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huffman_test.c
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huffman_test.c
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/* This file is part of hwzip from https://www.hanshq.net/zip.html
It is put in the public domain; see the LICENSE file for details. */
#include "huffman.h"
#include "test_utils.h"
void test_huffman_decode_basic(void)
{
static const uint8_t lens[] = {
3, /* sym 0: 000 */
3, /* sym 1: 001 */
3, /* sym 2: 010 */
3, /* sym 3: 011 */
3, /* sym 4: 100 */
3, /* sym 5: 101 */
4, /* sym 6: 1100 */
4, /* sym 7: 1101 */
0, /* sym 8: */
0, /* sym 9: */
0, /* sym 10: */
0, /* sym 11: */
0, /* sym 12: */
0, /* sym 13: */
0, /* sym 14: */
0, /* sym 15: */
6, /* sym 16: 111110 */
5, /* sym 17: 11110 */
4 /* sym 18: 1110 */
};
huffman_decoder_t d;
size_t used;
CHECK(huffman_decoder_init(&d, lens, sizeof(lens) / sizeof(lens[0])));
/* 000 (msb-first) -> 000 (lsb-first)*/
CHECK(huffman_decode(&d, 0x0, &used) == 0); CHECK(used == 3);
/* 011 (msb-first) -> 110 (lsb-first)*/
CHECK(huffman_decode(&d, 0x6, &used) == 3); CHECK(used == 3);
/* 11110 (msb-first) -> 01111 (lsb-first)*/
CHECK(huffman_decode(&d, 0x0f, &used) == 17); CHECK(used == 5);
/* 111110 (msb-first) -> 011111 (lsb-first)*/
CHECK(huffman_decode(&d, 0x1f, &used) == 16); CHECK(used == 6);
/* 1111111 (msb-first) -> 1111111 (lsb-first)*/
CHECK(huffman_decode(&d, 0x7f, &used) == -1);
/* Make sure used is set even when decoding fails. */
CHECK(used == 0);
}
void test_huffman_decode_canonical(void)
{
/* Long enough codewords to not just hit the lookup table. */
static const uint8_t lens[] = {
3, /* sym 0: 0000 (0x0) */
3, /* sym 1: 0001 (0x1) */
3, /* sym 2: 0010 (0x2) */
15, /* sym 3: 0011 0000 0000 0000 (0x3000) */
15, /* sym 4: 0011 0000 0000 0001 (0x3001) */
15, /* sym 5: 0011 0000 0000 0010 (0x3002) */
};
huffman_decoder_t d;
size_t used;
CHECK(huffman_decoder_init(&d, lens, sizeof(lens) / sizeof(lens[0])));
CHECK(huffman_decode(&d, reverse16(0x0, 3), &used) == 0);
CHECK(used == 3);
CHECK(huffman_decode(&d, reverse16(0x1, 3), &used) == 1);
CHECK(used == 3);
CHECK(huffman_decode(&d, reverse16(0x2, 3), &used) == 2);
CHECK(used == 3);
CHECK(huffman_decode(&d, reverse16(0x3000, 15), &used) == 3);
CHECK(used == 15);
CHECK(huffman_decode(&d, reverse16(0x3001, 15), &used) == 4);
CHECK(used == 15);
CHECK(huffman_decode(&d, reverse16(0x3002, 15), &used) == 5);
CHECK(used == 15);
CHECK(huffman_decode(&d, reverse16(0x3000, 15), &used) == 3);
CHECK(used == 15);
}
void test_huffman_decode_evil(void)
{
/* More length-4 symbols than are possible. */
static const uint8_t lens[] = {
1,
2,
3,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4
};
huffman_decoder_t d;
