+++ /dev/null
-//==========================================================================
-// Name: varicode.h
-// Purpose: Varicode encoded and decode functions
-// Created: Nov 24, 2012
-// Authors: David Rowe
-//
-// To test:
-// $ gcc varicode.c -o varicode -DVARICODE_UNITTEST -Wall
-// $ ./varicode
-//
-// License:
-//
-// This program is free software; you can redistribute it and/or modify
-// it under the terms of the GNU General Public License version 2.1,
-// as published by the Free Software Foundation. This program is
-// distributed in the hope that it will be useful, but WITHOUT ANY
-// WARRANTY; without even the implied warranty of MERCHANTABILITY or
-// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
-// License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program; if not, see <http://www.gnu.org/licenses/>.
-//
-//==========================================================================
-
-#include <assert.h>
-#include <ctype.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include "varicode.h"
-#include "varicode_table.h"
-
-
-/*
- output is an unpacked array of bits of maximum size max_out. Note
- unpacked arrays are a more suitable form for modulator input.
-
- Code 1 covers the entire ASCII char set.
-*/
-
-int varicode_encode1(short varicode_out[], char ascii_in[], int max_out, int n_in) {
- int n_out, index, n_zeros, v_len;
- unsigned short byte1, byte2, packed;
-
- n_out = 0;
-
- while(n_in && (n_out < max_out)) {
-
- assert((unsigned int)(*ascii_in) < 128);
-
- index = 2*(unsigned int)(*ascii_in);
- byte1 = varicode_table1[index];
- byte2 = varicode_table1[index+1];
- packed = (byte1 << 8) + byte2;
-
- //printf("n_in: %d ascii_in: %c index: %d packed 0x%x\n", n_in, *ascii_in, index, packed);
- ascii_in++;
-
- n_zeros = 0;
- v_len = 0;
- while ((n_zeros < 2) && (n_out < max_out) && (v_len <= VARICODE_MAX_BITS)) {
- if (packed & 0x8000) {
- *varicode_out = 1;
- n_zeros = 0;
- }
- else {
- *varicode_out = 0;
- n_zeros++;
- }
- //printf("packed: 0x%x *varicode_out: %d n_zeros: %d v_len: %d\n", packed, *varicode_out, n_zeros,v_len );
- packed <<= 1;
- varicode_out++;
- n_out++;
- v_len++;
- }
- assert(v_len <= VARICODE_MAX_BITS);
-
- n_in--;
- }
-
- return n_out;
-}
-
-
-/*
- Code 2 covers a subset, but is more efficient that Code 1 (282
- compared to 1315 bits on unittest) Unsupported characters are
- replaced by spaces. We encode/decode two bits at a time.
-*/
-
-int varicode_encode2(short varicode_out[], char ascii_in[], int max_out, int n_in) {
- int n_out, n_zeros, v_len, i;
- unsigned short packed;
-
- n_out = 0;
-
- while(n_in && (n_out < max_out)) {
-
- packed = varicode_table2[0]; // default to space if char not found
-
- // see if our character exists
- for(i=0; i<sizeof(varicode_table2); i+=2) {
- if (varicode_table2[i] == *ascii_in)
- packed = (unsigned short)varicode_table2[i+1] << 8;
- }
-
- //printf("n_in: %d ascii_in: %c index: %d packed 0x%x\n", n_in, *ascii_in, index, packed);
- ascii_in++;
-
- n_zeros = 0;
- v_len = 0;
- while ((n_zeros < 2) && (n_out < max_out) && (v_len <= VARICODE_MAX_BITS)) {
