Zlib::GzipWriter is a class for writing gzipped files. GzipWriter should be used with an instance of IO, or IO-like, object.
Following two example generate the same result.
Zlib::GzipWriter.open('hoge.gz') do |gz| gz.write 'jugemu jugemu gokou no surikire...' end File.open('hoge.gz', 'w') do |f| gz = Zlib::GzipWriter.new(f) gz.write 'jugemu jugemu gokou no surikire...' gz.close end
To make like gzip(1) does, run following:
orig = 'hoge.txt' Zlib::GzipWriter.open('hoge.gz') do |gz| gz.mtime = File.mtime(orig) gz.orig_name = orig gz.write IO.binread(orig) end
NOTE: Due to the limitation of Ruby's finalizer, you must explicitly close GzipWriter objects by Zlib::GzipFile#close etc. Otherwise, GzipWriter will be not able to write the gzip footer and will generate a broken gzip file.
Creates a GzipWriter object associated with
io
. level
and strategy
should be the
same as the arguments of Zlib::Deflate.new. The GzipWriter object writes gzipped data to
io
. io
must respond to the write
method that behaves the same as IO#write.
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.
static VALUE rb_gzwriter_initialize(int argc, VALUE *argv, VALUE obj) { struct gzfile *gz; VALUE io, level, strategy, opt = Qnil; int err; if (argc > 1) { opt = rb_check_convert_type(argv[argc-1], T_HASH, "Hash", "to_hash"); if (!NIL_P(opt)) argc--; } rb_scan_args(argc, argv, "12", &io, &level, &strategy); TypedData_Get_Struct(obj, struct gzfile, &gzfile_data_type, gz); /* this is undocumented feature of zlib */ gz->level = ARG_LEVEL(level); err = deflateInit2(&gz->z.stream, gz->level, Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, ARG_STRATEGY(strategy)); if (err != Z_OK) { raise_zlib_error(err, gz->z.stream.msg); } gz->io = io; ZSTREAM_READY(&gz->z); rb_gzfile_ecopts(gz, opt); if (rb_respond_to(io, id_path)) { gz->path = rb_funcall(gz->io, id_path, 0); rb_define_singleton_method(obj, "path", rb_gzfile_path, 0); } return obj; }
Opens a file specified by filename
for writing gzip compressed
data, and returns a GzipWriter object
associated with that file. Further details of this method are found in ::new and Zlib::GzipFile.wrap.
static VALUE rb_gzwriter_s_open(int argc, VALUE *argv, VALUE klass) { return gzfile_s_open(argc, argv, klass, "wb"); }
Document-method: << Same as IO.
#define rb_gzwriter_addstr rb_io_addstr
Flushes all the internal buffers of the GzipWriter object. The meaning of
flush
is same as in Zlib::Deflate#deflate.
Zlib::SYNC_FLUSH
is used if flush
is omitted. It
is no use giving flush Zlib::NO_FLUSH
.
static VALUE rb_gzwriter_flush(int argc, VALUE *argv, VALUE obj) { struct gzfile *gz = get_gzfile(obj); VALUE v_flush; int flush; rb_scan_args(argc, argv, "01", &v_flush); flush = FIXNUMARG(v_flush, Z_SYNC_FLUSH); if (flush != Z_NO_FLUSH) { /* prevent Z_BUF_ERROR */ zstream_run(&gz->z, (Bytef*)"", 0, flush); } gzfile_write_raw(gz); if (rb_respond_to(gz->io, id_flush)) { rb_funcall(gz->io, id_flush, 0); } return obj; }
Specify the modification time (mtime
) in the gzip header.
Using an Integer.
Setting the mtime in the gzip header does not effect the mtime of the file generated. Different utilities that expand the gzipped files may use the mtime header. For example the gunzip utility can use the `-N` flag which will set the resultant file's mtime to the value in the header. By default many tools will set the mtime of the expanded file to the mtime of the gzipped file, not the mtime in the header.
If you do not set an mtime, the default value will be the time when compression started. Setting a value of 0 indicates no time stamp is available.
static VALUE rb_gzfile_set_mtime(VALUE obj, VALUE mtime) { struct gzfile *gz = get_gzfile(obj); VALUE val; if (gz->z.flags & GZFILE_FLAG_HEADER_FINISHED) { rb_raise(cGzError, "header is already written"); } val = rb_Integer(mtime); gz->mtime = NUM2UINT(val); gz->z.flags |= GZFILE_FLAG_MTIME_IS_SET; return mtime; }
Specify the original name (str
) in the gzip header.
static VALUE rb_gzfile_set_orig_name(VALUE obj, VALUE str) { struct gzfile *gz = get_gzfile(obj); VALUE s; char *p; if (gz->z.flags & GZFILE_FLAG_HEADER_FINISHED) { rb_raise(cGzError, "header is already written"); } s = rb_str_dup(rb_str_to_str(str)); p = memchr(RSTRING_PTR(s), '\0', RSTRING_LEN(s)); if (p) { rb_str_resize(s, p - RSTRING_PTR(s)); } gz->orig_name = s; return str; }
Total number of input bytes read so far.
static VALUE rb_gzfile_total_in(VALUE obj) { return rb_uint2inum(get_gzfile(obj)->z.stream.total_in); }
Same as IO.
static VALUE rb_gzwriter_putc(VALUE obj, VALUE ch) { struct gzfile *gz = get_gzfile(obj); char c = NUM2CHR(ch); gzfile_write(gz, (Bytef*)&c, 1); return ch; }
Total number of input bytes read so far.
static VALUE rb_gzfile_total_in(VALUE obj) { return rb_uint2inum(get_gzfile(obj)->z.stream.total_in); }
Same as IO.
static VALUE rb_gzwriter_write(int argc, VALUE *argv, VALUE obj) { struct gzfile *gz = get_gzfile(obj); size_t total = 0; while (argc-- > 0) { VALUE str = *argv++; if (!RB_TYPE_P(str, T_STRING)) str = rb_obj_as_string(str); if (gz->enc2 && gz->enc2 != rb_ascii8bit_encoding()) { str = rb_str_conv_enc(str, rb_enc_get(str), gz->enc2); } gzfile_write(gz, (Bytef*)RSTRING_PTR(str), RSTRING_LEN(str)); total += RSTRING_LEN(str); RB_GC_GUARD(str); } return SIZET2NUM(total); }
Specify the comment (
str
) in the gzip header.