CHECK(!huffman_decoder_init(&d, lens, sizeof(lens) / sizeof(lens[0])));
}
/* Check that codewords up to MAX_HUFFMAN_BITS can be decoded. */
void test_huffman_decode_max_bits(void)
{
static const uint8_t lens[] = {
1, /* sym 0: 0 */
2, /* sym 1: 10 */
3, /* sym 2: 110 */
4, /* sym 3: 1110 */
5, /* sym 4: 1111 0 */
6, /* sym 5: 1111 10 */
7, /* sym 6: 1111 110 */
8, /* sym 7: ... */
9,
10,
11,
12,
13,
14,
15,
16, /* sym 15: 1111 1111 1111 1110 */
16, /* sym 16: 1111 1111 1111 1111 */
};
huffman_decoder_t d;
size_t used;
CHECK(huffman_decoder_init(&d, lens, sizeof(lens) / sizeof(lens[0])));
/* 10 (msb-first) -> 01 (lsb-first)*/
CHECK(huffman_decode(&d, 0x1, &used) == 1); CHECK(used == 2);
CHECK(huffman_decode(&d, 0xffff, &used) == 16);
CHECK(used == MAX_HUFFMAN_BITS);
}
void test_huffman_decode_empty(void)
{
huffman_decoder_t d;
size_t used;
CHECK(huffman_decoder_init(&d, NULL, 0));
/* Hit the lookup table. */
CHECK(huffman_decode(&d, 0x0, &used) == -1);
/* Hit the canonical decoder. */
CHECK(huffman_decode(&d, 0xffff, &used) == -1);
}
void test_huffman_encoder_init(void)
{
static const uint16_t freqs[] = {
/* 0 */ 8,
/* 1 */ 1,
/* 2 */ 1,
/* 3 */ 2,
/* 4 */ 5,
/* 5 */ 10,
/* 6 */ 9,
/* 7 */ 1,
/* 8 */ 0,
/* 9 */ 0,
/* 10 */ 0,
/* 11 */ 0,
/* 12 */ 0,
/* 13 */ 0,
/* 14 */ 0,
/* 15 */ 0,
/* 16 */ 1,
/* 17 */ 3,
/* 18 */ 5,
};
huffman_encoder_t e;
huffman_encoder_init(&e, freqs, sizeof(freqs) / sizeof(freqs[0]), 6);
/* Test expectations from running Huffman with pen and paper. */
CHECK(e.lengths[0 ] == 3);
CHECK(e.lengths[1 ] == 6);
CHECK(e.lengths[2 ] == 6);
CHECK(e.lengths[3 ] == 5);
CHECK(e.lengths[4 ] == 3);
CHECK(e.lengths[5 ] == 2);
CHECK(e.lengths[6 ] == 2);
CHECK(e.lengths[7 ] == 6);
CHECK(e.lengths[8 ] == 0);
CHECK(e.lengths[9 ] == 0);
CHECK(e.lengths[10] == 0);
CHECK(e.lengths[11] == 0);
CHECK(e.lengths[12] == 0);
CHECK(e.lengths[13] == 0);
CHECK(e.lengths[14] == 0);
CHECK(e.lengths[15] == 0);
CHECK(e.lengths[16] == 6);
CHECK(e.lengths[17] == 5);
CHECK(e.lengths[18] == 3);
CHECK(e.codewords[5 ] == 0x0);
CHECK(e.codewords[6 ] == 0x2);
CHECK(e.codewords[0 ] == 0x1);
CHECK(e.codewords[4 ] == 0x5);
CHECK(e.codewords[18] == 0x3);
CHECK(e.codewords[3 ] == 0x7);
CHECK(e.codewords[17] == 0x17);
CHECK(e.codewords[1 ] == 0x0f);
CHECK(e.codewords[2 ] == 0x2f);
CHECK(e.codewords[7 ] == 0x1f);
CHECK(e.codewords[16] == 0x3f);
}
void test_huffman_lengths_one(void)
{
static const uint16_t freqs[] = {
/* 0 */ 0,
/* 1 */ 0,
/* 2 */ 0,
/* 3 */ 4,
};
huffman_encoder_t e;
huffman_encoder_init(&e, freqs, sizeof(freqs) / sizeof(freqs[0]), 6);
CHECK(e.lengths[0] == 0);
CHECK(e.lengths[1] == 0);
CHECK(e.lengths[2] == 0);
CHECK(e.lengths[3] == 1);
}
void test_huffman_lengths_two(void)
