From 9f835f898c45670251836cc9219f632429cc4871 Mon Sep 17 00:00:00 2001
From: Steven Schveighoffer <schveiguy@gmail.com>
Date: Wed, 8 Mar 2023 13:56:56 -0500
Subject: [PATCH] Used max instead of min by accident. Fix unittest to pass on
 Apple M1

---
 source/iopipe/buffer.d   | 22 ++++++++++++----------
 source/iopipe/textpipe.d |  4 ++--
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/source/iopipe/buffer.d b/source/iopipe/buffer.d
index be32bea..602adb1 100644
--- a/source/iopipe/buffer.d
+++ b/source/iopipe/buffer.d
@@ -547,28 +547,30 @@ private:
 {
     RingBuffer!(ubyte, 8192) buf;
     assert(buf.extend(4096) == 4096);
-    assert(buf.avail == 8192 - 4096);
-    assert(buf.capacity == 8192);
+    // some systems do not have a page size of 4k
+    auto cap = buf.capacity;
+    assert(cap >= 8192);
+    assert(buf.avail == cap - 4096);
     buf.window[0] = 0;
-    assert(buf.buffer.length == 8192 * 2);
+    assert(buf.buffer.length == cap * 2);
 
     assert(buf.extend(4096) == 4096);
-    assert(buf.avail == 0);
-    assert(buf.capacity == 8192);
+    assert(buf.avail == cap - 8192);
+    assert(buf.capacity == cap);
 
     buf.releaseFront(4096);
-    assert(buf.avail == 4096);
-    assert(buf.capacity == 8192);
+    assert(buf.avail == cap - 4096);
+    assert(buf.capacity == cap);
     assert(buf.extend(4096) == 4096);
-    assert(buf.avail == 0);
-    assert(buf.capacity == 8192);
+    assert(buf.avail == cap - 8192);
+    assert(buf.capacity == cap);
     import std.algorithm : copy, map, equal;
     import std.range : iota;
     iota(8192).map!(a => cast(ubyte)a).copy(buf.window);
     assert(equal(iota(8192).map!(a => cast(ubyte)a), buf.window));
     buf.releaseFront(4096);
     assert(equal(iota(4096, 8192).map!(a => cast(ubyte)a), buf.window));
-    assert(buf.released == 0); // assure we wrap around
+    assert(buf.released <= cap); // assure we wrap around
     assert(buf.extend(8192) == 8192);
     assert(equal(iota(4096, 8192).map!(a => cast(ubyte)a), buf.window[0 .. 4096]));
 }
diff --git a/source/iopipe/textpipe.d b/source/iopipe/textpipe.d
index 1fa1ada..368fa91 100644
--- a/source/iopipe/textpipe.d
+++ b/source/iopipe/textpipe.d
@@ -934,14 +934,14 @@ template textConverter(bool ensureBOM = false, Chain)
             static if(is(Unqual!Char == Unqual!SrcChar))
             {
                 import std.algorithm.mutation: copy;
-                import std.algorithm.comparison: max;
+                import std.algorithm.comparison: min;
                 // try an extend when window length gets to be less than read size.
                 if(chain.window.length < buf.length)
                     chain.extend(buf.length - chain.window.length);
                 if(chain.window.length == 0)
                     // no more data
                     return 0;
-                immutable len = max(chain.window.length, buf.length);
+                immutable len = min(chain.window.length, buf.length);
                 copy(chain.window[0 .. len], buf[0 .. len]);
                 chain.release(len);
                 return result + len;