Symbian
Symbian Developer Library

SYMBIAN OS V9.4

Feedback

[Index] [Previous] [Next]

#include <e32std.h>
Link against: euser.lib

Class Mem

class Mem;

Description

Contains a set of static functions which perform manipulation of data in memory.

The arguments passed to the functions of this class are pointers to memory locations and length values. These functions are, therefore, not normally used in open code but are suitable for implementing data manipulation for other classes. Typically the interface provided by such classes is typesafe and hides this direct memory to memory manipulation.

Members

Defined in Mem:

Member functions

Copy(TAny *,const TAny *,TInt)

static inline TUint8* Copy(TAny *aTrg, const TAny *aSrc, TInt aLength);

Description

Copies data from a source location to a target location and returns a pointer to the end of the copied data.

The source and target areas can overlap.

The copy operation is optimised so that if both source and target locations are aligned on a word boundary, the operation performs the copy on a word by word basis.

Parameters

TAny *aTrg

A pointer to the target location for the copy operation.

const TAny *aSrc

A pointer to the source location for the copy operation.

TInt aLength

The number of bytes to be copied. This value must not be negative.

Return value

TUint8 *

A pointer to a location aLength bytes beyond aTrg (i.e. the location aTrg+aLength).

Panic codes

USER

90 In debug builds only, if aLength is negative.

Move(TAny *,const TAny *,TInt)

static inline TUint8* Move(TAny *aTrg, const TAny *aSrc, TInt aLength);

Description

Moves a block of data from a source location to a target location and returns a pointer to the end of the moved data.

The source and target areas can overlap.

Both source and target locations must be aligned on a word boundary. The specified length must also be a multiple of 4.

Parameters

TAny *aTrg

A pointer to the target location for the move operation. This pointer must be word aligned.

const TAny *aSrc

A pointer to the source location for the move operation. This pointer must be word aligned.

TInt aLength

The number of bytes to be copied. This value must be a multiple of 4.

Return value

TUint8 *

A pointer to a location aLength bytes beyond aTrg (i.e. the location aTrg+aLength).

Panic codes

USER

93 In debug builds only, if aTrg is not word aligned.
USER

92 In debug builds only, if aSrc is not word aligned.
USER

91 In debug builds only, if aLength is not a multiple of 4.

Fill(TAny *,TInt,TChar)

static inline void Fill(TAny *aTrg, TInt aLength, TChar aChar);

Description

Fills a specified block of data with a specified character, replacing any existing content.

The function assumes that the fill character is a non-Unicode character.

Parameters

TAny *aTrg

A pointer to the location where filling is to start.

TInt aLength

The number of bytes to be filled. This value must not be negative.

TChar aChar

The fill character.

Panic codes

USER

95 In debug builds only, if aLength is negative.

FillZ(TAny *,TInt)

static inline void FillZ(TAny *aTrg, TInt aLength);

Description

Fills a specified block of data with binary zeroes (i.e. 0x00), replacing any existing content.

Parameters

TAny *aTrg

A pointer to the location where filling is to start.

TInt aLength

The number of bytes to be filled. This value must not be negative.

Panic codes

USER

95 In debug builds only, if aLength is negative.

Compare(const TUint8 *,TInt,const TUint8 *,TInt)

static inline TInt Compare(const TUint8 *aLeft, TInt aLeftL, const TUint8 *aRight, TInt aRightL);

Description

Compares a block of data at one specified location with a block of data at another specified location.

The comparison proceeds on a byte for byte basis, the result of the comparison is based on the difference of the first bytes to disagree.

The data at the two locations are equal if they have the same length and content. Where the lengths are different and the shorter section of data is the same as the first part of the longer section of data, the shorter is considered to be less than the longer.

Parameters

const TUint8 *aLeft

A pointer to the first (or left) block of 8 bit data to be compared.

TInt aLeftL

The length of the first (or left) block of data to be compared, i.e. the number of bytes.

const TUint8 *aRight

A pointer to the second (or right) block of 8 bit data to be compared.

TInt aRightL

The length of the second (or right) block of data to be compared i.e. the number of bytes.

Return value

TInt

Positive, if the first (or left) block of data is greater than the second (or right) block of data. Negative, if the first (or left) block of data is less than the second (or right) block of data. Zero, if both the first (or left) and second (or right) blocks of data have the same length and the same content.

Compare(const TUint16 *,TInt,const TUint16 *,TInt)

IMPORT_C static TInt Compare(const TUint16 *aLeft, TInt aLeftL, const TUint16 *aRight, TInt aRightL);

Description

Compares a block of data at one specified location with a block of data at another specified location.

The comparison proceeds on a double-byte for double-byte basis, the result of the comparison is based on the difference of the first pair of bytes to disagree.

The data at the two locations are equal if they have the same length and content. Where the lengths are different and the shorter section of data is the same as the first part of the longer section of data, the shorter is considered to be less than the longer.

Parameters

const TUint16 *aLeft

A pointer to the first (or left) block of 16 bit data to be compared.

