Class TLex8

TLex8

Support

Supported from 5.0

Description

Provides general string-parsing functions suitable for numeric format conversions and syntactical-element parsing. The class is the 8 bit variant for non-Unicode strings and 8 bit wide characters.

An instance of this class stores a string, maintaining an extraction mark to indicate the current lexical element being analysed and a pointer to the next character to be examined.

Objects of this type are normally accessed through the build independent type TLex.

Defined in TLex8:
Assign(), Eos(), Get(), Inc(), Mark(), MarkedOffset(), MarkedToken(), NextToken(), Offset(), Peek(), Remainder(), RemainderFromMark(), SkipAndMark(), SkipCharacters(), SkipSpace(), SkipSpaceAndMark(), TLex8(), TokenLength(), UnGet(), UnGetToMark(), Val(), operator=()

See also:

• TLex
• Using TLex

TLex8();

Description

Constructs a TLex8, initialising its members to NULL.

TLex8(const TUint8* aString);

Description

Constructs the object with a pointer to a string. The extraction mark and next character members are initialised to point to the start of the string.

Parameters

const TUint8* aString String to be assigned.

TLex8(const TDesC8& aDes);

Description

Constructs the object with a descriptor. The extraction mark and next character members are initialised to point to the start of the string.

Parameters

const TDesC8& aDes Descriptor to be assigned by reference

TLex8(const TLex8& aLex);

Description

Constructs the object with a TLex8.

Parameters

const TLex8& aLex TLex8 to be copied by reference.

void Mark();

Description

Sets the TLex8’s next character position to its extraction mark.

void Mark(TLexMark8& aMark) const;

Description

Sets the supplied extraction mark to the TLex8’s next character position.

Parameters

TLexMark8& aMark On return, set to the next character position

void Inc();

Description

Increments to the next character position.

Note:

• If the increment puts the next character position beyond the end of the string, the function panics.

void Inc(TInt aNumber);

Description

Increments the next character position by aNumber.

Parameters

TInt aNumber The number of characters to increment the next character position by. If the increment puts the next character position before the start or beyond the end of the string, the function panics.

See also:

• Moving past a character

TChar Peek() const;

Description

Shows the next character to be returned by Get().

Return value

TChar Character to be returned by Get(). Returns 0 if at the end of the string.

See also:

• Peeking the next character

TChar Get();

Description

Gets the next character in the string and increments the next character position.

Return value

TChar Next character to be read. Returns 0 if at the end of the string.

void UnGet();

Description

Decrements the next character position, allowing the previously "got" character to be re-read.

Note:

• If the previous character is before the start of the string, the function panics.

See also:

• Restoring previously got char

void UnGetToMark();

Description

Sets the next character position to the current extraction mark position.

Note:

• If the extraction mark is before the start or beyond the end of the string, the function panics.

void UnGetToMark(const TLexMark8 aMark);

Description

Sets the next character position to the supplied extraction mark position.

Parameters

const TLexMark8& aMark Mark to copy to the next character position. If the extraction mark is before the start or beyond the end of the string, the function panics.

See also:

• Reset next character

void SkipSpace();

Description

Moves the next character position past any white space (space or separator). Stops if at the end of string.

void SkipSpaceAndMark();

Description

Moves the next character position past any white space and copies it to the TLex8’s extraction mark. Stops if at the end of the string.

void SkipSpaceAndMark(TLexMark8& aMark);

Description

Moves the next character position past any white space and copies it to the specified extraction mark. Stops if at the end of the string.

Parameters

TLexMark8& aMark On return contains a reference to the next character position.

void SkipCharacters();

Description

Moves the next character position to the next white space (space or separator). Stops if at the end of the string.

See also:

• Skipping non-white space

void SkipAndMark(TInt aNumber);

Description

Moves the next character position a specified number of characters. Stops if at the end of the string.

Parameters

TInt aNumber Number of characters to skip. If the skip moves the next character position to before the start or beyond the end of the string, the function panics.

void SkipAndMark(TInt aNumber, TLexMark8& aMark);

Description

Moves the next character position a specified number of characters and copies it to the specified extraction mark. Stops if at the end of the string.

Parameters

TInt aNumber Number of characters to skip. If the skip moves the next character position to before the start or beyond the end of the string, the function panics. TLexMark8& aMark On return, set to the next character position.

Description

A token is considered to be a character string delimited by white space (space or separator).

TInt TokenLength() const;

Description

Gets the length of the token. This is the difference of the next character position and the extraction mark.

