/* egprs_rlc_compression.h * Routines for EGPRS RLC bitmap compression handling */ #include #include #include #include #include #include #include extern "C" { #include #include #include } #define EGPRS_CODEWORDS 79 /* total number of codewords */ struct egprs_compress_node{ struct egprs_compress_node *left; struct egprs_compress_node *right; int run_length; }; extern void *tall_pcu_ctx; egprs_compress *egprs_compress::s_instance = 0; egprs_compress_node *egprs_compress::create_tree_node(void *parent) { egprs_compress_node *new_node; new_node = talloc_zero(parent, egprs_compress_node); new_node->left = NULL; new_node->right = NULL; new_node->run_length = -1; return new_node; } egprs_compress *egprs_compress::instance() { if (!egprs_compress::s_instance) egprs_compress::s_instance = new egprs_compress; return egprs_compress::s_instance; } /* Expands the given tree by incorporating * the given codewords. * \param root[in] Root of ones or zeros tree * \param cdwd[in] Array of code words * number of codewords is EGPRS_CODEWORDS */ void egprs_compress::build_codewords(egprs_compress_node *root, const char *cdwd[]) { egprs_compress_node *iter; int len; int i; int idx; for (idx = 0; idx < EGPRS_CODEWORDS; idx++) { len = strlen((const char *)cdwd[idx]); iter = root; for (i = 0; i < len; i++) { if (cdwd[idx][i] == '0') { if (!iter->left) iter->left = create_tree_node(root); iter = iter->left; } else { if (!iter->right) iter->right = create_tree_node(root); iter = iter->right; } } if (iter) { /* The first 64 run lengths are 0, 1, 2, ..., 63 * and the following ones are 64, 128, 192 described in * section 9.1.10 of 3gpp 44.060 */ if (idx < 64) iter->run_length = idx; else iter->run_length = (idx - 63) * 64; } } } /* * Terminating codes for uninterrupted sequences of 0 and 1 up to 64 bit length * according to TS 44.060 9.1.10 */ static const unsigned t4_term[2][64] = { { 0b0000110111, 0b10, 0b11, 0b010, 0b011, 0b0011, 0b0010, 0b00011, 0b000101, 0b000100, 0b0000100, 0b0000101, 0b0000111, 0b00000100, 0b00000111, 0b000011000, 0b0000010111, 0b0000011000, 0b0000001000, 0b00001100111, 0b00001101000, 0b00001101100, 0b00000110111, 0b00000101000, 0b00000010111, 0b00000011000, 0b000011001010, 0b000011001011, 0b000011001100, 0b000011001101, 0b000001101000, 0b000001101001, 0b000001101010, 0b000001101011, 0b000011010010, 0b000011010011, 0b000011010100, 0b000011010101, 0b000011010110, 0b000011010111, 0b000001101100, 0b000001101101, 0b000011011010, 0b000011011011, 0b000001010100, 0b000001010101, 0b000001010110, 0b000001010111, 0b000001100100, 0b000001100101, 0b000001010010, 0b000001010011, 0b000000100100, 0b000000110111, 0b000000111000, 0b000000100111, 0b000000101000, 0b000001011000, 0b000001011001, 0b000000101011, 0b000000101100, 0b000001011010, 0b000001100110, 0b000001100111 }, { 0b00110101, 0b000111, 0b0111, 0b1000, 0b1011, 0b1100, 0b1110, 0b1111, 0b10011, 0b10100, 0b00111, 0b01000, 0b001000, 0b000011, 0b110100, 0b110101, 0b101010, 0b101011, 0b0100111, 0b0001100, 0b0001000, 0b0010111, 0b0000011, 0b0000100, 0b0101000, 0b0101011, 0b0010011, 0b0100100, 0b0011000, 0b00000010, 0b00000011, 0b00011010, 0b00011011, 0b00010010, 0b00010011, 0b00010100, 0b00010101, 0b00010110, 0b00010111, 0b00101000, 0b00101001, 0b00101010, 0b00101011, 0b00101100, 0b00101101, 0b00000100, 0b00000101, 0b00001010, 0b00001011, 0b01010010, 0b01010011, 0b01010100, 