Class: CharlockHolmes::EncodingDetector

Inherits:
Object
  • Object
show all
Defined in:
lib/charlock_holmes/encoding_detector.rb,
ext/charlock_holmes/encoding_detector.c

Constant Summary collapse

DEFAULT_BINARY_SCAN_LEN =

Default length for which to scan content for NULL bytes

1024*1024

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(scan_len = DEFAULT_BINARY_SCAN_LEN) ⇒ EncodingDetector

Returns a new instance of EncodingDetector.



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# File 'lib/charlock_holmes/encoding_detector.rb', line 11

def initialize(scan_len=DEFAULT_BINARY_SCAN_LEN)
  @binary_scan_length = scan_len
end

Instance Attribute Details

#binary_scan_length ⇒ Object

Length for which to scan content for NULL bytes



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# File 'lib/charlock_holmes/encoding_detector.rb', line 7

def binary_scan_length
  @binary_scan_length
end

Class Method Details

.detect(str, hint_enc = nil) ⇒ Object

Attempt to detect the encoding of this string

NOTE: This will create a new CharlockHolmes::EncodingDetector instance on every call as well as use the default binary scan length

str - a String, what you want to detect the encoding of hint_enc - an optional String (like “UTF-8”), the encoding name which will

be used as an additional hint to the charset detector

Returns: a Hash with :encoding, :language, :type and :confidence



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# File 'lib/charlock_holmes/encoding_detector.rb', line 25

def self.detect(str, hint_enc=nil)
  new.detect(str, hint_enc)
end

.detect_all(str, hint_enc = nil) ⇒ Object

Attempt to detect the encoding of this string, and return a list with all the possible encodings that match it.

NOTE: This will create a new CharlockHolmes::EncodingDetector instance on every call as well as use the default binary scan length

str - a String, what you want to detect the encoding of hint_enc - an optional String (like “UTF-8”), the encoding name which will

be used as an additional hint to the charset detector

Returns: an Array with zero or more Hashes, each one of them with with :encoding, :language, :type and :confidence



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# File 'lib/charlock_holmes/encoding_detector.rb', line 41

def self.detect_all(str, hint_enc=nil)
  new.detect_all(str, hint_enc)
end

.detectable_encodings=(EncodingDetector) ⇒ Object

The list of detectable encodings supported by this library

Returns: an Array of Strings



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# File 'ext/charlock_holmes/encoding_detector.c', line 269

static VALUE rb_get_supported_encodings(VALUE klass)
{
	UCharsetDetector *csd;
	UErrorCode status = U_ZERO_ERROR;
	UEnumeration *encoding_list;
	VALUE rb_encoding_list;
	int32_t enc_count;
	int32_t i;
	const char *enc_name;
	int32_t enc_name_len;

	rb_encoding_list = rb_iv_get(klass, "encoding_list");

	// lazily populate the list
	if (NIL_P(rb_encoding_list)) {
		csd = ucsdet_open(&status);

		encoding_list = ucsdet_getAllDetectableCharsets(csd, &status);
		rb_encoding_list = rb_ary_new();
		enc_count = uenum_count(encoding_list, &status);

		for(i=0; i < enc_count; i++) {
			enc_name = uenum_next(encoding_list, &enc_name_len, &status);
			rb_ary_push(rb_encoding_list, charlock_new_str(enc_name, enc_name_len));
		}

		rb_iv_set(klass, "encoding_list", rb_encoding_list);
		ucsdet_close(csd);
	}

	return rb_encoding_list;
}

Instance Method Details

#detection_hash=(EncodingDetector) ⇒ Object

Attempt to detect the encoding of this string

str - a String, what you want to detect the encoding of hint_enc - an optional String (like “UTF-8”), the encoding name which will

be used as an additional hint to the charset detector

Returns: a Hash with :encoding, :language, :type and :confidence



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# File 'ext/charlock_holmes/encoding_detector.c', line 131

static VALUE rb_encdec_detect(int argc, VALUE *argv, VALUE self)
{
	UErrorCode status = U_ZERO_ERROR;
	charlock_detector_t *detector;
	VALUE rb_str;
	VALUE rb_enc_hint;

	rb_scan_args(argc, argv, "11", &rb_str, &rb_enc_hint);

