data

data

Functions

Types and Values

struct IptcData
enum IptcEncoding
#define IPTC_IIM_VERSION

Description

Functions

iptc_data_new ()

IptcData *
iptc_data_new (void);

Allocates a new collection of datasets, which is initialized to be empty. The default memory allocation functions (malloc, etc.) are used. If you need custom memory management functions, use iptc_data_new_mem() instead. This allocation will set the IptcData refcount to 1, so use iptc_data_unref() when finished with the pointer.

Returns

pointer to the new IptcData object, NULL on error


iptc_data_new_mem ()

IptcData *
iptc_data_new_mem (IptcMem *mem);

Allocates a new collection of datasets, which is initialized to be empty, using custom memory management functions. This allocation will set the IptcData refcount to 1, so use iptc_data_unref() when finished with the object.

Parameters

mem

Pointer to an IptcMem object that defines custom memory managment functions. The refcount of mem will be incremented. It is decremented when the returned IptcData object is freed.

 

Returns

pointer to the new IptcData object, NULL on error


iptc_data_ref ()

void
iptc_data_ref (IptcData *data);

Increments the reference count of an IptcData object. This function should be called whenever a copy of a pointer is made by the application. iptc_data_unref() can then be used when the pointer is no longer needed to ensure that the object is freed once the object is completely unused.

Parameters

data

the referenced pointer

 

iptc_data_unref ()

void
iptc_data_unref (IptcData *data);

Decrements the reference count of an IptcData object. The object will automatically be freed when the count reaches 0. This function should be called whenever a pointer is no longer needed by an application. It is also good practice to set the local copy of the pointer to NULL to shield against accidently reusing the value.

Parameters

data

the unreferenced pointer

 

iptc_data_free ()

void
iptc_data_free (IptcData *data);

Frees an IptcData object. This function should be used only for error handling since iptc_data_unref() provides a safer mechanism for freeing that allows multiple components to have access to an object. This function decrements the reference count of any datasets contained by the object. This will generally cause them to be freed as well unless other parts of the application are referencing them individually.

Parameters

data

the object to free

 

iptc_data_new_from_jpeg ()

IptcData *
iptc_data_new_from_jpeg (const char *path);

Allocates a new collection of datasets which is initialized by decoding the IPTC data in JPEG file path . This allocation will set the IptcData refcount to 1, so use iptc_data_unref() when finished with the object. This is a convenience function that reads the contents of the file, creates a new IptcData object, parses the file with iptc_jpeg_read_ps3() and iptc_jpeg_ps3_find_iptc(), and loads the data with iptc_data_load(). If more fine-grained error detection is needed, those functions should be used individually.

Parameters

path

filesystem path of the jpeg file to be read

 

Returns

pointer to the new IptcData object. NULL on error (including parsing errors or if the file did not include IPTC data).


iptc_data_new_from_data ()

IptcData *
iptc_data_new_from_data (const unsigned char *buf,
                         unsigned int size);

Allocates a new collection of datasets which is initialized by decoding the contents of buf . This allocation will set the IptcData refcount to 1, so use iptc_data_unref() when finished with the object. This is simply a convenience function that can be duplicated by calling iptc_data_new() followed by iptc_data_load().

Parameters

buf

the buffer of IPTC data to be decoded

 

size

the length to be read in bytes

 

Returns

pointer to the new IptcData object. NULL on error (including parsing errors in the contents of buf ).


iptc_data_load ()

int
iptc_data_load (IptcData *data,
                const unsigned char *buf,
                unsigned int size);

Parses a buffer containing raw IPTC data and adds the datasets to the IptcData object data .

Parameters

data

object to be populated with the loaded datasets

 

buf

data buffer to be parsed, containing IPTC data

 

size

length of data buffer to be parsed

 

Returns

0 on success, -1 on failure. Note that in the failure case, some datasets may still have been added to data .


iptc_data_save ()

int
iptc_data_save (IptcData *data,
                unsigned char **buf,
                unsigned int *size);

Outputs a collection of datasets as an IPTC bytestream. No memory allocation is required in advance. buf should point to a NULL pointer that will be set to the address of the output buffer by this function. size will contain this buffer's length after completion. The object data is unmodified by this function. The application should free the output buffer using iptc_data_free_buf() when it is no longer needed.

Parameters

data

collection of datasets to be saved

 

buf

pointer to a pointer that will hold the address of the output buffer

 

size

pointer to an integer that will hold the length of the output buffer

 

Returns

0 on success, -1 on failure. In the failure case, buf should still be checked for a non-NULL value, and freed using iptc_data_free_buf() if necessary.


iptc_data_free_buf ()

void
iptc_data_free_buf (IptcData *data,
                    unsigned char *buf);

Frees a temporary buffer created from an IptcData object by the iptc_data_save() function.

