diff options
| author | Wim Taymans <wim.taymans@collabora.co.uk> | 2010-05-13 17:57:02 +0200 |
|---|---|---|
| committer | Wim Taymans <wim.taymans@collabora.co.uk> | 2010-05-13 17:57:02 +0200 |
| commit | 0b73505c61dd3486dde1a4c35707743875fc869e (patch) | |
| tree | cea8683ae2008f290c50e7380d3cc3a257ee197f | |
| parent | 7f685c4a2133e4762bcc82f080a95a43967aa28d (diff) | |
rm: add function to descramble sipr
| -rw-r--r-- | gst/realmedia/rmutils.c | 48 | ||||
| -rw-r--r-- | gst/realmedia/rmutils.h | 1 |
2 files changed, 49 insertions, 0 deletions
diff --git a/gst/realmedia/rmutils.c b/gst/realmedia/rmutils.c index 397068e3..b1184257 100644 --- a/gst/realmedia/rmutils.c +++ b/gst/realmedia/rmutils.c @@ -140,3 +140,51 @@ gst_rm_utils_descramble_dnet_buffer (GstBuffer * buf) } return buf; } + +static const gint sipr_swaps[38][2] = { + {0, 63}, {1, 22}, {2, 44}, {3, 90}, + {5, 81}, {7, 31}, {8, 86}, {9, 58}, + {10, 36}, {12, 68}, {13, 39}, {14, 73}, + {15, 53}, {16, 69}, {17, 57}, {19, 88}, + {20, 34}, {21, 71}, {24, 46}, {25, 94}, + {26, 54}, {28, 75}, {29, 50}, {32, 70}, + {33, 92}, {35, 74}, {38, 85}, {40, 56}, + {42, 87}, {43, 65}, {45, 59}, {48, 79}, + {49, 93}, {51, 89}, {55, 95}, {61, 76}, + {67, 83}, {77, 80} +}; + +GstBuffer * +gst_rm_utils_descramble_sipr_buffer (GstBuffer * buf) +{ + guint8 *data; + guint size; + gint n, bs; + + buf = gst_buffer_make_writable (buf); + + data = GST_BUFFER_DATA (buf); + size = GST_BUFFER_SIZE (buf); + + bs = size * 2 / 96; + + for (n = 0; n < 38; n++) { + int j; + int i = bs * sipr_swaps[n][0]; + int o = bs * sipr_swaps[n][1]; + + /* swap 4bit-nibbles of block 'i' with 'o' */ + for (j = 0; j < bs; j++, i++, o++) { + int x, y; + + x = (data[i >> 1] >> (4 * (i & 1))) & 0xF; + y = (data[o >> 1] >> (4 * (o & 1))) & 0xF; + + data[o >> 1] = (x << (4 * (o & 1))) | + (data[o >> 1] & (0xF << (4 * !(o & 1)))); + data[i >> 1] = (y << (4 * (i & 1))) | + (data[i >> 1] & (0xF << (4 * !(i & 1)))); + } + } + return buf; +} diff --git a/gst/realmedia/rmutils.h b/gst/realmedia/rmutils.h index 26040398..ed0ace5a 100644 --- a/gst/realmedia/rmutils.h +++ b/gst/realmedia/rmutils.h @@ -39,6 +39,7 @@ GstTagList *gst_rm_utils_read_tags (const guint8 * data, GstRmUtilsStringReadFunc func); GstBuffer *gst_rm_utils_descramble_dnet_buffer (GstBuffer * buf); +GstBuffer *gst_rm_utils_descramble_sipr_buffer (GstBuffer * buf); G_END_DECLS |