	Check_Type(rb_str, T_STRING);
	Data_Get_Struct(self, charlock_detector_t, detector);

	// first lets see if this is binary content
	if (detect_binary_content(self, rb_str)) {
		return rb_encdec_binarymatch();
	}

	// if we got here - the data doesn't look like binary
	// lets try to figure out what encoding the text is in
	ucsdet_setText(detector->csd, RSTRING_PTR(rb_str), (int32_t)RSTRING_LEN(rb_str), &status);

	if (!NIL_P(rb_enc_hint)) {
		Check_Type(rb_enc_hint, T_STRING);
		ucsdet_setDeclaredEncoding(detector->csd, RSTRING_PTR(rb_enc_hint), RSTRING_LEN(rb_enc_hint), &status);
	}

	return rb_encdec_buildmatch(ucsdet_detect(detector->csd, &status));
}

#detection_hash_array=(EncodingDetector) ⇒ Object

Attempt to detect the encoding of this string, and return a list with all the possible encodings that match it.

str - a String, what you want to detect the encoding of hint_enc - an optional String (like “UTF-8”), the encoding name which will

be used as an additional hint to the charset detector

Returns: an Array with zero or more Hashes,

each one of them with with :encoding, :language, :type and :confidence



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# File 'ext/charlock_holmes/encoding_detector.c', line 175

static VALUE rb_encdec_detect_all(int argc, VALUE *argv, VALUE self)
{
	UErrorCode status = U_ZERO_ERROR;
	charlock_detector_t *detector;
	const UCharsetMatch **csm;
	VALUE rb_ret;
	int i, match_count;
	VALUE rb_str;
	VALUE rb_enc_hint;
	VALUE binary_match;

	rb_scan_args(argc, argv, "11", &rb_str, &rb_enc_hint);

	Check_Type(rb_str, T_STRING);
	Data_Get_Struct(self, charlock_detector_t, detector);

	rb_ret = rb_ary_new();

	// first lets see if this is binary content
	binary_match = Qnil;
	if (detect_binary_content(self, rb_str)) {
		binary_match = rb_encdec_binarymatch();
	}

	ucsdet_setText(detector->csd, RSTRING_PTR(rb_str), (int32_t)RSTRING_LEN(rb_str), &status);

	if (!NIL_P(rb_enc_hint)) {
		Check_Type(rb_enc_hint, T_STRING);
		ucsdet_setDeclaredEncoding(detector->csd, RSTRING_PTR(rb_enc_hint), RSTRING_LEN(rb_enc_hint), &status);
	}

	csm = ucsdet_detectAll(detector->csd, &match_count, &status);

	for (i = 0; i < match_count; ++i) {
		rb_ary_push(rb_ret, rb_encdec_buildmatch(csm[i]));
	}

	if (!NIL_P(binary_match))
		rb_ary_unshift(rb_ret, binary_match);

	return rb_ret;
}

#strip_tags? ⇒ Object Also known as: strip_tags?

Returns whether or not the strip_tags flag is set on this detector

Returns: Boolean



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# File 'ext/charlock_holmes/encoding_detector.c', line 225

static VALUE rb_get_strip_tags(VALUE self)
{
	charlock_detector_t *detector;
	UBool val;
	VALUE rb_val;

	Data_Get_Struct(self, charlock_detector_t, detector);

	val = ucsdet_isInputFilterEnabled(detector->csd);

	rb_val = val == 1 ? Qtrue : Qfalse;

	return rb_val;
}

#strip_tags=(true) ⇒ Object

Enable or disable the stripping of HTML/XML tags from the input before attempting any detection

Returns: Boolean, the value passed



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# File 'ext/charlock_holmes/encoding_detector.c', line 248

static VALUE rb_set_strip_tags(VALUE self, VALUE rb_val)
{
	charlock_detector_t *detector;
	UBool val;

	Data_Get_Struct(self, charlock_detector_t, detector);

	val = rb_val == Qtrue ? 1 : 0;

	ucsdet_enableInputFilter(detector->csd, val);

	return rb_val;
}