procyberian/emacs
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

(get_doc_string): Always read entire disk blocks.

Browse source
This commit is contained in:
Richard M. Stallman 1996-02-12 09:49:01 +00:00
parent 48919e0ff4
commit 0fded513b9
1 changed files with 23 additions and 38 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

61
src/doc.c
View file

@ -82,16 +82,15 @@ static Lisp_Object
get_doc_string (filepos)
Lisp_Object filepos;
{
char buf[512 * 32 + 1];
char *buffer;
int buffer_size;
int free_it;
static char *buffer;
static int buffer_size;
char *from, *to;
register int fd;
register char *name;
register char *p, *p1;
int minsize;
int position;
int offset, position;
Lisp_Object file, tem;
if (INTEGERP (filepos))
@ -150,12 +149,13 @@ get_doc_string (filepos)
fd = open (name, O_RDONLY, 0);
}
#endif
if (fd < 0)
error ("Cannot open doc string file \"%s\"", name);
}
if (0 > lseek (fd, position, 0))
/* Seek only to beginning of disk block. */
offset = position % (8 * 1024);
if (0 > lseek (fd, position - offset, 0))
{
close (fd);
error ("Position %ld out of range in doc string file \"%s\"",
@ -163,40 +163,26 @@ get_doc_string (filepos)
}
/* Read the doc string into a buffer.
Use the fixed buffer BUF if it is big enough;
otherwise allocate one and set FREE_IT.
We store the buffer in use in BUFFER and its size in BUFFER_SIZE. */
p points beyond the data just read. */
buffer = buf;
buffer_size = sizeof buf;
free_it = 0;
p = buf;
p = buffer;
while (1)
{
int space_left = buffer_size - (p - buffer);
int nread;
/* Switch to a bigger buffer if we need one. */
/* Allocate or grow the buffer if we need to. */
if (space_left == 0)
{
if (free_it)
{
int offset = p - buffer;
buffer = (char *) xrealloc (buffer,
buffer_size *= 2);
p = buffer + offset;
}
else
{
buffer = (char *) xmalloc (buffer_size *= 2);
bcopy (buf, buffer, p - buf);
p = buffer + (p - buf);
}
free_it = 1;
int in_buffer = p - buffer;
buffer_size += 16 * 1024;
buffer = (char *) xrealloc (buffer, buffer_size + 1);
p = buffer + in_buffer;
space_left = buffer_size - (p - buffer);
}
/* Don't read too too much at one go. */
/* Read a disk block at a time.
If we read the same block last time, maybe skip this? */
if (space_left > 1024 * 8)
space_left = 1024 * 8;
nread = read (fd, p, space_left);
@ -208,7 +194,10 @@ get_doc_string (filepos)
p[nread] = 0;
if (!nread)
break;
p1 = index (p, '\037');
if (p == buffer)
p1 = index (p + offset, '\037');
else
p1 = index (p, '\037');
if (p1)
{
*p1 = 0;
@ -221,8 +210,8 @@ get_doc_string (filepos)
/* Scan the text and perform quoting with ^A (char code 1).
^A^A becomes ^A, ^A0 becomes a null char, and ^A_ becomes a ^_. */
from = buffer;
to = buffer;
from = buffer + offset;
to = buffer + offset;
while (from != p)
{
if (*from == 1)
@ -244,11 +233,7 @@ get_doc_string (filepos)
*to++ = *from++;
}
tem = make_string (buffer, to - buffer);
if (free_it)
free (buffer);
return tem;
return make_string (buffer + offset, to - (buffer + offset));
}
/* Get a string from position FILEPOS and pass it through the Lisp reader.