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expanding range: <= 31 bits now 

git-svn-id: https://asn1c.svn.sourceforge.net/svnroot/asn1c/trunk@1016 59561ff5-6e30-0410-9f3c-9617f08c8826
This commit is contained in:
vlm 2005-11-28 06:58:11 +00:00
parent 9747e679c8
commit 17af7cc374
3 changed files with 30 additions and 7 deletions
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16
skeletons/per_support.c
View File

@ -6,7 +6,7 @@
#include <per_support.h>
/*
* Extract a small number of bits (<= 24) from the specified PER data pointer.
* Extract a small number of bits (<= 31) from the specified PER data pointer.
*/
int32_t
per_get_few_bits(asn_per_data_t *pd, int nbits) {
@ -16,8 +16,6 @@ per_get_few_bits(asn_per_data_t *pd, int nbits) {
if(nbits < 0 || pd->nboff + nbits > pd->nbits)
return -1;
if(nbits == 0)
return 0;
/*
* Normalize position indicator.
@ -34,7 +32,7 @@ per_get_few_bits(asn_per_data_t *pd, int nbits) {
* Extract specified number of bits.
*/
if(off <= 8)
accum = (buf[0]) >> (8 - off);
accum = nbits ? (buf[0]) >> (8 - off) : 0;
else if(off <= 16)
accum = ((buf[0] << 8) + buf[1]) >> (16 - off);
else if(off <= 24)
@ -42,12 +40,18 @@ per_get_few_bits(asn_per_data_t *pd, int nbits) {
else if(off <= 31)
accum = ((buf[0] << 24) + (buf[1] << 16)
+ (buf[2] << 8) + (buf[3])) >> (32 - off);
else {
else if(nbits <= 31) {
asn_per_data_t tpd = *pd;
/* Here are we with our 31-bits limit plus 1..7 bits offset. */
tpd.nboff -= nbits;
accum = per_get_few_bits(&tpd, nbits - 24) << 24;
accum |= per_get_few_bits(&tpd, 24);
} else {
pd->nboff -= nbits; /* Oops, revert back */
return -1;
}
return (accum & ((1 << nbits) - 1));
return (accum & (((uint32_t)1 << nbits) - 1));
}
/*

2
skeletons/per_support.h
View File

@ -21,7 +21,7 @@ typedef struct asn_per_data_s {
} asn_per_data_t;
/*
* Extract a small number of bits (<= 24) from the specified PER data pointer.
* Extract a small number of bits (<= 31) from the specified PER data pointer.
* This function returns -1 if the specified number of bits could not be
* extracted due to EOD or other conditions.
*/

19
skeletons/tests/check-PER.c
View File

@ -14,22 +14,27 @@ main() {
z = per_get_few_bits(&pos, 32);
assert(z == -1);
assert(pos.nbits == sizeof(buf) * 8);
z = per_get_few_bits(&pos, 0);
assert(z == 0);
assert(pos.nboff == 0);
assert(pos.nbits == sizeof(buf) * 8);
z = per_get_few_bits(&pos, 1);
assert(z == 1);
assert(pos.nboff == 1);
assert(pos.nbits == sizeof(buf) * 8);
z = per_get_few_bits(&pos, 2);
assert(z == 1);
assert(pos.nboff == 3);
assert(pos.nbits == sizeof(buf) * 8);
z = per_get_few_bits(&pos, 2);
assert(z == 2);
assert(pos.nboff == 5);
assert(pos.nbits == sizeof(buf) * 8);
z = per_get_few_bits(&pos, 3);
assert(z == 7);
@ -61,6 +66,20 @@ main() {
z = per_get_few_bits(&pos, 24);
assert(z == 14443711);
/* Get full 31-bit range */
pos.buffer = buf;
pos.nboff = 7;
pos.nbits = sizeof(buf) * 8;
z = per_get_few_bits(&pos, 31);
assert(z == 1179384747);
/* Get a bit shifted range */
pos.buffer = buf;
pos.nboff = 6;
pos.nbits = sizeof(buf) * 8;
z = per_get_few_bits(&pos, 31);
assert(z == 1663434197);
pos.buffer = buf;
pos.nboff = 0;
pos.nbits = sizeof(buf) * 8;