Note:

• If the value of (next character position - extraction mark) is negative, the function will panic.

Return value

TInt Length of the token.

See also:

• Getting token length

TInt TokenLength(const TLexMark8 aMark) const;

Description

Gets the length of the token starting at the specified extraction mark.

Parameters

const TLexMark8& aMark Extraction mark indicating the start of the token. If this mark is before the start or beyond the end of the string, the function panics.

Return value

TInt Length of the token.

TPtrC8 MarkedToken() const;

Description

Extracts the marked token.

Note:

• If the value of (next character position - extraction mark) is negative, the function will panic.

Return value

TPtrC8 Extracted token.

TPtrC8 MarkedToken(const TLexMark8 aMark) const;

Description

Extracts the token, starting at the specified mark

Parameters

const TLexMark8& aMark Extraction mark indicating the start of the token. If this mark is before the start or beyond the end of the string, the function panics.

Return value

TPtrC8 Extracted token.

TPtrC8 NextToken();

Description

Strips any white space and extracts the next token.

Return value

TPtrC8 Extracted token.

TPtrC8 Remainder() const;

Description

Gets a descriptor containing all the text from the next character position to the end of the string.

Note:

• If the value of (next character position - extraction mark) is negative, the function will panic.

Return value

TPtrC8 Text from the next character position onwards.

TPtrC8 RemainderFromMark() const;

Description

Gets a descriptor containing all the text from the extraction mark to the end of the string.

Note

• If the value of (next character position - extraction mark) is negative, the function will panic.

Return value

TPtrC8 Text from the extraction mark onwards.

TPtrC8 RemainderFromMark(const TLexMark8 aMark) const;

Description

Gets a descriptor containing all the text from the specified extraction mark to the end of the string.

Parameters

const TLexMark8& aMark Extraction mark indicating where remaining text starts. If this mark is before the start or beyond the end of the string, the function panics.

Return value

TPtrC8 Text from the specified extraction mark onwards.

TInt Offset() const;

Description

Gets the offset of the next character position from the start of the string.

Return value

TInt Offset of next character position.

See also:

• Offset next char position

TInt MarkedOffset() const;

Description

Gets the offset of the extraction mark from the start of the string.

Return value

TInt The offset of the extraction mark.

TInt MarkedOffset(const TLexMark8 aMark) const;

Description

Gets the offset of the specified extraction mark from the start of the string.

Parameters

const TLexMark8 aMark Extraction mark. If this mark is before the start or beyond the end of the string, the function panics.

Return value

TInt The offset of the extraction mark.

TInt Val(TInt& aVal);

Description

Parses the string to extract a signed integer.

Parameters

TInt& aVal On return, contains the extracted integer.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TInt8& aVal);

Description

Parses the string to extract a signed 8 bit integer.

Parameters

TInt8& aVal On return, contains the extracted integer.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TInt16& aVal);

Description

Parses the string to extract a signed 16 bit integer.

Parameters

TInt16& aVal On return, contains the extracted integer.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TInt32& aVal);

Description

Parses the string to extract a signed 32 bit integer.

Parameters

TInt32& aVal On return, contains the extracted integer.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TInt64& aVal);

Description

Parses the string to extract a signed 64 bit integer.

Parameters

TInt64& aVal On return, contains the extracted integer.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TInt32& aVal,TInt aLimit);

Description

Parses the string to extract a signed 32 bit integer, and returnsKErrOverflow if the integer exceeds a specified limit.

Parameters

TInt32& aVal On return, contains the extracted integer. TInt aLimit Limit value.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TInt64& aVal,const TInt64& aLimit);

Description

Parses the string to extract a signed 64 bit integer, and returnsKErrOverflow if the integer exceeds a specified limit.

Parameters

TInt64& aVal On return, contains the extracted integer. const TInt64& aLimit Limit value.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TUint& aVal,TRadix aRadix=EDecimal);

Description

Parses the string to extract an unsigned integer, using a specified radix. The specified radix is one of binary, octal, decimal, or hexadecimal.

Parameters

TUint& aVal On return, contains the extracted integer. TRadix aRadix Radix to use when converting number. The default radix for this function overload is decimal.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TUint8& aVal,TRadix aRadix);

Description

Parses the string to extract an 8 bit unsigned integer, using a specified radix. The specified radix is one of binary, octal, decimal, or hexadecimal.

