tclutil.c

tcl是工具命令语言

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ScanElement --
 *
 *	This procedure is a companion procedure to Tcl_ConvertElement.
 *	It scans a string to see what needs to be done to it (e.g. add
 *	backslashes or enclosing braces) to make the string into a
 *	valid Tcl list element.
 *
 * Results:
 *	The return value is an overestimate of the number of characters
 *	that will be needed by Tcl_ConvertElement to produce a valid
 *	list element from string.  The word at *flagPtr is filled in
 *	with a value needed by Tcl_ConvertElement when doing the actual
 *	conversion.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_ScanElement(string, flagPtr)
    register CONST char *string; /* String to convert to list element. */
    register int *flagPtr;	 /* Where to store information to guide
				  * Tcl_ConvertCountedElement. */
{
    return Tcl_ScanCountedElement(string, -1, flagPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ScanCountedElement --
 *
 *	This procedure is a companion procedure to
 *	Tcl_ConvertCountedElement.  It scans a string to see what
 *	needs to be done to it (e.g. add backslashes or enclosing
 *	braces) to make the string into a valid Tcl list element.
 *	If length is -1, then the string is scanned up to the first
 *	null byte.
 *
 * Results:
 *	The return value is an overestimate of the number of characters
 *	that will be needed by Tcl_ConvertCountedElement to produce a
 *	valid list element from string.  The word at *flagPtr is
 *	filled in with a value needed by Tcl_ConvertCountedElement
 *	when doing the actual conversion.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_ScanCountedElement(string, length, flagPtr)
    CONST char *string;		/* String to convert to Tcl list element. */
    int length;			/* Number of bytes in string, or -1. */
    int *flagPtr;		/* Where to store information to guide
				 * Tcl_ConvertElement. */
{
    int flags, nestingLevel;
    register CONST char *p, *lastChar;

    /*
     * This procedure and Tcl_ConvertElement together do two things:
     *
     * 1. They produce a proper list, one that will yield back the
     * argument strings when evaluated or when disassembled with
     * Tcl_SplitList.  This is the most important thing.
     * 
     * 2. They try to produce legible output, which means minimizing the
     * use of backslashes (using braces instead).  However, there are
     * some situations where backslashes must be used (e.g. an element
     * like "{abc": the leading brace will have to be backslashed.
     * For each element, one of three things must be done:
     *
     * (a) Use the element as-is (it doesn't contain any special
     * characters).  This is the most desirable option.
     *
     * (b) Enclose the element in braces, but leave the contents alone.
     * This happens if the element contains embedded space, or if it
     * contains characters with special interpretation ($, [, ;, or \),
     * or if it starts with a brace or double-quote, or if there are
     * no characters in the element.
     *
     * (c) Don't enclose the element in braces, but add backslashes to
     * prevent special interpretation of special characters.  This is a
     * last resort used when the argument would normally fall under case
     * (b) but contains unmatched braces.  It also occurs if the last
     * character of the argument is a backslash or if the element contains
     * a backslash followed by newline.
     *
     * The procedure figures out how many bytes will be needed to store
     * the result (actually, it overestimates). It also collects information
     * about the element in the form of a flags word.
     *
     * Note: list elements produced by this procedure and
     * Tcl_ConvertCountedElement must have the property that they can be
     * enclosing in curly braces to make sub-lists.  This means, for
     * example, that we must not leave unmatched curly braces in the
     * resulting list element.  This property is necessary in order for
     * procedures like Tcl_DStringStartSublist to work.
     */

    nestingLevel = 0;
    flags = 0;
    if (string == NULL) {
	string = "";
    }
    if (length == -1) {
	length = strlen(string);
    }
    lastChar = string + length;
    p = string;
    if ((p == lastChar) || (*p == '{') || (*p == '"')) {
	flags |= USE_BRACES;
    }
    for ( ; p < lastChar; p++) {
	switch (*p) {
	    case '{':
		nestingLevel++;
		break;
	    case '}':
		nestingLevel--;
		if (nestingLevel < 0) {
		    flags |= TCL_DONT_USE_BRACES|BRACES_UNMATCHED;
		}
		break;
	    case '[':
	    case '$':
	    case ';':
	    case ' ':
	    case '\f':
	    case '\n':
	    case '\r':
	    case '\t':
	    case '\v':
		flags |= USE_BRACES;
		break;
	    case '\\':
		if ((p+1 == lastChar) || (p[1] == '\n')) {
		    flags = TCL_DONT_USE_BRACES | BRACES_UNMATCHED;
		} else {
		    int size;