Parameters

data

the IptcData object that allocated the buffer

 

buf

the buffer to free

 

iptc_data_get_dataset ()

IptcDataSet *
iptc_data_get_dataset (IptcData *data,
                       IptcRecord record,
                       IptcTag tag);

Finds the first occurence of a dataset inside a collection with the specified record and tag identifiers.

Parameters

data

collection to search

 

record

record identifier of dataset

 

tag

tag identifier (dataset number) of dataset

 

Returns

pointer to dataset if found, NULL if no matching dataset found


iptc_data_get_next_dataset ()

IptcDataSet *
iptc_data_get_next_dataset (IptcData *data,
                            IptcDataSet *ds,
                            IptcRecord record,
                            IptcTag tag);

Finds the next occurence of a dataset inside a collection with the specified record and tag identifiers following ds . This is useful when a collection contains more than one dataset with the same record and tag identifier (for example, the keywords tag appears once for each keyword in the IPTC metadata). When ds is NULL, this function is equivalent to iptc_data_get_dataset().

Parameters

data

collection to search

 

ds

dataset where the search should originate (can be NULL)

 

record

record identifier of dataset

 

tag

tag identifier (dataset number) of dataset

 

Returns

pointer to dataset if found, NULL if no matching dataset found


iptc_data_add_dataset ()

int
iptc_data_add_dataset (IptcData *data,
                       IptcDataSet *ds);

Adds an IptcDataSet at the end of an existing collection. A dataset can only be a member of a single collection. This function will increment the reference count of dataset , so if the application no longer intends to use dataset directly, it should call iptc_dataset_unref() immediately following this call.

Parameters

data

the collection to which the dataset will be added

 

ds

dataset to add

 

Returns

0 on success, -1 on error


iptc_data_add_dataset_before ()

int
iptc_data_add_dataset_before (IptcData *data,
                              IptcDataSet *ds,
                              IptcDataSet *newds);

Same as iptc_data_add_dataset(), except the dataset will be added before an existing dataset ds , so that if they are enumerated, newds will appear before ds in the collection. ds must be a dataset already present in the collection.

Parameters

data

the collection to which the dataset will be added

 

ds

existing dataset before which newds will be added

 

newds

dataset to add

 

Returns

0 on success, -1 on error


iptc_data_add_dataset_after ()

int
iptc_data_add_dataset_after (IptcData *data,
                             IptcDataSet *ds,
                             IptcDataSet *newds);

Same as iptc_data_add_dataset(), except the dataset will be added after an existing dataset ds , so that if they are enumerated, newds will appear after ds in the collection. ds must be a dataset already present in the collection.

Parameters

data

the collection to which the dataset will be added

 

ds

existing dataset after which newds will be added

 

newds

dataset to add

 

Returns

0 on success, -1 on error


iptc_data_remove_dataset ()

int
iptc_data_remove_dataset (IptcData *data,
                          IptcDataSet *ds);

Removes a dataset from a collection. This function also calls iptc_dataset_unref() on ds .

Parameters

data

the collection from which to remove an entry

 

ds

the dataset to remove from the collection

 

Returns

0 on success, -1 on error


IptcDataForeachDataSetFunc ()

void
(*IptcDataForeachDataSetFunc) (IptcDataSet *dataset,
                               void *user_data);

iptc_data_foreach_dataset ()

void
iptc_data_foreach_dataset (IptcData *data,
                           IptcDataForeachDataSetFunc func,
                           void *user_data);

Iterates through each dataset in the collection and calls the callback function on that dataset.

Parameters

data

collection through which to iterate

 

func

callback function

 

user_data

arbitrary user data to be passed to the callback

 

iptc_data_sort ()

void
iptc_data_sort (IptcData *data);

Sorts a collection of datasets in ascending order first by record number and second by tag number. It can be useful to call this function before saving IPTC data in order to maintain a more organized file.

Parameters

data

collection of datasets to sort

 

iptc_data_get_encoding ()

IptcEncoding
iptc_data_get_encoding (IptcData *data);

Identifies the character encoding of the collection of datasets as specified by the "character set" dataset (1:90). The specification allows this dataset to contain control sequences from the ISO 2022 standard. Unfortunately, this standard is very complicated and generally not used by application writers. Thus, rather than attempt to decode any possible any possible control sequence, this function only attempts to recognize the control sequence that identifies the UTF-8 character set. If found, this function will return IPTC_ENCODING_UTF8. All character-based datasets in record 2 and higher are then expected to contain data encoded in the UTF-8 character set. Otherwise, this function will return IPTC_ENCODING_UNKNOWN, meaning that any other character set might be used, including ISO 2022 control sequences that have not been decoded. If dataset 1:90 is not present, this function returns IPTC_ENCODING_UNSPECIFIED, in which case character-based datasets will usually be plain ASCII, although broken applications may have used some other encoding.

