Implementation of the State_RemoveComments() function, along with the state machine used to filter out comments out of a piece of source code, as used in the State Pattern. More...

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "State_RemoveComments.h"

Include dependency graph for State_RemoveComments.c:

Go to the source code of this file.

Classes
struct	StateContext
	Represents the context in which the state machine runs. More...

struct	StateHandler
	Maps a value from the CurrentState enumeration to a function that handles the transition from that state to the next state based on the context. More...

Typedefs
typedef CurrentState(*	StateFunctionPtr) (struct StateContext *)
	Alias for a function pointer that takes a StateContext object and returns a value from the CurrentState enumeration.

typedef struct StateContext	StateContext
	Represents the context in which the state machine runs.

Enumerations
enum	CurrentState { State_Initial , State_NormalText , State_DoubleQuotedText , State_SingleQuotedText , State_EscapedDoubleQuoteText , State_EscapedSingleQuoteText , State_StartComment , State_LineComment , State_BlockComment , State_EndBlockComment , State_Done , State_Error }
	Represents the current state of the state machine. More...

enum	_Constants { EOF_CHAR = (char)-1 }
	Contains constants used in the state machine. More...

Functions
static const char *	_CurrentStateToString (CurrentState state)
	Convert the CurrentState enumeration to a string for output purposes.

static char	_GetNextCharacter (StateContext *context)
	Retrieve the next character from the input.

static void	_OutputCharacter (StateContext *context, char character)
	Save the character to the accumulation of the filtered text.

static CurrentState	_State_NormalText_GoNextState (StateContext *context)
	Handles the state of normal text behavior.

static CurrentState	_State_DoubleQuotedText_GoNextState (StateContext *context)
	Handles the state of being inside a double-quote string where filtering is essentially turned off until the end of the string is reached.

static CurrentState	_State_SingleQuotedText_GoNextState (StateContext *context)
	Handles the state of being inside a single-quoted string where filtering is effectively turned off until the end of the string is reached.

static CurrentState	_State_EscapedDoubleQuoteText_GoNextState (StateContext *context)
	Handles the state of being in an escaped character sequence inside a double-quoted string. We don't do anything with the escaped character other than output it. Handling escaped characters allows us to more accurately detect the end of the string.

static CurrentState	_State_EscapedSingleQuoteText_GoNextState (StateContext *context)
	Handles the state of being in an escaped character sequence inside a single-quoted string. We don't do anything with the escaped character other than output it. Handling escaped characters allows us to more accurately detect the end of the string.

static CurrentState	_State_StartComment_GoNextState (StateContext *context)
	Handles the state of being at the possible start of a line or block comment.

static CurrentState	_State_LineComment_GoNextState (StateContext *context)
	Handles the state of being in a line comment.

static CurrentState	_State_BlockComment_GoNextState (StateContext *context)
	Handles the state of being in a block comment.

static CurrentState	_State_EndBlockComment_GoNextState (StateContext *context)
	Handles the state of possibly being at the end of a block comment.

static CurrentState	_State_Done_GoNextState (StateContext *context)
	Handles the state of being done with input.

static StateFunctionPtr	_GetStateFunction (CurrentState state)
	Retrieve the function that is used to transition from the given state to another state.

static bool	_SetNextState (StateContext *context, CurrentState newState)
	Helper method to transition the state machine to the specified state. Does nothing if the new state is the same as the old state. Instantiates the state class the first time the state class is needed.

bool	State_RemoveComments (const char text, DynamicString filteredText)
	Entry point for callers to filter text. Removes C++-style line and block comments from the text.

Variables
static StateHandler	_stateHandlers []
	Array of StateHandler objects that map CurrentState value to functions that transition from that state to the next based on the context.

Detailed Description

Implementation of the State_RemoveComments() function, along with the state machine used to filter out comments out of a piece of source code, as used in the State Pattern.

Definition in file State_RemoveComments.c.

Typedef Documentation

◆ StateContext

typedef struct StateContext StateContext

Represents the context in which the state machine runs.

◆ StateFunctionPtr

typedef CurrentState(* StateFunctionPtr) (struct StateContext *)

Alias for a function pointer that takes a StateContext object and returns a value from the CurrentState enumeration.

Definition at line 36 of file State_RemoveComments.c.

Enumeration Type Documentation

◆ _Constants

enum _Constants

Contains constants used in the state machine.

Enumerator
EOF_CHAR	Indicates end of string.

Definition at line 41 of file State_RemoveComments.c.

