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Diffstat (limited to 'src/rfxencode_diff_rlgr1.c')
| -rw-r--r-- | src/rfxencode_diff_rlgr1.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/src/rfxencode_diff_rlgr1.c b/src/rfxencode_diff_rlgr1.c new file mode 100644 index 0000000..cd09f18 --- /dev/null +++ b/src/rfxencode_diff_rlgr1.c @@ -0,0 +1,252 @@ +/** + * FreeRDP: A Remote Desktop Protocol client. + * RemoteFX Codec Library - RLGR + * + * Copyright 2011 Vic Lee + * Copyright 2016-2017 Jay Sorg <jay.sorg@gmail.com> + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/** + * This implementation of RLGR refers to + * [MS-RDPRFX] 3.1.8.1.7.3 RLGR1/RLGR3 Pseudocode + */ + +#if defined(HAVE_CONFIG_H) +#include <config_ac.h> +#endif + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "rfxcommon.h" + +#define PIXELS_IN_TILE 4096 + +/* Constants used within the RLGR1/RLGR3 algorithm */ +#define KPMAX (80) /* max value for kp or krp */ +#define LSGR (3) /* shift count to convert kp to k */ +#define UP_GR (4) /* increase in kp after a zero run in RL mode */ +#define DN_GR (6) /* decrease in kp after a nonzero symbol in RL mode */ +#define UQ_GR (3) /* increase in kp after nonzero symbol in GR mode */ +#define DQ_GR (3) /* decrease in kp after zero symbol in GR mode */ + +#define GetNextInput do { \ + input = *coef; \ + coef++; \ + coef_size--; \ +} while (0) + +#define CheckWrite do { \ + while (bit_count >= 8) \ + { \ + bit_count -= 8; \ + *cdata = bits >> bit_count; \ + cdata++; \ + } \ +} while (0) + +/* output GR code for (mag - 1) */ +#define CodeGR(_krp, _lmag) do { \ + int lkr = _krp >> LSGR; \ + /* unary part of GR code */ \ + int lvk = _lmag >> lkr; \ + int llvk = lvk; \ + while (llvk >= 8) \ + { \ + bits <<= 8; \ + bits |= 0xFF; \ + llvk -= 8; \ + *cdata = bits >> bit_count; \ + cdata++; \ + } \ + bits <<= llvk; \ + bits |= (1 << llvk) - 1; \ + bit_count += llvk; \ + bits <<= 1; \ + bit_count++; \ + CheckWrite; \ + /* remainder part of GR code, if needed */ \ + if (lkr) \ + { \ + bits <<= lkr; \ + bits |= _lmag & ((1 << lkr) - 1); \ + bit_count += lkr; \ + } \ + /* update _krp, only if it is not equal to 1 */ \ + if (lvk == 0) \ + { \ + _krp = MAX(0, _krp - 2); \ + } \ + else if (lvk > 1) \ + { \ + _krp = MIN(KPMAX, _krp + lvk); \ + } \ +} while (0) + +int +rfx_encode_diff_rlgr1(sint16 *coef, uint8 *cdata, int cdata_size) +{ + int k; + int kp; + int krp; + + int input; + int numZeros; + int runmax; + int mag; + int sign; + int processed_size; + int lmag; + int coef_size; + int y; + + int bit_count; + unsigned int bits; + uint8 *cdata_org; + + uint32 twoMs; + + /* the last 64 bytes are diff */ + for (k = PIXELS_IN_TILE - 1; k > PIXELS_IN_TILE - 64; k--) + { + coef[k] -= coef[k - 1]; + } + + /* initialize the parameters */ + k = 1; + kp = 1 << LSGR; + krp = 1 << LSGR; + + bit_count = 0; + bits = 0; + cdata_org = cdata; + + /* process all the input coefficients */ + coef_size = PIXELS_IN_TILE; + while (coef_size > 0) + { + if (k) + { + + /* RUN-LENGTH MODE */ + + /* collect the run of zeros in the input stream */ + numZeros = 0; + + GetNextInput; + while (input == 0 && coef_size > 0) + { + numZeros++; + GetNextInput; + } + + /* emit output zeros */ + runmax = 1 << k; + while (numZeros >= runmax) + { + + bits <<= 1; + bit_count++; + + CheckWrite; + + numZeros -= runmax; + + kp = MIN(KPMAX, kp + UP_GR); + k = kp >> LSGR; + + runmax = 1 << k; + } + + /* output a 1 to terminate runs */ + bits <<= 1; + bits |= 1; + bit_count++; + + /* output the remaining run length using k bits */ + bits <<= k; + bits |= numZeros; + bit_count += k; + + CheckWrite; + + /* encode the nonzero value using GR coding */ + if (input < 0) + { + mag = -input; + sign = 1; + } + else + { + mag = input; + sign = 0; + } + + bits <<= 1; + bits |= sign; + bit_count++; + + lmag = mag ? mag - 1 : 0; + + CodeGR(krp, lmag); /* output GR code for (mag - 1) */ + CheckWrite; + + kp = MAX(0, kp - DN_GR); + k = kp >> LSGR; + + } + else + { + + /* GOLOMB-RICE MODE */ + + /* RLGR1 variant */ + + /* convert input to (2*magnitude - sign), encode using GR code */ + GetNextInput; + y = input >> 15; + twoMs = (((input ^ y) - y) << 1) + y; + CodeGR(krp, twoMs); + CheckWrite; + + /* update k, kp */ + if (twoMs) + { + kp = MAX(0, kp - DQ_GR); + k = kp >> LSGR; + } + else + { + kp = MIN(KPMAX, kp + UQ_GR); + k = kp >> LSGR; + } + + } + } + + if (bit_count > 0) + { + bits <<= 8 - bit_count; + *cdata = bits; + cdata++; + bit_count = 0; + } + + processed_size = cdata - cdata_org; + + return processed_size; +} + |