Class: Zlib::GzipWriter

Inherits:
GzipFile show all
Defined in:
ext/rubysl/zlib/zlib.c,
ext/rubysl/zlib/zlib.c

Overview

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::GzipWriter#close etc. Otherwise, GzipWriter will be not able to write the gzip footer and will generate a broken gzip file.

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from GzipFile

#close, #closed?, #comment, #crc, #finish, #level, #mtime, #orig_name, #os_code, #sync, #sync=, #to_io, wrap

Constructor Details

#Zlib::GzipWriter.new(io, level, strategy) ⇒ Object

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. At least, io must respond to the write method that behaves same as write method in IO class.



3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
 
# File 'ext/rubysl/zlib/zlib.c', line 3216

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);
    Data_Get_Struct(obj, struct gzfile, 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;
}

Class Method Details

.Zlib::GzipWriter.open(filename, level = nil, strategy = nil) {|gz| ... } ⇒ Object

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 Zlib::GzipWriter.new and Zlib::GzipFile.wrap.

Yields:

  • (gz) 


3202
3203
3204
3205
3206
 
# File 'ext/rubysl/zlib/zlib.c', line 3202

static VALUE
rb_gzwriter_s_open(int argc, VALUE *argv, VALUE klass)
{
    return gzfile_s_open(argc, argv, klass, "wb");
}

Instance Method Details

#<< ⇒ Object

Same as IO.

#comment=(str) ⇒ Object

Specify the comment (str) in the gzip header.



2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
 
# File 'ext/rubysl/zlib/zlib.c', line 2983

static VALUE
rb_gzfile_set_comment(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->comment = s;
    return str;
}

#flush(flush = nil) ⇒ Object

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.



3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
 
# File 'ext/rubysl/zlib/zlib.c', line 3257

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;
}

#mtime=(mtime) ⇒ Object

Specify the modification time (mtime) in the gzip header. Using a Fixnum or Integer



2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
 
# File 'ext/rubysl/zlib/zlib.c', line 2934

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");
    }

    if (FIXNUM_P(mtime)) {
        gz->mtime = FIX2INT(mtime);
    }
    else {
        val = rb_Integer(mtime);
        gz->mtime = FIXNUM_P(val) ? FIX2UINT(val) : rb_big2ulong(val);
    }
    return mtime;
}

#orig_name=(str) ⇒ Object

Specify the original name (str) in the gzip header.



2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
 
# File 'ext/rubysl/zlib/zlib.c', line 2959

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;
}

#pos ⇒ Object

Total number of input bytes read so far.



3103
3104
3105
3106
3107
 
# File 'ext/rubysl/zlib/zlib.c', line 3103

static VALUE
rb_gzfile_total_in(VALUE obj)
{
    return rb_uint2inum(get_gzfile(obj)->z.stream.total_in);
}

#print ⇒ Object

Same as IO.

#printf ⇒ Object

Same as IO.

#putc(ch) ⇒ Object

Same as IO.



3298
3299
3300
3301
3302
3303
3304
3305
3306
 
# File 'ext/rubysl/zlib/zlib.c', line 3298

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;
}

#puts ⇒ Object

Same as IO.

#tell ⇒ Object

Total number of input bytes read so far.



3103
3104
3105
3106
3107
 
# File 'ext/rubysl/zlib/zlib.c', line 3103

static VALUE
rb_gzfile_total_in(VALUE obj)
{
    return rb_uint2inum(get_gzfile(obj)->z.stream.total_in);
}

#write(str) ⇒ Object

Same as IO.



3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
 
# File 'ext/rubysl/zlib/zlib.c', line 3281

static VALUE
rb_gzwriter_write(VALUE obj, VALUE str)
{
    struct gzfile *gz = get_gzfile(obj);

    if (TYPE(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));
    return INT2FIX(RSTRING_LEN(str));
}