blob: fe4b89ba70065e6d7ff3f8ee146d68de412b10fb [file] [log] [blame]
/*
* Copyright (c) 2005-2017 Lev Walkin <vlm@lionet.info>.
* All rights reserved.
* Redistribution and modifications are permitted subject to BSD license.
*/
#include <asn_system.h>
#include <asn_internal.h>
#include <asn_bit_data.h>
/*
* Create a contiguous non-refillable bit data structure.
* Can be freed by FREEMEM().
*/
asn_bit_data_t *
asn_bit_data_new_contiguous(const void *data, size_t size_bits) {
size_t size_bytes = (size_bits + 7) / 8;
asn_bit_data_t *pd;
uint8_t *bytes;
/* Get the extensions map */
pd = CALLOC(1, sizeof(*pd) + size_bytes + 1);
if(!pd) {
return NULL;
}
bytes = (void *)(((char *)pd) + sizeof(*pd));
memcpy(bytes, data, size_bytes);
bytes[size_bytes] = 0;
pd->buffer = bytes;
pd->nboff = 0;
pd->nbits = size_bits;
return pd;
}
char *
asn_bit_data_string(asn_bit_data_t *pd) {
static char buf[2][32];
static int n;
n = (n+1) % 2;
snprintf(buf[n], sizeof(buf[n]),
"{m=%" ASN_PRI_SIZE " span %" ASN_PRI_SIZE "[%" ASN_PRI_SIZE
"..%" ASN_PRI_SIZE "] (%" ASN_PRI_SIZE ")}",
pd->moved, ((uintptr_t)(pd->buffer) & 0xf), pd->nboff, pd->nbits,
pd->nbits - pd->nboff);
return buf[n];
}
void
asn_get_undo(asn_bit_data_t *pd, int nbits) {
if((ssize_t)pd->nboff < nbits) {
assert((ssize_t)pd->nboff < nbits);
} else {
pd->nboff -= nbits;
pd->moved -= nbits;
}
}
/*
* Extract a small number of bits (<= 31) from the specified PER data pointer.
*/
int32_t
asn_get_few_bits(asn_bit_data_t *pd, int nbits) {
size_t off; /* Next after last bit offset */
ssize_t nleft; /* Number of bits left in this stream */
uint32_t accum;
const uint8_t *buf;
if(nbits < 0)
return -1;
nleft = pd->nbits - pd->nboff;
if(nbits > nleft) {
int32_t tailv, vhead;
if(!pd->refill || nbits > 31) return -1;
/* Accumulate unused bytes before refill */
ASN_DEBUG("Obtain the rest %d bits (want %d)",
(int)nleft, (int)nbits);
tailv = asn_get_few_bits(pd, nleft);
if(tailv < 0) return -1;
/* Refill (replace pd contents with new data) */
if(pd->refill(pd))
return -1;
nbits -= nleft;
vhead = asn_get_few_bits(pd, nbits);
/* Combine the rest of previous pd with the head of new one */
tailv = (tailv << nbits) | vhead; /* Could == -1 */
return tailv;
}
/*
* Normalize position indicator.
*/
if(pd->nboff >= 8) {
pd->buffer += (pd->nboff >> 3);
pd->nbits -= (pd->nboff & ~0x07);
pd->nboff &= 0x07;
}
pd->moved += nbits;
pd->nboff += nbits;
off = pd->nboff;
buf = pd->buffer;
/*
* Extract specified number of bits.
*/
if(off <= 8)
accum = nbits ? (buf[0]) >> (8 - off) : 0;
else if(off <= 16)
accum = ((buf[0] << 8) + buf[1]) >> (16 - off);
else if(off <= 24)
accum = ((buf[0] << 16) + (buf[1] << 8) + buf[2]) >> (24 - off);
else if(off <= 31)
accum = (((uint32_t)buf[0] << 24) + (buf[1] << 16)
+ (buf[2] << 8) + (buf[3])) >> (32 - off);
else if(nbits <= 31) {
asn_bit_data_t tpd = *pd;
/* Here are we with our 31-bits limit plus 1..7 bits offset. */
asn_get_undo(&tpd, nbits);
/* The number of available bits in the stream allow
* for the following operations to take place without
* invoking the ->refill() function */
accum = asn_get_few_bits(&tpd, nbits - 24) << 24;
accum |= asn_get_few_bits(&tpd, 24);
} else {
asn_get_undo(pd, nbits);
return -1;
}
accum &= (((uint32_t)1 << nbits) - 1);
ASN_DEBUG(" [PER got %2d<=%2d bits => span %d %+ld[%d..%d]:%02x (%d) => 0x%x]",
(int)nbits, (int)nleft,
(int)pd->moved,
(((long)pd->buffer) & 0xf),
(int)pd->nboff, (int)pd->nbits,
((pd->buffer != NULL)?pd->buffer[0]:0),
(int)(pd->nbits - pd->nboff),
(int)accum);
return accum;
}
/*
* Extract a large number of bits from the specified PER data pointer.
