psMetadata.h

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/** @file  psMetadata.h
*
*  @brief Contains metadata struuctures, enumerations and functions prototypes
*
*  This file defines metadata item, metadata type, metadata flags, metadata containers, and function
*  prototypes necessary creating psLib metadata APIs
*
*  @author Robert DeSonia, MHPCC
*  @author Ross Harman, MHPCC
*
*  @version $Revision: 1.94 $ $Name:  $
*  @date $Date: 2007/01/23 22:47:23 $
*
*  Copyright 2004-2005 Maui High Performance Computing Center, University of Hawaii
*/
#ifndef PS_METADATA_H
#define PS_METADATA_H

/// @addtogroup DataContainer Data Containers
/// @{

#include <stdarg.h>
#include <stdio.h>
#include <sys/types.h>
#include <regex.h>

#include "psHash.h"
#include "psList.h"
#include "psTime.h"
#include "psLookupTable.h"

#define PS_DATA_IS_PRIMITIVE(TYPE) \
(TYPE == PS_DATA_S8 || \
 TYPE == PS_DATA_S16 || \
 TYPE == PS_DATA_S32 || \
 TYPE == PS_DATA_S64 || \
 TYPE == PS_DATA_U8 || \
 TYPE == PS_DATA_U16 || \
 TYPE == PS_DATA_U32 || \
 TYPE == PS_DATA_U64 || \
 TYPE == PS_DATA_F32 || \
 TYPE == PS_DATA_F64 || \
 TYPE == PS_DATA_BOOL)

#define PS_DATA_PRIMITIVE_TYPE(DATATYPE) ( \
        (DATATYPE==PS_DATA_S8 || DATATYPE==PS_DATA_S16 || \
         DATATYPE==PS_DATA_S32 || DATATYPE==PS_DATA_S64 || DATATYPE==PS_DATA_U8 || \
         DATATYPE==PS_DATA_U16 || DATATYPE==PS_DATA_U32 || DATATYPE==PS_DATA_U64 || \
         DATATYPE==PS_DATA_F32 || DATATYPE==PS_DATA_F64 || DATATYPE==PS_DATA_BOOL) ? DATATYPE : 0)


/** Option flags for psMetadata functions
 *
 *  Enumeration for the modification of the behaviour in psMetadataAddItem.
 *
 *  @see psMetadataAddItem
 */
typedef enum {
    PS_META_DEFAULT = 0,               ///< default behaviour (duplicate entry is an error)
    PS_META_REPLACE = 0x1000000,       ///< allow entry to be replaced
    PS_META_NO_REPLACE = 0x2000000,    ///< duplicate entry is silently skipped
    PS_META_DUPLICATE_OK = 0x4000000,  ///< allow duplicate entries
    PS_META_NULL = 0x8000000           ///< psMetadataItem.data is a NULL value
} psMetadataFlags;

#define PS_METADATA_FLAGS_MASK 0xFF000000
#define PS_METADATA_TYPE_MASK 0x00FFFFFF

/** Metadata data structure.
 *
 *  Struct for holding metadata items. Metadata items are held in two
 *  containers. The first employs a doubly-linked list to preserve the order
 *  of the metadata. The second container employs a hash table which
 *  allows fast lookup when given a metadata keyword.
 */
typedef struct
{
    psList*  list;                     ///< Metadata in linked-list
    psHash*  hash;                     ///< Metadata in a hash table
    void *lock;                        ///< Optional lock for thread safety
}
psMetadata;

/** Metadata iterator
 *
 *  Iterator for metadata.
 */
typedef struct
{
    psListIterator* iter;              ///< iterator for the psMetadata's psList
    regex_t* regex;                    ///< the subsetting regular expression
}
psMetadataIterator;