TInt aLeftL

The length of the first (or left) block of data to be compared i.e. the number of double-bytes.

const TUint16 *aRight

A pointer to the second (or right) block of 16 bit data to be compared.

TInt aRightL

The length of the second (or right) block of data to be compared i.e. the number of double-bytes.

Return value

TInt

Positive, if the first (or left) block of data is greater than the second (or right) block of data. Negative, if the first (or left) block of data is less than the second (or right) block of data. Zero, if both the first (or left) and second (or right) blocks of data have the same length and the same content.

CompareF(const TUint8 *,TInt,const TUint8 *,TInt)

IMPORT_C static TInt CompareF(const TUint8 *aLeft, TInt aLeftL, const TUint8 *aRight, TInt aRightL);

Description

Compares a block of data at one specified location with a block of data at another specified location, using the standard folding method appropriate to the current locale.

Parameters

const TUint8 *aLeft

A pointer to the first (or left) block of 8 bit data to be compared.

TInt aLeftL

The length of the first (or left) block of data to be compared, i.e. the number of bytes.

const TUint8 *aRight

A pointer to the second (or right) block of 8 bit data to be compared.

TInt aRightL

The length of the second (or right) block of data to be compared, i.e. the number of bytes.

Return value

TInt

Positive, if the first (or left) block of data is greater than the second (or right) block of data. Negative, if the first (or left) block of data is less than the second (or right) block of data. Zero, if both the first (or left) and second (or right) blocks of data have the same length and the same content.

See also:

CompareF(const TUint16 *,TInt,const TUint16 *,TInt)

IMPORT_C static TInt CompareF(const TUint16 *aLeft, TInt aLeftL, const TUint16 *aRight, TInt aRightL);

Description

Compares a block of data at one specified location with a block of data at another specified location, using the standard folding method appropriate to the current locale.

Parameters

const TUint16 *aLeft

A pointer to the first (or left) block of 16 bit data to be compared.

TInt aLeftL

The length of the first (or left) block of data to be compared i.e. the number of double-bytes.

const TUint16 *aRight

A pointer to the second (or right) block of 16 bit data to be compared.

TInt aRightL

The length of the second (or right) block of data to be compared i.e the number of double-bytes.

Return value

TInt

Positive, if the first (or left) block of data is greater than the second (or right) block of data. Negative, if the first (or left) block of data is less than the second (or right) block of data. Zero, if both the first (or left) and second (or right) blocks of data have the same length and the same content.

See also:

CompareC(const TUint8 *,TInt,const TUint8 *,TInt)

Interface status: deprecated

IMPORT_C static TInt CompareC(const TUint8 *aLeft, TInt aLeftL, const TUint8 *aRight, TInt aRightL);

Description

Compares a block of data at one specified location with a block of data at another specified location using the standard collation method appropriate to the current locale.

Parameters

const TUint8 *aLeft

A pointer to the first (or left) block of 8 bit data to be compared.

TInt aLeftL

The length of the first (or left) block of data to be compared i.e. the number of bytes.

const TUint8 *aRight

A pointer to the second (or right) block of 8 bit data to be compared.

TInt aRightL

The length of the second (or right) block of data to be compared i.e. the number of bytes.

Return value

TInt

Positive, if the first (or left) block of data is greater than the second (or right) block of data. Negative, if the first (or left) block of data is less than the second (or right) block of data. Zero, if both the first (or left) and second (or right) blocks of data have the same length and the same content.

See also:

CompareC(const TUint16 *,TInt,const TUint16 *,TInt)

IMPORT_C static TInt CompareC(const TUint16 *aLeft, TInt aLeftL, const TUint16 *aRight, TInt aRightL);

Description

Compares a block of data at one specified location with a block of data at another specified location using the standard collation method appropriate to the current locale.

Parameters

const TUint16 *aLeft

A pointer to the first (or left) block of 16 bit data to be compared.

TInt aLeftL

The length of the first (or left) block of data to be compared i.e. the number of double-bytes).

const TUint16 *aRight

A pointer to the second (or right) block of 16 bit data to be compared.

TInt aRightL

The length of the second (or right) block of data to be compared i.e. the number of double-bytes.

Return value

TInt

Positive, if the first (or left) block of data is greater than the second (or right) block of data. Negative, if the first (or left) block of data is less than the second (or right) block of data. Zero, if both the first (or left) and second (or right) blocks of data have the same length and the same content.

See also:

CompareC(const TUint16 *,TInt,const TUint16 *,TInt,TInt,const TCollationMethod *)

IMPORT_C static TInt CompareC(const TUint16 *aLeft, TInt aLeftL, const TUint16 *aRight, TInt aRightL, TInt aMaxLevel, const TCollationMethod *aCollationMethod);

Description

Compares a block of data at one location with a block of data at another location using the specified collation method and collating to the specified maximum collation level.

If no collation method is supplied, a default method, appropriate to the current locale, is used.