0b01010101, 0b00100100, 0b00100101, 0b01011000, 0b01011001, 0b01011010, 0b01011011, 0b01001010, 0b01001011, 0b00110010, 0b00110011, 0b00110100 } }; static const unsigned t4_term_length[2][64] = { {10, 2, 2, 3, 3, 4, 4, 5, 6, 6, 7, 7, 7, 8, 8, 9, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12}, {8, 6, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8} }; static const unsigned t4_min_term_length[] = {2, 4}; static const unsigned t4_min_make_up_length[] = {10, 5}; static const unsigned t4_max_term_length[] = {12, 8}; static const unsigned t4_max_make_up_length[] = {13, 9}; static const unsigned t4_make_up_length[2][15] = { {10, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13}, {5, 5, 6, 7, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9} }; static const unsigned t4_make_up_ind[15] = {64, 128, 192, 256, 320, 384, 448, 512, 576, 640, 704, 768, 832, 896, 960}; static const unsigned t4_make_up[2][15] = { { 0b0000001111, 0b000011001000, 0b000011001001, 0b000001011011, 0b000000110011, 0b000000110100, 0b000000110101, 0b0000001101100, 0b0000001101101, 0b0000001001010, 0b0000001001011, 0b0000001001100, 0b0000001001101, 0b0000001110010, 0b0000001110011 }, { 0b11011, 0b10010, 0b010111, 0b0110111, 0b00110110, 0b00110111, 0b01100100, 0b01100101, 0b01101000, 0b01100111, 0b011001100, 0b011001101, 0b011010010, 0b011010011, 0b011010100 } }; /* The code words for one run length and zero * run length are described in table 9.1.10.1 * of 3gpp 44.060 */ const char *one_run_len_code_list[EGPRS_CODEWORDS] = { "00110101", "000111", "0111", "1000", "1011", "1100", "1110", "1111", "10011", "10100", "00111", "01000", "001000", "000011", "110100", "110101", "101010", "101011", "0100111", "0001100", "0001000", "0010111", "0000011", "0000100", "0101000", "0101011", "0010011", "0100100", "0011000", "00000010", "00000011", "00011010", "00011011", "00010010", "00010011", "00010100", "00010101", "00010110", "00010111", "00101000", "00101001", "00101010", "00101011", "00101100", "00101101", "00000100", "00000101", "00001010", "00001011", "01010010", "01010011", "01010100", "01010101", "00100100", "00100101", "01011000", "01011001", "01011010", "01011011", "01001010", "01001011", "00110010", "00110011", "00110100", "11011", "10010", "010111", "0110111", "00110110", "00110111", "01100100", "01100101", "01101000", "01100111", "011001100", "011001101", "011010010", "011010011", "011010100" }; const char *zero_run_len_code_list[EGPRS_CODEWORDS] = { "0000110111", "10", "11", "010", "011", "0011", "0010", "00011", "000101", "000100", "0000100", "0000101", "0000111", "00000100", "00000111", "000011000", "0000010111", "0000011000", "0000001000", "00001100111", "00001101000", "00001101100", "00000110111", "00000101000", "00000010111", "00000011000", "000011001010", "000011001011", "000011001100", "000011001101", "000001101000", "000001101001", "000001101010", "000001101011", "000011010010", "000011010011", "000011010100", "000011010101", "000011010110", "000011010111", "000001101100", "000001101101", "000011011010", "000011011011", "000001010100", "000001010101", "000001010110", "000001010111", "000001100100", "000001100101", "000001010010", "000001010011", "000000100100", "000000110111", "000000111000", "000000100111", "000000101000", "000001011000", "000001011001", "000000101011", "000000101100", "000001011010", "000001100110", "000001100111", "0000001111", "000011001000", "000011001001", "000001011011", "000000110011", "000000110100", "000000110101", "0000001101100", "0000001101101", "0000001001010", "0000001001011", "0000001001100", "0000001001101", "0000001110010", "0000001110011" }; /* Calculate