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(Fcompare_buffer_substrings): New function.

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Richard M. Stallman 1993-02-11 06:00:51 +00:00
parent 3220bb9113
commit e9cf2084dd
1 changed files with 117 additions and 0 deletions
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117
src/editfns.c
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@ -817,6 +817,122 @@ They default to the beginning and the end of BUFFER.")
return Qnil;
}
DEFUN ("compare-buffer-substrings", Fcompare_buffer_substrings, Scompare_buffer_substrings,
6, 6, 0,
"Compare two substrings of two buffers; return result as number.\n\
the value is -N if first string is less after N-1 chars,\n\
+N if first string is greater after N-1 chars, or 0 if strings match.\n\
Each substring is represented as three arguments: BUFFER, START and END.\n\
That makes six args in all, three for each substring.\n\n\
The value of `case-fold-search' in the current buffer\n\
determines whether case is significant or ignored.")
(buffer1, start1, end1, buffer2, start2, end2)
Lisp_Object buffer1, start1, end1, buffer2, start2, end2;
{
register int begp1, endp1, begp2, endp2, temp, len1, len2, length, i;
register struct buffer *bp1, *bp2;
register unsigned char *trt
= (!NILP (current_buffer->case_fold_search)
? XSTRING (current_buffer->case_canon_table)->data : 0);
/* Find the first buffer and its substring. */
if (NILP (buffer1))
bp1 = current_buffer;
else
{
buffer1 = Fget_buffer (buffer1);
bp1 = XBUFFER (buffer1);
}
if (NILP (start1))
begp1 = BUF_BEGV (bp1);
else
{
CHECK_NUMBER_COERCE_MARKER (start1, 1);
begp1 = XINT (start1);
}
if (NILP (end1))
endp1 = BUF_ZV (bp1);
else
{
CHECK_NUMBER_COERCE_MARKER (end1, 2);
endp1 = XINT (end1);
}
if (begp1 > endp1)
temp = begp1, begp1 = endp1, endp1 = temp;
if (!(BUF_BEGV (bp1) <= begp1
&& begp1 <= endp1
&& endp1 <= BUF_ZV (bp1)))
args_out_of_range (start1, end1);
/* Likewise for second substring. */
if (NILP (buffer2))
bp2 = current_buffer;
else
{
buffer2 = Fget_buffer (buffer2);
bp2 = XBUFFER (buffer2);
}
if (NILP (start2))
begp2 = BUF_BEGV (bp2);
else
{
CHECK_NUMBER_COERCE_MARKER (start2, 4);
begp2 = XINT (start2);
}
if (NILP (end2))
endp2 = BUF_ZV (bp2);
else
{
CHECK_NUMBER_COERCE_MARKER (end2, 5);
endp2 = XINT (end2);
}
if (begp2 > endp2)
temp = begp2, begp2 = endp2, endp2 = temp;
if (!(BUF_BEGV (bp2) <= begp2
&& begp2 <= endp2
&& endp2 <= BUF_ZV (bp2)))
args_out_of_range (start2, end2);
len1 = endp1 - begp1;
len2 = endp2 - begp2;
length = len1;
if (len2 < length)
length = len2;
for (i = 0; i < length; i++)
{
int c1 = *BUF_CHAR_ADDRESS (bp1, begp1 + i);
int c2 = *BUF_CHAR_ADDRESS (bp2, begp2 + i);
if (trt)
{
c1 = trt[c1];
c2 = trt[c2];
}
if (c1 < c2)
return make_number (- 1 - i);
if (c1 > c2)
return make_number (i + 1);
}
/* The strings match as far as they go.
If one is shorter, that one is less. */
if (length < len1)
return make_number (length + 1);
else if (length < len2)
return make_number (- length - 1);
/* Same length too => they are equal. */
return make_number (0);
}
DEFUN ("subst-char-in-region", Fsubst_char_in_region,
Ssubst_char_in_region, 4, 5, 0,
@ -1319,6 +1435,7 @@ syms_of_editfns ()
defsubr (&Sformat);
defsubr (&Sinsert_buffer_substring);
defsubr (&Scompare_buffer_substrings);
defsubr (&Ssubst_char_in_region);
defsubr (&Stranslate_region);
defsubr (&Sdelete_region);