From 2230c133a69e8f9660051aff61626996deba4ed8 Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Wed, 19 Jan 2011 10:10:16 +0100 Subject: [BITS] introduce new packed/unpacked bit conversion routines --- src/bits.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 src/bits.c (limited to 'src/bits.c') diff --git a/src/bits.c b/src/bits.c new file mode 100644 index 00000000..fb3c7224 --- /dev/null +++ b/src/bits.c @@ -0,0 +1,65 @@ + +#include + +#include + +/* convert unpacked bits to packed bits, return length in bytes */ +int osmo_ubit2pbit(pbit_t *out, const ubit_t *in, unsigned int num_bits) +{ + unsigned int i; + uint8_t curbyte = 0; + pbit_t *outptr = out; + + for (i = 0; i < num_bits; i++) { + uint8_t bitnum = 7 - (i % 8); + + curbyte |= (in[i] << bitnum); + + if (i > 0 && i % 8 == 0) { + *outptr++ = curbyte; + curbyte = 0; + } + } + /* we have a non-modulo-8 bitcount */ + if (i % 8) + *outptr++ = curbyte; + + return outptr - out; +} + +/* convert packed bits to unpacked bits, return length in bytes */ +int osmo_pbit2ubit(ubit_t *out, const pbit_t *in, unsigned int num_bits) +{ + unsigned int i; + ubit_t *cur = out; + ubit_t *limit = out + num_bits; + + for (i = 0; i < (num_bits/8)+1; i++) { + pbit_t byte = in[i]; + *cur++ = (byte >> 7) & 1; + if (cur >= limit) + break; + *cur++ = (byte >> 6) & 1; + if (cur >= limit) + break; + *cur++ = (byte >> 5) & 1; + if (cur >= limit) + break; + *cur++ = (byte >> 4) & 1; + if (cur >= limit) + break; + *cur++ = (byte >> 3) & 1; + if (cur >= limit) + break; + *cur++ = (byte >> 2) & 1; + if (cur >= limit) + break; + *cur++ = (byte >> 1) & 1; + if (cur >= limit) + break; + *cur++ = (byte >> 0) & 1; + if (cur >= limit) + break; + } + return cur - out; +} -- cgit v1.2.3