◆ CurrentState

enum CurrentState

Represents the current state of the state machine.

Enumerator
State_Initial	State before the state machine actually starts. transitions to NormalText.
State_NormalText	`"` transitions to QuotedText, / transitions to StartComment, EOF_CHAR transitions to Done
State_DoubleQuotedText	`\` transitions to EscapedDoubleQuoteText, " transitions to NormalText, EOF_CHAR transitions to Done
State_SingleQuotedText	' transitions to EscapedSingleQuoteText, \ transitions to NormalText, EOF_CHAR transitions to Done
State_EscapedDoubleQuoteText	`\` transitions to QuotedText, EOF_CHAR transitions to Done
State_EscapedSingleQuoteText	`\` transitions to SingleQuotedText, EOF_CHAR transitions to Done
State_StartComment	`/` transitions to LineComment, * transitions to BlockComment, EOF_CHAR transitions to Done, all else transitions to NormalText
State_LineComment	`\n` transitions to NormalText, EOF_CHAR transitions to Done
State_BlockComment	`*` transitions to EndBlockComment, EOF_CHAR transitions to Done
State_EndBlockComment	`/` transitions to NormalText, EOF_CHAR transitions to Done, all else transitions to BlockComment
State_Done	Indicates processing is done.
State_Error	Indicates an error occurred and the state machine needs to exit.

Definition at line 15 of file State_RemoveComments.c.

Function Documentation

◆ _CurrentStateToString()

static const char * _CurrentStateToString ( CurrentState state )

static

Convert the CurrentState enumeration to a string for output purposes.

Parameters

state A value from the CurrentState enumeration.

Returns: Returns a string containing the string version of the given state.

Definition at line 69 of file State_RemoveComments.c.

References State_BlockComment, State_Done, State_DoubleQuotedText, State_EndBlockComment, State_Error, State_EscapedDoubleQuoteText, State_EscapedSingleQuoteText, State_Initial, State_LineComment, State_NormalText, State_SingleQuotedText, and State_StartComment.

Referenced by _SetNextState().

◆ _GetNextCharacter()

static char _GetNextCharacter ( StateContext * context )

static

Retrieve the next character from the input.

Returns: Returns the next character from the input. Returns EOF_CHAR if there is no more input.

Definition at line 151 of file State_RemoveComments.c.

References EOF_CHAR, StateContext::inputText, and StateContext::textIndex.

Referenced by _State_BlockComment_GoNextState(), _State_DoubleQuotedText_GoNextState(), _State_EndBlockComment_GoNextState(), _State_EscapedDoubleQuoteText_GoNextState(), _State_EscapedSingleQuoteText_GoNextState(), _State_LineComment_GoNextState(), _State_NormalText_GoNextState(), _State_SingleQuotedText_GoNextState(), and _State_StartComment_GoNextState().

◆ _GetStateFunction()

static StateFunctionPtr _GetStateFunction ( CurrentState state )

static

Retrieve the function that is used to transition from the given state to another state.

Parameters

state A value from the CurrentState enumeration indicating state for which to get a transition function.

Returns: Returns a StateFunctionPtr for the specified state.

Definition at line 679 of file State_RemoveComments.c.

References _stateHandlers, and StateHandler::stateHandler.

Referenced by _SetNextState().

◆ _OutputCharacter()

static void _OutputCharacter	(	StateContext *	context,
		char	character
	)

static

Save the character to the accumulation of the filtered text.

Parameters

context	The StateContext object controlling the state machine and which contains the DynamicString object being used to accumulate the filtered text.
character	The character to save.

Definition at line 173 of file State_RemoveComments.c.

References EOF_CHAR, StateContext::outputText, and StateContext::outputTextIndex.

Referenced by _State_DoubleQuotedText_GoNextState(), _State_EscapedDoubleQuoteText_GoNextState(), _State_EscapedSingleQuoteText_GoNextState(), _State_LineComment_GoNextState(), _State_NormalText_GoNextState(), _State_SingleQuotedText_GoNextState(), and _State_StartComment_GoNextState().

◆ _SetNextState()

static bool _SetNextState	(	StateContext *	context,
		CurrentState	newState
	)

static

Helper method to transition the state machine to the specified state. Does nothing if the new state is the same as the old state. Instantiates the state class the first time the state class is needed.

Parameters

context	The StateContext object that controls the state machine.
newState	A value from the CurrentState enumeration indicating the state to which to transition.

Returns: Returns true if the next state was successfully set; otherwise, returns false, indicating some kind of problem.

