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authorDenys Vlasenko <vda.linux@googlemail.com>2017-09-14 00:04:16 +0200
committerDenys Vlasenko <vda.linux@googlemail.com>2017-09-14 00:04:16 +0200
commitd72e804e6db1bd6eb2417961004b4fe33aba9384 (patch)
tree72873b67871e955c0519a1d03045328153957549 /miscutils
parent62643017c3d5bc1bb9fff91553e52a47e7730a01 (diff)
downloadbusybox-d72e804e6db1bd6eb2417961004b4fe33aba9384.tar.gz
hexedit: optimize output buffering
function old new delta hexedit_main 970 998 +28 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'miscutils')
-rw-r--r--miscutils/hexedit.c19
1 files changed, 12 insertions, 7 deletions
diff --git a/miscutils/hexedit.c b/miscutils/hexedit.c
index a99569706..e8bc73b7e 100644
--- a/miscutils/hexedit.c
+++ b/miscutils/hexedit.c
@@ -38,8 +38,8 @@ struct globals {
/* Hopefully there aren't arches with PAGE_SIZE > 64k */
#define G_mapsize (64*1024)
-/* "12ef5670 (nn )*16 abcdef_1_3_5_7_9\n" */
-#define LINEBUF_SIZE (8 + 1 + 3*16 + 16 + 1 /*paranoia:*/ + 14)
+/* "12ef5670 (xx )*16 _1_3_5_7_9abcdef\n"NUL */
+#define LINEBUF_SIZE (8 + 1 + 3*16 + 16 + 1 + 1 /*paranoia:*/ + 13)
static int format_line(char *hex, uint8_t *data, off_t offset)
{
@@ -165,7 +165,7 @@ static void move_mapping_further(void)
pagesize = getpagesize(); /* constant on most arches */
pos = G.current_byte - G.addr;
if (pos >= pagesize) {
- /* Move offset up until current position is in 1st page */
+ /* move offset up until current position is in 1st page */
do {
G.offset += pagesize;
if (G.offset == 0) { /* whoops */
@@ -188,7 +188,7 @@ static void move_mapping_lower(void)
pagesize = getpagesize(); /* constant on most arches */
pos = G.current_byte - G.addr;
- /* Move offset down until current position is in last page */
+ /* move offset down until current position is in last page */
pos += pagesize;
while (pos < G_mapsize) {
pos += pagesize;
@@ -218,10 +218,15 @@ int hexedit_main(int argc UNUSED_PARAM, char **argv)
INIT_G();
- getopt32(argv, "");
- argv += optind;
-
get_terminal_width_height(-1, NULL, &G.height);
+ if (1) {
+ /* reduce number of write() syscalls while PgUp/Down: fully buffered output */
+ unsigned sz = (G.height | 0xf) * LINEBUF_SIZE;
+ setvbuf(stdout, xmalloc(sz), _IOFBF, sz);
+ }
+
+ getopt32(argv, "^" "" "\0" "=1"/*one arg*/);
+ argv += optind;
G.fd = xopen(*argv, O_RDWR);
G.size = xlseek(G.fd, 0, SEEK_END);