From 44c1d9c2480fe6ea37dbed6199b51acf035de0c2 Mon Sep 17 00:00:00 2001
From: madmaxoft <github@xoft.cz>
Date: Wed, 3 Sep 2014 19:36:53 +0200
Subject: Anvil: switched inflate to stream mode.

This removes the fixed-size buffer which could have caused #1307 and #1366.
---
 src/StringCompression.cpp     | 62 +++++++++++++++++++++++++++++++++++++++++++
 src/StringCompression.h       |  2 ++
 src/WorldStorage/WSSAnvil.cpp | 24 +++++------------
 3 files changed, 70 insertions(+), 18 deletions(-)

diff --git a/src/StringCompression.cpp b/src/StringCompression.cpp
index 71d64e71e..af9f1687f 100644
--- a/src/StringCompression.cpp
+++ b/src/StringCompression.cpp
@@ -180,3 +180,65 @@ extern int UncompressStringGZIP(const char * a_Data, size_t a_Length, AString &
 
 
 
+
+extern int InflateString(const char * a_Data, size_t a_Length, AString & a_Uncompressed)
+{
+	a_Uncompressed.reserve(a_Length);
+
+	char Buffer[64 KiB];
+	z_stream strm;
+	memset(&strm, 0, sizeof(strm));
+	strm.next_in = (Bytef *)a_Data;
+	strm.avail_in = (uInt)a_Length;
+	strm.next_out = (Bytef *)Buffer;
+	strm.avail_out = sizeof(Buffer);
+	
+	int res = inflateInit(&strm);  // Force GZIP decoding
+	if (res != Z_OK)
+	{
+		LOG("%s: inflation initialization failed: %d (\"%s\").", __FUNCTION__, res, strm.msg);
+		return res;
+	}
+	
+	for (;;)
+	{
+		res = inflate(&strm, Z_NO_FLUSH);
+		switch (res)
+		{
+			case Z_OK:
+			{
+				// Some data has been uncompressed. Consume the buffer and continue uncompressing
+				a_Uncompressed.append(Buffer, sizeof(Buffer) - strm.avail_out);
+				strm.next_out = (Bytef *)Buffer;
+				strm.avail_out = sizeof(Buffer);
+				if (strm.avail_in == 0)
+				{
+					// All data has been uncompressed
+					inflateEnd(&strm);
+					return Z_OK;
+				}
+				break;
+			}
+			
+			case Z_STREAM_END:
+			{
+				// Finished uncompressing. Consume the rest of the buffer and return
+				a_Uncompressed.append(Buffer, sizeof(Buffer) - strm.avail_out);
+				inflateEnd(&strm);
+				return Z_OK;
+			}
+			
+			default:
+			{
+				// An error has occurred, log it and return the error value
+				LOG("%s: inflation failed: %d (\"%s\").", __FUNCTION__, res, strm.msg);
+				inflateEnd(&strm);
+				return res;
+			}
+		}  // switch (res)
+	}  // while (true)
+}
+
+
+
+
diff --git a/src/StringCompression.h b/src/StringCompression.h
index 038240797..dde17ce30 100644
--- a/src/StringCompression.h
+++ b/src/StringCompression.h
@@ -21,5 +21,7 @@ extern int CompressStringGZIP(const char * a_Data, size_t a_Length, AString & a_
 /// Uncompresses a_Data into a_Uncompressed using GZIP; returns Z_OK for success or Z_XXX error constants same as zlib
 extern int UncompressStringGZIP(const char * a_Data, size_t a_Length, AString & a_Uncompressed);
 
+/** Uncompresses a_Data into a_Uncompressed using Inflate; returns Z_OK for success or Z_XXX error constants same as zlib */
+extern int InflateString(const char * a_Data, size_t a_Length, AString & a_Uncompressed);
 
 
diff --git a/src/WorldStorage/WSSAnvil.cpp b/src/WorldStorage/WSSAnvil.cpp
index 815b6544f..239f4a155 100644
--- a/src/WorldStorage/WSSAnvil.cpp
+++ b/src/WorldStorage/WSSAnvil.cpp
@@ -66,9 +66,6 @@ Since only the header is actually in the memory, this number can be high, but st
 */
 #define MAX_MCA_FILES 32
 
-/// The maximum size of an inflated chunk; raw chunk data is 192 KiB, allow 64 KiB more of entities
-#define CHUNK_INFLATE_MAX 256 KiB
-
 #define LOAD_FAILED(CHX, CHZ) \
 	{ \
 		const int RegionX = FAST_FLOOR_DIV(CHX, 32); \
@@ -260,27 +257,18 @@ cWSSAnvil::cMCAFile * cWSSAnvil::LoadMCAFile(const cChunkCoords & a_Chunk)
 
 bool cWSSAnvil::LoadChunkFromData(const cChunkCoords & a_Chunk, const AString & a_Data)
 {
-	// Decompress the data:
-	char Uncompressed[CHUNK_INFLATE_MAX];
-	z_stream strm;
-	strm.zalloc = (alloc_func)NULL;
-	strm.zfree = (free_func)NULL;
-	strm.opaque = NULL;
-	inflateInit(&strm);
-	strm.next_out  = (Bytef *)Uncompressed;
-	strm.avail_out = sizeof(Uncompressed);
-	strm.next_in   = (Bytef *)a_Data.data();
-	strm.avail_in  = (uInt)a_Data.size();
-	int res = inflate(&strm, Z_FINISH);
-	inflateEnd(&strm);
-	if (res != Z_STREAM_END)
+	// Uncompress the data:
+	AString Uncompressed;
+	int res = InflateString(a_Data.data(), a_Data.size(), Uncompressed);
+	if (res != Z_OK)
 	{
+		LOGWARNING("Uncompressing chunk [%d, %d] failed: %d", a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ, res);
 		LOAD_FAILED(a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ);
 		return false;
 	}
 	
 	// Parse the NBT data:
-	cParsedNBT NBT(Uncompressed, strm.total_out);
+	cParsedNBT NBT(Uncompressed.data(), Uncompressed.size());
 	if (!NBT.IsValid())
 	{
 		// NBT Parsing failed
-- 
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