LightJson.Serialization.TextScanner Class Reference

Represents a text scanner that reads one character at a time. More...

Collaboration diagram for LightJson.Serialization.TextScanner:

Public Member Functions
	TextScanner (TextReader reader)
	Initializes a new instance of TextScanner. More...
char	Peek ()
	Reads the next character in the stream without changing the current position. More...
char	Read ()
	Reads the next character in the stream, advancing the text position. More...
void	SkipWhitespace ()
	Advances the scanner to next non-whitespace character. More...
void	Assert (char next)
	Verifies that the given character matches the next character in the stream. If the characters do not match, an exception will be thrown. More...
void	Assert (string next)
	Verifies that the given string matches the next characters in the stream. If the strings do not match, an exception will be thrown. More...

Data Fields
TextPosition	Position => position
	The position of the scanner within the text. More...
bool	CanRead => reader.Peek() != -1
	Indicates whether there are still characters to be read. More...

Private Attributes
TextReader	reader
TextPosition	position

Detailed Description

Represents a text scanner that reads one character at a time.

Definition at line 12 of file TextScanner.cs.

Constructor & Destructor Documentation

TextScanner()

LightJson.Serialization.TextScanner.TextScanner ( TextReader  reader )

inline

Initializes a new instance of TextScanner.

Parameters

reader

The TextReader to read the text.

Definition at line 27 of file TextScanner.cs.

        {
            if (reader == null)
            {
                throw new ArgumentNullException(nameof(reader));
            }

            this.reader = reader;
        }

Member Function Documentation

Assert() [1/2]

void LightJson.Serialization.TextScanner.Assert ( char  next )

inline

Verifies that the given character matches the next character in the stream. If the characters do not match, an exception will be thrown.

Parameters

next	The expected character.

Definition at line 105 of file TextScanner.cs.

        {
            if (Peek() == next)
            {
                Read();
            }
            else
            {
                throw new JsonParseException(
                    message: $"Parser expected '{next}', found '{Peek()}'",
                    type: ErrorType.InvalidOrUnexpectedCharacter,
                    position: position);
            }
        }

Assert() [2/2]

void LightJson.Serialization.TextScanner.Assert ( string  next )

inline

Verifies that the given string matches the next characters in the stream. If the strings do not match, an exception will be thrown.

Parameters

next	The expected string.

Definition at line 125 of file TextScanner.cs.

References LightJson.Serialization.JsonParseException.Type.

        {
            try
            {
                for (int i = 0; i < next.Length; i += 1)
                {
                    Assert(next[i]);
                }
            }
            catch (JsonParseException e) when (e.Type == ErrorType.InvalidOrUnexpectedCharacter)
            {
                throw new JsonParseException(
                    message: $"Parser expected '{next}'",
                    type: ErrorType.InvalidOrUnexpectedCharacter,
                    position: position);
            }
        }

Peek()

char LightJson.Serialization.TextScanner.Peek ( )

inline

Reads the next character in the stream without changing the current position.

Definition at line 40 of file TextScanner.cs.

        {
            int next = reader.Peek();

            if (next == -1)
            {
                throw new JsonParseException(
                    type: ErrorType.IncompleteMessage,
                    position: position);
            }

            return (char)next;
        }

Read()

char LightJson.Serialization.TextScanner.Read ( )

inline

Reads the next character in the stream, advancing the text position.

Definition at line 57 of file TextScanner.cs.

References LightJson.Serialization.TextPosition.column, and LightJson.Serialization.TextPosition.line.

        {
            int next = reader.Read();

            if (next == -1)
            {
                throw new JsonParseException(
                    type: ErrorType.IncompleteMessage,
                    position: position);
            }

            switch (next)
            {
                case '\r':
                    // Normalize '\r\n' line encoding to '\n'.
                    if (reader.Peek() == '\n')
                    {
                        reader.Read();
                    }
                    goto case '\n';

                case '\n':
                    position.line += 1;
                    position.column = 0;
                    return '\n';

                default:
                    position.column += 1;
                    return (char)next;
            }
        }

SkipWhitespace()

void LightJson.Serialization.TextScanner.SkipWhitespace ( )

inline

Advances the scanner to next non-whitespace character.

Definition at line 92 of file TextScanner.cs.

        {
            while (char.IsWhiteSpace(Peek()))
            {
                Read();
            }
        }

Field Documentation

CanRead

bool LightJson.Serialization.TextScanner.CanRead => reader.Peek() != -1

Indicates whether there are still characters to be read.

Definition at line 21 of file TextScanner.cs.

position

TextPosition LightJson.Serialization.TextScanner.position

private

Definition at line 15 of file TextScanner.cs.

Position

TextPosition LightJson.Serialization.TextScanner.Position => position

The position of the scanner within the text.

Definition at line 18 of file TextScanner.cs.

reader

TextReader LightJson.Serialization.TextScanner.reader

private

Definition at line 14 of file TextScanner.cs.

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The documentation for this class was generated from the following file:

• LightJSON/Serialization/TextScanner.cs