get.c

Exuberant Ctags is a multilanguage reimplementation of the much-underused ctags(1) program and is i

		if (stringMatch (vStringValue (Cpp.directive.name), "weak"))
		{
			/* generate macro tag for weak name */
			do
			{
				c = fileGetc ();
			} while (c == SPACE);
			if (isident1 (c))
			{
				readIdentifier (c, Cpp.directive.name);
				makeDefineTag (vStringValue (Cpp.directive.name));
			}
		}
	}
	Cpp.directive.state = DRCTV_NONE;
}

static boolean directiveIf (const int c)
{
	DebugStatement ( const boolean ignore0 = isIgnore (); )
	const boolean ignore = pushConditional ((boolean) (c != '0'));

	Cpp.directive.state = DRCTV_NONE;
	DebugStatement ( debugCppNest (TRUE, Cpp.directive.nestLevel);
	                 if (ignore != ignore0) debugCppIgnore (ignore); )

	return ignore;
}

static boolean directiveHash (const int c)
{
	boolean ignore = FALSE;
	char directive [MaxDirectiveName];
	DebugStatement ( const boolean ignore0 = isIgnore (); )

	readDirective (c, directive, MaxDirectiveName);
	if (stringMatch (directive, "define"))
		Cpp.directive.state = DRCTV_DEFINE;
	else if (stringMatch (directive, "undef"))
		Cpp.directive.state = DRCTV_UNDEF;
	else if (strncmp (directive, "if", (size_t) 2) == 0)
		Cpp.directive.state = DRCTV_IF;
	else if (stringMatch (directive, "elif")  ||
			stringMatch (directive, "else"))
	{
		ignore = setIgnore (isIgnoreBranch ());
		if (! ignore  &&  stringMatch (directive, "else"))
			chooseBranch ();
		Cpp.directive.state = DRCTV_NONE;
		DebugStatement ( if (ignore != ignore0) debugCppIgnore (ignore); )
	}
	else if (stringMatch (directive, "endif"))
	{
		DebugStatement ( debugCppNest (FALSE, Cpp.directive.nestLevel); )
		ignore = popConditional ();
		Cpp.directive.state = DRCTV_NONE;
		DebugStatement ( if (ignore != ignore0) debugCppIgnore (ignore); )
	}
	else if (stringMatch (directive, "pragma"))
		Cpp.directive.state = DRCTV_PRAGMA;
	else
		Cpp.directive.state = DRCTV_NONE;

	return ignore;
}

/*  Handles a pre-processor directive whose first character is given by "c".
 */
static boolean handleDirective (const int c)
{
	boolean ignore = isIgnore ();

	switch (Cpp.directive.state)
	{
		case DRCTV_NONE:    ignore = isIgnore ();        break;
		case DRCTV_DEFINE:  directiveDefine (c);         break;
		case DRCTV_HASH:    ignore = directiveHash (c);  break;
		case DRCTV_IF:      ignore = directiveIf (c);    break;
		case DRCTV_PRAGMA:  directivePragma (c);         break;
		case DRCTV_UNDEF:   directiveDefine (c);         break;
	}
	return ignore;
}

/*  Called upon reading of a slash ('/') characters, determines whether a
 *  comment is encountered, and its type.
 */
static Comment isComment (void)
{
	Comment comment;
	const int next = fileGetc ();

	if (next == '*')
		comment = COMMENT_C;
	else if (next == '/')
		comment = COMMENT_CPLUS;
	else
	{
		fileUngetc (next);
		comment = COMMENT_NONE;
	}
	return comment;
}

/*  Skips over a C style comment. According to ANSI specification a comment
 *  is treated as white space, so we perform this subsitution.
 */
static int skipOverCComment (void)
{
	int c = fileGetc ();

	while (c != EOF)
	{
		if (c != '*')
			c = fileGetc ();
		else
		{
			const int next = fileGetc ();

			if (next != '/')
				c = next;
			else
			{
				c = SPACE;  /* replace comment with space */
				break;
			}
		}
	}
	return c;
}

/*  Skips over a C++ style comment.
 */
static int skipOverCplusComment (void)
{
	int c;

	while ((c = fileGetc ()) != EOF)
	{
		if (c == BACKSLASH)
			fileGetc ();  /* throw away next character, too */
		else if (c == NEWLINE)
			break;
	}
	return c;
}

