diff options
Diffstat (limited to 'src/cnki_jbig_dec.c')
| -rw-r--r-- | src/cnki_jbig_dec.c | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/src/cnki_jbig_dec.c b/src/cnki_jbig_dec.c new file mode 100644 index 0000000..5b262e6 --- /dev/null +++ b/src/cnki_jbig_dec.c @@ -0,0 +1,314 @@ +/* + * Copyright (c) 2022, yzrh <yzrh@noema.org> + * + * SPDX-License-Identifier: Apache-2.0 + */ + +#include <stdbool.h> +#include <stdint.h> +#include <stdlib.h> +#include <string.h> + +static const uint16_t _LSZ[0x71] = { + 0x5a1d, + 0x2586, 0x1114, 0x080b, 0x03d8, 0x01da, 0x00e5, 0x006f, 0x0036, + 0x001a, 0x000d, 0x0006, 0x0003, 0x0001, 0x5a7f, 0x3f25, 0x2cf2, + 0x207c, 0x17b9, 0x1182, 0x0cef, 0x09a1, 0x072f, 0x055c, 0x0406, + 0x0303, 0x0240, 0x01b1, 0x0144, 0x00f5, 0x00b7, 0x008a, 0x0068, + 0x004e, 0x003b, 0x002c, 0x5ae1, 0x484c, 0x3a0d, 0x2ef1, 0x261f, + 0x1f33, 0x19a8, 0x1518, 0x1177, 0x0e74, 0x0bfb, 0x09f8, 0x0861, + 0x0706, 0x05cd, 0x04de, 0x040f, 0x0363, 0x02d4, 0x025c, 0x01f8, + + 0x01a4, 0x0160, 0x0125, 0x00f6, 0x00cb, 0x00ab, 0x008f, 0x5b12, + 0x4d04, 0x412c, 0x37d8, 0x2fe8, 0x293c, 0x2379, 0x1edf, 0x1aa9, + 0x174e, 0x1424, 0x119c, 0x0f6b, 0x0d51, 0x0bb6, 0x0a40, 0x5832, + 0x4d1c, 0x438e, 0x3bdd, 0x34ee, 0x2eae, 0x299a, 0x2516, 0x5570, + 0x4ca9, 0x44d9, 0x3e22, 0x3824, 0x32b4, 0x2e17, 0x56a8, 0x4f46, + 0x47e5, 0x41cf, 0x3c3d, 0x375e, 0x5231, 0x4c0f, 0x4639, 0x415e, + 0x5627, 0x50e7, 0x4b85, 0x5597, 0x504f, 0x5a10, 0x5522, 0x59eb +}; + +static const uint8_t _NLPS[0x71] = { + 1, + 14, 16, 18, 20, 23, 25, 28, 30, + 33, 35, 9, 10, 12, 15, 36, 38, + 39, 40, 42, 43, 45, 46, 48, 49, + 51, 52, 54, 56, 57, 59, 60, 62, + 63, 32, 33, 37, 64, 65, 67, 68, + 69, 70, 72, 73, 74, 75, 77, 78, + 79, 48, 50, 50, 51, 52, 53, 54, + + 55, 56, 57, 58, 59, 61, 61, 65, + 80, 81, 82, 83, 84, 86, 87, 87, + 72, 72, 74, 74, 75, 77, 77, 80, + 88, 89, 90, 91, 92, 93, 86, 88, + 95, 96, 97, 99, 99, 93, 95, 101, + 102, 103, 104, 99, 105, 106, 107, 103, + 105, 108, 109, 110, 111, 110, 112, 112 +}; + +static const uint8_t _NMPS[0x71] = { + 1, + 2, 3, 4, 5, 6, 7, 8, 9, + 10, 11, 12, 13, 13, 15, 16, 17, + 18, 19, 20, 21, 22, 23, 24, 25, + 26, 27, 28, 29, 30, 31, 32, 33, + 34, 35, 9, 37, 38, 39, 40, 41, + 42, 43, 44, 45, 46, 47, 48, 49, + 50, 51, 52, 53, 54, 55, 56, 57, + + 58, 59, 60, 61, 62, 63, 32, 65, + 66, 67, 68, 69, 70, 71, 72, 73, + 74, 75, 76, 77, 78, 79, 48, 81, + 82, 83, 84, 85, 86, 87, 71, 89, + 90, 91, 92, 93, 94, 86, 96, 97, + 98, 99, 100, 93, 102, 103, 104, 99, + 106, 107, 103, 109, 107, 111, 109, 111 +}; + +static const bool _SWTCH[0x71] = { + 1, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + + 0, 0, 0, 0, 0, 0, 0, 1, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 1, + 0, 0, 0, 0, 0, 0, 0, 1, + 0, 0, 0, 0, 0, 0, 1, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 1, 0, 0, 0, 0, 1, 0, 1 +}; + +static uint8_t _ct; +static uint8_t _pix; + +static uint16_t _reg_a; +static uint32_t _reg_c; +static uint8_t _mps[0x1000]; +static uint8_t _st[0x1000]; + +static int _width; +static int _height; + +static int _width_padded; + +static int _ret_pos; +static unsigned char *_ret; + +static int _scd_size; +static unsigned char *_scd; + +static void +_bytein(void) +{ + if (_ret_pos < _scd_size) + _reg_c += _scd[_ret_pos++] << 