- if (packed & 0x8000)
- varicode_out[0] = 1;
- else
- varicode_out[0] = 0;
-
- if (packed & 0x4000)
- varicode_out[1] = 1;
- else
- varicode_out[1] = 0;
-
- if (packed & 0xc000)
- n_zeros = 0;
- else
- n_zeros += 2;
-
- //printf("packed: 0x%x *varicode_out: %d n_zeros: %d v_len: %d\n", packed, *varicode_out, n_zeros,v_len );
- packed <<= 2;
- varicode_out +=2;
- n_out += 2;
- v_len += 2;
- }
- assert(v_len <= VARICODE_MAX_BITS);
-
- n_in--;
- }
-
- assert((n_out % 2) == 0); /* outputs two bits at a time */
-
- return n_out;
-}
-
-
-int varicode_encode(short varicode_out[], char ascii_in[], int max_out, int n_in, int code_num) {
-
- assert((code_num ==1) || (code_num ==2));
-
- if (code_num == 1)
- return varicode_encode1(varicode_out, ascii_in, max_out, n_in);
- else
- return varicode_encode2(varicode_out, ascii_in, max_out, n_in);
-}
-
-
-void varicode_decode_init(struct VARICODE_DEC *dec_states, int code_num)
-{
- assert((code_num ==1) || (code_num == 2));
-
- dec_states->state = 0;
- dec_states->n_zeros = 0;
- dec_states->v_len = 0;
- dec_states->packed = 0;
- dec_states->code_num = code_num;
- dec_states->n_in = 0;
- dec_states->in[0] = dec_states->in[1] = 0;
-}
-
-
-/* Code 1 decode function, accepts one bit at a time */
-
-static int decode_one_bit(struct VARICODE_DEC *s, char *single_ascii, short varicode_in, int long_code)
-{
- int found=0, i;
- unsigned short byte1, byte2;
-
- //printf("decode_one_bit : state: %d varicode_in: %d packed: 0x%x n_zeros: %d\n",
- // s->state, varicode_in, s->packed, s->n_zeros);
-
- if (s->state == 0) {
- if (!varicode_in)
- return 0;
- else
- s->state = 1;
- }
-
- if (s->state == 1) {
- if (varicode_in) {
- s->packed |= (0x8000 >> s->v_len);
- s->n_zeros = 0;
- }
- else {
- s->n_zeros++;
- }
- s->v_len++;
- found = 0;
-
- /* end of character code */
-
- if (s->n_zeros == 2) {
- if (s->v_len) {
- /* run thru table but note with bit errors we might not actually find a match */
-
- byte1 = s->packed >> 8;
- //printf("looking for byte1 : 0x%x ... ", byte1);
- byte2 = s->packed & 0xff;
-
- for(i=0; i<128; i++) {
- if ((byte1 == varicode_table1[2*i]) && (byte2 == varicode_table1[2*i+1])) {
- found = 1;
- *single_ascii = i;
- }
- }
- }
- varicode_decode_init(s, s->code_num);
- }
-
- /* code can run too long if we have a bit error */
-
- if (s->v_len > VARICODE_MAX_BITS)
- varicode_decode_init(s, s->code_num);
- }
-
- return found;
-}
-
-
-/* Code 2 decode function, accepts two bits at a time */
-
-static int decode_two_bits(struct VARICODE_DEC *s, char *single_ascii, short varicode_in1, short varicode_in2)
-{
- int found=0, i;
- unsigned short byte1;
-
- if (s->state == 0) {
- if (!(varicode_in1 || varicode_in2))
- return 0;
- else
- s->state = 1;
- }
-
- if (s->state == 1) {
- if (varicode_in1)
- s->packed |= (0x8000 >> s->v_len);
- if (varicode_in2)
- s->packed |= (0x4000 >> s->v_len);
- if (varicode_in1 || varicode_in2)
- s->n_zeros = 0;
- else
- s->n_zeros+=2;
-
- s->v_len+=2;
-
- found = 0;
-
- /* end of character code */
-
- if (s->n_zeros == 2) {
- if (s->v_len) {
- /* run thru table but note with bit errors we might not actually find a match */
