Symbian
Symbian OS Library

SYMBIAN OS V9.3

[Index] [Spacer] [Previous] [Next]



Location: e32des8.h
Link against: euser.lib

Class TDes8

class TDes8 : public TDesC8;

Description

Abstract base class for 8-bit modifiable descriptors.

The class encapsulates the data member containing the maximum length of data represented by an 8-bit descriptor. It also provides member functions through which the data can be modified.

The class adds to the behaviour provided by TDesC8.

This class cannot be instantiated as it is intended to form part of a class hierarchy; it provides a well defined part of descriptor behaviour. It can, however, be passed as an argument type for functions which need to both modify and access descriptor data.

Derivation

Members

Defined in TDes8:
Append(), Append(), Append(), Append(), AppendFill(), AppendFormat(), AppendFormat(), AppendFormatList(), AppendJustify(), AppendJustify(), AppendJustify(), AppendJustify(), AppendNum(), AppendNum(), AppendNum(), AppendNumFixedWidth(), AppendNumFixedWidthUC(), AppendNumUC(), Capitalize(), Collapse(), Collate(), Copy(), Copy(), Copy(), Copy(), CopyC(), CopyCP(), CopyF(), CopyLC(), CopyUC(), Delete(), Expand(), Fill(), Fill(), FillZ(), FillZ(), Fold(), Format(), FormatList(), Insert(), Justify(), LeftTPtr(), LowerCase(), MaxLength(), MaxSize(), MidTPtr(), MidTPtr(), Num(), Num(), Num(), NumFixedWidth(), NumFixedWidthUC(), NumUC(), PtrZ(), Repeat(), Repeat(), Replace(), RightTPtr(), SetLength(), SetMax(), Swap(), TDes8(), TDes8(), Trim(), TrimAll(), TrimLeft(), TrimRight(), UpperCase(), WPtr(), Zero(), ZeroTerminate(), __DECLARE_TEST, iMaxLength, operator+=(), operator=(), operator=(), operator=(), operator[](), operator[]()

Inherited from TDesC8:
Alloc(), AllocL(), AllocLC(), AtC(), Compare(), CompareC(), CompareF(), DoSetLength(), Find(), FindC(), FindF(), Left(), Length(), Locate(), LocateF(), LocateReverse(), LocateReverseF(), Match(), MatchC(), MatchF(), Mid(), Ptr(), Right(), Size(), Type(), operator!=(), operator>(), operator>=(), operator<(), operator<=(), operator==()

See also:


Construction and destruction


TDes8()

protected: inline TDes8(TInt aType, TInt aLength, TInt aMaxLength);

Description

Parameters

TInt aType

TInt aLength

TInt aMaxLength


TDes8()

protected: inline TDes8();

Description

[Top]


Member functions


operator=()

inline TDes8 &operator=(const TUint8 *aString);

Description

Copies data into this descriptor replacing any existing data.

The length of this descriptor is set to reflect the new data.

Parameters

const TUint8 *aString

A pointer to a zero-terminated string.

Return value

TDes8 &

A reference to this, the target descriptor.

Panic codes

USER

23, if the length of the string, excluding the zero terminator, is greater than the maximum length of this (target) descriptor.


operator=()

inline TDes8 &operator=(const TDesC8 &aDes);

Description

Copies data into this descriptor replacing any existing data.

The length of this descriptor is set to reflect the new data.

Parameters

const TDesC8 &aDes

An 8-bit non-modifiable descriptor.

Return value

TDes8 &

A reference to this, the target descriptor.

Panic codes

USER

23, if the length of the descriptor aDes is greater than the maximum length of this (target) descriptor.


operator=()

inline TDes8 &operator=(const TDes8 &aDes);

Description

Copies data into this descriptor replacing any existing data.

The length of this descriptor is set to reflect the new data.

Parameters

const TDes8 &aDes

An 8-bit modifiable descriptor.

Return value

TDes8 &

A reference to this, the target descriptor.

Panic codes

USER

23, if the length of the descriptor aDes is greater than the maximum length of this (target) descriptor.


MaxLength()

inline TInt MaxLength() const;

Description

Gets the maximum length of the descriptor.

This is the upper limit for the number of 8-bit values or data items that the descriptor can represent.

Return value

TInt

The maximum length of data that the descriptor can represent.


MaxSize()

inline TInt MaxSize() const;

Description

Gets the maximum size of the descriptor.

This is the upper limit for the number of bytes which the data represented by the descriptor can occupy.

Return value

TInt

The maximum size of the descriptor data.


operator[]()

inline const TUint8 &operator[](TInt anIndex) const;

Description

Gets a const reference to a single data item within this descriptor's data.

Parameters

TInt anIndex

The position of the data item within this descriptor's data. This is an offset value; a zero value refers to the leftmost data position.

Return value

const TUint8 &

A const reference to the data item at the specified position.

Panic codes

USER

21, if anIndex is negative or is greater than or equal to the current length of this descriptor.


operator[]()

inline TUint8 &operator[](TInt anIndex);

Description

Gets a non-const reference to a single data item within this descriptor's data.

Parameters

TInt anIndex

The position of the data item within this descriptor's data. This is an offset value; a zero value refers to the leftmost data position.

Return value

TUint8 &

A non-const reference to the data item at the specified position.

Panic codes

USER

21, if anIndex is negative or is greater than or equal to the current length of this descriptor.


operator+=()

inline TDes8 &operator+=(const TDesC8 &aDes);

Description

Appends data onto the end of this descriptor's data and returns a reference to this descriptor.

The length of this descriptor is incremented to reflect the new content.

Parameters

const TDesC8 &aDes

An-8 bit non-modifiable descriptor whose data is to be appended.

Return value

TDes8 &

A reference to this descriptor.

Panic codes

USER

23, if the resulting length of this descriptor is greater than its maximum length.


Zero()

IMPORT_C void Zero();

Description

Sets the length of the data to zero.


SetLength()

IMPORT_C void SetLength(TInt aLength);

Description

Sets the length of the data represented by the descriptor to the specified value.

Parameters

TInt aLength

The new length of the descriptor.

Panic codes

USER

23 if alength is negative or is greater than the maximum length of this (target) descriptor.


SetMax()

IMPORT_C void SetMax();

Description

Sets the length of the data to the maximum length of the descriptor.


Copy()

IMPORT_C void Copy(const TDesC8 &aDes);

Description

Copies data into this descriptor replacing any existing data.

The length of this descriptor is set to reflect the new data.

Parameters

const TDesC8 &aDes

An 8-bit non-modifiable descriptor. The length of the data cannot be greater than the maximum length of the target descriptor.

Panic codes

USER

23 if the length of aDes is greater than the maximum length of this (target) descriptor.


Copy()

IMPORT_C void Copy(const TUint8 *aBuf, TInt aLength);

Description

Copies data into this descriptor replacing any existing data.

The length of this descriptor is set to reflect the new data.

Parameters

const TUint8 *aBuf

The start address of data to be copied.

TInt aLength

The length of data to be copied.

Panic codes

USER

23 if aLength is greater than the maximum length of this (target) descriptor.


Copy()

IMPORT_C void Copy(const TUint8 *aString);

Description

Copies data into this descriptor replacing any existing data.

The length of this descriptor is set to reflect the new data.

Parameters

const TUint8 *aString

A pointer to a zero-terminated string.

Panic codes

USER

23 if the length of aString, excluding the zero terminator, is greater than the maximum length of this (target) descriptor.


Copy()

IMPORT_C void Copy(const TDesC16 &aDes);

Description

Copies data into this descriptor replacing any existing data.

The length of this descriptor is set to reflect the new data.

Parameters

const TDesC16 &aDes

A 16-bit non-modifiable descriptor. Each double-byte value can only be copied into the corresponding single byte when the double-byte value is less than decimal 256. A double-byte value of 256 or greater cannot be copied and the corresponding single byte is set to a value of decimal 1.

Panic codes

USER

23 if the length of the aDes is greater than the maximum length of this (target) descriptor.


Append()

IMPORT_C void Append(TChar aChar);

Description

Appends a character onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

Parameters

TChar aChar

The single character to be appended. The length of the descriptor is incremented by one. The function assumes that the character is non-Unicode and that it can be represented by a single byte.

Panic codes

USER

23 if the resulting new length of this descriptor is greater than its maximum length.


Append()

IMPORT_C void Append(const TDesC8 &aDes);

Description

Appends data onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

Parameters

const TDesC8 &aDes

An 8-bit non-modifiable descriptor whose data is to be appended.

Panic codes

USER

23 if the resulting new length of this descriptor is greater than its maximum length.


Append()

IMPORT_C void Append(const TDesC16 &aDes);

Description

Appends data onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

Parameters

const TDesC16 &aDes

A 16-bit non-modifiable descriptor whose data is to be appended. Each double-byte value can only be appended as a single byte when the double-byte value is less than decimal 256. A double-byte value of 256 or greater cannot be appended and the corresponding single byte is set to a value of decimal 1.

Panic codes

USER

23 if the resulting new length of this descriptor is greater than its maximum length.


Append()

IMPORT_C void Append(const TUint8 *aBuf, TInt aLength);

Description

Appends data onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

Parameters

const TUint8 *aBuf

A pointer to the data to be copied.

TInt aLength

The length of the data to be copied.

Panic codes

USER

23 if the resulting new length of this descriptor is greater than its maximum length.

USER

29 if aLength is negative.


Fill()

IMPORT_C void Fill(TChar aChar);

Description

Fills the descriptor's data area with the specified character, replacing any existing data.

The descriptor is filled from the beginning up to its current length. The descriptor's length does not change. It is not filled to its maximum length.

Parameters

TChar aChar

The fill character. The function assumes that the character is non-Unicode, and that it can be represented by a single byte.


Fill()

IMPORT_C void Fill(TChar aChar, TInt aLength);

Description

Fills the descriptor's data area with the specified character, replacing any existing data.

The descriptor is filled with the specified number of characters. and its length is changed to reflect this.

Parameters

TChar aChar

The fill character. The function assumes that the character is non-Unicode, and that it can be represented by a single byte.

TInt aLength

The new length of the descriptor and the number of fill characters to be copied into it.

Panic codes

USER

23 if aLength is negative or is greater than the maximum length of this descriptor.