/** Metadata item data structure.
 *
 * Struct for maintaining metadata items of varying types. It also contains
 * information about the item name, flags, comments, and other items with the same name.
 */
typedef struct
{
    const psS32 id;                    ///< Unique ID for metadata item.
    psString name;                     ///< Name of metadata item.
    psDataType type;                   ///< Type of metadata item.
    union {
        psBool B;                      ///< boolean data
        psS8 S8;                       ///< Signed 8-bit integer data.
        psS16 S16;                     ///< Signed 16-bit integer data.
        psS32 S32;                     ///< Signed 32-bit integer data.
        psS64 S64;                     ///< Signed 64-bit integer data.
        psU8 U8;                       ///< Unsigned 8-bit integer data.
        psU16 U16;                     ///< Unsigned 16-bit integer data.
        psU32 U32;                     ///< Unsigned 32-bit integer data.
        psU64 U64;                     ///< Unsigned 64-bit integer data.
        psF32 F32;                     ///< Single-precision float data.
        psF64 F64;                     ///< Double-precision float data.
        psList *list;                  ///< List data.
        psMetadata *md;                ///< Metadata data.
        psString str;                  ///< string data
        psPtr V;                       ///< Pointer to other type of data.
    } data;                            ///< Union for data types.
    psString comment;                  ///< Optional comment ("", not NULL).
}
psMetadataItem;

/** Create a metadata item.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct. The name argument specifies the name to use for this item, and
 *  may include sprintf formatting codes. The format entry specifies both
 *  the metadata type and optional flags and is created by bit-wise or of the
 *  appropriate type and flag. The comment argument is a fixed string used to
 *  comment the metadata item. The arguments to the name formatting codes and
 *  the metadata itself are passed as arguments following the comment string.
 *  The data must be a pointer for any of the elements stored in data.void.
 *  The argument list must be interpreted appropriately by the va_list
 *  operators in the function specified size and type.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAlloc(
    const char *name,                  ///< Name of metadata item.
    psDataType type,                   ///< Type of metadata item.
    const char *comment,               ///< Comment for metadata item.
    ...                                ///< Arguments for name formatting and metadata item data.
)
;

/** Checks the type of a particular pointer.
 *
 *  Uses the appropriate deallocation function in psMemBlock to check the ptr datatype.
 *
 *  @return bool:       True if the pointer matches a psMetadataItem structure, false otherwise.
 */
bool psMemCheckMetadataItem(
    psPtr ptr                          ///< the pointer whose type to check
);


/** Create a metadata item with specified string data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocStr(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    const char* value                  ///< the value of the metadata item.
);

/** Create a metadata item with specified psF32 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocF32(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psF32 value                        ///< the value of the metadata item.
);

/** Create a metadata item with specified psF64 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocF64(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psF64 value                        ///< the value of the metadata item.
);

/** Create a metadata item with specified psS8 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocS8(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psS8 value                         ///< the value of the metadata item.
);

/** Create a metadata item with specified psS16 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocS16(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psS16 value                        ///< the value of the metadata item.
);

/** Create a metadata item with specified psS32 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocS32(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psS32 value                        ///< the value of the metadata item.
);

/** Create a metadata item with specified psS64 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocS64(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psS64 value                        ///< the value of the metadata item.
);

/** Create a metadata item with specified psU8 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocU8(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psU8 value                         ///< the value of the metadata item.
);

/** Create a metadata item with specified psU16 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocU16(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psU16 value                        ///< the value of the metadata item.
);

/** Create a metadata item with specified psU32 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocU32(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psU32 value                        ///< the value of the metadata item.
);

/** Create a metadata item with specified psU64 data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocU64(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psU64 value                        ///< the value of the metadata item.
);

/** Create a metadata item with specified psBool data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocBool(
    const char* name,                  ///< Name of metadata item.
    const char* comment,               ///< Comment for metadata item.
    bool value                         ///< the value of the metadata item.
);

/** Create a metadata item with specified psPtr data.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocPtr(
    const char* name,                  ///< Name of metadata item.
    psDataType type,                   ///< Data type of metadata item.
    const char* comment,               ///< Comment for metadata item.
    psPtr value                        ///< the value of the metadata item.
);

