From 7a743398cf4738e58a7a57f94dc079a6c529829d Mon Sep 17 00:00:00 2001 From: leo Date: Wed, 20 Feb 2008 02:28:51 +0000 Subject: channel decoding (gsmstack) --- gsm-tvoid/src/lib/interleave.c | 47 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 gsm-tvoid/src/lib/interleave.c (limited to 'gsm-tvoid/src/lib/interleave.c') diff --git a/gsm-tvoid/src/lib/interleave.c b/gsm-tvoid/src/lib/interleave.c new file mode 100644 index 0000000..437ed92 --- /dev/null +++ b/gsm-tvoid/src/lib/interleave.c @@ -0,0 +1,47 @@ + +#include +#include +#include "interleave.h" + +int +interleave_init(INTERLEAVE_CTX *ictx, int size, int block_size) +{ + ictx->trans_size = size; + ictx->trans = (unsigned short *)malloc(size * sizeof *ictx->trans); + +// DEBUGF("size: %d\n", size); +// DEBUGF("Block size: %d\n", block_size); + int j, k, B; + for (k = 0; k < size; k++) + { + B = k % 4; + j = 2 * ((49 * k) % 57) + ((k % 8) / 4); + ictx->trans[k] = B * block_size + j; + /* Mapping: pos1 goes to pos2: pos1 -> pos2 */ +// DEBUGF("%d -> %d\n", ictx->trans[k], k); + } +// exit(0); + return 0; +} + +int +interleave_deinit(INTERLEAVE_CTX *ictx) +{ + if (ictx->trans != NULL) + { + free(ictx->trans); + ictx->trans = NULL; + } + + return 0; +} + +void +interleave_decode(INTERLEAVE_CTX *ictx, unsigned char *dst, unsigned char *src) +{ + + int k; + for (k = 0; k < ictx->trans_size; k++) + dst[k] = src[ictx->trans[k]]; +} + -- cgit v1.2.3