-
- byte1 = s->packed >> 8;
- //printf("looking for byte1 : 0x%x ... ", byte1);
- for(i=0; i<sizeof(varicode_table2); i+=2) {
- //printf("byte1: 0x%x 0x%x\n", byte1, (unsigned char)varicode_table2[i+1]);
- if (byte1 == (unsigned char)varicode_table2[i+1]) {
- found = 1;
- *single_ascii = varicode_table2[i];
- //printf("found: %d i=%d char=%c ", found, i, *single_ascii);
- }
- }
- }
- varicode_decode_init(s, s->code_num);
- }
-
- /* code can run too long if we have a bit error */
-
- if (s->v_len > VARICODE_MAX_BITS)
- varicode_decode_init(s, s->code_num);
- }
-
- return found;
-}
-
-
-int varicode_decode1(struct VARICODE_DEC *dec_states, char ascii_out[], short varicode_in[], int max_out, int n_in) {
- int output, n_out;
- char single_ascii = 0;
-
- n_out = 0;
-
- //printf("varicode_decode: n_in: %d\n", n_in);
-
- while(n_in && (n_out < max_out)) {
- output = decode_one_bit(dec_states, &single_ascii, varicode_in[0], 0);
- varicode_in++;
- n_in--;
-
- if (output) {
- *ascii_out++ = single_ascii;
- n_out++;
- }
- }
-
- return n_out;
-}
-
-
-int varicode_decode2(struct VARICODE_DEC *dec_states, char ascii_out[], short varicode_in[], int max_out, int n_in) {
- int output, n_out;
- char single_ascii = 0;
-
- n_out = 0;
-
- //printf("varicode_decode2: n_in: %d varicode_in[0] %d dec_states->n_in: %d\n", n_in, varicode_in[0], dec_states->n_in);
- //printf("%d ", varicode_in[0]);
- while(n_in && (n_out < max_out)) {
-
- // keep two bit buffer so we can process two at a time
-
- dec_states->in[0] = dec_states->in[1];
- dec_states->in[1] = varicode_in[0];
- dec_states->n_in++;
- varicode_in++;
- n_in--;
-
- if (dec_states->n_in == 2) {
- output = decode_two_bits(dec_states, &single_ascii, dec_states->in[0], dec_states->in[1]);
-
- dec_states->n_in = 0;
-
- if (output) {
- //printf(" output: %d single_ascii: 0x%x %c\n", output, (int)single_ascii, single_ascii);
- *ascii_out++ = single_ascii;
- n_out++;
- }
- }
- }
-
- return n_out;
-}
-
-
-int varicode_decode(struct VARICODE_DEC *dec_states, char ascii_out[], short varicode_in[], int max_out, int n_in) {
- if (dec_states->code_num == 1)
- return varicode_decode1(dec_states, ascii_out, varicode_in, max_out, n_in);
- else
- return varicode_decode2(dec_states, ascii_out, varicode_in, max_out, n_in);
-}
-
-
-#ifdef VARICODE_UNITTEST
-void test_varicode(int code_num) {
- char *ascii_in;
- short *varicode;
- int i, n_varicode_bits_out, n_ascii_chars_out, length, half, n_out, j, len;
- char *ascii_out;
- struct VARICODE_DEC dec_states;
-
- if (code_num == 1) {
- printf("long code:\n");
- length = sizeof(varicode_table1)/2;
- }
- else {
- printf("short code:\n");
- length = sizeof(varicode_table2)/2;
- }
- //length = 10;
- ascii_in = (char*)malloc(length);
- varicode = (short*)malloc(VARICODE_MAX_BITS*sizeof(short)*length);
- ascii_out = (char*)malloc(length);
-
- // 1. test all Varicode codes -------------------------------------------------------------
-
- if (code_num == 1) {
- for(i=0; i<length; i++)
- ascii_in[i] = (char)i;
- }
- else {
- for(i=0; i<length; i++)
- ascii_in[i] = varicode_table2[2*i];