Definition at line 713 of file State_RemoveComments.c.

References _CurrentStateToString(), _GetStateFunction(), StateContext::currentState, and StateContext::currentStateBehavior.

Referenced by State_RemoveComments().

◆ _State_BlockComment_GoNextState()

static CurrentState _State_BlockComment_GoNextState ( StateContext * context )

static

Handles the state of being in a block comment.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

* - go to State_EndBlockComment (possible end of block comment)
EOF_CHAR - go to State_Done (no more input)

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 541 of file State_RemoveComments.c.

References _GetNextCharacter(), EOF_CHAR, State_BlockComment, State_Done, State_EndBlockComment, and State_Error.

◆ _State_Done_GoNextState()

static CurrentState _State_Done_GoNextState ( StateContext * context )

static

Handles the state of being done with input.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

Always stay in State_Done

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 626 of file State_RemoveComments.c.

References State_Done, and State_Error.

◆ _State_DoubleQuotedText_GoNextState()

static CurrentState _State_DoubleQuotedText_GoNextState ( StateContext * context )

static

Handles the state of being inside a double-quote string where filtering is essentially turned off until the end of the string is reached.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

" - go to State_NormalText (end of a double-quoted string)
\ - go to State_EscapedDoubleQuoteText (start of an escaped character)
EOF_CHAR - go to State_Done (no more input)

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 259 of file State_RemoveComments.c.

References _GetNextCharacter(), _OutputCharacter(), EOF_CHAR, State_Done, State_DoubleQuotedText, State_Error, State_EscapedDoubleQuoteText, and State_NormalText.

◆ _State_EndBlockComment_GoNextState()

static CurrentState _State_EndBlockComment_GoNextState ( StateContext * context )

static

Handles the state of possibly being at the end of a block comment.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

/ - go to State_NormalText (found end of block comment)
{ANY} - go to State_BlockComment (still in block comment)
EOF_CHAR - go to State_Done (no more input)

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 584 of file State_RemoveComments.c.

References _GetNextCharacter(), EOF_CHAR, State_BlockComment, State_Done, State_Error, and State_NormalText.

◆ _State_EscapedDoubleQuoteText_GoNextState()

static CurrentState _State_EscapedDoubleQuoteText_GoNextState ( StateContext * context )

static

Handles the state of being in an escaped character sequence inside a double-quoted string. We don't do anything with the escaped character other than output it. Handling escaped characters allows us to more accurately detect the end of the string.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

{ANY} - go to State_DoubleQuotedText (end of escape sequence)
EOF_CHAR - go to State_Done (no more input)

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 361 of file State_RemoveComments.c.

References _GetNextCharacter(), _OutputCharacter(), EOF_CHAR, State_Done, State_DoubleQuotedText, and State_Error.

◆ _State_EscapedSingleQuoteText_GoNextState()

static CurrentState _State_EscapedSingleQuoteText_GoNextState ( StateContext * context )

static

Handles the state of being in an escaped character sequence inside a single-quoted string. We don't do anything with the escaped character other than output it. Handling escaped characters allows us to more accurately detect the end of the string.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

{ANY} - go to State_SingleQuotedText (end of escape sequence)
EOF_CHAR - go to State_Done (no more input)

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 403 of file State_RemoveComments.c.

References _GetNextCharacter(), _OutputCharacter(), EOF_CHAR, State_Done, State_Error, and State_SingleQuotedText.

◆ _State_LineComment_GoNextState()

static CurrentState _State_LineComment_GoNextState ( StateContext * context )

static

Handles the state of being in a line comment.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

- go to State_NormalText (a newline is the end of a line comment)
EOF_CHAR - go to State_Done (no more input)

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 497 of file State_RemoveComments.c.

References _GetNextCharacter(), _OutputCharacter(), EOF_CHAR, State_Done, State_Error, State_LineComment, and State_NormalText.

◆ _State_NormalText_GoNextState()

static CurrentState _State_NormalText_GoNextState ( StateContext * context )

static

Handles the state of normal text behavior.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

" : go to State_DoubleQuotedText (start of a double-quoted string)
' : go to State_SingleQuotedText (start of a single-quoted string)
/ : go to State_StartComment (start of a line or block comment)
EOF_CHAR : go to State_Done (no more input)

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 204 of file State_RemoveComments.c.

References _GetNextCharacter(), _OutputCharacter(), EOF_CHAR, State_Done, State_DoubleQuotedText, State_Error, State_NormalText, State_SingleQuotedText, and State_StartComment.

