readstdin: reduce memory-usage by duplicating the line from getline() - dmenu - dynamic menu
HTML git clone git://git.suckless.org/dmenu
DIR Log
DIR Files
DIR Refs
DIR README
DIR LICENSE
---
DIR commit dfbbf7f6e1b22ccf9e5a45d77ee10995577fb4fc
DIR parent ba1a347dcaba055f824161007dfee60db3ea785b
HTML Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Wed, 8 Mar 2023 21:20:52 +0100
readstdin: reduce memory-usage by duplicating the line from getline()
Improves upon commit 32db2b125190d366be472ccb7cad833248696144
The getline() implementation often uses a more greedy way of allocating memory.
Using this buffer directly and forcing an allocation (by setting it to NULL)
would waste a bit of extra space, depending on the implementation of course.
Tested on musl libc and glibc.
The current glibc version allocates a minimum of 120 bytes per line.
For smaller lines musl libc seems less wasteful but still wastes a few bytes
per line.
On a dmenu_path listing on my system the memory usage was about 350kb (old) vs
30kb (new) on Void Linux glibc.
Side-note that getline() also reads NUL bytes in lines, while strdup() would
read until the NUL byte. Since dmenu reads text lines either is probably
fine(tm). Also rename junk to linesiz.
Diffstat:
M dmenu.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
---
DIR diff --git a/dmenu.c b/dmenu.c
@@ -550,11 +550,11 @@ static void
readstdin(void)
{
char *line = NULL;
- size_t i, junk, itemsiz = 0;
+ size_t i, itemsiz = 0, linesiz = 0;
ssize_t len;
/* read each line from stdin and add it to the item list */
- for (i = 0; (len = getline(&line, &junk, stdin)) != -1; i++) {
+ for (i = 0; (len = getline(&line, &linesiz, stdin)) != -1; i++) {
if (i + 1 >= itemsiz) {
itemsiz += 256;
if (!(items = realloc(items, itemsiz * sizeof(*items))))
@@ -562,9 +562,10 @@ readstdin(void)
}
if (line[len - 1] == '\n')
line[len - 1] = '\0';
- items[i].text = line;
+ if (!(items[i].text = strdup(line)))
+ die("strdup:");
+
items[i].out = 0;
- line = NULL; /* next call of getline() allocates a new line */
}
free(line);
if (items)