FillZ()

IMPORT_C void FillZ();

Description

Fills the descriptor's data area with binary zeroes, i.e. 0x00, replacing any existing data.

The descriptor is filled from the beginning up to its current length. The descriptor's length does not change. It is not filled to its maximum length.


FillZ()

IMPORT_C void FillZ(TInt aLength);

Description

Fills the descriptor's data area with binary zeroes, i.e. 0x00, replacing any existing data, and changes its length.

The descriptor is filled with the specified number of binary zeroes. The descriptor's length is changed to reflect this.

Parameters

TInt aLength

The new length of the descriptor and the number of binary zeroes to be copied into it.

Panic codes

USER

23 if aLength is negative, or is greater than the maximum length of this descriptor.


Num()

IMPORT_C void Num(TInt64 aVal);

Description

Converts the 64-bit signed integer into a decimal character representation and copies the conversion into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

If the integer is negative, the character representation is prefixed by a minus sign.

Parameters

TInt64 aVal

The 64-bit signed integer value.


Num()

IMPORT_C void Num(TUint64 aVal, TRadix aRadix);

Description

Converts the specified 64-bit unsigned integer into a character representation based on the specified number system and copies the conversion into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

When a hexadecimal conversion is specified, hexadecimal characters are in lower case.

Parameters

TUint64 aVal

The 64-bit integer value. This is treated as an unsigned value.

TRadix aRadix

The number system representation for the 64-bit integer.


NumFixedWidth()

IMPORT_C void NumFixedWidth(TUint aVal, TRadix aRadix, TInt aWidth);

Description

Converts the specified unsigned integer into a fixed width character representation based on the specified number system and copies the conversion into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

The function generates the exact number of specified characters, either padding to the left with character zeroes or discarding low order characters as necessary.

When a hexadecimal conversion is specified, hexadecimal characters are in lower case.

This function is equivalent to using Format() with parameters which specify:

1. a fixed length target field

2. padding with zero characters, for example "%08x".

When this is the case, always use NumFixedWidth() in preference to Format() as it is more efficient.

Parameters

TUint aVal

The unsigned integer value.

TRadix aRadix

The number system representation for the unsigned integer.

TInt aWidth

The number of characters: to be used to contain the conversion, to be copied into this descriptor.

See also:


AppendNum()

IMPORT_C void AppendNum(TInt64 aVal);

Description

Converts the 64-bit signed integer into a decimal character representation and appends the conversion onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

If the integer is negative, the character representation is prefixed by a minus sign.

Parameters

TInt64 aVal

The 64-bit signed integer value.


AppendNum()

IMPORT_C void AppendNum(TUint64 aVal, TRadix aRadix);

Description

Converts the specified 64-bit unsigned integer into a character representation based on the specified number system and appends the conversion onto the end of this descriptor's data. The length of this descriptor is incremented to reflect the new content

When a hexadecimal conversion is specified, hexadecimal characters are in lower case.

Parameters

TUint64 aVal

The 64-bit integer value. This is treated as an unsigned value.

TRadix aRadix

The number system representation for the 64-bit integer.


AppendNumFixedWidth()

IMPORT_C void AppendNumFixedWidth(TUint aVal, TRadix aRadix, TInt aWidth);

Description

Converts the specified unsigned integer into a fixed width character representation based on the specified number system and appends the conversion onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

The function generates the exact number of specified characters, either padding to the left with character zeroes or discarding low order characters as necessary.

When a hexadecimal conversion is specified, hexadecimal characters are in lower case.

Parameters

TUint aVal

The unsigned integer value.

TRadix aRadix

The number system representation for the unsigned integer.

TInt aWidth

The number of characters to be used to contain the conversion, and to be appended to this descriptor.


LeftTPtr()

IMPORT_C TPtr8 LeftTPtr(TInt aLength) const;

Description

Extracts the leftmost part of the data.

The function does not cut or remove any data but constructs a modifiable pointer descriptor to represent the leftmost part of the data.

Parameters

TInt aLength

The length of the data to be extracted. If this value is greater than the length of the descriptor, the function extracts the whole of the descriptor.

Return value

TPtr8

The 8-bit modifiable pointer descriptor representing the leftmost part of the data.

Panic codes

USER

22 if aLength is negative.


RightTPtr()

IMPORT_C TPtr8 RightTPtr(TInt aLength) const;

Description

Extracts the rightmost part of the data.

The function does not cut or remove any data but constructs a modifiable pointer descriptor to represent the rightmost part of the data.

Parameters

TInt aLength

The length of data to be extracted. If this value is greater than the length of the descriptor, the function extracts the whole of the descriptor.

Return value

TPtr8

The 8 bit modifiable pointer descriptor representing the rightmost part of the data.

Panic codes

USER

22 if aLength is negative.


MidTPtr()

IMPORT_C TPtr8 MidTPtr(TInt aPos) const;

Description

Extracts a portion of the data.

The function does not cut or remove any data but constructs a modifiable pointer descriptor to represent the defined portion.

The portion is identified by its starting position and by the length of the remainder of the data starting from the specified position.

Parameters

TInt aPos

The starting position of the data to be extracted. This is an offset value; a zero value refers to the leftmost data position.

Return value

TPtr8

The 8-bit modifiable pointer descriptor representing the specified portion of the data.