◆ _State_SingleQuotedText_GoNextState()

static CurrentState _State_SingleQuotedText_GoNextState ( StateContext * context )

static

Handles the state of being inside a single-quoted string where filtering is effectively turned off until the end of the string is reached.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

' - go to State_NormalText (end of a single-quoted string)
\ - go to State_EscapedSingleQuoteText (start of an escaped character)
EOF_CHAR - go to State_Done (no more input)

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 310 of file State_RemoveComments.c.

References _GetNextCharacter(), _OutputCharacter(), EOF_CHAR, State_Done, State_Error, State_EscapedSingleQuoteText, State_NormalText, and State_SingleQuotedText.

◆ _State_StartComment_GoNextState()

static CurrentState _State_StartComment_GoNextState ( StateContext * context )

static

Handles the state of being at the possible start of a line or block comment.

Process the next character from the context, returning the next state the context should move to.

Transitions to the following states for the seen input:

/ - go to State_LineComment (start of a line comment)
* - go to State_BlockComment (start of a block comment)
{ANY} - go to State_NormalText (not start of a comment)
EOF_CHAR - go to State_Done (no more input)

Parameters

context A StateContext object representing the context to use for getting the next character of input and to which to output characters.

Returns: Returns a value from the CurrentState enumeration indicating the next state to which the state machine should transition to.

Definition at line 445 of file State_RemoveComments.c.

References _GetNextCharacter(), _OutputCharacter(), EOF_CHAR, State_BlockComment, State_Done, State_Error, State_LineComment, State_NormalText, and State_StartComment.

◆ State_RemoveComments()

bool State_RemoveComments	(	const char *	text,
		DynamicString *	filteredText
	)

Entry point for callers to filter text. Removes C++-style line and block comments from the text.

Parameters

text	The text to filter.
filteredText	A DynamicString that returns the filtered text.

Returns: Returns true if the text was filtered successfully, otherwise, returns false if an out of memory condition occurs (or a NULL argument).

Definition at line 745 of file State_RemoveComments.c.

References _SetNextState(), StateContext::currentState, StateContext::currentStateBehavior, DynamicString_Set(), StateContext::inputText, StateContext::outputText, StateContext::outputTextIndex, State_Done, State_Error, State_Initial, State_NormalText, and StateContext::textIndex.

Referenced by State_Exercise().

Variable Documentation

◆ _stateHandlers

StateHandler _stateHandlers[]

static

Initial value:

= {
    { State_NormalText            , _State_NormalText_GoNextState             },
    { State_DoubleQuotedText      , _State_DoubleQuotedText_GoNextState       },
    { State_SingleQuotedText      , _State_SingleQuotedText_GoNextState       },
    { State_EscapedDoubleQuoteText, _State_EscapedDoubleQuoteText_GoNextState },
    { State_EscapedSingleQuoteText, _State_EscapedSingleQuoteText_GoNextState },
    { State_StartComment          , _State_StartComment_GoNextState           },
    { State_LineComment           , _State_LineComment_GoNextState            },
    { State_BlockComment          , _State_BlockComment_GoNextState           },
    { State_EndBlockComment       , _State_EndBlockComment_GoNextState        },
    { State_Done                  , _State_Done_GoNextState                   },
    { State_Initial               , NULL }, 
}

Array of StateHandler objects that map CurrentState value to functions that transition from that state to the next based on the context.

Definition at line 658 of file State_RemoveComments.c.

Referenced by _GetStateFunction().

Classes

Typedefs

Enumerations

Functions

Variables

Detailed Description

Typedef Documentation

◆ StateContext

◆ StateFunctionPtr

Enumeration Type Documentation

◆ _Constants

◆ CurrentState

Function Documentation

◆ _CurrentStateToString()

◆ _GetNextCharacter()

◆ _GetStateFunction()

◆ _OutputCharacter()

◆ _SetNextState()

◆ _State_BlockComment_GoNextState()

◆ _State_Done_GoNextState()

◆ _State_DoubleQuotedText_GoNextState()

◆ _State_EndBlockComment_GoNextState()

◆ _State_EscapedDoubleQuoteText_GoNextState()

◆ _State_EscapedSingleQuoteText_GoNextState()

◆ _State_LineComment_GoNextState()

◆ _State_NormalText_GoNextState()

◆ _State_SingleQuotedText_GoNextState()

◆ _State_StartComment_GoNextState()

◆ State_RemoveComments()

Variable Documentation

◆ _stateHandlers