/*  Skips to the end of a string, returning a special character to
 *  symbolically represent a generic string.
 */
static int skipToEndOfString (void)
{
	int c;

	while ((c = fileGetc ()) != EOF)
	{
		if (c == BACKSLASH)
			fileGetc ();  /* throw away next character, too */
		else if (c == DOUBLE_QUOTE)
			break;
	}
	return STRING_SYMBOL;  /* symbolic representation of string */
}

/*  Skips to the end of the three (possibly four) 'c' sequence, returning a
 *  special character to symbolically represent a generic character.
 *  Also detects Vera numbers that include a base specifier (ie. 'b1010).
 */
static int skipToEndOfChar (void)
{
	int c;
	int count = 0, veraBase = '\0';

	while ((c = fileGetc ()) != EOF)
	{
	    ++count;
		if (c == BACKSLASH)
			fileGetc ();  /* throw away next character, too */
		else if (c == SINGLE_QUOTE)
			break;
		else if (c == NEWLINE)
		{
			fileUngetc (c);
			break;
		}
		else if (count == 1  &&  strchr ("DHOB", toupper (c)) != NULL)
			veraBase = c;
		else if (veraBase != '\0'  &&  ! isalnum (c))
		{
			fileUngetc (c);
			break;
		}
	}
	return CHAR_SYMBOL;  /* symbolic representation of character */
}

/*  This function returns the next character, stripping out comments,
 *  C pre-processor directives, and the contents of single and double
 *  quoted strings. In short, strip anything which places a burden upon
 *  the tokenizer.
 */
extern int cppGetc (void)
{
	boolean directive = FALSE;
	boolean ignore = FALSE;
	int c;

	if (Cpp.ungetch != '\0')
	{
		c = Cpp.ungetch;
		Cpp.ungetch = Cpp.ungetch2;
		Cpp.ungetch2 = '\0';
		return c;  /* return here to avoid re-calling debugPutc () */
	}
	else do
	{
		c = fileGetc ();
process:
		switch (c)
		{
			case EOF:
				ignore    = FALSE;
				directive = FALSE;
				break;

			case TAB:
			case SPACE:
				break;  /* ignore most white space */

			case NEWLINE:
				if (directive  &&  ! ignore)
					directive = FALSE;
				Cpp.directive.accept = TRUE;
				break;

			case DOUBLE_QUOTE:
				Cpp.directive.accept = FALSE;
				c = skipToEndOfString ();
				break;

			case '#':
				if (Cpp.directive.accept)
				{
					directive = TRUE;
					Cpp.directive.state  = DRCTV_HASH;
					Cpp.directive.accept = FALSE;
				}
				break;

			case SINGLE_QUOTE:
				Cpp.directive.accept = FALSE;
				c = skipToEndOfChar ();
				break;

			case '/':
			{
				const Comment comment = isComment ();

				if (comment == COMMENT_C)
					c = skipOverCComment ();
				else if (comment == COMMENT_CPLUS)
				{
					c = skipOverCplusComment ();
					if (c == NEWLINE)
						fileUngetc (c);
				}
				else
					Cpp.directive.accept = FALSE;
				break;
			}

			case BACKSLASH:
			{
				int next = fileGetc ();

				if (next == NEWLINE)
					continue;
				else if (next == '?')
					cppUngetc (next);
				else
					fileUngetc (next);
				break;
			}

			case '?':
			{
				int next = fileGetc ();
				if (next != '?')
					fileUngetc (next);
				else
				{
					next = fileGetc ();
					switch (next)
					{
						case '(':          c = '[';       break;
						case ')':          c = ']';       break;
						case '<':          c = '{';       break;
						case '>':          c = '}';       break;
						case '/':          c = BACKSLASH; goto process;
						case '!':          c = '|';       break;
						case SINGLE_QUOTE: c = '^';       break;
						case '-':          c = '~';       break;
						case '=':          c = '#';       goto process;
						default:
							fileUngetc (next);
							cppUngetc ('?');
							break;
					}
				}
			} break;

			default:
				Cpp.directive.accept = FALSE;
				if (directive)
					ignore = handleDirective (c);
				break;
		}
	} while (directive || ignore);

	DebugStatement ( debugPutc (DEBUG_CPP, c); )
	DebugStatement ( if (c == NEWLINE)
				debugPrintf (DEBUG_CPP, "%6ld: ", getInputLineNumber () + 1); )

	return c;
}

/* vi:set tabstop=4 shiftwidth=4: */