Parameters

data

collection of datasets

 

iptc_data_set_encoding_utf8 ()

int
iptc_data_set_encoding_utf8 (IptcData *data);

Sets the contents of the "character set" dataset (1:90) to contain the control sequence that indicates UTF-8 as the character encoding for any character-based datasets in record 2 or higher. If dataset 1:90 is not present, it will be added to the collection. Any prior value of dataset 1:90 will be overwritten by this function. Note that some third-party applications (notably Picasa) will ignore all your IPTC data if this option is set.

Parameters

data

collection of datasets for which to specify the encoding

 

Returns

0 on success, -1 on failure.


iptc_data_set_version ()

int
iptc_data_set_version (IptcData *data,
                       unsigned int version);

Specifies the version of the IIM specification used by this library by setting the value of datasets 1:00 and 2:00. It is recommended to set the version number to IPTC_IIM_VERSION, which specifies the version implemented by this library (currently 4). If datasets 1:00 or 2:00 are not present, they will be added to the collection. Any prior value of the datasets will be overwritten by this function. To ensure strict compliance with the standard, this function should be called before saving a collection of datasets. However, in practice, some applications (notably Picasa) will ignore all your IPTC data if this option is set.

Parameters

data

collection of datasets for which to specify the version

 

version

version number to write

 

Returns

0 on success, -1 on failure.


iptc_data_add_dataset_with_value ()

int
iptc_data_add_dataset_with_value (IptcData *data,
                                  IptcRecord record,
                                  IptcTag tag,
                                  unsigned int value,
                                  IptcValidate validate);

This is a convenience function that creates a new dataset with the given record and tag, adds it to the specified collection of datasets, and stores the given numeric value as the contents of the dataset. It is equivalent to calling this sequence of functions: iptc_dataset_new(), iptc_dataset_set_tag(), iptc_data_add_dataset(), and iptc_dataset_set_value().

Parameters

data

collection to which the new dataset should be added

 

record

record number of the dataset to be added

 

tag

tag (dataset number) of the dataset to be added

 

value

value for the dataset

 

validate

whether or not the passed value should be validated against the IPTC specification for this dataset's tag.

 

Returns

-1 on error, 0 if validation failed, the number of bytes copied on success


iptc_data_add_dataset_with_contents ()

int
iptc_data_add_dataset_with_contents (IptcData *data,
                                     IptcRecord record,
                                     IptcTag tag,
                                     const unsigned char *buf,
                                     unsigned int size,
                                     IptcValidate validate);

This is a convenience function that creates a new dataset with the given record and tag, adds it to the specified collection of datasets, and stores a copy of the given data buffer as the contents of the dataset. It is equivalent to calling this sequence of functions: iptc_dataset_new(), iptc_dataset_set_tag(), iptc_data_add_dataset(), and iptc_dataset_set_data().

Parameters

data

collection to which the new dataset should be added

 

record

record number of the dataset to be added

 

tag

tag (dataset number) of the dataset to be added

 

buf

buffer containing the value

 

size

number of bytes to copy

 

validate

whether or not the passed value should be validated against the IPTC specification for this dataset's tag.

 

Returns

-1 on error, 0 if validation failed, the number of bytes copied on success


iptc_data_dump ()

void
iptc_data_dump (IptcData *data,
                unsigned int indent);

A debugging aid that prints out the contents of a collection of datasets to standard output.

Parameters

data

collection of datasets to print

 

indent

indentation level of the printout

 

iptc_data_log ()

void
iptc_data_log (IptcData *data,
               IptcLog *log);

Changes the logging object for a IptcData object. The logging object determines how warning and error messages are relayed back to the application. This function also calls iptc_log_ref() on the new log object and iptc_log_unref() on the previous log object.

Parameters

data

collection for which the log object should be changed.

 

log

log object to use for the collection

 

Types and Values

struct IptcData

struct IptcData {
        IptcDataSet **datasets;
        unsigned int count;

	IptcDataPrivate *priv;
};

enum IptcEncoding

Members

IPTC_ENCODING_UNKNOWN

   

IPTC_ENCODING_UNSPECIFIED

   

IPTC_ENCODING_UTF8

   

IPTC_IIM_VERSION

#define IPTC_IIM_VERSION 4