#ifndef SWIG
/** Create a metadata item with va_list.
 *
 *  Returns a fill psMetadataItem ready for insertion into the psMetadata
 *  struct. The name argument specifies the name to use for this item, and
 *  may include sprintf formatting codes. The format entry specifies both
 *  the metadata type and optional flags and is created by bit-wise or of the
 *  appropriate type and flag. The comment argument is a fixed string used to
 *  comment the metadata item. The arguments to the name formatting codes and
 *  the metadata itself are passed as arguments following the comment string.
 *  The data must be a pointer for any of the elements stored in data.void.
 *  The argument list must be interpreted appropriately by the va_list
 *  operators in the function specified size and type.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataItemAllocV(
    const char *name,                  ///< Name of metadata item.
    psDataType type,                   ///< Type of metadata item.
    const char *comment,               ///< Comment for metadata item.
    va_list list                       ///< Arguments for name formatting and metadata item data.
);
#endif // #ifndef SWIG

/** Create a metadata collection.
 *
 *  Returns an empty metadata container with fully allocated internal metadata
 *  containers.
 *
 *  @return psMetadata* : Pointer metadata.
 */
psMetadata* psMetadataAlloc(void);


/** Checks the type of a particular pointer.
 *
 *  Uses the appropriate deallocation function in psMemBlock to check the ptr datatype.
 *
 *  @return bool:       True if the pointer matches a psMetadata structure, false otherwise.
 */
bool psMemCheckMetadata(
    psPtr ptr                          ///< the pointer whose type to check
);

/** Creates a new copy of a psMetadataItem.
 *
 * @return psMetadataItem*: the copy of the psMetadataItem
 */
psMetadataItem *psMetadataItemCopy(
    const psMetadataItem *in           ///< metadata item to be copied
);

/** Create a copy of an existing psMetadata collection.
 *
 *  Creates a new copy of all the psMetadataItems in the psMetadata collection, in, and
 *  returns them in out, or creates a new container if out is NULL.  If an error occurs,
 *  NULL is returned but out may still have been updated if it is non-NULL.
 *
 *  @return psMetadata*:        the copy of the psMetadata container.
 */
psMetadata *psMetadataCopy(
    psMetadata *out,                   ///< output Metadata container for copying.
    const psMetadata *in               ///< Metadata collection to be copied.
);

/** Copy a metadata item from one psMetadata to another.
 *
 *  Creates a copy of a psMetadataItem from in and appends it to out.  If out is NULL,
 *  a new container is created.
 *
 *  @return bool:       True if successful, otherwise false.
 */
bool psMetadataItemTransfer(
    psMetadata *out,                   ///< output Metadata container for copying.
    const psMetadata *in,              ///< Metadata collection from which to copy.
    const char *key                    ///< key to identify the metadata item for copying.
);

/** Add existing metadata item to metadata collection.
 *
 *  Add a metadata item that has already been created to the metadata
 *  collection.
 *
 *  @return bool: True for success, false for failure.
 */
bool psMetadataAddItem(
    psMetadata*  md,                   ///< Metadata collection to insert metadata item.
    const psMetadataItem* item,        ///< Metadata item to be added.
    int location,                      ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    psS32 flags                        ///< Options flag mask, see psMetadataFlags enum
);

/** Create and add a metadata item to metadata collection.
 *
 * Creates a new metadata item add to the metadata collection.
 *
 * @return bool: True for success, false for failure.
 */
bool psMetadataAdd(
    psMetadata* md,                    ///< Metadata collection to insert metadata item.
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char *name,                  ///< Name of metadata item.
    int format,                        ///< psDataType of metadata item & options (psMetadataFlags)
    const char *comment,               ///< Comment for metadata item.
    ...                                ///< Arguments for name formatting and metadata item data.
);

