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xxd -r: handle offsets

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function                                             old     new   delta
xxd_main                                            1076    1439    +363
.rodata                                           105239  105251     +12
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 375/0)             Total: 375 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2022-08-22 17:28:43 +02:00
parent 0011a6bc20
commit 5eceafb1f8
1 changed files with 50 additions and 8 deletions
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58
util-linux/hexdump_xxd.c
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@ -55,6 +55,7 @@
//usage: "\n -r Reverse (with -p, assumes no offsets in input)"
#include "libbb.h"
#include "common_bufsiz.h"
#include "dump.h"
/* This is a NOEXEC applet. Be very careful! */
@ -69,10 +70,32 @@
#define OPT_c (1 << 7)
#define OPT_o (1 << 8)
static void reverse(unsigned opt, const char *filename)
#define fillbuf bb_common_bufsiz1
static void write_zeros(off_t count)
{
errno = 0;
do {
unsigned sz = count < COMMON_BUFSIZE ? (unsigned)count : COMMON_BUFSIZE;
if (fwrite(fillbuf, 1, sz, stdout) != sz)
bb_perror_msg_and_die("write error");
count -= sz;
} while (count != 0);
}
static void reverse(unsigned opt, const char *filename, char *opt_s)
{
FILE *fp;
char *buf;
off_t cur, opt_s_ofs;
memset(fillbuf, 0, COMMON_BUFSIZE);
opt_s_ofs = cur = 0;
if (opt_s) {
opt_s_ofs = BB_STRTOOFF(opt_s, NULL, 0);
if (errno || opt_s_ofs < 0)
bb_error_msg_and_die("invalid number '%s'", opt_s);
}
fp = filename ? xfopen_for_read(filename) : stdin;
@ -82,15 +105,31 @@ static void reverse(unsigned opt, const char *filename)
p = buf;
if (!(opt & OPT_p)) {
char *end;
off_t ofs;
skip_address:
p = skip_whitespace(p);
while (isxdigit(*p)) p++;
ofs = BB_STRTOOFF(p, &end, 16);
if ((errno && errno != EINVAL)
|| ofs < 0
/* -s SEEK value should be added before seeking */
|| (ofs += opt_s_ofs) < 0
) {
bb_error_msg_and_die("invalid number '%s'", p);
}
if (ofs != cur) {
if (fseeko(stdout, ofs, SEEK_SET) != 0) {
if (ofs < cur)
bb_perror_msg_and_die("cannot seek");
write_zeros(ofs - cur);
}
cur = ofs;
}
p = end;
/* NB: for xxd -r, first hex portion is address even without colon */
/* If it's there, skip it: */
if (*p == ':') p++;
//TODO: seek (or zero-pad if unseekable) to the address position
//NOTE: -s SEEK value should be added to the address before seeking
/* But if colon is there, skip it: */
if (*p == ':')
p++;
}
/* Process hex bytes optionally separated by whitespace */
@ -168,6 +207,7 @@ static void reverse(unsigned opt, const char *filename)
goto nibble2;
}
putchar(val);
cur++;
} /* for(;;) */
free(buf);
}
@ -195,6 +235,8 @@ int xxd_main(int argc UNUSED_PARAM, char **argv)
unsigned opt;
int r;
setup_common_bufsiz();
dumper = alloc_dumper();
opt = getopt32(argv, "^" "l:s:apirg:+c:+o:" "\0" "?1" /* 1 argument max */,
@ -222,7 +264,7 @@ int xxd_main(int argc UNUSED_PARAM, char **argv)
}
if (opt & OPT_r) {
reverse(opt, argv[0]);
reverse(opt, argv[0], opt_s);
}
if (opt & OPT_o) {