Panic codes

USER

22 if aPos is negative or aPos is greater than the length of the descriptor.


MidTPtr()

IMPORT_C TPtr8 MidTPtr(TInt aPos, TInt aLength) const;

Description

Extracts a portion of the data.

The function does not cut or remove any data but constructs a modifiable pointer descriptor to represent the defined portion.

The portion is identified by its starting position and by its length.

Parameters

TInt aPos

The starting position of the data to be extracted. This is an offset value; a zero value refers to the leftmost data position.

TInt aLength

The length of data to be extracted.

Return value

TPtr8

The 8 bit modifiable pointer descriptor representing the specified portion of the data.

Panic codes

USER

22 if aPos is negative or aPos plus aLength is greater than the length of the descriptor.


PtrZ()

IMPORT_C const TUint8 *PtrZ();

Description

Appends a zero terminator onto the end of this descriptor's data and returns a pointer to the data.

The length of the descriptor is not changed. It must, however, be strictly less than the descriptor's maximum length. This condition guarantees that there is sufficient space for the zero terminator.

Return value

const TUint8 *

A pointer to the descriptor's zero terminated data.

Panic codes

USER

23 if the descriptor's length is not strictly less than its maximum length.


CopyF()

IMPORT_C void CopyF(const TDesC8 &aDes);

Description

Copies and folds data from the specified descriptor into this descriptor replacing any existing data.

The length of this descriptor is set to reflect the new data.

Note that folding is locale-independent behaviour. It is also important to note that there can be no guarantee that folding is in any way culturally appropriate, and should not be used when dealing with strings in natural language.

Parameters

const TDesC8 &aDes

An 8-bit non-modifiable descriptor.

Panic codes

USER

23 if the length of aDes is greater than the maximum length of this target descriptor.


CopyC()

IMPORT_C void CopyC(const TDesC8 &aDes);

Description

Copies and collates data from the specified descriptor into this descriptor replacing any existing data.

The length of this descriptor is set to reflect the new data.

Parameters

const TDesC8 &aDes

An 8 bit non-modifiable descriptor.

Panic codes

USER

23 if the length of aDes is greater than the maximum length of this target descriptor.


CopyLC()

IMPORT_C void CopyLC(const TDesC8 &aDes);

Description

Copies text from the specified descriptor and converts it to lower case before putting it into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

Conversion to lower case is implemented as appropriate to the current locale.

Parameters

const TDesC8 &aDes

An 8-bit non-modifiable descriptor.

Panic codes

USER

23 if the length of aDes is greater than the maximum length of this target descriptor.


CopyUC()

IMPORT_C void CopyUC(const TDesC8 &aDes);

Description

Copies text from the specified descriptor and converts it to upper case before putting it into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

Conversion to upper case is implemented as appropriate to the current locale.

Parameters

const TDesC8 &aDes

An 8-bit non-modifiable descriptor.

Panic codes

USER

23 if the length of aDes is greater than the maximum length of this target descriptor.


CopyCP()

IMPORT_C void CopyCP(const TDesC8 &aDes);

Description

Copies text from the specified descriptor and capitalises it before putting it into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

Capitalisation is implemented as appropriate to the current locale.

Parameters

const TDesC8 &aDes

An 8-bit non-modifiable descriptor.

Panic codes

USER

23 if the length of aDes is greater than the maximum length of this target descriptor.


Swap()

IMPORT_C void Swap(TDes8 &aDes);

Description

Swaps the data represented by this descriptor with the data represented by the specified descriptor.

The lengths of both descriptors are swapped to reflect the change.

Note that each descriptor must be capable of accommodating the contents of the other descriptor.

Parameters

TDes8 &aDes

The 8-bit modifiable descriptor whose data is to be swapped with the data of this descriptor.

Panic codes

USER

23 if the maximum length of either descriptor is smaller than the length of the other descriptor.


AppendFill()

IMPORT_C void AppendFill(TChar aChar, TInt aLength);

Description

Appends and fills this descriptor with the specified character.

The descriptor is appended with the specified number of characters. and its length is changed to reflect this.

Parameters

TChar aChar

The fill character. The function assumes that the character is non-Unicode and that it can be represented by a single byte.

TInt aLength

The number of fill characters to be appended.

Panic codes

USER

23 if aLength is negative, or the resulting length of this descriptor is greater than its maximum length.


ZeroTerminate()

IMPORT_C void ZeroTerminate();

Description

Appends a zero terminator onto the end of this descriptor's data.

The length of the descriptor is not changed. It must, however, be strictly less than the descriptor's maximum length. This condition guarantees that there is sufficient space for the zero terminator.

Panic codes

USER

23 if the descriptor's length is not strictly less than its maximum length.


Fold()

IMPORT_C void Fold();

Description

Performs folding on the content of this descriptor.

Note that folding is locale-independent behaviour. It is also important to note that there can be no guarantee that folding is in any way culturally appropriate, and should not be used when dealing with strings in natural language.


Collate()

IMPORT_C void Collate();

Description

Performs collation on the content of this descriptor.


LowerCase()

IMPORT_C void LowerCase();

Description

Converts the content of this descriptor to lower case.

Conversion is implemented as appropriate to the current locale.