		    Tcl_UtfBackslash(p, &size, NULL);
		    p += size-1;
		    flags |= USE_BRACES;
		}
		break;
	}
    }
    if (nestingLevel != 0) {
	flags = TCL_DONT_USE_BRACES | BRACES_UNMATCHED;
    }
    *flagPtr = flags;

    /*
     * Allow enough space to backslash every character plus leave
     * two spaces for braces.
     */

    return 2*(p-string) + 2;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ConvertElement --
 *
 *	This is a companion procedure to Tcl_ScanElement.  Given
 *	the information produced by Tcl_ScanElement, this procedure
 *	converts a string to a list element equal to that string.
 *
 * Results:
 *	Information is copied to *dst in the form of a list element
 *	identical to src (i.e. if Tcl_SplitList is applied to dst it
 *	will produce a string identical to src).  The return value is
 *	a count of the number of characters copied (not including the
 *	terminating NULL character).
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_ConvertElement(src, dst, flags)
    register CONST char *src;	/* Source information for list element. */
    register char *dst;		/* Place to put list-ified element. */
    register int flags;		/* Flags produced by Tcl_ScanElement. */
{
    return Tcl_ConvertCountedElement(src, -1, dst, flags);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ConvertCountedElement --
 *
 *	This is a companion procedure to Tcl_ScanCountedElement.  Given
 *	the information produced by Tcl_ScanCountedElement, this
 *	procedure converts a string to a list element equal to that
 *	string.
 *
 * Results:
 *	Information is copied to *dst in the form of a list element
 *	identical to src (i.e. if Tcl_SplitList is applied to dst it
 *	will produce a string identical to src).  The return value is
 *	a count of the number of characters copied (not including the
 *	terminating NULL character).
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_ConvertCountedElement(src, length, dst, flags)
    register CONST char *src;	/* Source information for list element. */
    int length;			/* Number of bytes in src, or -1. */
    char *dst;			/* Place to put list-ified element. */
    int flags;			/* Flags produced by Tcl_ScanElement. */
{
    register char *p = dst;
    register CONST char *lastChar;

    /*
     * See the comment block at the beginning of the Tcl_ScanElement
     * code for details of how this works.
     */

    if (src && length == -1) {
	length = strlen(src);
    }
    if ((src == NULL) || (length == 0)) {
	p[0] = '{';
	p[1] = '}';
	p[2] = 0;
	return 2;
    }
    lastChar = src + length;
    if ((flags & USE_BRACES) && !(flags & TCL_DONT_USE_BRACES)) {
	*p = '{';
	p++;
	for ( ; src != lastChar; src++, p++) {
	    *p = *src;
	}
	*p = '}';
	p++;
    } else {
	if (*src == '{') {
	    /*
	     * Can't have a leading brace unless the whole element is
	     * enclosed in braces.  Add a backslash before the brace.
	     * Furthermore, this may destroy the balance between open
	     * and close braces, so set BRACES_UNMATCHED.
	     */

	    p[0] = '\\';
	    p[1] = '{';
	    p += 2;
	    src++;
	    flags |= BRACES_UNMATCHED;
	}
	for (; src != lastChar; src++) {
	    switch (*src) {
		case ']':
		case '[':
		case '$':
		case ';':
		case ' ':
		case '\\':
		case '"':
		    *p = '\\';
		    p++;
		    break;
		case '{':
		case '}':
		    /*
		     * It may not seem necessary to backslash braces, but
		     * it is.  The reason for this is that the resulting
		     * list element may actually be an element of a sub-list
		     * enclosed in braces (e.g. if Tcl_DStringStartSublist
		     * has been invoked), so there may be a brace mismatch
		     * if the braces aren't backslashed.
		     */