runlength of a codeword * \param root[in] Root of Ones or Zeros tree * \param bmbuf[in] Received compressed bitmap buf * \param length[in] Length of bitmap buf in bits * \param bit_pos[in] The start bit pos to read codeword * \param len_codewd[in] Length of code word * \param rlen[out] Calculated run length */ static int search_runlen( egprs_compress_node *root, const uint8_t *bmbuf, uint8_t length, uint8_t bit_pos, uint8_t *len_codewd, uint16_t *rlen) { egprs_compress_node *iter; uint8_t dir; iter = root; *len_codewd = 0; while (iter->run_length == -1) { if ((!iter->left) && (!iter->right)) return -1; if (bit_pos >= length) return -1; /* get the bit value at the bitpos and put it in right most of dir */ dir = (bmbuf[bit_pos/8] >> (7 - (bit_pos & 0x07))) & 0x01; bit_pos++; (*len_codewd)++; if (!dir && (iter->left != NULL)) iter = iter->left; else if (dir && (iter->right != NULL)) iter = iter->right; else return -1; } LOGP(DRLCMACUL, LOGL_DEBUG, "Run_length = %d\n", iter->run_length); *rlen = iter->run_length; return 1; } /* Decompress received block bitmap * \param compress_bmap_len[in] Compressed bitmap length * \param start[in] Starting Color Code, true if bitmap starts with a run * length of ones, false if zeros; see 9.1.10, 3GPP 44.060. * \param orig_crbb_buf[in] Received block crbb bitmap * \param dest[out] Uncompressed bitvector */ int egprs_compress::decompress_crbb( int8_t compress_bmap_len, bool start, const uint8_t *orig_crbb_buf, bitvec *dest) { int8_t remaining_bmap_len = compress_bmap_len; uint8_t bit_pos = 0; uint8_t data; egprs_compress_node *list = NULL; uint8_t nbits = 0; /* number of bits of codeword */ uint16_t run_length = 0; uint16_t cbmaplen = 0; /* compressed bitmap part after decompression */ unsigned wp = dest->cur_bit; int rc = 0; egprs_compress *compress = instance(); while (remaining_bmap_len > 0) { if (start) { data = 0xff; list = compress->ones_list; } else { data = 0x00; list = compress->zeros_list; } rc = search_runlen(list, orig_crbb_buf, compress_bmap_len, bit_pos, &nbits, &run_length); if (rc == -1) return -1; /* If run length > 64, need makeup and terminating code */ if (run_length < 64) start = !start; cbmaplen = cbmaplen + run_length; /* put run length of Ones in uncompressed bitmap */ while (run_length != 0) { if (run_length > 8) { bitvec_write_field(dest, &wp, data, 8); run_length = run_length - 8; } else { bitvec_write_field(dest, &wp, data, run_length); run_length = 0; } } bit_pos = bit_pos + nbits; remaining_bmap_len = remaining_bmap_len - nbits; } return 0; } void egprs_compress::decode_tree_init() { ones_list = create_tree_node(tall_pcu_ctx); zeros_list = create_tree_node(tall_pcu_ctx); build_codewords(ones_list, one_run_len_code_list); build_codewords(zeros_list, zero_run_len_code_list); } egprs_compress::egprs_compress() { decode_tree_init(); } /* Compress received block bitmap * \param run_len_cnt[in] Count of number of 1's and 0's * \param codewrd_bitmap[in] Code word for coresponding run length. * \param crbb_vec[out] compressed bitvector. */ static void compress_bitmap( uint16_t *run_len_cnt, /* cnt: run length count */ uint16_t *codewrd_bitmap, /* code word */ int16_t *codewrd_len, /* number of bits in the code word */ bitvec *crbb_vec, /* bitmap buffer to put code word in */ bool start) { int i = 0; unsigned writeIndex = crbb_vec->cur_bit; *codewrd_bitmap = 0; *codewrd_len = 0; if (*run_len_cnt >= 64) { for (i = 0; i < 15; i++) { if (t4_make_up_ind[i] == *run_len_cnt) { *codewrd_bitmap = t4_make_up[start][i]; *codewrd_len = t4_make_up_length[start][i]; } } } else { *codewrd_bitmap = t4_term[start][*run_len_cnt]; *codewrd_len = t4_term_length[start][*run_len_cnt]; } bitvec_write_field(crbb_vec, &writeIndex, *codewrd_bitmap, *codewrd_len); } /* Compress received block bitmap */ int egprs_compress::osmo_t4_compress(struct bitvec *bv) { uint8_t crbb_len = 0; uint8_t uclen_crbb = 0; uint8_t crbb_bitmap[127] = {'\0'}; bool start = (bv->data[0] & 0x80)>>7; struct bitvec crbb_vec; crbb_vec.data = crbb_bitmap; crbb_vec.cur_bit = 0; crbb_vec.data_len = 127; bv->data_len = bv->cur_bit; bv->cur_bit = 0; if (egprs_compress::compress_rbb(bv, &crbb_vec, &uclen_crbb, 23*8)) { memcpy(bv->data, crbb_bitmap, (crbb_len+7)/8); bv->cur_bit = crbb_len; bv->data_len = (crbb_len+7)/8; return start; } else printf("Encode failed\n"); return -1; } /*! \brief compression algorithm using T4 encoding * the compressed bitmap's are copied in crbb_bitmap * \param[in] rbb_vec bit vector to be encoded * \return 1 if compression is success or 0 for failure */ int egprs_compress::compress_rbb( struct bitvec *urbb_vec, struct bitvec *crbb_vec, uint8_t *uclen_crbb, /* Uncompressed bitmap len in CRBB */ uint8_t max_bits) /* max remaining bits */ { bool run_len_bit; int buflen = urbb_vec->cur_bit; int total_bits = urbb_vec->cur_bit; uint16_t rlen; uint16_t temprl = 0; uint16_t cbmap = 0; /* Compressed code word */ int16_t nbits; /* Length of code word */ uint16_t uclen = 0; int16_t clen = 0; bool start; /* Starting color code see 9.1.10, 3GPP 44.060 */ urbb_vec->cur_bit = 0; run_len_bit = (urbb_vec->data[0] & 0x80)>>7; while (buflen > 0) { temprl = 0; /* Find Run length */ if (run_len_bit == 1) rlen = bitvec_rl_curbit(urbb_vec, true, total_bits); else rlen = bitvec_rl_curbit(urbb_vec, false, total_bits); buflen = buflen - rlen; /* if rlen > 64 need Makeup code word */ /*Compress the bits */ if (run_len_bit == 0) { start = 0; if (rlen >= 64) { temprl = (rlen/64)*64; compress_bitmap(&temprl, &cbmap, &nbits, crbb_vec, start); clen = clen + nbits; } temprl = MOD64(rlen); compress_bitmap(&temprl, &cbmap, &nbits, crbb_vec, start); /* next time the run length will be Ones */ run_len_bit = 1; } else { start = 1; if (rlen >= 64) { temprl = (rlen/64)*64; compress_bitmap(&temprl, &cbmap, &nbits, crbb_vec, start); clen = clen + nbits; } temprl = MOD64(rlen); compress_bitmap(&temprl, &cbmap, &nbits, crbb_vec, start); /* next time the run length will be Zeros */ run_len_bit = 0; } uclen = uclen + rlen; clen = clen + nbits; /*compressed bitmap exceeds the buffer space */ if (clen > max_bits) { uclen = uclen - rlen; clen = clen - nbits; break; } } crbb_vec->cur_bit = clen; *uclen_crbb = uclen; if (clen >= uclen) /* No Gain is observed, So no need to compress */ return 0; LOGP(DRLCMACUL, LOGL_DEBUG, "CRBB bitmap = %s\n", osmo_hexdump(crbb_vec->data, (crbb_vec->cur_bit+7)/8)); /* Add compressed bitmap to final buffer */ return 1; }