UpperCase()

IMPORT_C void UpperCase();

Description

Converts the content of this descriptor to upper case.

Conversion is implemented as appropriate to the current locale.


Capitalize()

IMPORT_C void Capitalize();

Description

Capitalises the content of this descriptor.

Capitalisation is implemented as appropriate to the current locale.


Repeat()

IMPORT_C void Repeat(const TUint8 *aBuf, TInt aLength);

Description

Copies data with repetition into this descriptor, from a memory location specified by pointer, replacing any existing data.

Copying proceeds until this descriptor is filled up to its current length. If it cannot contain a whole number of copies of the source data, then the last copy is truncated.

Parameters

const TUint8 *aBuf

A pointer to data to be repeatedly copied.

TInt aLength

The length of data to be copied.

Panic codes

USER

29 if aLength is negative.


Repeat()

IMPORT_C void Repeat(const TDesC8 &aDes);

Description

Copies data with repetition into this descriptor, from another descriptor, replacing any existing data.

Copying proceeds until this descriptor is filled up to its current length. If it cannot contain a whole number of copies of the source data, then the last copy is truncated.

Parameters

const TDesC8 &aDes

An 8-bit non-modifiable descriptor whose data is to be repeatedly copied.


Trim()

IMPORT_C void Trim();

Description

Deletes leading and trailing whitespace characters from the descriptor's data.

The length of the descriptor is reduced to reflect the loss of the whitespace characters.

See also:


TrimAll()

IMPORT_C void TrimAll();

Description

Deletes leading and trailing whitespace characters from the descriptor's data and replaces each contiguous set of whitespace characters within the data by one whitespace character.

The length of the descriptor is reduced to reflect the loss of the whitespace characters.

See also:


TrimLeft()

IMPORT_C void TrimLeft();

Description

Deletes leading whitespace characters from the descriptor's data.

All whitespace characters up to, but not including the first non-whitespace character, are deleted.

The length of the descriptor is reduced to reflect the loss of the whitespace characters.


TrimRight()

IMPORT_C void TrimRight();

Description

Deletes trailing whitespace characters from the descriptor's data.

The process starts on the right hand side of the descriptor's data and proceeds to the left.

All whitespace characters up to, but not including the first non-whitespace character, are deleted.

The length of the descriptor is reduced to reflect the loss of the whitespace characters.


Insert()

IMPORT_C void Insert(TInt aPos, const TDesC8 &aDes);

Description

Inserts data into this descriptor.

The length of this descriptor is changed to reflect the extra data.

Parameters

TInt aPos

The position within the data where insertion is to start. This is an offset value; a zero value refers to the leftmost data position.

const TDesC8 &aDes

An 8 bit non modifiable descriptor whose data is to be inserted.

Panic codes

USER

22 if aPos is negative or is greater than the length of this descriptor.

USER

23 if the resulting length of this descriptor is greater than its maximum length.


Delete()

IMPORT_C void Delete(TInt aPos, TInt aLength);

Description

Deletes data from this descriptor.

The length of this descriptor is changed to reflect the loss of data.

Parameters

TInt aPos

The position within the data where deletion is to start. This is an offset value; a zero value refers to the leftmost data position.

TInt aLength

The length of data to be deleted. If necessary, the function adjusts this value to ensure that no data beyond the end of the descriptor data area is deleted.

Panic codes

USER

22 if aPos is negative or is greater than the length of this descriptor.


Replace()

IMPORT_C void Replace(TInt aPos, TInt aLength, const TDesC8 &aDes);

Description

Replaces data in this descriptor.

The specified length can be different to the length of the replacement data. The length of this descriptor changes to reflect the change of data.

Parameters

TInt aPos

The position within the data where replacement is to start. This is an offset value; a zero value refers to the leftmost data position.

TInt aLength

The length of data to be replaced.

const TDesC8 &aDes

The source 8-bit non-modifiable descriptor whose data is to replace the target descriptor's data at aPos.

Panic codes

USER

20 if aLength is negative or the sum of aLength and aPos is greater than the length of this descriptor.

USER

22 if aPos is negative or is greater than the length of this descriptor.

USER

23 if the resulting length of this descriptor is greater than its maximum length.

USER

28 if the length of the source descriptor aDes is negative or is greater than the maximum length of this target descriptor,


Justify()

IMPORT_C void Justify(const TDesC8 &aDes, TInt aWidth, TAlign anAlignment, TChar aFill);

Description

Copies data into this descriptor and justifies it, replacing any existing data.

The length of this descriptor is set to reflect the new data.

The target area is considered to be an area of specified width positioned at the beginning of this descriptor's data area. Source data is copied into, and aligned within this target area according to the specified alignment instruction.

If the length of the target area is larger than the length of the source, then spare space within the target area is padded with the fill character.

Parameters

const TDesC8 &aDes

An 8-bit non-modifiable descriptor containing the source data. The length of the data to be copied is the smaller of: the length of the source descriptor, and the width of the target area (only if this is not the explicit negative value KDefaultJustifyWidth).

TInt aWidth

The width of the target area. If this has the specific negative value KDefaultJustifyWidth, then the width is re-set to the length of the data source.

TAlign anAlignment

The alignment of the data within the target area

TChar aFill

The fill character used to pad the target area.

