category Z? or C? are not composable except for ZWNJ and ZWJ. */
#define CHAR_COMPOSABLE_P(C) \
- ((C) == 0x200C || (C) == 0x200D \
- || (_work_val = CHAR_TABLE_REF (Vunicode_category_table, (C)), \
- (SYMBOLP (_work_val) \
- && (_work_char = SDATA (SYMBOL_NAME (_work_val))[0]) != 'C' \
- && _work_char != 'Z')))
+ ((C) > ' ' \
+ && ((C) == 0x200C || (C) == 0x200D \
+ || (_work_val = CHAR_TABLE_REF (Vunicode_category_table, (C)), \
+ (SYMBOLP (_work_val) \
+ && (_work_char = SDATA (SYMBOL_NAME (_work_val))[0]) != 'C' \
+ && _work_char != 'Z'))))
/* Update cmp_it->stop_pos to the next position after CHARPOS (and
BYTEPOS) where character composition may happen. If BYTEPOS is
/* Update the members of POSITION to the previous character boundary. */
#define BACKWARD_CHAR(POSITION, STOP) \
do { \
- if ((POSITION).pos == STOP) \
+ if ((POSITION).pos == (STOP)) \
(POSITION).p = GPT_ADDR; \
do { \
(POSITION).pos_byte--; \
} while (0)
/* This is like find_composition, but find an automatic composition
- instead. If found, set *GSTRING to the glyph-string representing
- the composition, and return 1. Otherwise, return 0. */
+ instead. It is assured that POS is not within a static
+ composition. If found, set *GSTRING to the glyph-string
+ representing the composition, and return 1. Otherwise, *GSTRING to
+ Qnil, and return 0. */
static int
-find_automatic_composition (EMACS_INT pos, EMACS_INT limit, EMACS_INT *start, EMACS_INT *end, Lisp_Object *gstring, Lisp_Object string)
+find_automatic_composition (EMACS_INT pos, EMACS_INT limit,
+ EMACS_INT *start, EMACS_INT *end,
+ Lisp_Object *gstring, Lisp_Object string)
{
EMACS_INT head, tail, stop;
- /* Limit to check a composition after POS. */
+ /* Forward limit position of checking a composition taking a
+ looking-back count into account. */
EMACS_INT fore_check_limit;
- struct position_record orig, cur;
-
- /* FIXME: It's not obvious whether these two variables need initialization.
- If they do, please supply initial values.
- If not, please remove this comment. */
- struct position_record check IF_LINT (= {0}), prev IF_LINT (= {0});
-
- Lisp_Object check_val, val, elt;
+ struct position_record cur, prev;
int c;
Lisp_Object window;
struct window *w;
+ int need_adjustment = 0;
window = Fget_buffer_window (Fcurrent_buffer (), Qnil);
if (NILP (window))
return 0;
w = XWINDOW (window);
- orig.pos = pos;
+ cur.pos = pos;
if (NILP (string))
{
head = BEGV, tail = ZV, stop = GPT;
- orig.pos_byte = CHAR_TO_BYTE (orig.pos);
- orig.p = BYTE_POS_ADDR (orig.pos_byte);
+ cur.pos_byte = CHAR_TO_BYTE (cur.pos);
+ cur.p = BYTE_POS_ADDR (cur.pos_byte);
}
else
{
head = 0, tail = SCHARS (string), stop = -1;
- orig.pos_byte = string_char_to_byte (string, orig.pos);
- orig.p = SDATA (string) + orig.pos_byte;
+ cur.pos_byte = string_char_to_byte (string, cur.pos);
+ cur.p = SDATA (string) + cur.pos_byte;
}
- if (limit < pos)
- fore_check_limit = min (tail, pos + MAX_AUTO_COMPOSITION_LOOKBACK);
+ if (limit < 0)
+ /* Finding a composition covering the character after POS is the
+ same as setting LIMIT to POS. */
+ limit = pos;
+ if (limit <= pos)
+ fore_check_limit = min (tail, pos + 1 + MAX_AUTO_COMPOSITION_LOOKBACK);
else