- }
- //printf(" ascii_in: %s\n", ascii_in);
- n_varicode_bits_out = varicode_encode(varicode, ascii_in, VARICODE_MAX_BITS*length, length, code_num);
-
- printf(" n_varicode_bits_out: %d\n", n_varicode_bits_out);
- //for(i=0; i<n_varicode_bits_out; i++) {
- // printf("%d \n", varicode[i]);
- //}
-
- // split decode in half to test how it preserves state between calls
-
- varicode_decode_init(&dec_states, code_num);
- half = n_varicode_bits_out/2;
- n_ascii_chars_out = varicode_decode(&dec_states, ascii_out, varicode, length, half);
- // printf(" n_ascii_chars_out: %d\n", n_ascii_chars_out);
-
- n_ascii_chars_out += varicode_decode(&dec_states, &ascii_out[n_ascii_chars_out],
- &varicode[half], length-n_ascii_chars_out, n_varicode_bits_out - half);
- assert(n_ascii_chars_out == length);
-
- printf(" n_ascii_chars_out: %d\n", n_ascii_chars_out);
- printf(" average bits/character: %3.2f\n", (float)n_varicode_bits_out/n_ascii_chars_out);
-
- //printf("ascii_out: %s\n", ascii_out);
-
- if (memcmp(ascii_in, ascii_out, length) == 0)
- printf(" Test 1 Pass\n");
- else
- printf(" Test 1 Fail\n");
-
- // 2. Test some ascii with a run of zeros -----------------------------------------------------
-
- sprintf(ascii_in, "CQ CQ CQ this is VK5DGR");
-
- assert(strlen(ascii_in) < length);
- if (code_num == 2)
- for(i=0; i<strlen(ascii_in); i++)
- ascii_in[i] = tolower(ascii_in[i]);
-
- for(i=0; i<3; i++) {
- n_varicode_bits_out = varicode_encode(varicode, ascii_in, VARICODE_MAX_BITS*length, strlen(ascii_in), code_num);
- n_ascii_chars_out = varicode_decode(&dec_states, ascii_out, varicode, length, n_varicode_bits_out);
- ascii_out[n_ascii_chars_out] = 0;
-
- printf(" ascii_out: %s\n", ascii_out);
- if (strcmp(ascii_in, ascii_out) == 0)
- printf(" Test 2 Pass\n");
- else
- printf(" Test 2 Fail\n");
-
- memset(varicode, 0, sizeof(short)*20);
- n_ascii_chars_out = varicode_decode(&dec_states, ascii_out, varicode, length, 20);
- assert(n_ascii_chars_out == 0);
- }
-
- // 3. Test receiving one bit at a time -----------------------------------------------------
-
- sprintf(ascii_in, "s=vk5dgr qth=adelaide");
- len = strlen(ascii_in);
- ascii_in[len] = 13;
- ascii_in[len+1] = 0;
-
- assert(strlen(ascii_in) < length);
- if (code_num == 2)
- for(i=0; i<strlen(ascii_in); i++)
- ascii_in[i] = tolower(ascii_in[i]);
-
- for(i=0; i<3; i++) {
- n_varicode_bits_out = varicode_encode(varicode, ascii_in, VARICODE_MAX_BITS*length, strlen(ascii_in), code_num);
- printf("n_varicode_bits_out: %d\n", n_varicode_bits_out);
-
- n_ascii_chars_out = 0;
- for(j=0; j<n_varicode_bits_out; j++) {
- n_out = varicode_decode(&dec_states, &ascii_out[n_ascii_chars_out], &varicode[j], 1, 1);
- if (n_out)
- n_ascii_chars_out++;
- }
- ascii_out[n_ascii_chars_out] = 0;
-
- printf(" ascii_out: %s\n", ascii_out);
- if (strcmp(ascii_in, ascii_out) == 0)
- printf(" Test 3 Pass\n");
- else
- printf(" Test 3 Fail\n");
- }
-
- free(ascii_in);
- free(ascii_out);
- free(varicode);
-}
-
-int main(void) {
- test_varicode(1);
- test_varicode(2);
- return 0;
-}
-#endif
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