{
static const uint16_t freqs[] = {
/* 0 */ 1,
/* 1 */ 0,
/* 2 */ 0,
/* 3 */ 4,
};
huffman_encoder_t e;
huffman_encoder_init(&e, freqs, sizeof(freqs) / sizeof(freqs[0]), 6);
CHECK(e.lengths[0] == 1);
CHECK(e.lengths[1] == 0);
CHECK(e.lengths[2] == 0);
CHECK(e.lengths[3] == 1);
}
void test_huffman_lengths_none(void)
{
static const uint16_t freqs[] = {
/* 0 */ 0,
/* 1 */ 0,
/* 2 */ 0,
/* 3 */ 0,
};
huffman_encoder_t e;
huffman_encoder_init(&e, freqs, sizeof(freqs) / sizeof(freqs[0]), 6);
CHECK(e.lengths[0] == 0);
CHECK(e.lengths[1] == 0);
CHECK(e.lengths[2] == 0);
CHECK(e.lengths[3] == 0);
}
void test_huffman_lengths_limited(void)
{
static const uint16_t freqs[] = {
/* 0 */ 1,
/* 1 */ 2,
/* 2 */ 4,
/* 3 */ 8,
};
huffman_encoder_t e;
huffman_encoder_init(&e, freqs, sizeof(freqs) / sizeof(freqs[0]), 2);
CHECK(e.lengths[0] == 2);
CHECK(e.lengths[1] == 2);
CHECK(e.lengths[2] == 2);
CHECK(e.lengths[3] == 2);
}
void test_huffman_lengths_max_freq(void)
{
static const uint16_t freqs[] = {
/* 0 */ 16383,
/* 1 */ 16384,
/* 2 */ 16384,
/* 3 */ 16384
};
huffman_encoder_t e;
assert(freqs[0] + freqs[1] + freqs[2] + freqs[3] == UINT16_MAX);
huffman_encoder_init(&e, freqs, sizeof(freqs) / sizeof(freqs[0]), 10);
CHECK(e.lengths[0] == 2);
CHECK(e.lengths[1] == 2);
CHECK(e.lengths[2] == 2);
CHECK(e.lengths[3] == 2);
}
void test_huffman_lengths_max_syms(void)
{
uint16_t freqs[MAX_HUFFMAN_SYMBOLS];
huffman_encoder_t e;
size_t i;
for (i = 0; i < sizeof(freqs) / sizeof(freqs[0]); i++) {
freqs[i] = 1;
}
huffman_encoder_init(&e, freqs, sizeof(freqs) / sizeof(freqs[0]), 15);
for (i = 0; i < MAX_HUFFMAN_SYMBOLS; i++) {
CHECK(e.lengths[i] == 8 || e.lengths[i] == 9);
}
}
void test_huffman_encoder_init2(void)
{
uint8_t lens[288];
size_t i;
huffman_encoder_t e;
/* Code lengths used for fixed Huffman code deflate blocks. */
for (i = 0; i <= 143; i++) {
lens[i] = 8;
}
for (; i <= 255; i++) {
lens[i] = 9;
}
for (; i <= 279; i++) {
lens[i] = 7;
}
for (; i <= 287; i++) {
lens[i] = 8;
}
huffman_encoder_init2(&e, lens, sizeof(lens) / sizeof(lens[0]));
CHECK(e.codewords[255] == 0x1ff);
}
/* Check that codewords up to MAX_HUFFMAN_BITS are generated. */
void test_huffman_encoder_max_bits(void)
{
static const uint16_t freqs[] = {
/* 0 */ 1,
/* 1 */ 1,
/* 2 */ 2,
/* 3 */ 3,
/* 4 */ 5,
/* 5 */ 8,
/* 6 */ 13,
/* 7 */ 21,
/* 8 */ 34,
/* 9 */ 55,
/* 10 */ 89,
/* 11 */ 144,
/* 12 */ 233,
/* 13 */ 377,
/* 14 */ 610,
/* 15 */ 987,
/* 16 */ 1597,
};
huffman_encoder_t e;
huffman_encoder_init(&e, freqs, sizeof(freqs) / sizeof(freqs[0]), 16);
CHECK(e.lengths[0 ] == 16);
CHECK(e.lengths[1 ] == 16);
CHECK(e.lengths[16] == 1);
CHECK(e.codewords[0 ] == 0x7fff);
CHECK(e.codewords[1 ] == 0xffff);
CHECK(e.codewords[16] == 0x0);
}