fore_check_limit = min (tail, limit + MAX_AUTO_COMPOSITION_LOOKBACK);
- cur = orig;
- retry:
- check_val = Qnil;
- /* At first, check if POS is composable. */
- c = STRING_CHAR (cur.p);
- if (! CHAR_COMPOSABLE_P (c))
- {
- if (limit < 0)
- return 0;
- if (limit >= cur.pos)
- goto search_forward;
- }
- else
- {
- val = CHAR_TABLE_REF (Vcomposition_function_table, c);
- if (! NILP (val))
- check_val = val, check = cur;
- else
- while (cur.pos + 1 < fore_check_limit)
- {
- EMACS_INT b, e;
+ /* Provided that we have these possible compositions now:
- FORWARD_CHAR (cur, stop);
- if (get_property_and_range (cur.pos, Qcomposition, &val, &b, &e,
- Qnil)
- && COMPOSITION_VALID_P (b, e, val))
- {
- fore_check_limit = cur.pos;
- break;
- }
- c = STRING_CHAR (cur.p);
- if (! CHAR_COMPOSABLE_P (c))
- break;
- val = CHAR_TABLE_REF (Vcomposition_function_table, c);
- if (NILP (val))
- continue;
- check_val = val, check = cur;
- break;
- }
- cur = orig;
- }
- /* Rewind back to the position where we can safely search forward
- for compositions. */
- while (cur.pos > head)
- {
- EMACS_INT b, e;
+ POS: 1 2 3 4 5 6 7 8 9
+ |-A-|
+ |-B-|-C-|--D--|
- BACKWARD_CHAR (cur, stop);
- if (get_property_and_range (cur.pos, Qcomposition, &val, &b, &e, Qnil)
- && COMPOSITION_VALID_P (b, e, val))
- break;
+ Here, it is known that characters after positions 1 and 9 can
+ never be composed (i.e. ! CHAR_COMPOSABLE_P (CH)), and
+ composition A is an invalid one because it's partially covered by
+ the valid composition C. And to know whether a composition is
+ valid or not, the only way is to start searching forward from a
+ position that can not be a tail part of composition (it's 2 in
+ the above case).
+
+ Now we have these cases (1 through 4):
+
+ -- character after POS is ... --
+ not composable composable
+ LIMIT <= POS (1) (3)
+ POS < LIMIT (2) (4)
+
+ Among them, in case (2), we simply search forward from POS.
+
+ In the other cases, we at first rewind back to the position where
+ the previous character is not composable or the beginning of
+ buffer (string), then search compositions forward. In case (1)
+ and (3) we repeat this process until a composition is found. */
+
+ while (1)
+ {
c = STRING_CHAR (cur.p);
if (! CHAR_COMPOSABLE_P (c))
- break;
- val = CHAR_TABLE_REF (Vcomposition_function_table, c);
- if (! NILP (val))
- check_val = val, check = cur;
- }
- prev = cur;
- /* Now search forward. */
- search_forward:
- *gstring = Qnil;
- if (! NILP (check_val) || limit >= orig.pos)
- {
- if (NILP (check_val))
- cur = orig;
- else
- cur = check;
- while (cur.pos < fore_check_limit)
{
- int need_adjustment = 0;
+ if (limit <= pos) /* case (1) */
+ {
+ do {
+ if (cur.pos == limit)
+ return 0;
+ BACKWARD_CHAR (cur, stop);
+ c = STRING_CHAR (cur.p);
+ } while (! CHAR_COMPOSABLE_P (c));
+ fore_check_limit = cur.pos + 1;
+ }
+ else /* case (2) */
+ /* No need of rewinding back. */
+ goto search_forward;
+ }
- if (NILP (check_val))
+ /* Rewind back to the position where we can safely search
+ forward for compositions. It is assured that the character
+ at cur.pos is composable. */
+ while (head < cur.pos)
+ {
+ prev = cur;
+ BACKWARD_CHAR (cur, stop);
+ c = STRING_CHAR (cur.p);