#ifndef SWIG
/** Create and add a metadata item to metadata collection.
 *
 * Creates a new metadata item add to the metadata collection.
 *
 * @return bool: True for success, false for failure.
 */
bool psMetadataAddV(
    psMetadata* md,                    ///< Metadata collection to insert metadata item.
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char *name,                  ///< Name of metadata item.
    int format,                        ///< psDataType of metadata item & options (psMetadataFlags)
    const char *comment,               ///< Comment for metadata item.
    va_list list                       ///< Arguments for name formatting and metadata item data.
);
#endif // #ifndef SWIG

/** Add a psBool value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddBool(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    bool value                         ///< Value for metadata item data
);

/** Add a psS8 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddS8(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psS8 value                         ///< Value for metadata item data
);

/** Add a psS16 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddS16(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psS16 value                        ///< Value for metadata item data
);

/** Add a psS32 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddS32(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psS32 value                        ///< Value for metadata item data
);

/** Add a psS64 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddS64(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psS64 value                        ///< Value for metadata item data
);

/** Add a psU8 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddU8(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psU8 value                         ///< Value for metadata item data
);

/** Add a psU16 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddU16(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psU16 value                        ///< Value for metadata item data
);

/** Add a psU32 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddU32(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psU32 value                        ///< Value for metadata item data
);

/** Add a psU64 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddU64(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psU64 value                        ///< Value for metadata item data
);

/** Add a psF32 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
*/
bool psMetadataAddF32(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psF32 value                        ///< Value for metadata item data
);

/** Add a psF64 value to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
*/
bool psMetadataAddF64(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psF64 value                        ///< Value for metadata item data
);

/** Add a psList to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddList(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psList* value                      ///< psList for metadata item data
);

/** Add a string to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddStr(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    const char* value                  ///< String for metadata item data
);

/** Add a vector to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddVector(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psVector* value                    ///< Vector for metadata item data
);

/** Add a array to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddArray(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psArray* value                     ///< Vector for metadata item data
);

/** Add an Image to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddImage(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psImage* value                     ///< Image for metadata item data
);

/** Add a Time to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddTime(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psTime* value                      ///< Time for metadata item data
);

/** Add a Hash to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddHash(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psHash* value                      ///< Hash for metadata item data
);

/** Add a LookupTable to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddLookupTable(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psLookupTable* value               ///< LookupTable for metadata item data
);

/** Add an Unknown (psPtr) to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddUnknown(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psPtr value                        ///< Unknown for metadata item data
);

/** Add a psPtr to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddPtr(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    psDataType type,                   ///< psDataType for metadata item
    const char* comment,               ///< Comment for metadata item
    psPtr value                        ///< Unknown for metadata item data
);

/** Add Metadata to metadata collection.
 *
 *  @return bool:  True for success, False for failure.
 */
bool psMetadataAddMetadata(
    psMetadata* md,                    ///< Metadata collection to insert metadata item
    long location,                     ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* name,                  ///< Name of metadata item
    int format,                        ///< psMetadataFlag options/flags
    const char* comment,               ///< Comment for metadata item
    psMetadata* value                  ///< Metadata for metadata item data
);

/** Removes an item from metadata by key name.
 *
 *  @return bool:  True for success, false for failure.
 */
bool psMetadataRemoveKey(
    psMetadata *md,                    ///< Metadata collection to remove metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Removes an item from metadata by index number.
 *
 *  @return bool:  True for success, false for failure.
 */
bool psMetadataRemoveIndex(
    psMetadata *md,                    ///< Metadata collection to remove metadata item.
    long location                       ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
);

