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This commit is contained in:
Lev Walkin 2017-08-06 00:03:46 -07:00
parent 2888f6c886
commit 5d20588ef7
1 changed files with 23 additions and 17 deletions
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40
skeletons/per_support.c
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@ -161,30 +161,36 @@ per_get_many_bits(asn_per_data_t *pd, uint8_t *dst, int alright, int nbits) {
}
/*
* Get the length "n" from the stream.
* X.691-201508 #10.9 General rules for encoding a length determinant.
* Get the optionally constrained length "n" from the stream.
*/
ssize_t
uper_get_length(asn_per_data_t *pd, int ebits, int *repeat) {
ssize_t value;
ssize_t value;
*repeat = 0;
*repeat = 0;
if(ebits >= 0) return per_get_few_bits(pd, ebits);
/* #11.9.4.1 Encoding if constrained (according to effective bits) */
if(ebits >= 0 && ebits <= 16) {
return per_get_few_bits(pd, ebits);
}
value = per_get_few_bits(pd, 8);
if(value < 0) return -1;
if((value & 128) == 0) /* #10.9.3.6 */
return (value & 0x7F);
if((value & 64) == 0) { /* #10.9.3.7 */
value = ((value & 63) << 8) | per_get_few_bits(pd, 8);
if(value < 0) return -1;
return value;
}
value &= 63; /* this is "m" from X.691, #10.9.3.8 */
if(value < 1 || value > 4)
return -1;
*repeat = 1;
return (16384 * value);
if((value & 0x80) == 0) { /* #11.9.3.6 */
return (value & 0x7F);
} else if((value & 0x40) == 0) { /* #11.9.3.7 */
/* bit 8 ... set to 1 and bit 7 ... set to zero */
value = ((value & 0x3f) << 8) | per_get_few_bits(pd, 8);
return value; /* potential -1 from per_get_few_bits passes through. */
} else if(value < 0) {
return -1;
}
value &= 0x3f; /* this is "m" from X.691, #11.9.3.8 */
if(value < 1 || value > 4) {
return -1; /* Prohibited by #11.9.3.8 */
}
*repeat = 1;
return (16384 * value);
}
/*