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dd: support iflag=count_bytes

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It allows passing amount of bytes in the count=

function                                             old     new   delta
packed_usage                                       33599   33617     +18
static.iflag_words                                    29      41     +12
dd_main                                             1601    1607      +6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 36/0)               Total: 36 bytes

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Rafał Miłecki 2021-03-24 16:01:42 +01:00 committed by Denys Vlasenko
parent 7b5cbfd6d6
commit 4eb46e1be6
2 changed files with 33 additions and 18 deletions
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50
coreutils/dd.c
View File

@ -59,7 +59,7 @@
//usage: "[if=FILE] [of=FILE] [" IF_FEATURE_DD_IBS_OBS("ibs=N obs=N/") "bs=N] [count=N] [skip=N] [seek=N]\n"
//usage: IF_FEATURE_DD_IBS_OBS(
//usage: " [conv=notrunc|noerror|sync|fsync]\n"
//usage: " [iflag=skip_bytes|fullblock|direct] [oflag=seek_bytes|append|direct]"
//usage: " [iflag=skip_bytes|count_bytes|fullblock|direct] [oflag=seek_bytes|append|direct]"
//usage: )
//usage:#define dd_full_usage "\n\n"
//usage: "Copy a file with converting and formatting\n"
@ -82,6 +82,7 @@
//usage: "\n conv=fsync Physically write data out before finishing"
//usage: "\n conv=swab Swap every pair of bytes"
//usage: "\n iflag=skip_bytes skip=N is in bytes"
//usage: "\n iflag=count_bytes count=N is in bytes"
//usage: "\n oflag=seek_bytes seek=N is in bytes"
//usage: "\n iflag=direct O_DIRECT input"
//usage: "\n oflag=direct O_DIRECT output"
@ -136,21 +137,22 @@ enum {
FLAG_SWAB = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
/* end of conv flags */
/* start of input flags */
FLAG_IFLAG_SHIFT = 5,
FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_FULLBLOCK = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_IDIRECT = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_IFLAG_SHIFT = 5,
FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_COUNT_BYTES = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_FULLBLOCK = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_IDIRECT = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
/* end of input flags */
/* start of output flags */
FLAG_OFLAG_SHIFT = 8,
FLAG_SEEK_BYTES = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_APPEND = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_ODIRECT = (1 << 10) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_OFLAG_SHIFT = 9,
FLAG_SEEK_BYTES = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_APPEND = (1 << 10) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_ODIRECT = (1 << 11) * ENABLE_FEATURE_DD_IBS_OBS,
/* end of output flags */
FLAG_TWOBUFS = (1 << 11) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_COUNT = 1 << 12,
FLAG_STATUS_NONE = 1 << 13,
FLAG_STATUS_NOXFER = 1 << 14,
FLAG_TWOBUFS = (1 << 12) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_COUNT = 1 << 13,
FLAG_STATUS_NONE = 1 << 14,
FLAG_STATUS_NOXFER = 1 << 15,
};
static void dd_output_status(int UNUSED_PARAM cur_signal)
@ -175,8 +177,9 @@ static void dd_output_status(int UNUSED_PARAM cur_signal)
//So far we react to it (we print the stats),
//status=none only suppresses final, non-USR1 generated status message.
# endif
fprintf(stderr, "%llu bytes (%sB) copied, ",
G.total_bytes,
fprintf(stderr, /*G.total_bytes < 1024
? "%llu bytes copied, " : */ "%llu bytes (%sB) copied, "
, G.total_bytes,
/* show fractional digit, use suffixes */
make_human_readable_str(G.total_bytes, 1, 0)
);
@ -317,7 +320,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
static const char conv_words[] ALIGN1 =
"notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
static const char iflag_words[] ALIGN1 =
"skip_bytes\0""fullblock\0""direct\0";
"skip_bytes\0""count_bytes\0""fullblock\0""direct\0";
static const char oflag_words[] ALIGN1 =
"seek_bytes\0append\0""direct\0";
#endif
@ -359,6 +362,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
/* Partially implemented: */
//swab swap every pair of input bytes: will abort on non-even reads
OP_iflag_skip_bytes,
OP_iflag_count_bytes,
OP_iflag_fullblock,
OP_iflag_direct,
OP_oflag_seek_bytes,
@ -551,8 +555,17 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
goto die_outfile;
}
while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
ssize_t n = dd_read(ibuf, ibs);
while (1) {
ssize_t n = ibs;
if (G.flags & FLAG_COUNT) {
if (count == 0)
break;
if ((G.flags & FLAG_COUNT_BYTES) && count < ibs)
n = count;
}
n = dd_read(ibuf, n);
if (n == 0)
break;
if (n < 0) {
@ -587,6 +600,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
p16++;
}
}
count -= (G.flags & FLAG_COUNT_BYTES) ? n : 1;
if ((size_t)n == ibs)
G.in_full++;
else {

1
testsuite/dd/dd-count-bytes Normal file
View File

@ -0,0 +1 @@
test "$(echo I WANT | busybox dd count=3 iflag=count_bytes 2>/dev/null)" = "I W"