1 files changed, 7 insertions, 35 deletions
diff --git a/generic/tclUtf.c b/generic/tclUtf.c
index ef3fd9e..91a4b89 100644
--- a/generic/tclUtf.c
+++ b/generic/tclUtf.c
@@ -753,43 +753,15 @@ Tcl_UtfNext(
  *
  * Tcl_UtfPrev --
  *
- *	The aim of this routine is to provide a way to move backward
- *	through a UTF-8 string. The caller is expected to pass non-NULL
- *	pointer arguments start and src. start points to the beginning
- *	of a string, and src >= start points to a location within (or just
- *	past the end) of the string. This routine always returns a
- *	pointer within the string (>= start).  When (src == start), it
- *	returns start. When (src > start), it returns a pointer (< src)
- *	and (>= src - TCL_UTF_MAX).  Subject to these constraints, the
- *	routine returns a pointer to the earliest byte in the string that
- *	starts a character when characters are read starting at start and
- *	that character might include the byte src[-1]. The routine will
- *	examine only those bytes in the range that might be returned.
- *	It will not examine the byte *src, and because of that cannot
- *	determine for certain in all circumstances whether the character
- *	that begins with the returned pointer will or will not include
- *	the byte src[-1]. In the scenario, where src points to the end of
- *	a buffer being filled, the returned pointer points to either the
- *	final complete character in the string or to the earliest byte
- *	that might start an incomplete character waiting for more bytes to
- *	complete.
- *
- *	Because this routine always returns a value < src until the point
- *	it is forced to return start, it is useful as a backward iterator
- *	through a string that will always make progress and always be
- *	prevented from running past the beginning of the string.
- *
- *	In a string where all characters are complete and properly formed,
- *	and the value of src points to the first byte of a character,
- *	repeated Tcl_UtfPrev calls will step to the starting bytes of
- *	characters, one character at a time. Within those limitations,
- *	Tcl_UtfPrev and Tcl_UtfNext are inverses. If either condition cannot
- *	be met, Tcl_UtfPrev and Tcl_UtfNext may not function as inverses and
- *	the caller will have to take greater care.
+ *	Given a pointer to some current location in a UTF-8 string, move
+ *	backwards one character. This works correctly when the pointer is in
+ *	the middle of a UTF-8 character.
  *
  * Results:
- *	A pointer to the start of a character in the string as described
- *	above.
+ *	The return value is a pointer to the previous character in the UTF-8
+ *	string. If the current location was already at the beginning of the
+ *	string, the return value will also be a pointer to the beginning of
+ *	the string.
  *
  * Side effects:
  *	None.