From 2d2671a6866864bc8fb927a63e2d6eecddff3d6a Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Sun, 1 Feb 2015 06:04:56 +0100
Subject: Use buffer API for chunk decompression

---
 src/Buffer.hpp       |  4 ++++
 src/World/Chunk.cpp  | 19 ++++++++-----------
 src/World/Chunk.hpp  |  5 +++--
 src/World/Region.cpp |  2 +-
 4 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/Buffer.hpp b/src/Buffer.hpp
index 3bf1ef0..9975dcb 100644
--- a/src/Buffer.hpp
+++ b/src/Buffer.hpp
@@ -56,6 +56,10 @@ public:
 
 	Buffer(const uint8_t *data0, size_t len0) : data(data0), len(len0) {}
 
+	size_t getRemaining() const {
+		return len;
+	}
+
 	const uint8_t * get(size_t n) {
 		if (n > len)
 			throw std::runtime_error("Buffer::get(): buffer underrun");
diff --git a/src/World/Chunk.cpp b/src/World/Chunk.cpp
index c2c59e0..915e5f3 100644
--- a/src/World/Chunk.cpp
+++ b/src/World/Chunk.cpp
@@ -39,7 +39,7 @@
 namespace MinedMap {
 namespace World {
 
-void Chunk::inflateChunk(uint8_t *buffer, size_t buflen) {
+void Chunk::inflateChunk(Buffer buffer) {
 	size_t outlen = 0;
 	uint8_t *output = nullptr;
 
@@ -48,8 +48,8 @@ void Chunk::inflateChunk(uint8_t *buffer, size_t buflen) {
 	if (ret != Z_OK)
 		throw std::runtime_error("inflateInit() failed");
 
-	stream.next_in = buffer;
-	stream.avail_in = buflen;
+	stream.avail_in = buffer.getRemaining();
+	stream.next_in = const_cast<uint8_t *>(buffer.get(stream.avail_in));
 
 	while (stream.avail_in) {
 		outlen += 65536;
@@ -111,19 +111,16 @@ uint8_t Chunk::getDataAt(const std::shared_ptr<const NBT::CompoundTag> &section,
 		return (v & 0xf);
 }
 
-Chunk::Chunk(uint8_t *buffer, size_t buflen) {
-	if (buflen < 5)
-		throw std::invalid_argument("short chunk");
+Chunk::Chunk(Buffer buffer) {
+	size_t size = buffer.get32();
 
-	size_t size = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
-	if (size < 1 || size > (buflen - 4))
-		throw std::invalid_argument("invalid chunk size");
+	Buffer buffer2(buffer.get(size), size);
 
-	uint8_t format = buffer[4];
+	uint8_t format = buffer2.get8();
 	if (format != 2)
 		throw std::invalid_argument("unknown chunk format");
 
-	inflateChunk(buffer+5, size-1);
+	inflateChunk(buffer2);
 	parseChunk();
 	analyzeChunk();
 }
diff --git a/src/World/Chunk.hpp b/src/World/Chunk.hpp
index 36628b4..d063d48 100644
--- a/src/World/Chunk.hpp
+++ b/src/World/Chunk.hpp
@@ -27,6 +27,7 @@
 #pragma once
 
 
+#include "../Buffer.hpp"
 #include "../UniqueCPtr.hpp"
 #include "../NBT/CompoundTag.hpp"
 #include "../NBT/ListTag.hpp"
@@ -51,7 +52,7 @@ private:
 
 	unsigned maxY;
 
-	void inflateChunk(uint8_t *data, size_t len);
+	void inflateChunk(Buffer buffer);
 	void parseChunk();
 	void analyzeChunk();
 
@@ -66,7 +67,7 @@ private:
 	uint8_t getDataAt(const std::shared_ptr<const NBT::CompoundTag> &section, size_t x, size_t y, size_t z);
 
 public:
-	Chunk(uint8_t *buffer, size_t buflen);
+	Chunk(Buffer buffer);
 
 	const NBT::ListTag<NBT::CompoundTag> & getSections() const {
 		return *sections;
diff --git a/src/World/Region.cpp b/src/World/Region.cpp
index 4f69059..fec732c 100644
--- a/src/World/Region.cpp
+++ b/src/World/Region.cpp
@@ -86,7 +86,7 @@ Region::Region(const char *filename) {
 		uint8_t buffer[len * 4096];
 		file.read((char *)buffer, len * 4096);
 
-		chunks[x][z].reset(new Chunk(buffer, len * 4096));
+		chunks[x][z].reset(new Chunk(Buffer(buffer, len * 4096)));
 
 		i += len;
 		c++;
-- 
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