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Update for aecunpack.c #462

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merged 2 commits into from
Dec 20, 2023
Merged

Update for aecunpack.c #462

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0fb484a
Update for aecunpack.c
EricEngle-NOAA Dec 5, 2023
1481005
Update aecunpack.c
EricEngle-NOAA Dec 5, 2023
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32 changes: 27 additions & 5 deletions src/aecunpack.c
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Original file line number Diff line number Diff line change
Expand Up @@ -44,18 +44,19 @@ aecunpack_int(unsigned char *cpack, g2int len, g2int *idrstmpl, g2int ndpts,
void *fld, int fld_is_double, int verbose)
{
g2int *ifld;
g2int j, ctemplen, nbits;
g2int j, ctemplen = 0 , nbits;
g2int ccsds_flags, ccsds_block_size, ccsds_rsi;
//g2int ifld1 = 0;
int ret = 0;
float ref, bscale, dscale;
float *ffld = fld;
double *dfld = fld;
unsigned char *ctemp;

ctemplen = 0;
size_t nbytes = 0;

LOG((2, "aecunpack_int len %ld ndpts %ld fld_is_double %d", len, ndpts, fld_is_double));

/* Get compression parameters from data representation template array. */
rdieee(idrstmpl, &ref, 1);
bscale = int_power(2.0, idrstmpl[1]);
dscale = int_power(10.0, -idrstmpl[2]);
Expand All @@ -75,17 +76,36 @@ aecunpack_int(unsigned char *cpack, g2int len, g2int *idrstmpl, g2int ndpts,
return G2C_ENOMEM;
}

ctemplen = ((nbits + 7)/8) * (size_t) ndpts;
/* Determine the number of bytes needed for each value, then allocate the
* buffer for the decoded AEC stream. */
nbytes = (nbits + 7)/8;
if (nbytes == 3)
nbytes = 4;
ctemplen = nbytes * ndpts;
if ((ctemp = (unsigned char *) malloc(ctemplen)) == NULL)
{
if (verbose)
fprintf(stderr, "Allocation error.\n");
return G2C_ENOMEM;
}

/* Decode the AEC stream. */
ret = dec_aec(cpack, len, nbits, ccsds_flags, ccsds_block_size, ccsds_rsi, ctemp, ctemplen);
if (ret < 0)
return ret;
gbits(ctemp, ifld, 0, nbits, 0, ndpts);

/* IMPORTANT: The decoded AEC stream is byte-aligned (not bit), so when extracting the data
* values from the buffer via gbits, we need to pass the byte size in bits, not nbits. */
gbits(ctemp, ifld, 0, nbytes*8, 0, ndpts);

/* Zero out all higher-order bits, preserving nbits. NOTE: This might be unecessary. */
//for (j = 0; j < ndpts; j++)
// ifld1 = ifld[j];
// ifld1 = ifld1 << (sizeof(ifld1)*8-nbits);
// ifld1 = ifld1 >> (sizeof(ifld1)*8-nbits);
// ifld[j] = ifld1;

/* Unscale data. */
if (fld_is_double)
{
for (j = 0; j < ndpts; j++)
Expand All @@ -96,6 +116,8 @@ aecunpack_int(unsigned char *cpack, g2int len, g2int *idrstmpl, g2int ndpts,
for (j = 0; j < ndpts; j++)
ffld[j] = (((float)ifld[j] * bscale) + ref) * dscale;
}

/* Clean up. */
free(ctemp);
free(ifld);
}
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