Symbian^3 Application Developer Library >

Mem Class Reference

class Mem

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.

Public Member Functions
IMPORT_C const TCollationMethod * CollationMethodById ( TUint )
IMPORT_C const TCollationMethod * CollationMethodByIndex ( TInt )
IMPORT_C TUint CollationMethodId ( TInt )
IMPORT_C TInt CollationMethods ()
IMPORT_C TInt Compare (const TUint8 *, TInt , const TUint8 *, TInt )
IMPORT_C TInt Compare (const TUint16 *, TInt , const TUint16 *, TInt )
IMPORT_C TInt CompareC (const TUint8 *, TInt , const TUint8 *, TInt )
IMPORT_C TInt CompareC (const TUint16 *, TInt , const TUint16 *, TInt )
IMPORT_C TInt CompareC (const TUint16 *, TInt , const TUint16 *, TInt , TInt , const TCollationMethod *)
IMPORT_C TInt CompareF (const TUint8 *, TInt , const TUint8 *, TInt )
IMPORT_C TInt CompareF (const TUint16 *, TInt , const TUint16 *, TInt )
TUint8 * Copy ( TAny *, const TAny *, TInt )
IMPORT_C void Crc ( TUint16 &, const TAny *, TInt )
IMPORT_C void Crc32 ( TUint32 &, const TAny *, TInt )
void Fill ( TAny *, TInt , TChar )
void FillZ ( TAny *, TInt )
IMPORT_C const TCollationMethod * GetDefaultMatchingTable ()
TUint8 * Move ( TAny *, const TAny *, TInt )
IMPORT_C void Swap ( TAny *, TAny *, TInt )

Member Functions Documentation

CollationMethodById(TUint)

IMPORT_C const TCollationMethod * CollationMethodById ( TUint aId ) [static]

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.

CollationMethodByIndex(TInt)

IMPORT_C const TCollationMethod * CollationMethodByIndex ( TInt aIndex ) [static]

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.

panic
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.

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.

CollationMethodId(TInt)

IMPORT_C TUint CollationMethodId ( TInt aIndex ) [static]

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.

panic
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.

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.

CollationMethods()

IMPORT_C TInt CollationMethods ( ) [static]

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.

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

IMPORT_C TInt Compare ( const TUint8 * aLeft,
TInt aLeftL,
const TUint8 * aRight,
TInt aRightL
) [static]

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.

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

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

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.

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

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

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.

Mem::Compare

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.

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

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

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.

Mem::Compare

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.

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

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

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.

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

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

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.

Mem::Compare

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.

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

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

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.

Mem::Compare

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.

Copy(TAny *, const TAny *, TInt)

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

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.

panic
USER 90 In debug builds only, if aLength is negative.

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.

Crc(TUint16 &, const TAny *, TInt)

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

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 void Crc32 ( TUint32 & aCrc,
const TAny * aPtr,
TInt aLength
) [static]

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.

Fill(TAny *, TInt, TChar)

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

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.

panic
USER 95 In debug builds only, if aLength is negative.

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.

FillZ(TAny *, TInt)

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

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

panic
USER 95 In debug builds only, if aLength is negative.

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.

GetDefaultMatchingTable()

IMPORT_C const TCollationMethod * GetDefaultMatchingTable ( ) [static]

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.

Move(TAny *, const TAny *, TInt)

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

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.

panic
USER 93 In debug builds only, if aTrg is not word aligned.
panic
USER 92 In debug builds only, if aSrc is not word aligned.
panic
USER 91 In debug builds only, if aLength is not 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.

Swap(TAny *, TAny *, TInt)

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

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

The source and target areas can overlap.

panic
USER 94 In debug builds only, if aLength is negative.

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.

Copyright ©2010 Nokia Corporation and/or its subsidiary(-ies).
All rights reserved. Unless otherwise stated, these materials are provided under the terms of the Eclipse Public License v1.0.