Class: Libdeflate::Decompressor

Inherits:
Object
  • Object
show all
Defined in:
ext/libdeflate/libdeflate_ext.c

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Object

Returns a new Libdeflate::Decompressor object.

Libdeflate::Decompressor.new #=> #<Libdeflate::Decompressor:0x007fde591a6500>



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# File 'ext/libdeflate/libdeflate_ext.c', line 254

static VALUE
rb_decompressor_initialize(VALUE self)
{
    struct libdeflate_decompressor *d = libdeflate_alloc_decompressor();
    if (d == NULL) {
        rb_raise(rb_eLibdefalteError, "libdeflate_alloc_decompressor");
    }

    DATA_PTR(self) = d;

    return self;
}

Instance Method Details

#decompress(str, format = nil, outbuf = nil) ⇒ String

Decompresses the given string compressed in format. Valid values of format are DEFLATE (default), ZLIB and GZIP. If outbuf is given, the resulting uncompressed data will be written to it.

decompressor.decompress("\x01\x03\x00\xFC\xFFfoo")                                     #=> "foo"
decompressor.decompress("x\x9C\x01\x03\x00\xFC\xFFfoo\x02\x82\x01E", Libdeflate::ZLIB) #=> "foo"

outbuf = 'bar'
decompressor.decompress("\x01\x03\x00\xFC\xFFfoo", nil, outbuf) #=> "foo"
outbuf                                                          #=> "foo"

Returns:

  • (String) 


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# File 'ext/libdeflate/libdeflate_ext.c', line 303

static VALUE
rb_compressor_decompress(int argc, VALUE *argv, VALUE self)
{
    struct libdeflate_decompressor *d = check_decompressor(self);
    VALUE str, format, outbuf;
    enum libdeflate_result (*decompress_func)(struct libdeflate_decompressor *, const void *, size_t, void *, size_t, size_t *);
    size_t actual_out_nbytes_ret;
    enum libdeflate_result decompress_result;

    rb_scan_args(argc, argv, "12", &str, &format, &outbuf);

    StringValue(str);

    switch (NIL_P(format) ? FORMAT_DEFLATE : FIX2INT(format)) {
        case FORMAT_DEFLATE:
            decompress_func = &libdeflate_deflate_decompress;
            break;
        case FORMAT_ZLIB:
            decompress_func = &libdeflate_zlib_decompress;
            break;
        case FORMAT_GZIP:
            decompress_func = &libdeflate_gzip_decompress;
            break;
        default:
            rb_raise(rb_eLibdefalteError, "unknown compressed data format: %d", FIX2INT(format));
    }

    if (NIL_P(outbuf)) {
        outbuf = rb_str_buf_new(next_power_of_two(RSTRING_LEN(str)) << 4);
    } else {
        StringValue(outbuf);
        rb_str_modify(outbuf);
    }

    for (;;) {
        decompress_result = decompress_func(d,
                                            RSTRING_PTR(str),
                                            RSTRING_LEN(str),
                                            RSTRING_PTR(outbuf),
                                            rb_str_capacity(outbuf),
                                            &actual_out_nbytes_ret);

        if (decompress_result != LIBDEFLATE_INSUFFICIENT_SPACE) {
            break;
        }

        rb_str_modify_expand(outbuf, (rb_str_capacity(outbuf) << 1) - RSTRING_LEN(outbuf));
    }

    if (decompress_result == LIBDEFLATE_BAD_DATA) {
        rb_raise(rb_eBadDataError, "failed to decompress data");
    } else if (decompress_result != LIBDEFLATE_SUCCESS) {
        rb_raise(rb_eLibdefalteError, "failed to decompress data");
    }

    rb_str_set_len(outbuf, actual_out_nbytes_ret);
    OBJ_INFECT(outbuf, str);

    return outbuf;
}