Commit 79fd0489 authored by YAMAMOTO Mitsuharu's avatar YAMAMOTO Mitsuharu
Browse files

(find_string_data_in_pure): New function.

(make_pure_string): Use it to reuse existing string data if possible.
parent 303b246d
......@@ -4767,6 +4767,73 @@ check_pure_size ()
}
/* Find the byte sequence {DATA[0], ..., DATA[NBYTES-1], '\0'} from
the non-Lisp data pool of the pure storage, and return its start
address. Return NULL if not found. */
static char *
find_string_data_in_pure (data, nbytes)
char *data;
int nbytes;
{
int i, skip, bm_skip[256], last_char_skip, infinity, start, start_max;
unsigned char *p;
char *non_lisp_beg;
if (pure_bytes_used_non_lisp < nbytes + 1)
return NULL;
/* Set up the Boyer-Moore table. */
skip = nbytes + 1;
for (i = 0; i < 256; i++)
bm_skip[i] = skip;
p = (unsigned char *) data;
while (--skip > 0)
bm_skip[*p++] = skip;
last_char_skip = bm_skip['\0'];
non_lisp_beg = purebeg + pure_size - pure_bytes_used_non_lisp;
start_max = pure_bytes_used_non_lisp - (nbytes + 1);
/* See the comments in the function `boyer_moore' (search.c) for the
use of `infinity'. */
infinity = pure_bytes_used_non_lisp + 1;
bm_skip['\0'] = infinity;
p = (unsigned char *) non_lisp_beg + nbytes;
start = 0;
do
{
/* Check the last character (== '\0'). */
do
{
start += bm_skip[*(p + start)];
}
while (start <= start_max);
if (start < infinity)
/* Couldn't find the last character. */
return NULL;
/* No less than `infinity' means we could find the last
character at `p[start - infinity]'. */
start -= infinity;
/* Check the remaining characters. */
if (memcmp (data, non_lisp_beg + start, nbytes) == 0)
/* Found. */
return non_lisp_beg + start;
start += last_char_skip;
}
while (start <= start_max);
return NULL;
}
/* Return a string allocated in pure space. DATA is a buffer holding
NCHARS characters, and NBYTES bytes of string data. MULTIBYTE
non-zero means make the result string multibyte.
......@@ -4785,11 +4852,15 @@ make_pure_string (data, nchars, nbytes, multibyte)
struct Lisp_String *s;
s = (struct Lisp_String *) pure_alloc (sizeof *s, Lisp_String);
s->data = find_string_data_in_pure (data, nbytes);
if (s->data == NULL)
{
s->data = (unsigned char *) pure_alloc (nbytes + 1, -1);
s->size = nchars;
s->size_byte = multibyte ? nbytes : -1;
bcopy (data, s->data, nbytes);
s->data[nbytes] = '\0';
}
s->size = nchars;
s->size_byte = multibyte ? nbytes : -1;
s->intervals = NULL_INTERVAL;
XSETSTRING (string, s);
return string;
......
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