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dec_naive.c
119 lines (110 loc) · 3.16 KB
/
dec_naive.c
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#include <stdio.h>
void huffman_decode(char *input, int len, char *output) {
int i;
int out_idx;
unsigned char val, run;
i = 0;
out_idx = 0;
val = 0;
run = 0;
for (i = 0; i < len; i++) {
// Grab next input bit
val <<= 1;
val |= input[i];
run++;
// Look for matching codes, first by how many bits we have, then by pattern
if (run == 3) {
switch (val) {
case 0x07:
output[out_idx++] = 'P';
val = run = 0;
break;
case 0x05:
output[out_idx++] = 'O';
val = run = 0;
break;
case 0x04:
output[out_idx++] = 'N';
val = run = 0;
break;
case 0x01:
output[out_idx++] = 'M';
val = run = 0;
break;
case 0x00:
output[out_idx++] = 'L';
val = run = 0;
break;
}
} else if (run == 4) {
switch (val) {
case 0x0C:
output[out_idx++] = 'K';
val = run = 0;
break;
case 0x07:
output[out_idx++] = 'J';
val = run = 0;
break;
case 0x06:
output[out_idx++] = 'I';
val = run = 0;
break;
case 0x04:
output[out_idx++] = 'H';
val = run = 0;
break;
}
} else if (run == 5) {
switch (val) {
case 0x0A:
output[out_idx++] = 'G';
val = run = 0;
break;
case 0x0B:
output[out_idx++] = 'F';
val = run = 0;
break;
}
} else if (run == 6) {
switch (val) {
case 0x34:
output[out_idx++] = 'E';
val = run = 0;
break;
case 0x35:
output[out_idx++] = 'D';
val = run = 0;
break;
case 0x37:
output[out_idx++] = 'C';
val = run = 0;
break;
}
} else if (run == 7) {
switch (val) {
case 0x6D:
output[out_idx++] = 'B';
val = run = 0;
break;
case 0x6C:
output[out_idx++] = 'A';
val = run = 0;
break;
}
}
}
output[out_idx] = '\0';
}
int main(void) {
char input[512];
char output[512];
int i;
scanf("%s", input);
// Convert '0' and '1' to integers 0 and 1, respectively
for (i = 0; input[i] != '\0'; i++) {
input[i] = input[i] - 0x30;
}
huffman_decode(input, i, output);
printf("%s\n", output);
}