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Diffstat (limited to 'converter/other/fiasco/input/weights.c')
| -rw-r--r-- | converter/other/fiasco/input/weights.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/converter/other/fiasco/input/weights.c b/converter/other/fiasco/input/weights.c new file mode 100644 index 00000000..55339980 --- /dev/null +++ b/converter/other/fiasco/input/weights.c @@ -0,0 +1,200 @@ +/* + * weights.c: Input of weights + * + * Written by: Ullrich Hafner + * + * This file is part of FIASCO («F»ractal «I»mage «A»nd «S»equence «CO»dec) + * Copyright (C) 1994-2000 Ullrich Hafner <hafner@bigfoot.de> + */ + +/* + * $Date: 2000/06/14 20:50:13 $ + * $Author: hafner $ + * $Revision: 5.1 $ + * $State: Exp $ + */ + +#include "config.h" + +#include "types.h" +#include "macros.h" +#include "error.h" + +#include "bit-io.h" +#include "arith.h" +#include "rpf.h" +#include "misc.h" + +#include "weights.h" + +/***************************************************************************** + + public code + +*****************************************************************************/ + +void +read_weights (unsigned total, wfa_t *wfa, bitfile_t *input) +/* + * Read #'total' weights from input stream 'input' and + * update transitions of the WFA states with corresponding weights. + * + * No return value. + * + * Side effects: + * 'wfa->weights' are filled with the decoded values + */ +{ + unsigned state; + unsigned label; + unsigned edge; /* current edge */ + unsigned *weights_array; /* array of weights to encode */ + unsigned *level_array; /* array of corresponding levels */ + unsigned offset1, offset2; /* prob. model offsets. */ + unsigned offset3, offset4; /* prob. model offsets. */ + bool_t delta_approx = NO; /* true if delta has been used */ + + /* + * Check whether delta approximation has been used + */ + for (state = wfa->basis_states; state < wfa->states; state++) + if (wfa->delta_state [state]) + { + delta_approx = YES; + break; + } + + /* + * Generate array of corresponding levels (context of probability model) + */ + { + int min_level, max_level; /* min and max range level */ + int d_min_level, d_max_level; /* min and max range level (delta) */ + unsigned *lptr; /* pointer to current corresp. level */ + int domain; /* current domain */ + bool_t dc, d_dc; /* indicates whether DC is used */ + + /* + * Compute minimum and maximum level of delta and normal approximations + */ + min_level = d_min_level = MAXLEVEL; + max_level = d_max_level = 0; + dc = d_dc = NO; + + for (state = wfa->basis_states; state < wfa->states; state++) + for (label = 0; label < MAXLABELS; label++) + if (isrange (wfa->tree [state][label])) + { + if (delta_approx && wfa->delta_state [state]) + { + d_min_level = min (d_min_level, + wfa->level_of_state [state] - 1); + d_max_level = max (d_max_level, + wfa->level_of_state [state] - 1); + if (wfa->into [state][label][0] == 0) + d_dc = YES; + } + else + { + min_level = min (min_level, wfa->level_of_state [state] - 1); + max_level = max (max_level, wfa->level_of_state [state] - 1); + if (wfa->into [state][label][0] == 0) + dc = YES; + } + } + if (min_level > max_level) /* no lc found */ + max_level = min_level - 1; + if (d_min_level > d_max_level) + d_max_level = d_min_level - 1; + + offset1 = dc ? 1 : 0; + offset2 = offset1 + (d_dc ? 1 : 0); + offset3 = offset2 + (max_level - min_level + 1); + offset4 = offset3 + (d_max_level - d_min_level + 1); + + lptr = level_array = Calloc (total, sizeof (int)); + for (state = wfa->basis_states; state < wfa->states; state++) + for (label = 0; label < MAXLABELS; label++) + if (isrange (wfa->tree[state][label])) + for (edge = 0; isedge (domain = wfa->into[state][label][edge]); + edge++) + { + if ((unsigned) (lptr - level_array) >= total) + error ("Can't read more than %d weights.", total); + if (domain) + { + if (delta_approx && wfa->delta_state [state]) + *lptr++ = offset3 + wfa->level_of_state [state] + - 1 - d_min_level; + else + *lptr++ = offset2 + wfa->level_of_state [state] + - 1 - min_level; + } + else + *lptr++ = delta_approx && wfa->delta_state [state] + ? offset1 : 0; + } + } + + /* + * Decode the list of weights with an arithmetic decoder + */ + { + unsigned i; + unsigned *c_symbols = Calloc (offset4, sizeof (unsigned)); + const unsigned scale = 500; /* scaling of probability model */ + + c_symbols [0] = 1 << (wfa->wfainfo->dc_rpf->mantissa_bits + 1); + if (offset1 != offset2) + c_symbols [offset1] = 1 << (wfa->wfainfo->d_dc_rpf->mantissa_bits + + 1); + for (i = offset2; i < offset3; i++) + c_symbols [i] = 1 << (wfa->wfainfo->rpf->mantissa_bits + 1); + for (; i < offset4; i++) + c_symbols [i] = 1 << (wfa->wfainfo->d_rpf->mantissa_bits + 1); + + weights_array = decode_array (input, level_array, c_symbols, + offset4, total, scale); + Free (c_symbols); + } + Free (level_array); + + /* + * Update transitions with decoded weights + */ + { + unsigned *wptr = weights_array; /* pointer to current weight */ + int domain; /* current domain */ + + for (state = wfa->basis_states; state < wfa->states; state++) + for (label = 0; label < MAXLABELS; label++) + if (isrange (wfa->tree[state][label])) + for (edge = 0; isedge (domain = wfa->into[state][label][edge]); + edge++) + { + if (domain) /* not DC component */ + { + if (delta_approx && wfa->delta_state [state]) + wfa->weight [state][label][edge] + = btor (*wptr++, wfa->wfainfo->d_rpf); + else + wfa->weight [state][label][edge] + = btor (*wptr++, wfa->wfainfo->rpf); + } + else + { + if (delta_approx && wfa->delta_state [state]) + wfa->weight [state][label][edge] + = btor (*wptr++, wfa->wfainfo->d_dc_rpf); + else + wfa->weight [state][label][edge] + = btor (*wptr++, wfa->wfainfo->dc_rpf); + } + wfa->int_weight [state][label][edge] + = wfa->weight [state][label][edge] * 512 + 0.5; + } + } + + Free (weights_array); +} + |