1 files changed, 274 insertions, 0 deletions
diff --git a/src/app/deflatetest/main.cc b/src/app/deflatetest/main.cc
new file mode 100644
index 0000000..21c48bd
--- /dev/null
+++ b/src/app/deflatetest/main.cc
@@ -0,0 +1,274 @@
+/*
+ * Copyright 2020 Daniel Friesel
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+#include "arch.h"
+#include "driver/gpio.h"
+#include "driver/stdout.h"
+#include "driver/uptime.h"
+
+unsigned char const deflate_input[] = {
+	120, 1, 5, 193, 193, 13, 192, 32, 16, 3, 193, 86, 182, 182, 196, 68, 220,
+	135, 147, 12, 86, 218, 103, 102, 198, 70, 133, 98, 147, 37, 118, 243, 143,
+	58, 195, 100, 137, 221, 124, 237, 195, 140, 141, 10, 197, 102, 191, 51, 79,
+	41, 23, 153, 255, 22, 11
+};
+
+unsigned char* udeflate_input_end;
+unsigned char* udeflate_input_now;
+uint8_t udeflate_bit_offset = 0;
+
+unsigned char deflate_output[1024];
+
+uint16_t const udeflate_length_offsets[] = {
+	3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67,
+	83, 99, 115, 131, 163, 195, 227, 258
+};
+
+// TODO (index < 4 || index == 28) ? 0 : (index-4) >> 2
+uint8_t const udeflate_length_bits[] = {
+	0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5,
+	5, 5, 5, 0
+};
+
+uint16_t const udeflate_distance_offsets[] = {
+	1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513,
+	769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577
+};
+
+// TODO index < 2 ? 0 : (index-2) >> 1
+uint8_t const udeflate_distance_bits[] = {
+	0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10,
+	11, 11, 12, 12, 13, 13
+};
+
+uint8_t const udeflate_hclen_index[] = {
+	16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
+};
+
+uint8_t udeflate_hc_lengths[19];
+uint8_t udeflate_lld_lengths[337];
+
+static uint16_t udeflate_rev_word(uint16_t word, uint8_t bits)
+{
+	uint16_t ret = 0;
+	uint16_t mask = 1;
+	for (uint16_t rmask = 1 << (bits-1); rmask > 0; rmask >>= 1) {
+		if (word & rmask) {
+			ret |= mask;
+		}
+		mask <<= 1;
+	}
+	return ret;
+}
+
+static uint8_t udeflate_bitmask(uint8_t bit_count)
+{
+	return (1 << bit_count) - 1;
+}
+
+static uint16_t udeflate_get_word()
+{
+	uint16_t ret = 0;
+	ret |= (udeflate_input_now[0] >> udeflate_bit_offset);
+	ret |= (uint16_t)udeflate_input_now[1] << (8 - udeflate_bit_offset);
+	if (udeflate_bit_offset) {
+		ret |= (uint16_t)(udeflate_input_now[2] & udeflate_bitmask(udeflate_bit_offset)) << (16 - udeflate_bit_offset);
+	}
+	kout << "get_word = " << bin << ret << dec << endl;
+	return ret;
+}
+
+static uint16_t udeflate_get_bits(uint8_t num_bits)
+{
+	uint16_t ret = udeflate_get_word();
+	udeflate_bit_offset += num_bits;
+	while (udeflate_bit_offset >= 8) {
+		udeflate_input_now++;
+		udeflate_bit_offset -= 8;
+	}
+	return ret & udeflate_bitmask(num_bits);
+}
+
+/*
+ * Assumptions:
+ * * huffman code length is limited to 11 bits
+ * * there are no more than 255 huffman codes with the same length
+ *
+ * Rationale: longer huffman codes might appear when handling large data
+ * sets. We don't do that; instead, we expect the uncompressed source to
+ * be no more than a few kB of data.
+ */
+uint8_t udeflate_bl_count[12];
+uint16_t udeflate_next_code[12];
+
+// TODO specify bl_count and next_code lists
+// (length and distance codes may use separate alphabets)
+static void udeflate_build_alphabet(uint8_t* lengths, uint16_t size)
+{
+	uint16_t i;
+	uint16_t code = 0;
+	uint8_t max_len = 0;
+	for (i = 0; i < 12; i++) {
+		udeflate_bl_count[i] = 0;
+	}
+
+	for (i = 0; i < size; i++) {
+		if (lengths[i]) {
+			udeflate_bl_count[lengths[i]]++;
+		}
+		if (lengths[i] > max_len) {
+			max_len = lengths[i];
+		}
+	}
+
+	for (i = 1; i < max_len+1; i++) {
+		code = (code + udeflate_bl_count[i-1]) << 1;
+		udeflate_next_code[i] = code;
+	}
+
+	for (i = 0; i < 12; i++) {
+		kout << "bl_count[" << i << "] = " << udeflate_bl_count[i] << endl;
+	}
+	for (i = 0; i < 12; i++) {
+		kout << "next_code[" << i << "] = " << udeflate_next_code[i] << endl;
+	}
+}
+
+static uint16_t udeflate_huff(uint8_t* lengths, uint16_t size)
+{
+	uint16_t next_word = udeflate_get_word();
+	for (uint8_t num_bits = 1; num_bits < 12; num_bits++) {
+		uint16_t next_bits = udeflate_rev_word(next_word, num_bits);
+		// TODO benötigt bit reversal bei der Abgleichung code <-> next_bits
+		// (geeignete is_bit_eq(next_bits, code_candidate, num_bits) Funktion?)