Panic codes

USER

23 if the resulting length of this descriptor is greater than its maximum length or aWidth has a negative value other than KDefaultJustifyWidth.


NumFixedWidthUC()

IMPORT_C void NumFixedWidthUC(TUint aVal, TRadix aRadix, TInt aWidth);

Description

Converts the specified unsigned integer into a fixed width character representation based on the specified number system and copies the conversion into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

The function generates the exact number of specified characters, either padding to the left with character zeroes or discarding low order characters as necessary.

When a hexadecimal conversion is specified, hexadecimal characters are in upper case.

This function is equivalent to using Format() with parameters which specify:

1. a fixed length target field

2. padding with zero characters, for example "%08x".

When this is the case, always use NumFixedWidthUC() in preference to Format() as it is more efficient.

Parameters

TUint aVal

The unsigned integer value.

TRadix aRadix

The number system representation for the unsigned integer.

TInt aWidth

The number of characters to be used to contain the conversion, and to be copied into this descriptor.

See also:


NumUC()

IMPORT_C void NumUC(TUint64 aVal, TRadix aRadix=EDecimal);

Description

Converts the specified 64-bit unsigned integer into a character representation based on the specified number system and copies the conversion into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

When a hexadecimal conversion is specified, hexadecimal characters are in upper case.

Parameters

TUint64 aVal

The 64-bit integer value. This is treated as an unsigned value.

TRadix aRadix

The number system representation for the 64-bit integer. If no explicit value is specified, then EDecimal is the default.


Num()

IMPORT_C TInt Num(TReal aVal, const TRealFormat &aFormat) __SOFTFP;

Description

Converts the specified floating point number into a character representation and copies the conversion into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

The character representation of the real number is dictated by the specified format.

Note that the function leaves if the iType data member of the specified TRealFormat object has both an invalid character representation format (i.e. the format type) and invalid format flags.

1.KErrArgument - the supplied floating point number is not a valid number. The three characters NaN are appended to this descriptor.

2.KErrOverflow - the number is too large to represent. 2.1 For positive overflow, the three characters Inf are appended to this descriptor. 2.2 For negative overflow, the four characters -Inf are appended to this descriptor.

3.KErrUnderflow - the number is too small to represent. 3.1 For positive underflow, the three characters Inf are appended to this descriptor. 3.2 For negative underflow, the four characters -Inf are appended to this descriptor.

4.KErrGeneral - the conversion cannot be completed. There are a number of possible reasons for this, but the two most common are: 4.1 the maximum number of characters necessary to represent the number, as defined in the TRealFormat object, is greater than the maximum length of this descriptor 4.2 the character representation format (i.e. the format type), as defined in the TRealFormat object is not recognised.

Parameters

TReal aVal

The floating point number to be converted.

const TRealFormat &aFormat

The format of the conversion.

Return value

TInt

If the conversion is successful, the length of this descriptor. If the conversion fails, a negative value indicating the cause of failure. In addition, extra information on the cause of the failure may be appended onto this descriptor. The possible values and their meaning are:

See also:


AppendNumFixedWidthUC()

IMPORT_C void AppendNumFixedWidthUC(TUint aVal, TRadix aRadix, TInt aWidth);

Description

Converts the specified unsigned integer into a fixed width character representation based on the specified number system and appends the conversion onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

The function generates the exact number of specified characters, either padding to the left with character zeroes or discarding low order characters as necessary.

When a hexadecimal conversion is specified, hexadecimal characters are in upper case.

Parameters

TUint aVal

The unsigned integer value.

TRadix aRadix

The number system representation for the unsigned integer.

TInt aWidth

The number of characters to be used to contain the conversion, and to be appended to this descriptor.


AppendNum()

IMPORT_C TInt AppendNum(TReal aVal, const TRealFormat &aFormat) __SOFTFP;

Description

Converts the specified floating point number into a character representation and appends the conversion onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

The character representation of the real number is dictated by the specified format.

1.KErrArgument - the supplied floating point number is not a valid number. The three characters NaN are appended to this descriptor.

2.KErrOverflow - the number is too large to represent. 2.1 For positive overflow, the three characters Inf are appended to this descriptor. 2.2 For negative overflow, the four characters -Inf are appended to this descriptor.

3.KErrUnderflow - the number is too small to represent. 3.1 For positive underflow, the three characters Inf are appended to this descriptor. 3.2 For negative underflow, the four characters -Inf are appended to this descriptor.

4.KErrGeneral - the conversion cannot be completed. There are a number of possible reasons for this, but the two most common are: 4.1 the maximum number of characters necessary to represent the number, as defined in the TRealFormat object, is greater than the maximum length of this descriptor 4.2 the character representation format (i.e. the format type), as defined in the TRealFormat object is not recognised

Parameters

TReal aVal

The floating point number to be converted.

const TRealFormat &aFormat

The format of the conversion.

Return value

TInt

If the conversion is successful, the length of this descriptor. If the conversion fails, a negative value indicating the cause of failure. In addition, extra information on the cause of the failure may be appended onto this descriptor. The possible values and their meaning are:


AppendNumUC()

IMPORT_C void AppendNumUC(TUint64 aVal, TRadix aRadix=EDecimal);

Description

Converts the specified 64-bit unsigned integer into a character representation based on the specified number system and appends the conversion onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

When a hexadecimal conversion is specified, hexadecimal characters are in upper case.

Parameters

TUint64 aVal

The 64-bit integer value. This is treated as an unsigned value.

TRadix aRadix

The number system representation for the 64-bit integer. If no explicit value is specified, then EDecimal is the default.


Format()

IMPORT_C void Format(TRefByValue< const TDesC8 > aFmt,...);

Description

Formats and copies text into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

The function takes a format string and a variable number of arguments. The format string contains literal text embedded with directives for converting the trailing list of arguments into text.

The embedded directives are character sequences prefixed with the '%' character. The literal text is simply copied into this descriptor unaltered while the '%' directives are used to convert successive arguments from the trailing list.

The resulting stream of literal text and converted arguments is copied into this descriptor.

The syntax of the embedded directives follows one of four general patterns.

Note that formatting of single numerical values can be achieved more conveniently using the Num() and NumUC() member functions of this class.

The full description of the syntax of a format string cannot be included here. For full details, navigate to the Symbian OS guide, and follow the hierarchy of links:

Symbian OS Guide
    Base
        Using  User Library (E32)
            Buffers and Strings
                Using Descriptors
                    How to Use Descriptors
                        Format string syntax

Parameters

TRefByValue< const TDesC8 > aFmt

The descriptor containing the format string. The TRefByValue class provides a constructor which takes a TDesC8 type.

...

Panic codes

USER

23 if the resulting length of text in this descriptor exceeds the descriptor's maximum length.

USER

24 if the format string has incorrect syntax.

See also:


FormatList()

IMPORT_C void FormatList(const TDesC8 &aFmt, VA_LIST aList);

Description

Formats and copies text into this descriptor, replacing any existing data.

The length of this descriptor is set to reflect the new data.

The behaviour of this function is the same as Format(). In practice, it is better and easier to use Format(), passing a variable number of arguments as required by the format string.

Parameters

const TDesC8 &aFmt

The descriptor containing the format string.

VA_LIST aList

A pointer to an argument list.

See also

See also:


AppendJustify()

IMPORT_C void AppendJustify(const TDesC8 &Des, TInt aWidth, TAlign anAlignment, TChar aFill);

Description

Appends data onto the end of this descriptor's data and justifies it.

The source of the appended data is an existing descriptor.

The target area is considered to be an area of specified width, immediately following this descriptor's existing data. Source data is copied into, and aligned within this target area according to the specified alignment instruction.

If the length of the target area is larger than the length of the source, then spare space within the target area is padded with the fill character.

Parameters

const TDesC8 &Des

An 8-bit non-modifiable descriptor containing the source data. The length of the data to be copied is the smaller of: the length of the source descriptor, and the width of the target area (only if this is not the explicit negative value KDefaultJustifyWidth).

TInt aWidth

The width of the target area. If this has the specific negative value KDefaultJustifyWidth, then the width is re-set to the length of the data source.

TAlign anAlignment

The alignment of the data within the target area.

TChar aFill

The fill character used to pad the target area.

Panic codes

USER

23 if the resulting length of this descriptor is greater than its maximum length or aWidth has a negative value other than KDefaultJustifyWidth.


AppendJustify()

IMPORT_C void AppendJustify(const TDesC8 &Des, TInt aLength, TInt aWidth, TAlign anAlignment, TChar aFill);

Description

Appends data onto the end of this descriptor's data and justifies it.

The source of the appended data is an existing descriptor.

The target area is considered to be an area of specified width, immediately following this descriptor's existing data. Source data is copied into, and aligned within this target area according to the specified alignment instruction.

If the length of the target area is larger than the length of the source, then spare space within the target area is padded with the fill character.

Parameters

const TDesC8 &Des

An 8-bit non-modifiable descriptor containing the source data.

TInt aLength

The length of data to be copied from the source descriptor. If this is greater than the width of the target area, then the length of data copied is limited to the width. The length of data to be copied must not be greater than the length of the source descriptor. Note that this condition is not automatically tested.

TInt aWidth

The width of the target area. If this has the specific negative value KDefaultJustifyWidth, then the width is re-set to the length of the data source.

TAlign anAlignment

The alignment of the data within the target area.

TChar aFill

The fill character used to pad the target area.

Panic codes

USER

23 if the resulting length of this descriptor is greater than its maximum length or aWidth has a negative value other than KDefaultJustifyWidth.


AppendJustify()

IMPORT_C void AppendJustify(const TUint8 *aString, TInt aWidth, TAlign anAlignment, TChar aFill);

Description

Appends a zero terminated string onto the end of this descriptor's data and justifies it.

The zero terminator is not copied.

The target area is considered to be an area of specified width, immediately following this descriptor's existing data. Source data is copied into, and aligned within, this target area according to the specified alignment instruction.

If the length of the target area is larger than the length of the source, then spare space within the target area is padded with the fill character.

Parameters

const TUint8 *aString

A pointer to a zero terminated string. The length of the data to be copied is the smaller of: the length of the string (excluding the zero terminator), and the width of the target area (only if this is not the explicit negative value KDefaultJustifyWidth).