+ if (! CHAR_COMPOSABLE_P (c))
{
- c = STRING_CHAR (cur.p);
- check_val = CHAR_TABLE_REF (Vcomposition_function_table, c);
+ cur = prev;
+ break;
}
- for (; CONSP (check_val); check_val = XCDR (check_val))
+ }
+
+ search_forward:
+ /* Now search forward. */
+ *gstring = Qnil;
+ prev = cur; /* remember the start of searching position. */
+ while (cur.pos < fore_check_limit)
+ {
+ Lisp_Object val;
+
+ c = STRING_CHAR (cur.p);
+ for (val = CHAR_TABLE_REF (Vcomposition_function_table, c);
+ CONSP (val); val = XCDR (val))
{
- elt = XCAR (check_val);
- if (VECTORP (elt) && ASIZE (elt) == 3 && NATNUMP (AREF (elt, 1))
- && cur.pos - XFASTINT (AREF (elt, 1)) >= head)
+ Lisp_Object elt = XCAR (val);
+
+ if (VECTORP (elt) && ASIZE (elt) == 3 && NATNUMP (AREF (elt, 1)))
{
- check.pos = cur.pos - XFASTINT (AREF (elt, 1));
- if (check.pos == cur.pos)
- check.pos_byte = cur.pos_byte;
- else
- check.pos_byte = CHAR_TO_BYTE (check.pos);
- val = autocmp_chars (elt, check.pos, check.pos_byte,
- tail, w, NULL, string);
+ EMACS_INT check_pos = cur.pos - XFASTINT (AREF (elt, 1));
+ struct position_record check;
+
+ if (check_pos < head
+ || (limit <= pos ? pos < check_pos
+ : limit <= check_pos))
+ continue;
+ for (check = cur; check_pos < check.pos; )
+ BACKWARD_CHAR (check, stop);
+ *gstring = autocmp_chars (elt, check.pos, check.pos_byte,
+ tail, w, NULL, string);
need_adjustment = 1;
- if (! NILP (val))
+ if (NILP (*gstring))
{
- *gstring = val;
+ /* As we have called Lisp, there's a possibility
+ that buffer/string is relocated. */
+ if (NILP (string))
+ cur.p = BYTE_POS_ADDR (cur.pos_byte);
+ else
+ cur.p = SDATA (string) + cur.pos_byte;
+ }
+ else
+ {
+ /* We found a candidate of a target composition. */
*start = check.pos;
*end = check.pos + LGSTRING_CHAR_LEN (*gstring);
- if (*start <= orig.pos ? *end > orig.pos
- : limit >= orig.pos)
+ if (pos < limit
+ ? pos < *end
+ : *start <= pos && pos < *end)
+ /* This is the target composition. */
return 1;
cur.pos = *end;
- cur.pos_byte = CHAR_TO_BYTE (cur.pos);
+ if (NILP (string))
+ {
+ cur.pos_byte = CHAR_TO_BYTE (cur.pos);
+ cur.p = BYTE_POS_ADDR (cur.pos_byte);
+ }
+ else
+ {
+ cur.pos_byte = string_char_to_byte (string, cur.pos);
+ cur.p = SDATA (string) + cur.pos_byte;
+ }
break;
}
}
}
- if (need_adjustment)
- {
- /* As we have called Lisp, there's a possibility that
- buffer/string is relocated. */
- if (NILP (string))
- cur.p = BYTE_POS_ADDR (cur.pos_byte);
- else
- cur.p = SDATA (string) + cur.pos_byte;
- }
- if (! CONSP (check_val))
+ if (! CONSP (val))
+ /* We found no composition here. */
FORWARD_CHAR (cur, stop);
- check_val = Qnil;
}
- }
- if (! NILP (*gstring))
- return (limit >= 0 || (*start <= orig.pos && *end > orig.pos));
- if (limit >= 0 && limit < orig.pos && prev.pos > head)
- {
+
+ if (pos < limit) /* case (2) and (4)*/
+ return 0;
+ if (! NILP (*gstring))
+ return 1;
+ if (prev.pos == head)
+ return 0;
cur = prev;
+ if (need_adjustment)
+ {
+ if (NILP (string))
+ cur.p = BYTE_POS_ADDR (cur.pos_byte);
+ else
+ cur.p = SDATA (string) + cur.pos_byte;
+ }
BACKWARD_CHAR (cur, stop);
- orig = cur;
- fore_check_limit = orig.pos;
- goto retry;
}
return 0;
}
projects / emacs.git / commitdiff