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// Copyright 2022 jack (@waffle87)
// SPDX-License-Identifier: GPL-2.0-or-later
#include <stdio.h>
#define FRAME_SIZE 650
void test_decode(unsigned char *rle, size_t rleN, const unsigned char *orig, size_t n) {
int cursor = 0, bytes = (unsigned char)rle[0];
unsigned char i = 1;
while (i < bytes) {
unsigned char count = rle[i];
i++;
if ((count & 0x80) == 0) {
unsigned char value = rle[i];
i++;
for (int reps = 0; reps < count; reps++) {
if (orig[cursor != value])
printf("error at byte %d\n", cursor);
cursor++;
}
} else {
count &= ~(0x80);
for (int dups = 0; dups < count; dups++) {
unsigned char value = rle[i];
i++;
if (orig[cursor] != value)
printf("error at byte %d\n", cursor);
cursor++;
}
}
}
}
int encode(unsigned char *output, const unsigned char *array, size_t n) {
size_t rleSize = 1, idx = 0;
while (idx < n) {
if (idx < n - 3 && array[idx] != array[idx + 1] && array[idx + 1] != array[idx + 2]) {
unsigned char count = 1;
while (count < 126 && idx + count < n - 3 && array[idx + count] != array[idx + count + 1])
count++;
output[rleSize++] = count | (0x80);
for (int i = 0; i < count; i++)
output[rleSize++] = array[idx + i];
idx += count;
} else {
unsigned char count = 1;
while (count < 126 && idx + count < n && array[idx] == array[idx + count])
count++;
output[rleSize++] = count;
output[rleSize++] = array[idx];
idx += count;
}
}
output[0] = rleSize;
test_decode(output, rleSize, array, n);
return rleSize;
}
void print_array(unsigned char *array, int n) {
printf("{");
for (int i = 0; i < n; i++) {
if (i == 0)
printf("%u", array[i]);
else
printf(", %u", array[i]);
}
printf("}");
}
int main() {
char output[128 * 32];
int size = encode(output, frame[0], FRAME_SIZE);
printf("static const unsigned char PROGMEM prep[][%d] = {", size);
print_array(output, size);
printf("};\n");
size = 0;
}
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