/** Find an item in the metadata collection based on key name.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the first item is returned. If the item is not found, null is
 *  returned.
 *
 * @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataLookup(
    const psMetadata * md,             ///< Metadata collection to lookup metadata item.
    const char * key                   ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its double precision value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psF64 : Value of metadata item.
 */
psF64 psMetadataLookupF64(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its single precision value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psF32 : Value of metadata item.
 */
psF32 psMetadataLookupF32(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its integer value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psS8 : Value of metadata item.
 */
psS8 psMetadataLookupS8(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its integer value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psS16 : Value of metadata item.
 */
psS16 psMetadataLookupS16(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its integer value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psS32 : Value of metadata item.
 */
psS32 psMetadataLookupS32(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its integer value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psS64 : Value of metadata item.
 */
psS64 psMetadataLookupS64(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its integer value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psU8 : Value of metadata item.
 */
psU8 psMetadataLookupU8(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its integer value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psU16 : Value of metadata item.
 */
psU16 psMetadataLookupU16(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its integer value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psU32 : Value of metadata item.
 */
psU32 psMetadataLookupU32(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its integer value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return psU64 : Value of metadata item.
 */
psU64 psMetadataLookupU64(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its boolean value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return bool : Value of metadata item.
 */
bool psMetadataLookupBool(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its integer value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 * @return void* : Value of metadata item.
 */
psPtr psMetadataLookupPtr(
    bool *status,                      ///< Status of lookup.
    const psMetadata* md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on list index.
 *
 *  Items may be found in the metadata by their entry position in the list
 *  container.
 *
 *  @return psMetadataItem* : Pointer metadata item.
 */
psMetadataItem* psMetadataGet(
    const psMetadata* md,              ///< Metadata collection to retrieve metadata item.
    int location                       ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
);

/** Creates a psMetadataIterator to iterate over the specified psMetadata.
 *
 *  Supports the subsetting of the metadata via keyword using regular
 *  expression.  If no regular expression is specified, iteration
 *  over the entire psMetadata is performed.
 *
 *  @return psMetadataIterator*        a new psMetadataIterator, of NULL if error occurred
 */
psMetadataIterator* psMetadataIteratorAlloc(
    const psMetadata* md,  ///< the psMetadata to iterate with
    long location,   ///< Index number, PS_LIST_HEAD, or PS_LIST_TAIL
    const char* regex
    ///< A regular expression for subsetting the psMetadata.  If NULL, no
    ///< subsetting is performed.
);

/** Set the iterator of the psMetadat to a given position.  If location is
 *  invalid the iterator position is not changed.
 *
 *  @return bool        TRUE if iterator successfully set, otherwise FALSE.
*/
bool psMetadataIteratorSet(
    psMetadataIterator* iterator,      ///< psMetadata iterator
    long location                      ///< index number, PS_LIST_HEAD, or PS_LIST_TAIL
);

/** Position the specified iterator to the next matching item in psMetadata,
 *  given the regular expression of the iterator
 *
 *  @return psPtr       the psMetadataItem at the original iterator position
 *                      or NULL if the iterator went past the end of the list.
 */
psMetadataItem* psMetadataGetAndIncrement(
    psMetadataIterator* iterator       ///< iterator to move
);

/** Position the specified iterator to the previous matching item in psMetadata,
 *  given the regular expression of the iterator
 *
 *  @return psPtr       the psMetadataItem at the original iterator position
 *                      or NULL if the iterator went past the beginning of the
 *                      list.
 */
psMetadataItem* psMetadataGetAndDecrement(
    psMetadataIterator* iterator       ///< iterator to move
);

/** Find an item in the metadata collection based on key name and return its metadata value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 *  @return psMetadata*:        Value of metadata item.
 */
psMetadata *psMetadataLookupMetadata(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return its string value.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 *  @return psString:           Value of metadata item.
 */
psString psMetadataLookupStr(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);

/** Find an item in the metadata collection based on key name and return it as a psTime pointer.
 *
 *  Items may be found in the metadata by providing a key. If the key is
 *  non-unique, the value of the first item is returned. If the item is not found, zero is
 *  returned.
 *
 *  @return psTime:           Value of metadata item.
 */

psTime *psMetadataLookupTime(
    bool *status,                      ///< Status of lookup.
    const psMetadata *md,              ///< Metadata collection to lookup metadata item.
    const char *key                    ///< Name of metadata key.
);


/** Prints metadata collection.
 *
 *  Metadata contents are printed to a valid file descriptor if one exists.  Otherwise,
 *  fd should be NULL and the contents are printed to the screen (stdout).
 *
 *  @return bool:           True if successful, otherwise false.
*/
bool psMetadataPrint(
    FILE *fd,                          ///< File Descriptor or NULL
    const psMetadata *md,              ///< Metadata collection to print.
    int level                          ///< the level of metadata items.
);

