From d7a2b98b4d9ab773e16697f63d7be1d243f52b73 Mon Sep 17 00:00:00 2001
From: drmortalwombat <90205530+drmortalwombat@users.noreply.github.com>
Date: Wed, 12 Jun 2024 21:07:58 +0200
Subject: [PATCH] Add buffered lzo decompress

---
 include/oscar.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 include/oscar.h |  4 ++++
 2 files changed, 47 insertions(+)

diff --git a/include/oscar.c b/include/oscar.c
index 5704091..d2384b6 100644
--- a/include/oscar.c
+++ b/include/oscar.c
@@ -86,3 +86,46 @@ const char * oscar_expand_rle(char * dp, const char * sp)
 
 	return sp + 1;
 }
+
+__native const char * oscar_expand_lzo_buf(char * dp, const char * sp)
+{
+	char	buf[256];
+	char	b = 0;
+
+	char	cmd = sp[0];
+	do
+	{
+		if (cmd & 0x80)
+		{
+			char i = b - sp[1];
+			cmd &= 0x7f;
+			sp += 2;
+
+			char n = 0;
+			do 	{
+				buf[b] = dp[n] = buf[i];
+				b++;
+				i++;
+				n++;
+			} while (n != cmd);
+		}
+		else
+		{
+			sp += 1;
+
+			char n = 0;
+			do 	{
+				buf[b] = dp[n] = sp[n];
+				b++;
+				n++;
+			} while (n != cmd);
+
+			sp += cmd;
+		}
+		dp += cmd;
+
+		cmd = sp[0];
+	} while (cmd);
+
+	return sp + 1;
+}
diff --git a/include/oscar.h b/include/oscar.h
index 590867d..6101a06 100644
--- a/include/oscar.h
+++ b/include/oscar.h
@@ -6,6 +6,10 @@ __native const char * oscar_expand_lzo(char * dp, const char * sp);
 
 __native const char * oscar_expand_rle(char * dp, const char * sp);
 
+// Same as oscar_expand_lzo, but does not need read access to the
+// target memory area.  On the downside, it uses 256 bytes of stack
+// memory as buffer
+__native const char * oscar_expand_lzo_buf(char * dp, const char * sp);
 
 #pragma compile("oscar.c")