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| author | Denys Vlasenko <vda.linux@googlemail.com> | 2017-09-14 00:04:16 +0200 |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2017-09-14 00:04:16 +0200 |
| commit | d72e804e6db1bd6eb2417961004b4fe33aba9384 (patch) | |
| tree | 72873b67871e955c0519a1d03045328153957549 | |
| parent | 62643017c3d5bc1bb9fff91553e52a47e7730a01 (diff) | |
| download | busybox-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>
| -rw-r--r-- | miscutils/hexedit.c | 19 |
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); |