(dst)) {
dst = INT2FIX((unsigned int)(RSTRING_PTR(dst)[0]) & 0xff);
}
return dst;
}
|
#getc ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4061
static VALUE
rb_gzreader_getc(VALUE obj)
{
struct gzfile *gz = get_gzfile(obj);
return gzfile_getc(gz);
}
|
#gets(*args) ⇒ Object
See Zlib::GzipReader documentation for a description. However, note that this method can return nil
even if #eof? returns false, unlike the behavior of File#gets.
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# File 'ext/zlib/zlib.c', line 4384
static VALUE
rb_gzreader_gets(int argc, VALUE *argv, VALUE obj)
{
VALUE dst;
dst = gzreader_gets(argc, argv, obj);
if (!NIL_P(dst)) {
rb_lastline_set(dst);
}
return dst;
}
|
#lineno ⇒ Object
The line number of the last row read from this file.
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# File 'ext/zlib/zlib.c', line 3338
static VALUE
rb_gzfile_lineno(VALUE obj)
{
return INT2NUM(get_gzfile(obj)->lineno);
}
|
#lineno=(lineno) ⇒ Object
Specify line number of the last row read from this file.
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# File 'ext/zlib/zlib.c', line 3349
static VALUE
rb_gzfile_set_lineno(VALUE obj, VALUE lineno)
{
struct gzfile *gz = get_gzfile(obj);
gz->lineno = NUM2INT(lineno);
return lineno;
}
|
#pos ⇒ Object
Total number of output bytes output so far.
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# File 'ext/zlib/zlib.c', line 3557
static VALUE
rb_gzfile_total_out(VALUE obj)
{
struct gzfile *gz = get_gzfile(obj);
uLong total_out = gz->z.stream.total_out;
long buf_filled = ZSTREAM_BUF_FILLED(&gz->z);
if (total_out >= (uLong)buf_filled) {
return rb_uint2inum(total_out - buf_filled);
} else {
return LONG2FIX(-(buf_filled - (long)total_out));
}
}
|
#read(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4007
static VALUE
rb_gzreader_read(int argc, VALUE *argv, VALUE obj)
{
struct gzfile *gz = get_gzfile(obj);
VALUE vlen;
long len;
rb_scan_args(argc, argv, "01", &vlen);
if (NIL_P(vlen)) {
return gzfile_read_all(gz);
}
len = NUM2INT(vlen);
if (len < 0) {
rb_raise(rb_eArgError, "negative length %ld given", len);
}
return gzfile_read(gz, len);
}
|
#readbyte ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4108
static VALUE
rb_gzreader_readbyte(VALUE obj)
{
VALUE dst;
dst = rb_gzreader_getbyte(obj);
if (NIL_P(dst)) {
rb_raise(rb_eEOFError, "end of file reached");
}
return dst;
}
|
#readchar ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4074
static VALUE
rb_gzreader_readchar(VALUE obj)
{
VALUE dst;
dst = rb_gzreader_getc(obj);
if (NIL_P(dst)) {
rb_raise(rb_eEOFError, "end of file reached");
}
return dst;
}
|
#readline(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4400
static VALUE
rb_gzreader_readline(int argc, VALUE *argv, VALUE obj)
{
VALUE dst;
dst = rb_gzreader_gets(argc, argv, obj);
if (NIL_P(dst)) {
rb_raise(rb_eEOFError, "end of file reached");
}
return dst;
}
|
#readlines(*args) ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4434
static VALUE
rb_gzreader_readlines(int argc, VALUE *argv, VALUE obj)
{
VALUE str, dst;
dst = rb_ary_new();
while (!NIL_P(str = gzreader_gets(argc, argv, obj))) {
rb_ary_push(dst, str);
}
return dst;
}
|
#readpartial(*args) ⇒ Object
call-seq:
gzipreader.readpartial(maxlen [, outbuf]) => string, outbuf
Reads at most <i>maxlen</i> bytes from the gziped stream but
it blocks only if <em>gzipreader</em> has no data immediately available.
If the optional <i>outbuf</i> argument is present,
it must reference a String, which will receive the data.
It raises <code>EOFError</code> on end of file.
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# File 'ext/zlib/zlib.c', line 4038
static VALUE
rb_gzreader_readpartial(int argc, VALUE *argv, VALUE obj)
{
struct gzfile *gz = get_gzfile(obj);
VALUE vlen, outbuf;
long len;
rb_scan_args(argc, argv, "11", &vlen, &outbuf);
len = NUM2INT(vlen);
if (len < 0) {
rb_raise(rb_eArgError, "negative length %ld given", len);
}
if (!NIL_P(outbuf))
Check_Type(outbuf, T_STRING);
return gzfile_readpartial(gz, len, outbuf);
}
|
#rewind ⇒ Object
Resets the position of the file pointer to the point created the GzipReader object. The associated IO object needs to respond to the seek
method.
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# File 'ext/zlib/zlib.c', line 3980
static VALUE
rb_gzreader_rewind(VALUE obj)
{
struct gzfile *gz = get_gzfile(obj);
gzfile_reader_rewind(gz);
return INT2FIX(0);
}
|
#tell ⇒ Object
Total number of output bytes output so far.
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# File 'ext/zlib/zlib.c', line 3557
static VALUE
rb_gzfile_total_out(VALUE obj)
{
struct gzfile *gz = get_gzfile(obj);
uLong total_out = gz->z.stream.total_out;
long buf_filled = ZSTREAM_BUF_FILLED(&gz->z);
if (total_out >= (uLong)buf_filled) {
return rb_uint2inum(total_out - buf_filled);
} else {
return LONG2FIX(-(buf_filled - (long)total_out));
}
}
|
#ungetbyte(ch) ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4182
static VALUE
rb_gzreader_ungetbyte(VALUE obj, VALUE ch)
{
struct gzfile *gz = get_gzfile(obj);
gzfile_ungetbyte(gz, NUM2CHR(ch));
return Qnil;
}
|
#ungetc(s) ⇒ Object
See Zlib::GzipReader documentation for a description.
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# File 'ext/zlib/zlib.c', line 4160
static VALUE
rb_gzreader_ungetc(VALUE obj, VALUE s)
{
struct gzfile *gz;
if (FIXNUM_P(s))
return rb_gzreader_ungetbyte(obj, s);
gz = get_gzfile(obj);
StringValue(s);
if (gz->enc2 && gz->enc2 != rb_ascii8bit_encoding()) {
s = rb_str_conv_enc(s, rb_enc_get(s), gz->enc2);
}
gzfile_ungets(gz, (const Bytef*)RSTRING_PTR(s), RSTRING_LEN(s));
RB_GC_GUARD(s);
return Qnil;
}
|
#unused ⇒ Object
Returns the rest of the data which had read for parsing gzip format, or nil
if the whole gzip file is not parsed yet.
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# File 'ext/zlib/zlib.c', line 3994
static VALUE
rb_gzreader_unused(VALUE obj)
{
struct gzfile *gz;
TypedData_Get_Struct(obj, struct gzfile, &gzfile_data_type, gz);
return gzfile_reader_get_unused(gz);
}
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