exiv2._value

Exiv2 metadata value classes.

Classes

AsciiValue	Value for an Ascii string type.
CommentValue	Value for an Exif comment.
DataValue	Value for an undefined data type.
Date	Simple Date helper structure
DateValue	Value for simple ISO 8601 dates
DoubleValue	Sequence of double values.
FloatValue	Sequence of float values.
LangAltValue	Value type for XMP language alternative properties.
LongValue	Sequence of int32_t values.
RationalValue	Sequence of Exiv2::Rational values.
ShortValue	Sequence of int16_t values.
StringValue	Value for string type.
StringValueBase	Abstract base class for a string based Value type.
Time	Simple Time helper structure
TimeValue	Value for simple ISO 8601 times.
ULongValue	Sequence of uint32_t values.
URationalValue	Sequence of Exiv2::URational values.
UShortValue	Sequence of uint16_t values.
Value	Common interface for all types of values used with metadata.
XmpArrayValue	Value type for simple arrays.
XmpTextValue	Value type suitable for simple XMP properties and XMP nodes of complex types which are not parsed into specific values.
XmpValue	Base class for all Exiv2 values used to store XMP property values.

class AsciiValue

Bases: StringValueBase

Value for an Ascii string type.

This class is for null terminated single byte Ascii strings. This class also ensures that the string is null terminated.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

read()

Read the value from buf. This default implementation uses buf as it is.

class CommentValue

Bases: StringValueBase

Value for an Exif comment.

This can be a plain Ascii string or a multiple byte encoded string. The comment is expected to be encoded in the character set indicated (default undefined), but this is not checked. It is left to caller to decode and encode the string to and from readable text if that is required.

class CharsetId

Bases: IntEnum

Character set identifiers for the character sets defined by Exif.

ascii = 0

invalidCharsetId = 4

jis = 1

lastCharsetId = 5

undefined = 3

unicode = 2

byteOrder_

charsetId()

Return the Exif charset id of the comment

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

comment()

Return the comment (without a charset=”…” prefix)

The comment is decoded to UTF-8. For Exif UNICODE comments, the function makes an attempt to correctly determine the character encoding of the value. Alternatively, the optional encoding parameter can be used to specify it.

Parameters:

encoding (string, optional) – Optional argument to specify the character encoding that the comment is encoded in, as an iconv(3) name. Only used for Exif UNICODE comments.

Return type:

str

Returns:

A string containing the comment converted to UTF-8.

copy()

Write value to a character data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Note

The byte order is required by the interface but not used by this method, so just use the default.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder, optional) – Byte order. Not used.

Return type:

int

Returns:

Number of characters written.

detectCharset()

Determine the character encoding that was used to encode the UNICODE comment value as an iconv(3) name.

If the comment c starts with a BOM, the BOM is interpreted and removed from the string.

Todo: Implement rules to guess if the comment is UTF-8 encoded.

read()

Read the value from a comment

The format of comment is:

[charset=["]Ascii|Jis|Unicode|Undefined["] ]comment

The default charset is Undefined.

Return type:

int

Returns:

0 if successful

1 if an invalid character set is encountered

class DataValue

Bases: Value

Value for an undefined data type.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a character data buffer.

Note

The byte order is required by the interface but not used by this method, so just use the default.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder, optional) – Byte order. Not needed.

Return type:

int

Returns:

Number of characters written.

count()

Return the number of components of the value

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

size()

Return the size of the value in bytes

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class Date

Bases: SwigPyObject

Simple Date helper structure

day

Day

items()

Get structure members.

Return type:

list of (str, value) tuple

Returns:

structure member (name, value) pairs (with any trailing underscores removed from names).

keys()

Get structure member names.

Return type:

list of str

Returns:

structure member names (with any trailing underscores removed).

month

Month

values()

Get structure member values.

Return type:

list of value

Returns:

structure member values.

year

Year

class DateValue

Bases: Value

Value for simple ISO 8601 dates

This class is limited to parsing simple date strings in the ISO 8601 format CCYYMMDD (century, year, month, day).

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a character data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Note

The byte order is required by the interface but not used by this method, so just use the default.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder, optional) – Byte order. Not used.

Return type:

int

Returns:

Number of characters written.

count()

Return the number of components of the value

getDate()

Return date struct containing date information

read()

Overload 1:

Return type:

int

Returns:

0 if successful

1 in case of an unsupported date format

Overload 2:

Set the value to that of the string buf.

