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mt: eliminate vector of structures with pointers (bad for libbusybox).

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It's a win for static build too:

function                                             old     new   delta
opcode_name                                            -     213    +213
opcode_value                                           -      68     +68
mt_main                                              281     256     -25
opcodes                                              280       -    -280
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 0/1 up/down: 281/-305)          Total: -24 bytes
   text    data     bss     dec     hex filename
 767403     974    9420  777797   bde45 busybox_old
 767224     974    9420  777618   bdd92 busybox_unstripped
This commit is contained in:
Denis Vlasenko 2007-10-11 19:38:59 +00:00
parent 2ea8c40e8f
commit 8add068573
1 changed files with 79 additions and 56 deletions
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135
miscutils/mt.c
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@ -6,58 +6,87 @@
#include "libbb.h"
#include <sys/mtio.h>
struct mt_opcodes {
const char *name;
short value;
/* missing: eod/seod, stoptions, stwrthreshold, densities */
static const short opcode_value[] = {
MTBSF,
MTBSFM,
MTBSR,
MTBSS,
MTCOMPRESSION,
MTEOM,
MTERASE,
MTFSF,
MTFSFM,
MTFSR,
MTFSS,
MTLOAD,
MTLOCK,
MTMKPART,
MTNOP,
MTOFFL,
MTOFFL,
MTRAS1,
MTRAS2,
MTRAS3,
MTRESET,
MTRETEN,
MTREW,
MTSEEK,
MTSETBLK,
MTSETDENSITY,
MTSETDRVBUFFER,
MTSETPART,
MTTELL,
MTWSM,
MTUNLOAD,
MTUNLOCK,
MTWEOF,
MTWEOF
};
/* missing: eod/seod, stoptions, stwrthreshold, densities */
static const struct mt_opcodes opcodes[] = {
{"bsf", MTBSF},
{"bsfm", MTBSFM},
{"bsr", MTBSR},
{"bss", MTBSS},
{"datacompression", MTCOMPRESSION},
{"eom", MTEOM},
{"erase", MTERASE},
{"fsf", MTFSF},
{"fsfm", MTFSFM},
{"fsr", MTFSR},
{"fss", MTFSS},
{"load", MTLOAD},
{"lock", MTLOCK},
{"mkpart", MTMKPART},
{"nop", MTNOP},
{"offline", MTOFFL},
{"rewoffline", MTOFFL},
{"ras1", MTRAS1},
{"ras2", MTRAS2},
{"ras3", MTRAS3},
{"reset", MTRESET},
{"retension", MTRETEN},
{"rewind", MTREW},
{"seek", MTSEEK},
{"setblk", MTSETBLK},
{"setdensity", MTSETDENSITY},
{"drvbuffer", MTSETDRVBUFFER},
{"setpart", MTSETPART},
{"tell", MTTELL},
{"wset", MTWSM},
{"unload", MTUNLOAD},
{"unlock", MTUNLOCK},
{"eof", MTWEOF},
{"weof", MTWEOF},
{0, 0}
};
static const char opcode_name[] ALIGN1 =
"bsf" "\0"
"bsfm" "\0"
"bsr" "\0"
"bss" "\0"
"datacompression" "\0"
"eom" "\0"
"erase" "\0"
"fsf" "\0"
"fsfm" "\0"
"fsr" "\0"
"fss" "\0"
"load" "\0"
"lock" "\0"
"mkpart" "\0"
"nop" "\0"
"offline" "\0"
"rewoffline" "\0"
"ras1" "\0"
"ras2" "\0"
"ras3" "\0"
"reset" "\0"
"retension" "\0"
"rewind" "\0"
"seek" "\0"
"setblk" "\0"
"setdensity" "\0"
"drvbuffer" "\0"
"setpart" "\0"
"tell" "\0"
"wset" "\0"
"unload" "\0"
"unlock" "\0"
"eof" "\0"
"weof" "\0";
int mt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int mt_main(int argc, char **argv)
{
const char *file = "/dev/tape";
const struct mt_opcodes *code = opcodes;
struct mtop op;
struct mtpos position;
int fd, mode;
int fd, mode, idx;
if (argc < 2) {
bb_show_usage();
@ -72,24 +101,18 @@ int mt_main(int argc, char **argv)
argc -= 2;
}
while (code->name != 0) {
if (strcmp(code->name, argv[1]) == 0)
break;
code++;
}
idx = index_in_strings(opcode_name, argv[1]);
if (code->name == 0) {
bb_error_msg("unrecognized opcode %s", argv[1]);
return EXIT_FAILURE;
}
if (idx < 0)
bb_error_msg_and_die("unrecognized opcode %s", argv[1]);
op.mt_op = code->value;
op.mt_op = opcode_value[idx];
if (argc >= 3)
op.mt_count = xatoi_u(argv[2]);
else
op.mt_count = 1; /* One, not zero, right? */
switch (code->value) {
switch (opcode_value[idx]) {
case MTWEOF:
case MTERASE:
case MTWSM:
@ -104,10 +127,10 @@ int mt_main(int argc, char **argv)
fd = xopen(file, mode);
switch (code->value) {
switch (opcode_value[idx]) {
case MTTELL:
ioctl_or_perror_and_die(fd, MTIOCPOS, &position, "%s", file);
printf("At block %d.\n", (int) position.mt_blkno);
printf("At block %d\n", (int) position.mt_blkno);
break;
default: