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authorDenys Vlasenko <vda.linux@googlemail.com>2013-08-19 07:01:39 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2013-08-19 07:01:39 (GMT)
commitb941316ae5313be523b64f0a9151ee4decb2b35b (patch)
tree9a9d7b7d93214eca477e4fca5a7f2d7c2f05f30d
parent4b1896cd2ccdb3e09070035f86a48d42b678d8ff (diff)
downloadbusybox-b941316ae5313be523b64f0a9151ee4decb2b35b.tar.gz
busybox-b941316ae5313be523b64f0a9151ee4decb2b35b.tar.bz2
dd: support conv=swab
function old new delta dd_main 1482 1520 +38 static.conv_words 28 33 +5 packed_usage 29377 29375 -2 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--coreutils/dd.c29
1 files changed, 23 insertions, 6 deletions
diff --git a/coreutils/dd.c b/coreutils/dd.c
index 9cb96bb..1732a5c 100644
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -30,10 +30,10 @@
//usage: "\n conv=noerror Continue after read errors"
//usage: "\n conv=sync Pad blocks with zeros"
//usage: "\n conv=fsync Physically write data out before finishing"
+//usage: "\n conv=swab Swap every pair of bytes"
//usage: )
//usage: "\n"
-//usage: "\nNumbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024),"
-//usage: "\nMD (x1000000), M (x1048576), GD (x1000000000) or G (x1073741824)"
+//usage: "\nN may be suffixed by c (1), w (2), b (512), kD (1000), k (1024), MD, M, GD, G"
//usage:
//usage:#define dd_example_usage
//usage: "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
@@ -155,9 +155,10 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
FLAG_SYNC = 1 << 1,
FLAG_NOERROR = 1 << 2,
FLAG_FSYNC = 1 << 3,
+ FLAG_SWAB = 1 << 4,
/* end of conv flags */
- FLAG_TWOBUFS = 1 << 4,
- FLAG_COUNT = 1 << 5,
+ FLAG_TWOBUFS = 1 << 5,
+ FLAG_COUNT = 1 << 6,
};
static const char keywords[] ALIGN1 =
"bs\0""count\0""seek\0""skip\0""if\0""of\0"
@@ -167,7 +168,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
;
#if ENABLE_FEATURE_DD_IBS_OBS
static const char conv_words[] ALIGN1 =
- "notrunc\0""sync\0""noerror\0""fsync\0";
+ "notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
#endif
enum {
OP_bs = 0,
@@ -185,11 +186,11 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
OP_conv_sync,
OP_conv_noerror,
OP_conv_fsync,
+ OP_conv_swab,
/* Unimplemented conv=XXX: */
//nocreat do not create the output file
//excl fail if the output file already exists
//fdatasync physically write output file data before finishing
- //swab swap every pair of input bytes
//lcase change upper case to lower case
//ucase change lower case to upper case
//block pad newline-terminated records with spaces to cbs-size
@@ -197,6 +198,8 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
//ascii from EBCDIC to ASCII
//ebcdic from ASCII to EBCDIC
//ibm from ASCII to alternate EBCDIC
+ /* Partially implemented: */
+ //swab swap every pair of input bytes: will abort on non-even reads
#endif
};
int exitcode = EXIT_FAILURE;
@@ -377,6 +380,20 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
* conv=noerror just ignores input bad blocks */
n = 0;
}
+ if (flags & FLAG_SWAB) {
+ /* If n is odd, last byte is not swapped:
+ * echo -n "qwe" | dd conv=swab bs=1
+ * prints "wqe".
+ * The code does not handle correctly odd-sized reads
+ * in the *middle* of the input. FIXME.
+ */
+ uint16_t *p16 = (void*) ibuf;
+ uint16_t *end = (void*) (ibuf + (n & ~(ssize_t)1));
+ while (p16 < end) {
+ *p16 = bswap_16(*p16);
+ p16++;
+ }
+ }
if ((size_t)n == ibs)
G.in_full++;
else {