Parameters:

buf (str) – String containing the date

Return type:

int

Returns:

0 if successful

1 in case of an unsupported date format

setDate()

Set the date

size()

Return the size of the value in bytes

toFloat()

Return the value as a UNIX calendar time converted to float.

toInt64()

Return the value as a UNIX calendar time converted to int64_t.

toRational()

Return the value as a UNIX calendar time converted to Rational.

toUint32()

Return the value as a UNIX calendar time converted to uint32_t.

class DoubleValue

Bases: Value

Sequence of double values. The data components can be accessed like a Python list.

append()

Append a double component to the value.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

Number of bytes written.

count()

Return the number of components of the value

dataArea()

Return a copy of the data area in a DataBuf. The caller owns this copy and DataBuf ensures that it will be deleted.

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

setDataArea()

Set the data area. This method copies (clones) the buffer pointed to by buf.

size()

Return the size of the value in bytes

sizeDataArea()

Return the size of the data area.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class FloatValue

Bases: Value

Sequence of float values. The data components can be accessed like a Python list.

append()

Append a float component to the value.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

Number of bytes written.

count()

Return the number of components of the value

dataArea()

Return a copy of the data area in a DataBuf. The caller owns this copy and DataBuf ensures that it will be deleted.

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

setDataArea()

Set the data area. This method copies (clones) the buffer pointed to by buf.

size()

Return the size of the value in bytes

sizeDataArea()

Return the size of the data area.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class LangAltValue

Bases: XmpValue

Value type for XMP language alternative properties.

A language alternative is an array consisting of simple text values, each of which has a language qualifier.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

count()

Return the number of components of the value

items()

Get key, value pairs (i.e. language, text) of the LangAltValue components.

keys()

Get keys (i.e. languages) of the LangAltValue components.

read()

Overload 1:

Note

Uses read(const std::string& buf)

Overload 2:

Read a simple property value from buf and append it to the value.

Appends buf to the value after the last existing array element. Subsequent calls will therefore populate multiple array elements in the order they are read.

The format of buf is:

[lang=["]language code["] ]text

The XMP default language code x-default is used if buf doesn’t start with the keyword lang.

Return type:

int

Returns:

0 if successful.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Overload 1:

Return the text value associated with the default language qualifier x-default. The parameter n is not used, but it is suggested that only 0 is passed in. Returns an empty string and sets the ok-flag to false if there is no default value.

Overload 2:

Return the text value associated with the language qualifier qualifier. Returns an empty string and sets the ok-flag to false if there is no entry for the language qualifier.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

values()

Get values (i.e. text strings) of the LangAltValue components.

class LongValue

Bases: Value

Sequence of int32_t values. The data components can be accessed like a Python list.

append()

Append a int32_t component to the value.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

Number of bytes written.

count()

Return the number of components of the value

dataArea()

Return a copy of the data area in a DataBuf. The caller owns this copy and DataBuf ensures that it will be deleted.

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

setDataArea()

Set the data area. This method copies (clones) the buffer pointed to by buf.

size()

Return the size of the value in bytes

sizeDataArea()

Return the size of the data area.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class RationalValue

Bases: Value

Sequence of Exiv2::Rational values. The data components can be accessed like a Python list.

append()

Append a Exiv2::Rational component to the value.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

Number of bytes written.

count()

Return the number of components of the value

dataArea()

Return a copy of the data area in a DataBuf. The caller owns this copy and DataBuf ensures that it will be deleted.

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

setDataArea()

Set the data area. This method copies (clones) the buffer pointed to by buf.

size()

Return the size of the value in bytes

sizeDataArea()

Return the size of the data area.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class ShortValue

Bases: Value

Sequence of int16_t values. The data components can be accessed like a Python list.

append()

Append a int16_t component to the value.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

Number of bytes written.

count()

Return the number of components of the value

dataArea()

Return a copy of the data area in a DataBuf. The caller owns this copy and DataBuf ensures that it will be deleted.

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

setDataArea()

Set the data area. This method copies (clones) the buffer pointed to by buf.

size()

Return the size of the value in bytes

sizeDataArea()

Return the size of the data area.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class StringValue

Bases: StringValueBase

Value for string type.

This can be a plain Ascii string or a multiple byte encoded string. It is left to caller to decode and encode the string to and from readable text if that is required.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

class StringValueBase

Bases: Value

Abstract base class for a string based Value type.

Uses a std::string to store the value and implements defaults for most operations.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a character data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Note

The byte order is required by the interface but not used by this method, so just use the default.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder, optional) – Byte order. Not used.

Return type:

int

Returns:

Number of characters written.

count()

Return the number of components of the value

data()

Returns a temporary Python memoryview of the object’s data.

Warning

do not resize or delete the object while using the view.

Return type:

memoryview

read()

Read the value from buf. This default implementation uses buf as it is.

size()

Return the size of the value in bytes

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class Time

Bases: SwigPyObject

Simple Time helper structure

hour

Hour

items()

Get structure members.

Return type:

list of (str, value) tuple

Returns:

structure member (name, value) pairs (with any trailing underscores removed from names).

keys()

Get structure member names.

Return type:

list of str

Returns:

structure member names (with any trailing underscores removed).

minute

Minute

second

Second

tzHour

Hours ahead or behind UTC

tzMinute

Minutes ahead or behind UTC

values()

Get structure member values.

Return type:

list of value

Returns:

structure member values.

class TimeValue

Bases: Value

Value for simple ISO 8601 times.

This class is limited to handling simple time strings in the ISO 8601 format HHMMSS±HHMM where HHMMSS refers to local hour, minute and seconds and ±HHMM refers to hours and minutes ahead or behind Universal Coordinated Time.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a character data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Note

The byte order is required by the interface but not used by this method, so just use the default.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder, optional) – Byte order. Not used.

Return type:

int

Returns:

Number of characters written.

count()

Return the number of components of the value

getTime()

Return time struct containing time information

read()

Overload 1:

Return type:

int

Returns:

0 if successful

1 in case of an unsupported time format

Overload 2:

Set the value to that of the string buf.

Parameters:

buf (str) – String containing the time.

Return type:

int

Returns:

0 if successful

1 in case of an unsupported time format

setTime()

Set the time

size()

Return the size of the value in bytes

toFloat()

Returns number of seconds in the day in UTC converted to float.

toInt64()

Returns number of seconds in the day in UTC.

toRational()

Returns number of seconds in the day in UTC converted to Rational.

toUint32()

Returns number of seconds in the day in UTC.

class ULongValue

Bases: Value

Sequence of uint32_t values. The data components can be accessed like a Python list.

append()

Append a uint32_t component to the value.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

Number of bytes written.

count()

Return the number of components of the value

dataArea()

Return a copy of the data area in a DataBuf. The caller owns this copy and DataBuf ensures that it will be deleted.

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

setDataArea()

Set the data area. This method copies (clones) the buffer pointed to by buf.

size()

Return the size of the value in bytes

sizeDataArea()

Return the size of the data area.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class URationalValue

Bases: Value

Sequence of Exiv2::URational values. The data components can be accessed like a Python list.

append()

Append a Exiv2::URational component to the value.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

Number of bytes written.

count()

Return the number of components of the value

dataArea()

Return a copy of the data area in a DataBuf. The caller owns this copy and DataBuf ensures that it will be deleted.

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

setDataArea()

Set the data area. This method copies (clones) the buffer pointed to by buf.

size()

Return the size of the value in bytes

sizeDataArea()

Return the size of the data area.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class UShortValue

Bases: Value

Sequence of uint16_t values. The data components can be accessed like a Python list.

append()

Append a uint16_t component to the value.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

Number of bytes written.

count()

Return the number of components of the value

dataArea()

Return a copy of the data area in a DataBuf. The caller owns this copy and DataBuf ensures that it will be deleted.

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

setDataArea()

Set the data area. This method copies (clones) the buffer pointed to by buf.

size()

Return the size of the value in bytes

sizeDataArea()

Return the size of the data area.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class Value

Bases: SwigPyObject

Common interface for all types of values used with metadata.

The interface provides a uniform way to access values independent of their actual C++ type for simple tasks like reading the values from a string or data buffer. For other tasks, like modifying values you may need to downcast it to a specific subclass to access its interface.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

copy()

Write value to a data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

Number of bytes written.

count()

Return the number of components of the value

static create()

A (simple) factory to create a Value type.

The following Value subclasses are created depending on typeId:

typeId	Value subclass
invalidTypeId	DataValue (invalidTypeId)
unsignedByte	DataValue (unsignedByte)
asciiString	AsciiValue
string	StringValue
unsignedShort	ValueType < uint16_t >
unsignedLong	ValueType < uint32_t >
unsignedRational	ValueType < URational >
invalid6	DataValue (invalid6)
undefined	DataValue
signedShort	ValueType < int16_t >
signedLong	ValueType < int32_t >
signedRational	ValueType < Rational >
tiffFloat	ValueType < float >
tiffDouble	ValueType < double >
tiffIfd	ValueType < uint32_t >
date	DateValue
time	TimeValue
comment	CommentValue
xmpText	XmpTextValue
xmpBag	XmpArrayValue
xmpSeq	XmpArrayValue
xmpAlt	XmpArrayValue
langAlt	LangAltValue
default	DataValue (typeId)

Parameters:

typeId (TypeId) – Type of the value.

Return type:

Value

Returns:

Auto-pointer to the newly created Value. The caller owns this copy and the auto-pointer ensures that it will be deleted.

dataArea()

Return a copy of the data area if the value has one. The caller owns this copy and DataBuf ensures that it will be deleted.

Values may have a data area, which can contain additional information besides the actual value. This method is used to access such a data area.

