package/utils/busybox/patches/008-backport-dd-conv-swab.patch

   1 --- a/coreutils/dd.c
   2 +++ b/coreutils/dd.c
   3 @@ -10,7 +10,7 @@
   4
   5  //usage:#define dd_trivial_usage
   6  //usage:       "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
   7 -//usage:       "       [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync]")
   8 +//usage:       "       [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync|swab]")
   9  //usage:#define dd_full_usage "\n\n"
  10  //usage:       "Copy a file with converting and formatting\n"
  11  //usage:     "\n       if=FILE         Read from FILE instead of stdin"
  12 @@ -30,6 +30,7 @@
  13  //usage:     "\n       conv=noerror    Continue after read errors"
  14  //usage:     "\n       conv=sync       Pad blocks with zeros"
  15  //usage:     "\n       conv=fsync      Physically write data out before finishing"
  16 +//usage:     "\n       conv=swab       Swap every pair of bytes"
  17  //usage:       )
  18  //usage:     "\n"
  19  //usage:     "\nNumbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024),"
  20 @@ -155,9 +156,10 @@ int dd_main(int argc UNUSED_PARAM, char
  21                 FLAG_SYNC    = 1 << 1,
  22                 FLAG_NOERROR = 1 << 2,
  23                 FLAG_FSYNC   = 1 << 3,
  24 +               FLAG_SWAB    = 1 << 4,
  25                 /* end of conv flags */
  26 -               FLAG_TWOBUFS = 1 << 4,
  27 -               FLAG_COUNT   = 1 << 5,
  28 +               FLAG_TWOBUFS = 1 << 5,
  29 +               FLAG_COUNT   = 1 << 6,
  30         };
  31         static const char keywords[] ALIGN1 =
  32                 "bs\0""count\0""seek\0""skip\0""if\0""of\0"
  33 @@ -167,7 +169,7 @@ int dd_main(int argc UNUSED_PARAM, char
  34                 ;
  35  #if ENABLE_FEATURE_DD_IBS_OBS
  36         static const char conv_words[] ALIGN1 =
  37 -               "notrunc\0""sync\0""noerror\0""fsync\0";
  38 +               "notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
  39  #endif
  40         enum {
  41                 OP_bs = 0,
  42 @@ -185,11 +187,11 @@ int dd_main(int argc UNUSED_PARAM, char
  43                 OP_conv_sync,
  44                 OP_conv_noerror,
  45                 OP_conv_fsync,
  46 +               OP_conv_swab,
  47         /* Unimplemented conv=XXX: */
  48         //nocreat       do not create the output file
  49         //excl          fail if the output file already exists
  50         //fdatasync     physically write output file data before finishing
  51 -       //swab          swap every pair of input bytes
  52         //lcase         change upper case to lower case
  53         //ucase         change lower case to upper case
  54         //block         pad newline-terminated records with spaces to cbs-size
  55 @@ -207,12 +209,14 @@ int dd_main(int argc UNUSED_PARAM, char
  56         struct {
  57                 int flags;
  58                 size_t oc;
  59 +               ssize_t prev_read_size; /* for detecting swab failure */
  60                 off_t count;
  61                 off_t seek, skip;
  62                 const char *infile, *outfile;
  63         } Z;
  64  #define flags   (Z.flags  )
  65  #define oc      (Z.oc     )
  66 +#define prev_read_size (Z.prev_read_size)
  67  #define count   (Z.count  )
  68  #define seek    (Z.seek   )
  69  #define skip    (Z.skip   )
  70 @@ -375,6 +379,27 @@ int dd_main(int argc UNUSED_PARAM, char
  71                          * conv=noerror just ignores input bad blocks */
  72                         n = 0;
  73                 }
  74 +               if (flags & FLAG_SWAB) {
  75 +                       uint16_t *p16;
  76 +                       ssize_t n2;
  77 +
  78 +                       /* Our code allows only last read to be odd-sized */
  79 +                       if (prev_read_size & 1)
  80 +                               bb_error_msg_and_die("can't swab %lu byte buffer",
  81 +                                               (unsigned long)prev_read_size);
  82 +                       prev_read_size = n;
  83 +
  84 +                       /* If n is odd, last byte is not swapped:
  85 +                        *  echo -n "qwe" | dd conv=swab
  86 +                        * prints "wqe".
  87 +                        */
  88 +                       p16 = (void*) ibuf;
  89 +                       n2 = (n >> 1);
  90 +                       while (--n2 >= 0) {
  91 +                               *p16 = bswap_16(*p16);
  92 +                               p16++;
  93 +                       }
  94 +               }
  95                 if ((size_t)n == ibs)
  96                         G.in_full++;
  97                 else {