Parameters

TUint8& aVal On return, contains the extracted integer. TRadix aRadix Radix to use when converting number.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TUint16& aVal,TRadix aRadix);

Description

Parses the string to extract a 16 bit unsigned integer, using a specified radix. The specified radix is one of binary, octal, decimal, or hexadecimal.

Parameters

TUint16& aVal On return, contains the extracted integer. TRadix aRadix Radix to use when converting number.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TUint32& aVal,TRadix aRadix);

Description

Parses the string to extract a 32 bit unsigned integer, using a specified radix. The specified radix is one of binary, octal, decimal, or hexadecimal.

Parameters

TUint32& aVal On return, contains the extracted integer. TRadix aRadix Radix to use when converting number.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TInt64& aVal,TRadix aRadix);

Description

Parses the string to extract a 64 bit unsigned integer, using a specified radix. The specified radix is one of binary, octal, decimal, or hexadecimal.

Parameters

TInt64& aVal On return, contains the extracted integer. TRadix aRadix Radix to use when converting number.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TUint32& aVal,TRadix aRadix,TUint aLimit);

Description

Parses the string to extract an unsigned 32 bit integer using a specified radix, and returns KErrOverflow if the integer exceeds a specified limit.

Parameters

TUint32& aVal On return, contains the extracted integer. TRadix aRadix Radix to use when converting number. TUint aLimit Limit value.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TInt64& aVal,TRadix aRadix,const TInt64& aLimit);

Description

Parses the string to extract an unsigned 64 bit integer using a specified radix, and returns KErrOverflow if the integer exceeds a specified limit.

Parameters

TInt64& aVal On return, contains the extracted integer. TRadix aRadix Radix to use when converting number. const TInt64& aLimit Limit value.

Return value

TInt KErrNone if successful, KErrGeneral if the next character position initially at end of string or no valid characters found initially, or KErrOverflow if there is sign overflow — converted value greater than limit. If error codesKErrGeneral or KErrOverflow are returned, the object's members are left unaltered.

TInt Val(TReal32& aVal);

Description

Parses the string to extract a 32 bit real number. The character interpreted as the decimal point is the current locale's decimal separator value.

Parameters

TReal32& aVal On return, contains the extracted number.

Return value

TInt KErrNone if successful, otherwise another of the system-wide error codes.

TInt Val(TReal64& aVal);

Description

Parses the string to extract a 64 bit real number. The character interpreted as the decimal point is the current locale's decimal separator value.

Parameters

TReal64& aVal On return, contains the extracted number.

Return value

TInt KErrNone if successful, otherwise another of the system-wide error codes.

TInt Val(TReal32& aVal,TChar aPoint);

Description

Parses the string to extract a 32 bit real number, specifying the character to be interpreted as the decimal point.

Parameters

TReal32& aVal On return, contains the extracted number. TChar aPoint Character to be interpreted as the decimal point.

Return value

TInt KErrNone if successful, otherwise another of the system-wide error codes.

TInt Val(TReal64& aVal,TChar aPoint);

Description

Parses the string to extract a 64 bit real number, specifying the character to be interpreted as the decimal point.

Parameters

TReal64& aVal On return, contains the extracted number. TChar aPoint Character to be interpreted as the decimal point.

Return value

TInt KErrNone if successful, otherwise another of the system-wide error codes.

TLex8& operator=(const TLex8& aLex);

Description

Allows TLex8 objects to be assigned to aTLex8when the = operator is overloaded.

Parameters

const TLex8& aLex TLex8 to be assigned to the TLex8.

Return value

TLex8& TLex8 descriptor

TLex8& operator=(const TUint8* aString);

Description

Allows descriptors to be assigned to a TLex8 when the = operator is overloaded.

Parameters

const TUint8* aString String to be assigned to the TLex8.

Return value

TLex8& TLex8 descriptor

TLex8& operator=(const TDesC8& aDes);

Description

Allows pointers to strings to be assigned to a TLex8 when the = operator is overloaded.

Parameters

const TDesC8& aDes Descriptor to be assigned to the TLex8.

Return value

TLex8& TLex8 descriptor

void Assign(const TLex8& aLex);
void Assign(const TUint8* aString);
void Assign(const TDesC8& aDes);

Description

Assigns a string to this object from another TLex8 object, from another string or from a descriptor.

Parameters

const TLex8& aLex The object to be assigned. const TUint8* aString A pointer to a string to be assigned. const TDesC8& aDes A descriptor containing a string to be assigned

TBool Eos() const;

Description

Tests to see if the next character position is at the end of the string.

Return value

TBool True if at end of string, false otherwise.