Module: Zstd

Defined in:
lib/zstd-ruby.rb,
lib/zstd-ruby/version.rb,
lib/zstd-ruby/stream_reader.rb,
lib/zstd-ruby/stream_writer.rb,
ext/zstdruby/main.c

Defined Under Namespace

Classes: CDict, DDict, StreamReader, StreamWriter, StreamingCompress, StreamingDecompress

Constant Summary collapse

VERSION = 
"2.0.4"

Class Method Summary collapse

Class Method Details

.compress(*args) ⇒ Object 



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# File 'ext/zstdruby/zstdruby.c', line 11

static VALUE rb_compress(int argc, VALUE *argv, VALUE self)
{
  VALUE input_value;
  VALUE kwargs;
  rb_scan_args(argc, argv, "10:", &input_value, &kwargs);

  StringValue(input_value);

  ZSTD_CCtx* const ctx = ZSTD_createCCtx();
  if (ctx == NULL) {
    rb_raise(rb_eRuntimeError, "%s", "ZSTD_createCCtx error");
  }

  set_compress_params(ctx, kwargs);

  char* input_data = RSTRING_PTR(input_value);
  size_t input_size = RSTRING_LEN(input_value);

  size_t max_compressed_size = ZSTD_compressBound(input_size);
  VALUE output = rb_str_new(NULL, max_compressed_size);
  char* output_data = RSTRING_PTR(output);

  size_t const ret = zstd_compress(ctx, output_data, max_compressed_size, input_data, input_size, false);
  ZSTD_freeCCtx(ctx);
  if (ZSTD_isError(ret)) {
    rb_raise(rb_eRuntimeError, "compress error error code: %s", ZSTD_getErrorName(ret));
  }
  rb_str_resize(output, ret);

  return output;
}

.decompress(*args) ⇒ Object 



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# File 'ext/zstdruby/zstdruby.c', line 74

static VALUE rb_decompress(int argc, VALUE *argv, VALUE self)
{
  VALUE input_value, kwargs;
  rb_scan_args(argc, argv, "10:", &input_value, &kwargs);
  StringValue(input_value);

  size_t in_size = RSTRING_LEN(input_value);
  const unsigned char *in_r = (const unsigned char *)RSTRING_PTR(input_value);
  unsigned char *in = ALLOC_N(unsigned char, in_size);
  memcpy(in, in_r, in_size);

  size_t off = 0;
  const uint32_t ZSTD_MAGIC = 0xFD2FB528U;
  const uint32_t SKIP_LO    = 0x184D2A50U; /* ...5F */

  while (off + 4 <= in_size) {
    uint32_t magic = (uint32_t)in[off]
                   | ((uint32_t)in[off+1] << 8)
                   | ((uint32_t)in[off+2] << 16)
                   | ((uint32_t)in[off+3] << 24);

    if ((magic & 0xFFFFFFF0U) == (SKIP_LO & 0xFFFFFFF0U)) {
      if (off + 8 > in_size) break;
      uint32_t skipLen = (uint32_t)in[off+4]
                       | ((uint32_t)in[off+5] << 8)
                       | ((uint32_t)in[off+6] << 16)
                       | ((uint32_t)in[off+7] << 24);
      size_t adv = (size_t)8 + (size_t)skipLen;
      if (off + adv > in_size) break;
      off += adv;
      continue;
    }

    if (magic == ZSTD_MAGIC) {
      ZSTD_DCtx *dctx = ZSTD_createDCtx();
      if (!dctx) {
        xfree(in);
        rb_raise(rb_eRuntimeError, "ZSTD_createDCtx failed");
      }

      VALUE out = decode_one_frame(dctx, in + off, in_size - off, kwargs);

      ZSTD_freeDCtx(dctx);
      xfree(in);
      RB_GC_GUARD(input_value);
      return out;
    }

    off += 1;
  }

  xfree(in);
  RB_GC_GUARD(input_value);
  rb_raise(rb_eRuntimeError, "not a zstd frame (magic not found)");
}

.read_skippable_frame(input_value) ⇒ Object 



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# File 'ext/zstdruby/skippable_frame.c', line 37

static VALUE rb_read_skippable_frame(VALUE self, VALUE input_value)
{
  char* input_data = RSTRING_PTR(input_value);
  size_t input_size = RSTRING_LEN(input_value);

  if (ZSTD_isSkippableFrame(input_data, input_size) == 0) {
    return Qnil;
  }
  // ref https://github.com/facebook/zstd/blob/321490cd5b9863433b3d44816d04012874e5ecdb/tests/fuzzer.c#L2096
  size_t const skipLen = 129 * 1024;
  VALUE output = rb_str_new(NULL, skipLen);
  char* output_data = RSTRING_PTR(output);
  unsigned readMagic;
  size_t output_size = ZSTD_readSkippableFrame((void*)output_data, skipLen, &readMagic, (const void*)input_data, input_size);
  if (ZSTD_isError(output_size)) {
    rb_raise(rb_eRuntimeError, "%s: %s", "read skippable frame failed", ZSTD_getErrorName(output_size));
  }
  rb_str_resize(output, output_size);
  return output;
}

.write_skippable_frame(*args) ⇒ Object 



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# File 'ext/zstdruby/skippable_frame.c', line 5

static VALUE rb_write_skippable_frame(int argc, VALUE *argv, VALUE self)
{
  VALUE input_value;
  VALUE skip_value;
  VALUE kwargs;
  rb_scan_args(argc, argv, "2:", &input_value, &skip_value, &kwargs);

  ID kwargs_keys[1];
  kwargs_keys[0] = rb_intern("magic_variant");
  VALUE kwargs_values[1];
  rb_get_kwargs(kwargs, kwargs_keys, 0, 1, kwargs_values);
  unsigned magic_variant = (kwargs_values[0] != Qundef) ? (NUM2INT(kwargs_values[0])) : 0;

  StringValue(input_value);
  StringValue(skip_value);
  char* input_data = RSTRING_PTR(input_value);
  size_t input_size = RSTRING_LEN(input_value);
  char* skip_data = RSTRING_PTR(skip_value);
  size_t skip_size = RSTRING_LEN(skip_value);

  size_t dst_size = input_size + ZSTD_SKIPPABLEHEADERSIZE + skip_size;
  VALUE output = rb_str_new(input_data, dst_size);
  char* output_data = RSTRING_PTR(output);
  size_t output_size = ZSTD_writeSkippableFrame((void*)output_data, dst_size, (const void*)skip_data, skip_size, magic_variant);
  if (ZSTD_isError(output_size)) {
    rb_raise(rb_eRuntimeError, "%s: %s", "write skippable frame failed", ZSTD_getErrorName(output_size));
  }

  rb_str_resize(output, output_size);
  return output;
}

.zstd_version ⇒ Object 



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# File 'ext/zstdruby/zstdruby.c', line 5

static VALUE zstdVersion(VALUE self)
{
  unsigned version = ZSTD_versionNumber();
  return INT2NUM(version);
}