+		if (udeflate_bl_count[num_bits] && next_bits >= udeflate_next_code[num_bits] && next_bits < udeflate_next_code[num_bits] + udeflate_bl_count[num_bits] ) {
+			kout << "found huffman code, length = " << num_bits << endl;
+			udeflate_bit_offset += num_bits;
+			while (udeflate_bit_offset >= 8) {
+				udeflate_input_now++;
+				udeflate_bit_offset -= 8;
+			}
+			uint8_t len_pos = next_bits;
+			uint8_t cur_pos = udeflate_next_code[num_bits];
+			for (uint16_t i = 0; i < size; i++) {
+				if (lengths[i] == num_bits) {
+					if (cur_pos == len_pos) {
+						return i;
+					}
+					cur_pos++;
+				}
+			}
+		}
+	}
+	return 65535;
+}
+
+static int8_t udeflate_dynamic_huffman()
+{
+	uint8_t i;
+	uint16_t hlit = 257 + udeflate_get_bits(5);
+	kout << "hlit=" << hlit << endl;
+	uint8_t hdist = 1 + udeflate_get_bits(5);
+	kout << "hdist=" << hdist << endl;
+	uint8_t hclen = 4 + udeflate_get_bits(4);
+	kout << "hclen=" << hclen << endl;
+
+	for (i = 0; i < hclen; i++) {
+		udeflate_hc_lengths[udeflate_hclen_index[i]] = udeflate_get_bits(3);
+	}
+	for (i = hclen; i < sizeof(udeflate_hc_lengths); i++) {
+		udeflate_hc_lengths[udeflate_hclen_index[i]] = 0;
+	}
+
+	udeflate_build_alphabet(udeflate_hc_lengths, sizeof(udeflate_hc_lengths));
+
+	uint16_t items_processed = 0;
+	while (items_processed < hlit + hdist) {
+		uint8_t code = udeflate_huff(udeflate_hc_lengths, 19);
+		kout << "code = " << code << endl;
+		if (code == 16) {
+			uint8_t copy_count = 3 + udeflate_get_bits(2);
+			for (uint8_t i = 0; i < copy_count; i++) {
+				udeflate_lld_lengths[items_processed] = udeflate_lld_lengths[items_processed-1];
+				items_processed++;
+			}
+		}
+		else if (code == 17) {
+			uint8_t null_count = 3 + udeflate_get_bits(3);
+			for (uint8_t i = 0; i < null_count; i++) {
+				udeflate_lld_lengths[items_processed] = 0;
+				items_processed++;
+			}
+		}
+		else if (code == 18) {
+			uint8_t null_count = 11 + udeflate_get_bits(7);
+			for (uint8_t i = 0; i < null_count; i++) {
+				udeflate_lld_lengths[items_processed] = 0;
+				items_processed++;
+			}
+		}
+		else {
+			udeflate_lld_lengths[items_processed] = code;
+			items_processed++;
+		}
+	}
+
+	return 0;
+}
+
+int8_t udeflate(unsigned char* buf, uint16_t buf_len)
+{
+	uint8_t is_final = buf[0] & 0x01;
+	uint8_t block_type = (buf[0] & 0x06) >> 1;
+	kout << "is_final=" << is_final << " block_type=" << block_type << endl;
+
+	udeflate_input_now = buf;
+	udeflate_input_end = buf + buf_len;
+	udeflate_bit_offset = 3;
+
+	if (block_type == 2) {
+		return udeflate_dynamic_huffman();
+	}
+
+	return -4;
+}
+
+int8_t udeflate_zlib(unsigned char* buf, uint16_t buf_len)
+{
+	if (buf_len < 4) {
+		return -1;
+	}
+	uint8_t zlib_method = buf[0] & 0x0f;
+	uint16_t zlib_window_size = 1 << (8 + ((buf[0] & 0xf0) >> 4));
+	uint8_t zlib_flags = buf[1];
+	kout << "zlib_method=" << zlib_method << endl;
+	kout << "zlib_window_size=" << zlib_window_size << endl;
+
+	if (zlib_method != 8) {
+		return -2;
+	}
+
+	if (zlib_flags & 0x10) {
+		return -3;
+	}
+
+	return udeflate(buf+2, buf_len-2);
+}
+
+int main(void)
+{
+	arch.setup();
+	gpio.setup();
+	kout.setup();
+
+	for (uint8_t i = 0; i < 5; i++) {
+		int8_t ret = udeflate_zlib((unsigned char*)deflate_input, sizeof(deflate_input));
+		kout << "udeflate returned " << ret << endl;
+	}
+
+	arch.idle();
+
+	return 0;
+}