From 9ac742d56bec171a0d252e7ef33b501466448f2b Mon Sep 17 00:00:00 2001
From: Tom Schumm <fwiffo@gmail.com>
Date: Mon, 2 Jul 2018 14:26:02 -0700
Subject: [PATCH 1/3] Fix copypasta in getMansionPos()

---
 finders.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/finders.c b/finders.c
index 4ea06da..7bc2afd 100644
--- a/finders.c
+++ b/finders.c
@@ -809,7 +809,7 @@ Pos getMansionPos(long seed, const long area80X, const long area80Z)
     pos.z += (seed >> 17) % 60;
 
     pos.x = area80X*80 + (pos.x >> 1);
-    pos.z = area80X*80 + (pos.z >> 1);
+    pos.z = area80Z*80 + (pos.z >> 1);
     pos.x = pos.x*16 + 8;
     pos.z = pos.z*16 + 8;
     return pos;

From 6558f5b7a6112f17837fa535652926dfcc6eca7f Mon Sep 17 00:00:00 2001
From: Tom Schumm <fwiffo@gmail.com>
Date: Mon, 2 Jul 2018 14:30:12 -0700
Subject: [PATCH 2/3] Add comments noting some not-thread-safe functions.

---
 finders.c | 2 ++
 finders.h | 1 +
 layers.c  | 1 +
 layers.h  | 1 +
 4 files changed, 5 insertions(+)

diff --git a/finders.c b/finders.c
index 7bc2afd..81beca0 100644
--- a/finders.c
+++ b/finders.c
@@ -660,6 +660,8 @@ void baseQuadTempleSearch(const char *fnam, const int threads, const int quality
 /* getBiomeAtPos
  * ----------------
  * Returns the biome for the specified block position.
+ * (Alternatives should be considered in performance critical code.)
+ * This function is not threadsafe.
  */
 int getBiomeAtPos(const LayerStack g, const Pos pos)
 {
diff --git a/finders.h b/finders.h
index 6254e12..1ad6407 100644
--- a/finders.h
+++ b/finders.h
@@ -126,6 +126,7 @@ void baseQuadTempleSearch(const char *fnam, int threads, int quality);
  * ----------------
  * Returns the biome for the specified block position.
  * (Alternatives should be considered in performance critical code.)
+ * This function is not threadsafe.
  */
 int getBiomeAtPos(const LayerStack g, const Pos pos);
 
diff --git a/layers.c b/layers.c
index 3c6d648..7d37557 100644
--- a/layers.c
+++ b/layers.c
@@ -861,6 +861,7 @@ void mapBiomeEdge(Layer *l, int * __restrict out, int areaX, int areaZ, int area
 }
 
 
+/* This function is not threadsafe. */
 void mapHills(Layer *l, int * __restrict out, int areaX, int areaZ, int areaWidth, int areaHeight)
 {
     int pX = areaX - 1;
diff --git a/layers.h b/layers.h
index 9dfefcf..f707efc 100644
--- a/layers.h
+++ b/layers.h
@@ -376,6 +376,7 @@ void mapDeepOcean(Layer *l, int * __restrict out, int x, int z, int w, int h);
 void mapBiome(Layer *l, int * __restrict out, int x, int z, int w, int h);
 void mapRiverInit(Layer *l, int * __restrict out, int x, int z, int w, int h);
 void mapBiomeEdge(Layer *l, int * __restrict out, int x, int z, int w, int h);
+/* This function is not threadsafe. */
 void mapHills(Layer *l, int * __restrict out, int x, int z, int w, int h);
 void mapRiver(Layer *l, int * __restrict out, int x, int z, int w, int h);
 void mapSmooth(Layer *l, int * __restrict out, int x, int z, int w, int h);

From 9ead1a03d6da9944a834a625d9f1e16dd1adef50 Mon Sep 17 00:00:00 2001
From: Tom Schumm <fwiffo@gmail.com>
Date: Mon, 2 Jul 2018 14:34:01 -0700
Subject: [PATCH 3/3] Exit gracefully when seed files can't be open for
 writing.

---
 finders.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/finders.c b/finders.c
index 81beca0..0f7da93 100644
--- a/finders.c
+++ b/finders.c
@@ -531,6 +531,10 @@ static void *baseQuadTempleSearchThread(void *data)
     sprintf(fnam, "%s.part%d", info.fnam, info.threadID);
 
     FILE *fp = fopen(fnam, "a+");
+    if (fp == NULL) {
+        fprintf(stderr, "Could not open \"%s\" for writing.\n", fnam);
+        exit(-1);
+    }
 
     seed = start;
 
@@ -617,6 +621,10 @@ void baseQuadTempleSearch(const char *fnam, const int threads, const int quality
     char fnamThread[256];
     char buffer[4097];
     FILE *fp = fopen(fnam, "w");
+    if (fp == NULL) {
+        fprintf(stderr, "Could not open \"%s\" for writing.\n", fnam);
+        exit(-1);
+    }
     FILE *fpart;
     int n;