--- /dev/null
+/*
+ * 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;
+ }
+}
+
git.stg.codes / stg.git / blobdiff