		    if (flags & BRACES_UNMATCHED) {
			*p = '\\';
			p++;
		    }
		    break;
		case '\f':
		    *p = '\\';
		    p++;
		    *p = 'f';
		    p++;
		    continue;
		case '\n':
		    *p = '\\';
		    p++;
		    *p = 'n';
		    p++;
		    continue;
		case '\r':
		    *p = '\\';
		    p++;
		    *p = 'r';
		    p++;
		    continue;
		case '\t':
		    *p = '\\';
		    p++;
		    *p = 't';
		    p++;
		    continue;
		case '\v':
		    *p = '\\';
		    p++;
		    *p = 'v';
		    p++;
		    continue;
	    }
	    *p = *src;
	    p++;
	}
    }
    *p = '\0';
    return p-dst;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_Merge --
 *
 *	Given a collection of strings, merge them together into a
 *	single string that has proper Tcl list structured (i.e.
 *	Tcl_SplitList may be used to retrieve strings equal to the
 *	original elements, and Tcl_Eval will parse the string back
 *	into its original elements).
 *
 * Results:
 *	The return value is the address of a dynamically-allocated
 *	string containing the merged list.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

char *
Tcl_Merge(argc, argv)
    int argc;			/* How many strings to merge. */
    CONST char * CONST *argv;	/* Array of string values. */
{
#   define LOCAL_SIZE 20
    int localFlags[LOCAL_SIZE], *flagPtr;
    int numChars;
    char *result;
    char *dst;
    int i;

    /*
     * Pass 1: estimate space, gather flags.
     */

    if (argc <= LOCAL_SIZE) {
	flagPtr = localFlags;
    } else {
	flagPtr = (int *) ckalloc((unsigned) argc*sizeof(int));
    }
    numChars = 1;
    for (i = 0; i < argc; i++) {
	numChars += Tcl_ScanElement(argv[i], &flagPtr[i]) + 1;
    }

    /*
     * Pass two: copy into the result area.
     */

    result = (char *) ckalloc((unsigned) numChars);
    dst = result;
    for (i = 0; i < argc; i++) {
	numChars = Tcl_ConvertElement(argv[i], dst, flagPtr[i]);
	dst += numChars;
	*dst = ' ';
	dst++;
    }
    if (dst == result) {
	*dst = 0;
    } else {
	dst[-1] = 0;
    }

    if (flagPtr != localFlags) {
	ckfree((char *) flagPtr);
    }
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_Backslash --
 *
 *	Figure out how to handle a backslash sequence.
 *
 * Results:
 *	The return value is the character that should be substituted
 *	in place of the backslash sequence that starts at src.  If
 *	readPtr isn't NULL then it is filled in with a count of the
 *	number of characters in the backslash sequence.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

char
Tcl_Backslash(src, readPtr)
    CONST char *src;		/* Points to the backslash character of
				 * a backslash sequence. */
    int *readPtr;		/* Fill in with number of characters read
				 * from src, unless NULL. */
{
    char buf[TCL_UTF_MAX];
    Tcl_UniChar ch;

    Tcl_UtfBackslash(src, readPtr, buf);
    TclUtfToUniChar(buf, &ch);
    return (char) ch;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_Concat --
 *
 *	Concatenate a set of strings into a single large string.
 *
 * Results:
 *	The return value is dynamically-allocated string containing
 *	a concatenation of all the strings in argv, with spaces between
 *	the original argv elements.
 *
 * Side effects:
 *	Memory is allocated for the result;  the caller is responsible
 *	for freeing the memory.
 *
 *----------------------------------------------------------------------
 */

char *
Tcl_Concat(argc, argv)
    int argc;			/* Number of strings to concatenate. */
    CONST char * CONST *argv;	/* Array of strings to concatenate. */
{
    int totalSize, i;
    char *p;
    char *result;

    for (totalSize = 1, i = 0; i < argc; i++) {
	totalSize += strlen(argv[i]) + 1;
    }
    result = (char *) ckalloc((unsigned) totalSize);
    if (argc == 0) {
	*result = '\0';
	return result;
    }
    for (p = result, i = 0; i < argc; i++) {
	CONST char *element;