/** Allocates a new psPolynomial1D structure with information from a psMetadata.
 *
 *  Parses a psMetadata container with psPolynomial1D information.  The first two
 *  elements of the metadata folder specify the order of the x & y variables.  (ie,
 *  NORDER_X, NORDER_Y).  The following elements are the values of the coefficients
 *  and the coefficient errors.  (ie, VAL_X00_Y00, ERR_X00_Y00, etc.).  If the orders
 *  or any coefficients are missing or have incorrect syntax, NULL is returned.
 *
 *  @return psPolynomial1D*:        Newly allocated psPolynomial1D from metadata.
 */
psPolynomial1D *psPolynomial1DfromMetadata(
    const psMetadata *folder                 ///< folder containing the polynomial info.
);

/** Stores the information from a psPolynomial1D structure in a psMetadata container.
 *
 *  Creates a psMetadata folder with psPolynomial1D information.  The first two
 *  elements of the metadata folder specify the order of the x & y variables.  (ie,
 *  NORDER_X, NORDER_Y).  The following elements are the values of the coefficients
 *  and the coefficient errors.  (ie, VAL_X00_Y00, ERR_X00_Y00, etc.).  The input
 *  polynomial must be of ordinary type and have a valid name format.  False is also
 *  returned if any inputs are NULL.  *If a particular mask element is non-zero, that
 *  polynomial coefficient (and error) are skipped.
 *
 *  @return bool:       True if successful, otherwise false.
 */
bool psPolynomial1DtoMetadata(
    psMetadata *md,                    ///< Metadata container for polynomial storage.
    const psPolynomial1D *poly,        ///< Polynomial information to be stored.
    const char *format,                ///< Name of polynomial folder.
    ...                                ///< Arguments for name formatting.
);

/** Allocates a new psPolynomial2D structure with information from a psMetadata.
 *
 *  Parses a psMetadata container with psPolynomial2D information.  The first two
 *  elements of the metadata folder specify the order of the x & y variables.  (ie,
 *  NORDER_X, NORDER_Y).  The following elements are the values of the coefficients
 *  and the coefficient errors.  (ie, VAL_X00_Y00, ERR_X00_Y00, etc.).  If the orders
 *  or any coefficients are missing or have incorrect syntax, NULL is returned.
 *
 *  @return psPolynomial2D*:        Newly allocated psPolynomial2D from metadata.
 */
psPolynomial2D *psPolynomial2DfromMetadata(
    const psMetadata *folder                 ///< folder containing the polynomial info.
);

/** Stores the information from a psPolynomial2D structure in a psMetadata container.
 *
 *  Creates a psMetadata folder with psPolynomial2D information.  The first two
 *  elements of the metadata folder specify the order of the x & y variables.  (ie,
 *  NORDER_X, NORDER_Y).  The following elements are the values of the coefficients
 *  and the coefficient errors.  (ie, VAL_X00_Y00, ERR_X00_Y00, etc.).  The input
 *  polynomial must be of ordinary type and have a valid name format.  False is also
 *  returned if any inputs are NULL.  *If a particular mask element is non-zero, that
 *  polynomial coefficient (and error) are skipped.
 *
 *  @return bool:       True if successful, otherwise false.
 */
bool psPolynomial2DtoMetadata(
    psMetadata *md,                    ///< Metadata container for polynomial storage.
    const psPolynomial2D *poly,              ///< Polynomial information to be stored.
    const char *format,                      ///< Name of polynomial folder.
    ...                                ///< Arguments for name formatting.
);