This function is only defined for 16 bit (Unicode) build variants. This means that the function is not defined for 8 bit build variants, even when an explicit 16 bit descriptor is used.

Parameters

const TUint16 *aLeft

A pointer to the first (or left) block of 16 bit data to be compared.

TInt aLeftL

The length of the first (or left) block of data to be compared. This is the number of double-bytes.

const TUint16 *aRight

A pointer to the second (or right) block of 16 bit data to be compared.

TInt aRightL

The length of the second (or right) block of data to be compared. This is the number of double-bytes.

TInt aMaxLevel

The maximum collation level.

const TCollationMethod *aCollationMethod

A pointer to the collation method or NULL.

Return value

TInt

Positive, if this descriptor is greater than the specified descriptor. Negative, if this descriptor is less than the specified descriptor. Zero, if both descriptors have the same length and their contents are the same.

CollationMethods()

IMPORT_C static TInt CollationMethods();

Description

Gets the number of collation methods in this locale.

This function is only defined for 16 bit (Unicode) build variants. This means that the function is not defined for 8 bit build variants, even when an explicit 16 bit descriptor is used.

Return value

TInt

The number of collation methods.

CollationMethodId(TInt)

IMPORT_C static TUint CollationMethodId(TInt aIndex);

Description

Gets the Uid associated with the specified collation method.

This function is only defined for 16 bit (Unicode) build variants. This means that the function is not defined for 8 bit build variants, even when an explicit 16 bit descriptor is used.

Parameters

TInt aIndex

An index into the set of collation methods in thie locale. This value is relative to zero; i.e. a zero value refers to the first collation method. This value must not be negative, and must be less than the total number of collation methods in this locale.

Return value

TUint

The Uid of the collation method.

Panic codes

USER

132 In debug builds only, if aIndex is negative or is greater than or equal to the total number of collation methods in this locale.

CollationMethodByIndex(TInt)

IMPORT_C static const TCollationMethod* CollationMethodByIndex(TInt aIndex);

Description

Gets the collation method identified by the specified index.

This function is only defined for 16 bit (Unicode) build variants. This means that the function is not defined for 8 bit build variants, even when an explicit 16 bit descriptor is used.

Parameters

TInt aIndex

An index into the set of collation methods in this locale. This value is relative to zero; i.e. a zero value refers to the first collation method. This value must not be negative, and must be less than the total number of collation methods in this locale.

Return value

const TCollationMethod *

A pointer to the collation method.

Panic codes

USER

132 In debug builds only, if aIndex is negative or is greater than or equal to the total number of collation methods in this locale.

CollationMethodById(TUint)

IMPORT_C static const TCollationMethod* CollationMethodById(TUint aId);

Description

Gets the collation method identified by the specified Uid.

This function is only defined for 16 bit (Unicode) build variants. This means that the function is not defined for 8 bit build variants, even when an explicit 16 bit descriptor is used.

Parameters

TUint aId

The Uid of a collation method in the set of collation methods in this locale.

Return value

const TCollationMethod *

A pointer to the collation method.

GetDefaultMatchingTable()

IMPORT_C static const TCollationMethod* GetDefaultMatchingTable();

Description

Gets the collation method specific for matching purpose.

This function is only defined for 16 bit (Unicode) build variants. This means that the function is not defined for 8 bit build variants, even when an explicit 16 bit descriptor is used.

Return value

const TCollationMethod *

A pointer to the collation method

Swap(TAny *,TAny *,TInt)

IMPORT_C static void Swap(TAny *aPtr1, TAny *aPtr2, TInt aLength);

Description

Swaps a number of bytes of data between two specified locations.

The source and target areas can overlap.

Parameters

TAny *aPtr1

A pointer to the first location taking part in the swap.

TAny *aPtr2

A pointer to second location taking part in the swap.

TInt aLength

The number of bytes to be swapped between the two locations. This value must not be negative.

Panic codes

USER

94 In debug builds only, if aLength is negative.

Crc(TUint16 &,const TAny *,TInt)

IMPORT_C static void Crc(TUint16 &aCrc, const TAny *aPtr, TInt aLength);

Description

Performs a CCITT CRC checksum on the specified data.

On return from this function, the referenced 16 bit integer contains the checksummed value.

Parameters

TUint16 &aCrc

A reference to a 16 bit integer to contain the checksummed value.

const TAny *aPtr

A pointer to the start of the data to be checksummed.

TInt aLength

The length of the data to be checksummed.

Crc32(TUint32 &,const TAny *,TInt)

IMPORT_C static void Crc32(TUint32 &aCrc, const TAny *aPtr, TInt aLength);

Description

Performs a CCITT CRC-32 checksum on the specified data.

On return from this function, the referenced 32 bit integer contains the CRC value.

Parameters

TUint32 &aCrc

A reference to a 32 bit integer to contain the CRC value.

const TAny *aPtr

A pointer to the start of the data to be checksummed.

TInt aLength

The length of the data to be checksummed.

[Previous] [Top] [Next]