8; + + _ct = 8; +} + +static void +_initdec(void) +{ + memset(_mps, 0, 0x1000); + memset(_st, 0, 0x1000); + + _reg_c = 0; + _bytein(); + _reg_c <<= 8; + _bytein(); + _reg_c <<= 8; + _bytein(); + _reg_a = 0x0000; +} + +static void +_exchange_lps(uint16_t cx) +{ + uint8_t st_cx = _st[cx]; + uint16_t lsz_st_cx = _LSZ[_st[cx]]; + + if (_reg_a < lsz_st_cx) { + _pix = _mps[cx]; + _st[cx] = _NMPS[st_cx]; + } else { + _pix = 1 - _mps[cx]; + + if (_SWTCH[st_cx]) + _mps[cx] = _pix; + + _st[cx] = _NLPS[st_cx]; + } + + _reg_c -= _reg_a << 16; + _reg_a = lsz_st_cx; +} + +static void +_exchange_mps(uint16_t cx) +{ + uint8_t st_cx = _st[cx]; + uint16_t lsz_st_cx = _LSZ[_st[cx]]; + + if (_reg_a < lsz_st_cx) { + _pix = 1 - _mps[cx]; + + if (_SWTCH[st_cx]) + _mps[cx] = _pix; + + _st[cx] = _NLPS[st_cx]; + } else { + _pix = _mps[cx]; + _st[cx] = _NMPS[st_cx]; + } +} + +static void +_renormd(void) +{ + do { + if (_ct == 0) + _bytein(); + + _reg_a <<= 1; + _reg_c <<= 1; + _ct--; + } while (_reg_a < 0x8000); + + if (_ct == 0) + _bytein(); +} + +static void +_decode(uint16_t cx) +{ + _reg_a -= _LSZ[_st[cx]]; + + if (_reg_a > _reg_c >> 16) { + if (_reg_a < 0x8000) { + _exchange_mps(cx); + _renormd(); + } else { + _pix = _mps[cx]; + } + } else { + _exchange_lps(cx); + _renormd(); + } +} + +static void +_procline(int line, char *a, char *b, char *c) +{ + /* The encoder must be erroneous */ + uint16_t cx = 0; + + if (line > 0) { + cx += (_ret[_width_padded * (_height - line)] & 0x20) << 2; + cx += _ret[_width_padded * (_height - line)] & 0x40; + cx += (_ret[_width_padded * (_height - line)] & 0x80) >> 2; + } + + if (line > 1) { + cx += (_ret[_width_padded * (_height - line + 1)] & 0x40) >> 4; + cx += (_ret[_width_padded * (_height - line + 1)] & 0x80) >> 6; + } + + for (int i = 0; i < _width; i++) { + _decode(cx); + + cx >>= 1; + + if (_pix == 1) { + _ret[_width_padded * (_height - line - 1) + i / 8] |= _pix << (7 - (i & 0x07)); + c[i] = 1; + cx |= 0x0200; + } else { + cx &= 0xfdff; + } + + if (i + 2 < _width && a[i + 2] == 1) + cx |= 0x0004; + else + cx &= 0xfffb; + + if (i + 3 < _width && b[i + 3] == 1) + cx |= 0x0080; + else + cx &= 0xff7f; + } +} + +static int +_procstripe(void) +{ + if (_height <= 0 || _width_padded <= 0) + return 1; + + int pix_size = 8 * _width_padded; + + char *buf = malloc(3 * pix_size); + + if (buf == NULL) + return 1; + + memset(buf, 0, 3 * pix_size); + + char *a = buf; + char *b = a + pix_size; + char *c = b + pix_size; + char *z; + + for (int i = 0; i < _height; i++) { + _decode(0x029c); + + if (_pix == 1) { + if (i > 0) + memcpy(_ret + _width_padded * (_height - i - 1), + _ret + _width_padded * (_height - i), + _width_padded); + + memcpy(c, b, pix_size); + } else { + /* line atypical */ + memset(c, 0, pix_size); + _procline(i, a, b, c); + } + + z = a; + a = b; + b = c; + c = z; + } + + free(buf); + + return 0; +} + +int +strdec_jbig(char **bitmap, int width, int height, + const char * restrict jbig, int jbig_size) +{ + _width = width; + _height = height; + + _width_padded = (_width + 7) / 8; + + memset(*bitmap, 0, _height * _width_padded); + + _ret_pos = 0; + _ret = (unsigned char *) *bitmap; + + _scd_size = jbig_size; + _scd = (unsigned char *) jbig; + + _initdec(); + return _procstripe(); +} |