/** Allocates a new psPolynomial3D structure with information from a psMetadata.
 *
 *  Parses a psMetadata container with psPolynomial3D information.  The first three
 *  elements of the metadata folder specify the order of the x, y, & z variables.  (ie,
 *  NORDER_X, NORDER_Y, NORDER_Z).  The following elements are the values of the
 *  coefficients and the coefficient errors.  (ie, VAL_X00_Y00_Z00, ERR_X00_Y00_Z00,
 *  etc.).  If the orders or any coefficients are missing or have incorrect syntax,
 *  NULL is returned.
 *
 *  @return psPolynomial3D*:        Newly allocated psPolynomial3D from metadata.
 */
psPolynomial3D *psPolynomial3DfromMetadata(
    const psMetadata *folder                 ///< folder containing the polynomial info.
);

/** Stores the information from a psPolynomial3D structure in a psMetadata container.
 *
 *  Creates a psMetadata folder with psPolynomial3D information.  The first three
 *  elements of the metadata folder specify the order of the x, y, & z variables.  (ie,
 *  NORDER_X, NORDER_Y, NORDER_Z).  The following elements are the values of the
 *  coefficients and the coefficient errors.  (ie, VAL_X00_Y00_Z00, ERR_X00_Y00_Z00,
 *  etc.).  The input polynomial must be of ordinary type and have a valid name format.
 *  False is also returned if any inputs are NULL.  *If a particular mask element is
 *  non-zero, that polynomial coefficient (and error) are skipped.
 *
 *  @return bool:       True if successful, otherwise false.
 */
bool psPolynomial3DtoMetadata(
    psMetadata *md,                    ///< Metadata container for polynomial storage.
    const psPolynomial3D *poly,              ///< Polynomial information to be stored.
    const char *format,                      ///< Name of polynomial folder.
    ...                                ///< Arguments for name formatting.
);

/** Allocates a new psPolynomial4D structure with information from a psMetadata.
 *
 *  Parses a psMetadata container with psPolynomial4D information.  The first four
 *  elements of the metadata folder specify the order of the x, y, z, & t variables.
 *  (ie, NORDER_X, NORDER_Y, NORDER_Z, NORDER_T).  The following elements are the
 *  values of the coefficients and the coefficient errors.  (ie, VAL_X00_Y00_Z00_T00,
 *  ERR_X00_Y00_Z00_T00, etc.).  If the orders or any coefficients are missing or
 *  have incorrect syntax, NULL is returned.
 *
 *  @return psPolynomial4D*:        Newly allocated psPolynomial4D from metadata.
 */
psPolynomial4D *psPolynomial4DfromMetadata(
    const psMetadata *folder                 ///< folder containing the polynomial info.
);

/** Stores the information from a psPolynomial4D structure in a psMetadata container.
 *
 *  Creates a psMetadata folder with psPolynomial4D information.  The first four
 *  elements of the metadata folder specify the order of the x, y, z, & t variables.
 *  (ie, NORDER_X, NORDER_Y, NORDER_Z, NORDER_T).  The following elements are the values
 *  of the coefficients and the coefficient errors.  (ie, VAL_X00_Y00_Z00_T00,
 *  ERR_X00_Y00_Z00_T00, etc.).  The input polynomial must be of ordinary type and have
 *  a valid name format.  False is also returned if any inputs are NULL.  *If a particular
 *  mask element is non-zero, that polynomial coefficient (and error) are skipped.
 *
 *  @return bool:       True if successful, otherwise false.
 */
bool psPolynomial4DtoMetadata(
    psMetadata *md,                    ///< Metadata container for polynomial storage.
    const psPolynomial4D *poly,              ///< Polynomial information to be stored.
    const char *format,                      ///< Name of polynomial folder.
    ...                                ///< Arguments for name formatting.
);


/// Assert on metadata with extant hash and list components
#define PS_ASSERT_METADATA_NON_NULL(NAME, RVAL) \
if (!(NAME) || !(NAME)->hash || !(NAME)->list) { \
    psError(PS_ERR_BAD_PARAMETER_VALUE, true, \
            "Error: Metadata %s or one of its components is NULL.", \
            #NAME); \
    return RVAL; \
}

/// @}
#endif // #ifndef PS_METADATA_H

---