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/*
* init.c * * Initialise encoder */#include "encoder.h"
#define MEM_WINDOW_ALLOC_SIZE \
(context->enc_window_size+(MAX_MATCH+EXTRA_SIZE)+context->enc_encoder_second_partition_size)
/*
* Initialise encoder */void init_compression_memory(t_encoder_context *context){ /* set all root pointers to NULL */#ifdef MULTIPLE_SEARCH_TREES
memset( context->enc_tree_root, 0, NUM_SEARCH_TREES * sizeof(context->enc_tree_root[0]) );#else
context->enc_single_tree_root = 0;#endif
context->enc_MemWindow = context->enc_RealMemWindow - context->enc_window_size; context->enc_Left = context->enc_RealLeft - context->enc_window_size; context->enc_Right = context->enc_RealRight - context->enc_window_size; context->enc_BufPos = context->enc_window_size;
/*
* Set initial state of repeated match offsets */ context->enc_last_matchpos_offset[0] = 1; context->enc_last_matchpos_offset[1] = 1; context->enc_last_matchpos_offset[2] = 1;
/*
* repeated offset states the last time we output a block * see block.c/encdata.c */ context->enc_repeated_offset_at_literal_zero[0] = 1; context->enc_repeated_offset_at_literal_zero[1] = 1; context->enc_repeated_offset_at_literal_zero[2] = 1;
/* this is the first compressed block in the file */ context->enc_first_block = true;
/* we don't have any cumulative stats yet */ context->enc_need_to_recalc_stats = true;
/* bufpos @ last time we output a block */ context->enc_bufpos_last_output_block = context->enc_BufPos;
/* initialise bit buffer */ context->enc_bitcount = 32; context->enc_bitbuf = 0; context->enc_output_overflow = false;
/*
* The last lengths are zeroed in both the encoder and decoder, * since our tree representation is delta format. */ memset(context->enc_main_tree_prev_len, 0, MAIN_TREE_ELEMENTS); memset(context->enc_secondary_tree_prev_len, 0, NUM_SECONDARY_LENGTHS);
/*
* Set the default last tree lengths for cost estimation */ memset(context->enc_main_tree_len, 8, NUM_CHARS); memset(&context->enc_main_tree_len[NUM_CHARS], 9, MAIN_TREE_ELEMENTS-NUM_CHARS); memset(context->enc_secondary_tree_len, 6, NUM_SECONDARY_LENGTHS); memset(context->enc_aligned_tree_len, 3, ALIGNED_NUM_ELEMENTS); prevent_far_matches(context); /* prevent far match 2's from being taken */
context->enc_bufpos_at_last_block = context->enc_BufPos; context->enc_earliest_window_data_remaining = context->enc_BufPos; context->enc_input_running_total = 0; context->enc_first_time_this_group = true;
/* Clear the literal types array */ memset(context->enc_ItemType, 0, MAX_LITERAL_ITEMS/8);
/* No literals or distances encoded yet */ context->enc_literals = 0; context->enc_distances = 0;
/* No block splits yet */ context->enc_num_block_splits = 0;
context->enc_repeated_offset_at_literal_zero[0] = 1; context->enc_repeated_offset_at_literal_zero[1] = 1; context->enc_repeated_offset_at_literal_zero[2] = 1;
/* reset instruction pointer (for translation) to zero */ reset_translation(context);
context->enc_num_cfdata_frames = 0;}
/*
* Allocate memory for the compressor * * Returns true if successful, false otherwise */bool comp_alloc_compress_memory(t_encoder_context *context){ ulong pos_start;
#ifdef MULTIPLE_SEARCH_TREES
context->enc_tree_root = NULL;#endif
context->enc_RealLeft = NULL; context->enc_RealRight = NULL; context->enc_MemWindow = NULL; context->enc_decision_node = NULL; context->enc_LitData = NULL;#ifdef EXTRALONGMATCHES
context->enc_ExtraLength = NULL;#endif
context->enc_DistData = NULL; context->enc_ItemType = NULL; context->enc_output_buffer_start = NULL;
/* ALSO NULLIFY BUFFERS! */
/*
* Determine the number of position slots in the main tree */ context->enc_num_position_slots = 4; pos_start = 4;
while (1) { pos_start += 1 << enc_extra_bits[context->enc_num_position_slots];
context->enc_num_position_slots++;
if (pos_start >= context->enc_window_size) break; }
#ifdef MULTIPLE_SEARCH_TREES
context->enc_tree_root = (ulong *) context->enc_malloc( context->enc_mallochandle, sizeof(context->enc_tree_root[0]) * NUM_SEARCH_TREES );
if (context->enc_tree_root == NULL) { return false; }#endif
context->enc_RealLeft = (ulong *) context->enc_malloc( context->enc_mallochandle, sizeof(ulong) * MEM_WINDOW_ALLOC_SIZE );
if (context->enc_RealLeft == NULL) { return false; }
context->enc_RealRight = (ulong *) context->enc_malloc( context->enc_mallochandle, sizeof(ulong) * MEM_WINDOW_ALLOC_SIZE );
if (context->enc_RealRight == NULL) { return false; }
context->enc_RealMemWindow = (byte *) context->enc_malloc( context->enc_mallochandle, MEM_WINDOW_ALLOC_SIZE );
if (context->enc_RealMemWindow == NULL) { return false; }
context->enc_MemWindow = context->enc_RealMemWindow;
context->enc_LitData = (byte *) context->enc_malloc( context->enc_mallochandle, MAX_LITERAL_ITEMS * sizeof(*context->enc_LitData) );
if (context->enc_LitData == NULL) { return false; }
#ifdef EXTRALONGMATCHES
context->enc_ExtraLength = (ushort *) context->enc_malloc( context->enc_mallochandle, MAX_LITERAL_ITEMS * sizeof(*context->enc_ExtraLength) );
if (context->enc_ExtraLength == NULL) { return false; }
#endif
context->enc_DistData = (ulong *) context->enc_malloc( context->enc_mallochandle, MAX_DIST_ITEMS * sizeof(*context->enc_DistData) );
if (context->enc_DistData == NULL) { return false; }
context->enc_ItemType = (byte *) context->enc_malloc( context->enc_mallochandle, MAX_LITERAL_ITEMS/8 );
if (context->enc_ItemType == NULL) { return false; }
create_slot_lookup_table(context); create_ones_table(context);
if (init_compressed_output_buffer(context) == false) { return false; }
context->enc_decision_node = context->enc_malloc( context->enc_mallochandle, sizeof(decision_node) * (LOOK+MAX_MATCH+16) );
if (context->enc_decision_node == NULL) { return false; }
/* success */ return true;}
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