TInt aWidth

The width of the target area. If this has the specific negative value KDefaultJustifyWidth, then the width is re-set to the length of the zero terminated string (excluding the zero terminator).

TAlign anAlignment

The alignment of the data within the target area.

TChar aFill

The fill character used to pad the target area.

Panic codes

USER

23 if the resulting length of this descriptor is greater than its maximum length or aWidth has a negative value other than KDefaultJustifyWidth.


AppendJustify()

IMPORT_C void AppendJustify(const TUint8 *aString, TInt aLength, TInt aWidth, TAlign anAlignment, TChar aFill);

Description

Appends data onto the end of this descriptor's data and justifies it.

The source of the appended data is a memory location.

The target area is considered to be an area of specified width, immediately following this descriptor's existing data. Source data is copied into, and aligned within, this target area according to the specified alignment instruction.

If the length of the target area is larger than the length of the source, then spare space within the target area is padded with the fill character.

Parameters

const TUint8 *aString

A pointer to a source memory location.

TInt aLength

The length of data to be copied. If this is greater than the width of the target area, then the length of data copied is limited to the width.

TInt aWidth

The width of the target area. If this has the specific negative value KDefaultJustifyWidth, then the width is re-set to the length of the data source.

TAlign anAlignment

The alignment of the data within the target area.

TChar aFill

The fill character used to pad the target area.

Panic codes

USER

23 if the resulting length of this descriptor is greater than its maximum length or aWidth has a negative value other than KDefaultJustifyWidth.

USER

29 if aLength is negative.


AppendFormat()

IMPORT_C void AppendFormat(TRefByValue< const TDesC8 > aFmt, TDes8Overflow *aOverflowHandler,...);

Description

Formats and appends text onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

The function takes a format string and a variable number of arguments. The format string contains literal text, embedded with directives, for converting the trailing list of arguments into text.

The embedded directives are character sequences prefixed with the '%' character. The literal text is simply copied into this descriptor unaltered while the '%' directives are used to convert successive arguments from the trailing list. See the description of the Format() function.

Literal text is appended on a character by character basis. If it results in the length of this descriptor exceeding its maximum length, then the function:

1. calls the Overflow() member function of the overflow handler, if an overflow handler is supplied 2 raises a USER 23 panic, if no overflow handler is supplied.

As much literal text as possible will have been copied into this descriptor and this descriptor will have reached its maximum length.

Text converted from a trailing argument is appended as a complete string. If an attempt to append this string fails because the resulting length of this descriptor would exceed its maximum length, then the function:

1. calls the Overflow() member function of the overflow handler, if an overflow handler is supplied

2 raises a USER 23 panic, if no overflow handler is supplied.

None of the generated text is appended and length of this descriptor may be less than the maximum.

Parameters

TRefByValue< const TDesC8 > aFmt

The 8-bit non-modifiable descriptor containing the format string. The TRefByValue class provides a constructor which takes a TDesC8 type.

TDes8Overflow *aOverflowHandler

A pointer to the overflow handler.

...

Panic codes

USER

23 if the length of the descriptor exceeds its maximum length and no overflow handler has been supplied.

USER

24 if the format string has incorrect syntax.

See also

See also:


AppendFormat()

IMPORT_C void AppendFormat(TRefByValue< const TDesC8 > aFmt,...);

Description

Formats and appends text onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

The function takes a format string and a variable number of arguments. The format string contains literal text, embedded with directives, for converting the trailing list of arguments into text.

The embedded directives are character sequences prefixed with the '%' character. The literal text is simply copied into this descriptor unaltered while the '%' directives are used to convert successive arguments from the trailing list. See the description of the Format() function.

Literal text is appended on a character by character basis.

Text converted from a trailing argument is appended as a complete string.

Parameters

TRefByValue< const TDesC8 > aFmt

The 8-bit non-modifiable descriptor containing the format string. The TRefByValue class provides a constructor which takes a TDesC8 type.

...

Panic codes

USER

23 if the resulting length of text in this descriptor exceeds the descriptor's maximum length.

USER

24 if the format string has incorrect syntax.

See also

See also:


AppendFormatList()

IMPORT_C void AppendFormatList(const TDesC8 &aFmt, VA_LIST aList, TDes8Overflow *aOverflowHandler=NULL);

Description

Formats and appends text onto the end of this descriptor's data.

The length of this descriptor is incremented to reflect the new content.

The behaviour of this function is the same as AppendFormat(TRefByValue<const TDesC8> aFmt,TDes8Overflow *aOverflowHandler,...). In practice, it is better and easier to use AppendFormat(), passing a variable number of arguments as required by the format string.

Parameters

const TDesC8 &aFmt

The descriptor containing the format string.

VA_LIST aList

A pointer to an argument list.

TDes8Overflow *aOverflowHandler

If supplied, a pointer to the overflow handler.

See also

See also:


Expand()

IMPORT_C TPtr16 Expand();

Description

Return value

TPtr16


Collapse()

IMPORT_C void Collapse();

Description


WPtr()

protected: inline TUint8 *WPtr() const;

Description

Return value

TUint8 *

[Top]


Member data


iMaxLength

protected: TInt iMaxLength;

Description


__DECLARE_TEST

protected: __DECLARE_TEST;

Description