Initial commit

Bringing a lot of stuff over from my maze-reader project in an attempt
to split the image reading code off into a library.

1 files changed, 52 insertions, 0 deletions

diff --git a/src/zlib.h b/src/zlib.h
new file mode 100644
index 0000000..d9d6b44
--- /dev/null
+++ b/src/zlib.h
@@ -0,0 +1,52 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+struct HuffmanTree
+{
+	uint16_t val = 0xFFFF;
+	HuffmanTree* left = nullptr; // 0
+	HuffmanTree* right = nullptr; // 1
+	HuffmanTree() = default;
+	~HuffmanTree();
+	void free();
+};
+
+struct StreamData
+{
+	uint8_t* data;
+	unsigned long length;
+	unsigned long pos;
+};
+
+class ZLibInflator
+{
+private:
+	HuffmanTree tree;
+	HuffmanTree distTree;
+	bool staticTree = false;
+	bool haveTree = false;
+public:
+	ZLibInflator() = default;
+	~ZLibInflator() = default;
+
+	static bool nextBit(StreamData* stream);
+	static uint16_t nextBits(StreamData* stream, int bits); // Max 16 bits
+
+	void calculateCodes(uint8_t* lengths, uint16_t* codesOut, int codeCount);
+
+	void buildHuffmanTree(uint8_t* lengths, uint16_t* codes, int codeCount);
+	void buildHuffmanTree(uint8_t* lengths, uint16_t* codes, int codeCount, HuffmanTree* treeOut);
+
+	void buildStaticHuffmanTree();
+	void buildStaticHuffmanTree(HuffmanTree* treeOut, HuffmanTree* distTreeOut);
+
+	void buildDynamicHuffmanTree(StreamData* stream);
+	void buildDynamicHuffmanTree(StreamData* stream, HuffmanTree* treeOut, HuffmanTree* distTreeOut);
+
+	uint16_t getNextCode(StreamData* stream);
+	uint16_t getNextCode(StreamData* stream, HuffmanTree* tree);
+
+	int decodeData(uint8_t* data, unsigned long length, uint8_t* out, unsigned long outLength);
+};