| /* egprs_rlc_compression.h |
| * Routines for EGPRS RLC bitmap compression handling |
| */ |
| #include <errno.h> |
| #include <decoding.h> |
| #include <arpa/inet.h> |
| #include <string.h> |
| #include <gprs_debug.h> |
| #include <gprs_rlcmac.h> |
| #include <egprs_rlc_compression.h> |
| |
| extern "C" { |
| #include <osmocom/core/talloc.h> |
| #include <osmocom/core/msgb.h> |
| #include <osmocom/core/stats.h> |
| } |
| |
| #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(); |
| } |
| |