📄 tclutil.c
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/*
* tclUtil.c --
*
* This file contains utility procedures that are used by many Tcl
* commands.
*
* Copyright 1987-1991 Regents of the University of California
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies. The University of California
* makes no representations about the suitability of this
* software for any purpose. It is provided "as is" without
* express or implied warranty.
*
* $Id: tclUtil.c,v 1.1.1.1 2001/04/29 20:35:11 karll Exp $
*/
#include "tclInt.h"
//#include <varargs.h>
#include <stdarg.h>
/*
* The following values are used in the flags returned by Tcl_ScanElement
* and used by Tcl_ConvertElement. The value TCL_DONT_USE_BRACES is also
* defined in tcl.h; make sure its value doesn't overlap with any of the
* values below.
*
* TCL_DONT_USE_BRACES - 1 means the string mustn't be enclosed in
* braces (e.g. it contains unmatched braces,
* or ends in a backslash character, or user
* just doesn't want braces); handle all
* special characters by adding backslashes.
* USE_BRACES - 1 means the string contains a special
* character that can be handled simply by
* enclosing the entire argument in braces.
* BRACES_UNMATCHED - 1 means that braces aren't properly matched
* in the argument.
*/
#define USE_BRACES 2
#define BRACES_UNMATCHED 4
/*
* The variable below is set to NULL before invoking regexp functions
* and checked after those functions. If an error occurred then regerror
* will set the variable to point to a (static) error message. This
* mechanism unfortunately does not support multi-threading, but then
* neither does the rest of the regexp facilities.
*/
char *tclRegexpError = NULL;
/*
* Function prototypes for local procedures in this file:
*/
static void SetupAppendBuffer _ANSI_ARGS_((Interp *iPtr,
int newSpace));
/*
*----------------------------------------------------------------------
*
* TclFindElement --
*
* Given a pointer into a Tcl list, locate the first (or next)
* element in the list.
*
* Results:
* The return value is normally TCL_OK, which means that the
* element was successfully located. If TCL_ERROR is returned
* it means that list didn't have proper list structure;
* interp->result contains a more detailed error message.
*
* If TCL_OK is returned, then *elementPtr will be set to point
* to the first element of list, and *nextPtr will be set to point
* to the character just after any white space following the last
* character that's part of the element. If this is the last argument
* in the list, then *nextPtr will point to the NULL character at the
* end of list. If sizePtr is non-NULL, *sizePtr is filled in with
* the number of characters in the element. If the element is in
* braces, then *elementPtr will point to the character after the
* opening brace and *sizePtr will not include either of the braces.
* If there isn't an element in the list, *sizePtr will be zero, and
* both *elementPtr and *termPtr will refer to the null character at
* the end of list. Note: this procedure does NOT collapse backslash
* sequences.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
int TclFindElement(Tcl_Interp *interp, char *list, char **elementPtr, char **nextPtr, int *sizePtr, int *bracePtr)
// Tcl_Interp *interp; /* Interpreter to use for error reporting. */
//register char *list; /* String containing Tcl list with zero
// * or more elements (possibly in braces). */
//char **elementPtr; /* Fill in with location of first significant
// * character in first element of list. */
//char **nextPtr; /* Fill in with location of character just
// * after all white space following end of
// * argument (i.e. next argument or end of
// * list). */
//int *sizePtr; /* If non-zero, fill in with size of
// * element. */
//int *bracePtr; /* If non-zero fill in with non-zero/zero
// * to indicate that arg was/wasn't
// * in braces. */
{
register char *p;
int openBraces = 0;
int inQuotes = 0;
int size;
/*
* Skim off leading white space and check for an opening brace or
* quote. Note: use of "isascii" below and elsewhere in this
* procedure is a temporary hack (7/27/90) because Mx uses characters
* with the high-order bit set for some things. This should probably
* be changed back eventually, or all of Tcl should call isascii.
*/
while (isprint(*list) && isspace(*list)) {
list++;
}
if (*list == '{') {
openBraces = 1;
list++;
} else if (*list == '"') {
inQuotes = 1;
list++;
}
if (bracePtr != 0) {
*bracePtr = openBraces;
}
p = list;
/*
* Find the end of the element (either a space or a close brace or
* the end of the string).
*/
while (1) {
switch (*p) {
/*
* Open brace: don't treat specially unless the element is
* in braces. In this case, keep a nesting count.
*/
case '{':
if (openBraces != 0) {
openBraces++;
}
break;
/*
* Close brace: if element is in braces, keep nesting
* count and quit when the last close brace is seen.
*/
case '}':
if (openBraces == 1) {
char *p2;
size = p - list;
p++;
if ((isprint(*p) && isspace(*p)) || (*p == 0)) {
goto done;
}
for (p2 = p; (*p2 != 0) && (!isspace(*p2)) && (p2 < p+20);
p2++) {
/* null body */
}
Tcl_ResetResult(interp);
sprintf(interp->result,
"list element in braces followed by \"%.*s\" instead of space",
(int)(p2-p), p);
return TCL_ERROR;
} else if (openBraces != 0) {
openBraces--;
}
break;
/*
* Backslash: skip over everything up to the end of the
* backslash sequence.
*/
case '\\': {
int size;
(void) Tcl_Backslash(p, &size);
p += size - 1;
break;
}
/*
* Space: ignore if element is in braces or quotes; otherwise
* terminate element.
*/
case ' ':
case '\f':
case '\n':
case '\r':
case '\t':
case '\v':
if ((openBraces == 0) && !inQuotes) {
size = p - list;
goto done;
}
break;
/*
* Double-quote: if element is in quotes then terminate it.
*/
case '"':
if (inQuotes) {
char *p2;
size = p-list;
p++;
if ((isprint(*p) && isspace(*p)) || (*p == 0)) {
goto done;
}
for (p2 = p; (*p2 != 0) && (!isspace(*p2)) && (p2 < p+20);
p2++) {
/* null body */
}
Tcl_ResetResult(interp);
sprintf(interp->result,
"list element in quotes followed by \"%.*s\" %s",
(int)(p2-p), p, "instead of space");
return TCL_ERROR;
}
break;
/*
* End of list: terminate element.
*/
case 0:
if (openBraces != 0) {
Tcl_SetResult(interp, "unmatched open brace in list",
TCL_STATIC);
return TCL_ERROR;
} else if (inQuotes) {
Tcl_SetResult(interp, "unmatched open quote in list",
TCL_STATIC);
return TCL_ERROR;
}
size = p - list;
goto done;
}
p++;
}
done:
while (isprint(*p) && isspace(*p)) {
p++;
}
*elementPtr = list;
*nextPtr = p;
if (sizePtr != 0) {
*sizePtr = size;
}
return TCL_OK;
}
/*
*----------------------------------------------------------------------
*
* TclCopyAndCollapse --
*
* Copy a string and eliminate any backslashes that aren't in braces.
*
* Results:
* There is no return value. Count chars. get copied from src
* to dst. Along the way, if backslash sequences are found outside
* braces, the backslashes are eliminated in the copy.
* After scanning count chars. from source, a null character is
* placed at the end of dst.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
void TclCopyAndCollapse(int count, char *src, char *dst)
// int count; /* Total number of characters to copy
// * from src. */
//register char *src; /* Copy from here... */
//register char *dst; /* ... to here. */
{
register char c;
int numRead;
for (c = *src; count > 0; src++, c = *src, count--) {
if (c == '\\') {
*dst = Tcl_Backslash(src, &numRead);
if (*dst != 0) {
dst++;
}
src += numRead-1;
count -= numRead-1;
} else {
*dst = c;
dst++;
}
}
*dst = 0;
}
/*
*----------------------------------------------------------------------
*
* Tcl_SplitList --
*
* Splits a list up into its constituent fields.
*
* Results
* The return value is normally TCL_OK, which means that
* the list was successfully split up. If TCL_ERROR is
* returned, it means that "list" didn't have proper list
* structure; interp->result will contain a more detailed
* error message.
*
* *argvPtr will be filled in with the address of an array
* whose elements point to the elements of list, in order.
* *argcPtr will get filled in with the number of valid elements
* in the array. A single block of memory is dynamically allocated
* to hold both the argv array and a copy of the list (with
* backslashes and braces removed in the standard way).
* The caller must eventually free this memory by calling free()
* on *argvPtr. Note: *argvPtr and *argcPtr are only modified
* if the procedure returns normally.
*
* Side effects:
* Memory is allocated.
*
*----------------------------------------------------------------------
*/
int Tcl_SplitList(Tcl_Interp *interp, char *list, int *argcPtr, char ***argvPtr)
// Tcl_Interp *interp; /* Interpreter to use for error reporting. */
//char *list; /* Pointer to string with list structure. */
//int *argcPtr; /* Pointer to location to fill in with
// * the number of elements in the list. */
//char ***argvPtr; /* Pointer to place to store pointer to array
// * of pointers to list elements. */
{
char **argv;
register char *p;
int size, i, result, elSize, brace;
char *element;
/*
* Figure out how much space to allocate. There must be enough
* space for both the array of pointers and also for a copy of
* the list. To estimate the number of pointers needed, count
* the number of space characters in the list.
*/
for (size = 1, p = list; *p != 0; p++) {
if (isspace(*p)) {
size++;
}
}
size++; /* Leave space for final NULL pointer. */
argv = (char **) ckalloc((unsigned)
((size * sizeof(char *)) + (p - list) + 1));
for (i = 0, p = ((char *) argv) + size*sizeof(char *);
*list != 0; i++) {
result = TclFindElement(interp, list, &element, &list, &elSize, &brace);
if (result != TCL_OK) {
ckfree((char *) argv);
return result;
}
if (*element == 0) {
break;
}
if (i >= size) {
ckfree((char *) argv);
Tcl_SetResult(interp, "internal error in Tcl_SplitList",
TCL_STATIC);
return TCL_ERROR;
}
argv[i] = p;
if (brace) {
strncpy(p, element, elSize);
p += elSize;
*p = 0;
p++;
} else {
TclCopyAndCollapse(elSize, element, p);
p += elSize+1;
}
}
argv[i] = NULL;
*argvPtr = argv;
*argcPtr = i;
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(char *string, int *flagPtr)
// char *string; /* String to convert to Tcl list element. */
//int *flagPtr; /* Where to store information to guide
// * Tcl_ConvertElement. */
{
int flags, nestingLevel;
register char *p;
/*
* 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 anything 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.
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