diff options
Diffstat (limited to 'gr-vocoder/lib/codec2/pack.c')
| -rw-r--r-- | gr-vocoder/lib/codec2/pack.c | 49 |
1 files changed, 42 insertions, 7 deletions
diff --git a/gr-vocoder/lib/codec2/pack.c b/gr-vocoder/lib/codec2/pack.c index 3f8f93e422..1c07230a70 100644 --- a/gr-vocoder/lib/codec2/pack.c +++ b/gr-vocoder/lib/codec2/pack.c @@ -52,8 +52,22 @@ pack( unsigned int fieldWidth/* Width of the field in BITS, not bytes. */ ) { - /* Convert the field to Gray code */ - field = (field >> 1) ^ field; + pack_natural_or_gray(bitArray, bitIndex, field, fieldWidth, 1); +} + +void +pack_natural_or_gray( + unsigned char * bitArray, /* The output bit string. */ + unsigned int * bitIndex, /* Index into the string in BITS, not bytes.*/ + int field, /* The bit field to be packed. */ + unsigned int fieldWidth,/* Width of the field in BITS, not bytes. */ + unsigned int gray /* non-zero for gray coding */ + ) +{ + if (gray) { + /* Convert the field to Gray code */ + field = (field >> 1) ^ field; + } do { unsigned int bI = *bitIndex; @@ -81,6 +95,21 @@ unpack( unsigned int fieldWidth/* Width of the field in BITS, not bytes. */ ) { + return unpack_natural_or_gray(bitArray, bitIndex, fieldWidth, 1); +} + +/** Unpack a field from a bit string, to binary, optionally using + * natural or Gray code. + * + */ +int +unpack_natural_or_gray( + const unsigned char * bitArray, /* The input bit string. */ + unsigned int * bitIndex, /* Index into the string in BITS, not bytes.*/ + unsigned int fieldWidth,/* Width of the field in BITS, not bytes. */ + unsigned int gray /* non-zero for Gray coding */ + ) +{ unsigned int field = 0; unsigned int t; @@ -96,10 +125,16 @@ unpack( fieldWidth -= sliceWidth; } while ( fieldWidth != 0 ); - /* Convert from Gray code to binary. Works for maximum 8-bit fields. */ - t = field ^ (field >> 8); - t ^= (t >> 4); - t ^= (t >> 2); - t ^= (t >> 1); + if (gray) { + /* Convert from Gray code to binary. Works for maximum 8-bit fields. */ + t = field ^ (field >> 8); + t ^= (t >> 4); + t ^= (t >> 2); + t ^= (t >> 1); + } + else { + t = field; + } + return t; } |