*/
int
asn_get_many_bits(asn_bit_data_t *pd, uint8_t *dst, int alright, int nbits) {
int32_t value;
if(alright && (nbits & 7)) {
/* Perform right alignment of a first few bits */
value = asn_get_few_bits(pd, nbits & 0x07);
if(value < 0) return -1;
*dst++ = value; /* value is already right-aligned */
nbits &= ~7;
}
while(nbits) {
if(nbits >= 24) {
value = asn_get_few_bits(pd, 24);
if(value < 0) return -1;
*(dst++) = value >> 16;
*(dst++) = value >> 8;
*(dst++) = value;
nbits -= 24;
} else {
value = asn_get_few_bits(pd, nbits);
if(value < 0) return -1;
if(nbits & 7) { /* implies left alignment */
value <<= 8 - (nbits & 7),
nbits += 8 - (nbits & 7);
if(nbits > 24)
*dst++ = value >> 24;
}
if(nbits > 16)
*dst++ = value >> 16;
if(nbits > 8)
*dst++ = value >> 8;
*dst++ = value;
break;
}
}
return 0;
}
/*
* Put a small number of bits (<= 31).
*/
int
asn_put_few_bits(asn_bit_outp_t *po, uint32_t bits, int obits) {
size_t off; /* Next after last bit offset */
size_t omsk; /* Existing last byte meaningful bits mask */
uint8_t *buf;
if(obits <= 0 || obits >= 32) return obits ? -1 : 0;
ASN_DEBUG("[PER put %d bits %x to %p+%d bits]",
obits, (int)bits, (void *)po->buffer, (int)po->nboff);
/*
* Normalize position indicator.
*/
if(po->nboff >= 8) {
po->buffer += (po->nboff >> 3);
po->nbits -= (po->nboff & ~0x07);
po->nboff &= 0x07;
}
/*
* Flush whole-bytes output, if necessary.
*/
if(po->nboff + obits > po->nbits) {
size_t complete_bytes;
if(!po->buffer) po->buffer = po->tmpspace;
complete_bytes = (po->buffer - po->tmpspace);
ASN_DEBUG("[PER output %ld complete + %ld]",
(long)complete_bytes, (long)po->flushed_bytes);
if(po->output(po->tmpspace, complete_bytes, po->op_key) < 0)
return -1;
if(po->nboff)
po->tmpspace[0] = po->buffer[0];
po->buffer = po->tmpspace;
po->nbits = 8 * sizeof(po->tmpspace);
po->flushed_bytes += complete_bytes;
}
/*
* Now, due to sizeof(tmpspace), we are guaranteed large enough space.
*/
buf = po->buffer;
omsk = ~((1 << (8 - po->nboff)) - 1);
off = (po->nboff + obits);
/* Clear data of debris before meaningful bits */
bits &= (((uint32_t)1 << obits) - 1);
ASN_DEBUG("[PER out %d %u/%x (t=%d,o=%d) %x&%x=%x]", obits,
(int)bits, (int)bits,
(int)po->nboff, (int)off,
buf[0], (int)(omsk&0xff),
(int)(buf[0] & omsk));
if(off <= 8) /* Completely within 1 byte */
po->nboff = off,
bits <<= (8 - off),
buf[0] = (buf[0] & omsk) | bits;
else if(off <= 16)
po->nboff = off,
bits <<= (16 - off),
buf[0] = (buf[0] & omsk) | (bits >> 8),
buf[1] = bits;
else if(off <= 24)
po->nboff = off,
bits <<= (24 - off),
buf[0] = (buf[0] & omsk) | (bits >> 16),
buf[1] = bits >> 8,
buf[2] = bits;
else if(off <= 31)
po->nboff = off,
bits <<= (32 - off),
buf[0] = (buf[0] & omsk) | (bits >> 24),
buf[1] = bits >> 16,
buf[2] = bits >> 8,
buf[3] = bits;
else {
if(asn_put_few_bits(po, bits >> (obits - 24), 24)) return -1;
if(asn_put_few_bits(po, bits, obits - 24)) return -1;
}
ASN_DEBUG("[PER out %u/%x => %02x buf+%ld]",
(int)bits, (int)bits, buf[0],
(long)(po->buffer - po->tmpspace));
return 0;
}
/*
* Output a large number of bits.
*/
int
asn_put_many_bits(asn_bit_outp_t *po, const uint8_t *src, int nbits) {
while(nbits) {
uint32_t value;
if(nbits >= 24) {
value = (src[0] << 16) | (src[1] << 8) | src[2];
src += 3;
nbits -= 24;
if(asn_put_few_bits(po, value, 24))
return -1;
} else {
value = src[0];
if(nbits > 8)
value = (value << 8) | src[1];
if(nbits > 16)
value = (value << 8) | src[2];
if(nbits & 0x07)
value >>= (8 - (nbits & 0x07));
if(asn_put_few_bits(po, value, nbits))
return -1;
break;
}
}
return 0;
}
int
asn_put_aligned_flush(asn_bit_outp_t *po) {
uint32_t unused_bits = (0x7 & (8 - (po->nboff & 0x07)));
size_t complete_bytes =
(po->buffer ? po->buffer - po->tmpspace : 0) + ((po->nboff + 7) >> 3);
if(unused_bits) {
po->buffer[po->nboff >> 3] &= ~0u << unused_bits;
}
if(po->output(po->tmpspace, complete_bytes, po->op_key) < 0) {
return -1;
} else {
po->buffer = po->tmpspace;
po->nboff = 0;
po->nbits = 8 * sizeof(po->tmpspace);
po->flushed_bytes += complete_bytes;
return 0;
}
}