Return type:

DataBuf

Returns:

A DataBuf containing a copy of the data area or an empty DataBuf if the value does not have a data area assigned.

ok()

Check the ok status indicator. After a to<Type> conversion, this indicator shows whether the conversion was successful.

read()

Overload 1:

Read the value from a character buffer.

Parameters:

• buf (bytes-like object) – Pointer to the data buffer to read from

• len (int) – Number of bytes in the data buffer

• byteOrder (ByteOrder) – Applicable byte order (little or big endian).

Return type:

int

Returns:

0 if successful.

Overload 2:

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters:

buf (str) – The string to read from.

Return type:

int

Returns:

0 if successful.

setDataArea()

Set the data area, if the value has one by copying (cloning) the buffer pointed to by buf.

Values may have a data area, which can contain additional information besides the actual value. This method is used to set such a data area.

Parameters:

• buf (bytes-like object) – Pointer to the source data area

• len (int) – Size of the data area

Return type:

int

Returns:

Return -1 if the value has no data area, else 0.

size()

Return the size of the value in bytes

sizeDataArea()

Return the size of the data area, 0 if there is none.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Overload 1:

Return the value as a string. Implemented in terms of write(std::ostream& os) const of the concrete class.

Overload 2:

Return the n-th component of the value as a string. The default implementation returns toString(). The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

typeId()

Return the type identifier (Exif data format type).

class XmpArrayValue

Bases: XmpValue

Value type for simple arrays. Each item in the array is a simple value, without qualifiers. The array may be an ordered (seq), unordered (bag) or alternative array (alt). The array items must not contain qualifiers. For language alternatives use LangAltValue.

Uses a vector of std::string to store the value(s).

append()

appends another ‘this’ object

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

count()

Return the number of components of the value

read()

Overload 1:

Note

Uses read(const std::string& buf)

Overload 2:

Read a simple property value from buf and append it to the value.

Appends buf to the value after the last existing array element. Subsequent calls will therefore populate multiple array elements in the order they are read.

Return type:

int

Returns:

0 if successful.

toFloat()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

toRational()

Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

Return type:

(int, int) tuple

Returns:

The converted value.

toString()

Return the n-th component of the value as a string. The behaviour of this method may be undefined if there is no n-th component.

toUint32()

Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

Return type:

int

Returns:

The converted value.

class XmpTextValue

Bases: XmpValue

Value type suitable for simple XMP properties and XMP nodes of complex types which are not parsed into specific values.

Uses a std::string to store the value.

clone()

Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

count()

Return the number of components of the value

data()

Returns a temporary Python memoryview of the object’s data.

Warning

do not resize or delete the object while using the view.

Return type:

memoryview

read()

Overload 1:

Note

Uses read(const std::string& buf)

Overload 2:

Read a simple property value from buf to set the value.

Sets the value to the contents of buf. A optional keyword, type is supported to set the XMP value type. This is useful for complex value types for which Exiv2 does not have direct support.

The format of buf is:

[type=["]Alt|Bag|Seq|Struct["] ]text

Return type:

int

Returns:

0 if successful.

size()

Return the size of the value in bytes

toFloat()

Convert the value to a float. The optional parameter n is not used and is ignored.

Return type:

float

Returns:

The converted value.

toInt64()

Convert the value to an int64_t. The optional parameter n is not used and is ignored.

Return type:

int

Returns:

The converted value.

toRational()

Convert the value to a Rational. The optional parameter n is not used and is ignored.

Return type:

(int, int) tuple

Returns:

The converted value.

toUint32()

Convert the value to an uint32_t. The optional parameter n is not used and is ignored.

Return type:

int

Returns:

The converted value.

class XmpValue

Bases: Value

Base class for all Exiv2 values used to store XMP property values.

class XmpArrayType

Bases: IntEnum

XMP array types.

xaAlt = 1

xaBag = 2

xaNone = 0

xaSeq = 3

class XmpStruct

Bases: IntEnum

XMP structure indicator.

xsNone = 0

xsStruct = 1

copy()

Write value to a character data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Note

The byte order is required by the interface but not used by this method, so just use the default.

Parameters:

• buf (writeable bytes-like object) – Data buffer to write to.

• byteOrder (ByteOrder, optional) – Byte order. Not used.

Return type:

int

Returns:

Number of characters written.

read()

Note

Uses read(const std::string& buf)

setXmpArrayType()

Set the XMP array type to indicate that an XMP value is an array.

setXmpStruct()

Set the XMP struct type to indicate that an XMP value is a structure.

size()

Return the size of the value in bytes

xmpArrayType()

Return XMP array type, indicates if an XMP value is an array.

xmpStruct()

Return XMP struct, indicates if an XMP value is a structure.