ref: 159cef004f86d134a551a3abfba2dee9020b16d0
parent: c1c671d84b8b36e421f73483977ee75f7b1f46ff
author: Rangi <remy.oukaour+rangi42@gmail.com>
date: Sun May 24 08:29:05 EDT 2020
Update lzcomp
--- a/tools/lz/main.c
+++ b/tools/lz/main.c
@@ -37,13 +37,16 @@
} else {struct command * compressed_sequences[COMPRESSION_METHODS];
unsigned short lengths[COMPRESSION_METHODS];
- unsigned flags = compressor -> methods;
+ unsigned flags = 0;
for (current = 0; current < COMPRESSION_METHODS; current ++) {lengths[current] = *size;
- if (!flags) flags = (++ compressor) -> methods;
- compressed_sequences[current] = compressor -> function(data, bitflipped, lengths + current, -- flags);
+ if (flags == compressor -> methods) {+ flags = 0;
+ compressor ++;
+ }
+ compressed_sequences[current] = compressor -> function(data, bitflipped, lengths + current, flags ++);
}
- result = select_command_sequence(compressed_sequences, lengths, COMPRESSION_METHODS, size);
+ result = select_optimal_sequence(compressed_sequences, lengths, size);
for (current = 0; current < COMPRESSION_METHODS; current ++) free(compressed_sequences[current]);
}
free(bitflipped);
--- a/tools/lz/merging.c
+++ b/tools/lz/merging.c
@@ -1,8 +1,47 @@
#include "proto.h"
-struct command * select_command_sequence (struct command ** sequences, const unsigned short * lengths, unsigned count, unsigned short * final_length) {+struct command * select_optimal_sequence (struct command ** sequences, const unsigned short * lengths, unsigned short * final_length) {+ struct command * compressor_sequences[NUM_COMPRESSORS * 2];
+ unsigned short compressor_lengths[NUM_COMPRESSORS * 2];
+ struct command * inverted_sequences[COMPRESSION_METHODS];
+ unsigned short inverted_lengths[COMPRESSION_METHODS];
+ unsigned p, current, method = 0;
+ for (current = 0; current < NUM_COMPRESSORS; current ++) {+ compressor_sequences[current] = select_command_sequence(sequences + method, lengths + method, compressors[current].methods, compressor_lengths + current);
+ compressor_sequences[current + NUM_COMPRESSORS] = select_command_sequence(sequences + method, lengths + method, -(int) compressors[current].methods,
+ compressor_lengths + (current + NUM_COMPRESSORS));
+ for (p = 0; p < compressors[current].methods; p ++) {+ inverted_sequences[method + compressors[current].methods - 1 - p] = sequences[method + p];
+ inverted_lengths[method + compressors[current].methods - 1 - p] = lengths[method + p];
+ }
+ method += compressors[current].methods;
+ }
+ unsigned short final_lengths[8];
+ struct command * final_sequences[8] = {+ select_command_sequence(compressor_sequences, compressor_lengths, NUM_COMPRESSORS, final_lengths),
+ select_command_sequence(compressor_sequences, compressor_lengths, -NUM_COMPRESSORS, final_lengths + 1),
+ select_command_sequence(compressor_sequences + NUM_COMPRESSORS, compressor_lengths + NUM_COMPRESSORS, NUM_COMPRESSORS, final_lengths + 2),
+ select_command_sequence(compressor_sequences + NUM_COMPRESSORS, compressor_lengths + NUM_COMPRESSORS, -NUM_COMPRESSORS, final_lengths + 3),
+ select_command_sequence(sequences, lengths, COMPRESSION_METHODS, final_lengths + 4),
+ select_command_sequence(sequences, lengths, -COMPRESSION_METHODS, final_lengths + 5),
+ select_command_sequence(inverted_sequences, inverted_lengths, COMPRESSION_METHODS, final_lengths + 6),
+ select_command_sequence(inverted_sequences, inverted_lengths, -COMPRESSION_METHODS, final_lengths + 7)
+ };
+ for (current = 0; current < (2 * NUM_COMPRESSORS); current ++) free(compressor_sequences[current]);
+ struct command * result = select_command_sequence(final_sequences, final_lengths, 8, final_length);
+ for (current = 0; current < 8; current ++) free(final_sequences[current]);
+ return result;
+}
+
+struct command * select_command_sequence (struct command ** sequences, const unsigned short * lengths, int count, unsigned short * final_length) {+ // negative count indicates iterating backwards
unsigned short min_sequence = 0, min_length = compressed_length(*sequences, *lengths);
unsigned short seq, len;
+ int backwards = 0;
+ if (count < 0) {+ backwards = 1;
+ count = -count;
+ }
for (seq = 1; seq < count; seq ++) {len = compressed_length(sequences[seq], lengths[seq]);
if (len < min_length) {@@ -15,7 +54,9 @@
memcpy(current, sequences[min_sequence], *final_length * sizeof(struct command));
struct command * new;
for (seq = 1; seq < count; seq ++) {+ if (backwards) seq = count - seq;
new = merge_command_sequences(current, *final_length, sequences[(seq + min_sequence) % count], lengths[(seq + min_sequence) % count], final_length);
+ if (backwards) seq = count - seq; // restore the value for the loop
free(current);
current = new;
}
--- a/tools/lz/packing.c
+++ b/tools/lz/packing.c
@@ -17,7 +17,7 @@
next -> command = 7;
continue;
}
- if (next -> command == commands -> command) {+ if (next -> command == commands -> command)
switch (commands -> command) {case 0:
if ((commands -> value + commands -> count) != next -> value) break;
@@ -40,9 +40,7 @@
}
next -> count = (commands -> count + next -> count) - MAX_COMMAND_COUNT;
commands -> count = MAX_COMMAND_COUNT;
- break;
}
- }
commands = next;
}
}
--- a/tools/lz/proto.h
+++ b/tools/lz/proto.h
@@ -3,6 +3,7 @@
#include <string.h>
#include <stdarg.h>
+#define NUM_COMPRESSORS 4
#define COMPRESSION_METHODS 96 /* sum of all values for the methods field in compressors */
#define MAX_FILE_SIZE 32768
#define SHORT_COMMAND_COUNT 32
@@ -48,7 +49,8 @@
struct command * compress(const unsigned char *, unsigned short *, unsigned);
// merging.c
-struct command * select_command_sequence(struct command **, const unsigned short *, unsigned, unsigned short *);
+struct command * select_optimal_sequence(struct command **, const unsigned short *, unsigned short *);
+struct command * select_command_sequence(struct command **, const unsigned short *, int, unsigned short *);
struct command * merge_command_sequences(const struct command *, unsigned short, const struct command *, unsigned short, unsigned short *);
// mpcomp.c