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