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Include pack_ambe and unpack_ambe functions and use during certain keystream applications;

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lwvmobile
2024-07-20 16:41:35 -04:00
parent 8b76daa35f
commit f6fc91a051
3 changed files with 60 additions and 184 deletions
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32
src/dsd_file.c
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@@ -600,4 +600,36 @@ void unpack_byte_array_into_bit_array (uint8_t * input, uint8_t * output, int le
output[k++] = (input[i] >> 1) & 1;
output[k++] = (input[i] >> 0) & 1;
}
}
//take len amount of bits and pack into x amount of bytes (asymmetrical)
void pack_ambe (char * input, uint8_t * output, int len)
{
int i = 0; int k = len % 8;
for (i = 0; i < len; i++)
{
output[i/8] <<= 1;
output[i/8] |= (uint8_t)input[i];
}
//if any leftover bits that don't flush the last byte fully packed, shift them over left
if (k)
output[i/8] <<= 8-k;
}
//unpack byte array with ambe data into a 49-bit bitwise array
void unpack_ambe (uint8_t * input, char * ambe)
{
int i = 0, k = 0;
for (i = 0; i < 7; i++)
{
ambe[k++] = (input[i] >> 7) & 1;
ambe[k++] = (input[i] >> 6) & 1;
ambe[k++] = (input[i] >> 5) & 1;
ambe[k++] = (input[i] >> 4) & 1;
ambe[k++] = (input[i] >> 3) & 1;
ambe[k++] = (input[i] >> 2) & 1;
ambe[k++] = (input[i] >> 1) & 1;
ambe[k++] = (input[i] >> 0) & 1;
}
ambe[48] = input[6] >> 7;
}