/* 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; } } } /* 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 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 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; /* 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) { 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 (compress_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, 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; compress_bmap_len = compress_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(); }