From 536075b00a3d36973b123b5d54f32cc2b7ee3b58 Mon Sep 17 00:00:00 2001
From: GenericHeroGuy <genericheroguy@noreply.codeberg.org>
Date: Tue, 13 May 2025 22:28:29 +0200
Subject: [PATCH] Add string buffer library

---
 src/Sourcefile |  1 +
 src/strbuf.c   | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/strbuf.h   | 29 ++++++++++++++++++++++++++
 src/typedef.h  |  3 +++
 4 files changed, 88 insertions(+)
 create mode 100644 src/strbuf.c
 create mode 100644 src/strbuf.h

diff --git a/src/Sourcefile b/src/Sourcefile
index 36b9a0e79..e8e6eb5f7 100644
--- a/src/Sourcefile
+++ b/src/Sourcefile
@@ -1,5 +1,6 @@
 qs22j.c
 string.c
+strbuf.c
 d_main.cpp
 d_clisrv.c
 d_net.c
diff --git a/src/strbuf.c b/src/strbuf.c
new file mode 100644
index 000000000..a38db9aad
--- /dev/null
+++ b/src/strbuf.c
@@ -0,0 +1,55 @@
+// BLANKART
+//-----------------------------------------------------------------------------
+// Copyright (C) 2025 by Team BlanKart.
+//
+// This program is free software distributed under the
+// terms of the GNU General Public License, version 2.
+// See the 'LICENSE' file for more details.
+//-----------------------------------------------------------------------------
+/// \file  strbuf.c
+/// \brief string buffer library, for making chunks of many small strings
+
+#include "doomdef.h"
+#include "strbuf.h"
+#include "z_zone.h"
+
+#define STRBUF_BLOCKSIZE 16384 // 16K pages are the future, son!
+
+// allocates and returns a new string buffer
+// free with Z_Free
+strbuf_t *strbuf_alloc(void)
+{
+	strbuf_t *buf = Z_Malloc(STRBUF_BLOCKSIZE, PU_STATIC, NULL);
+	if (!buf)
+		I_Error("Failed to allocate string buffer");
+	buf->size = sizeof(UINT32);
+	return buf;
+}
+
+// appends a string to the buffer
+// returns an offset to the newly appended string
+UINT32 strbuf_append(strbuf_t **strbuf, const char *str)
+{
+	strbuf_t *buf = *strbuf;
+	size_t addbytes = strlen(str) + 1;
+	UINT32 oldsize = buf->size;
+
+	buf->size += addbytes;
+	if ((oldsize % STRBUF_BLOCKSIZE) + addbytes >= STRBUF_BLOCKSIZE) {
+		UINT32 newsize = buf->size + STRBUF_BLOCKSIZE - (buf->size % STRBUF_BLOCKSIZE);
+		if (newsize <= oldsize)
+			I_Error("String buffer size wrapped around!?");
+		buf = *strbuf = Z_Realloc(buf, newsize, PU_STATIC, NULL);
+		if (!buf)
+			I_Error("Failed to allocate string buffer");
+	}
+
+	strcpy(buf->buf - sizeof(UINT32) + oldsize, str);
+	return oldsize;
+}
+
+// returns the string at the given offset
+char *strbuf_get(strbuf_t *strbuf, UINT32 ofs)
+{
+	return strbuf->buf - sizeof(UINT32) + ofs;
+}
diff --git a/src/strbuf.h b/src/strbuf.h
new file mode 100644
index 000000000..238e5bf7f
--- /dev/null
+++ b/src/strbuf.h
@@ -0,0 +1,29 @@
+// BLANKART
+//-----------------------------------------------------------------------------
+// Copyright (C) 2025 by Team BlanKart.
+//
+// This program is free software distributed under the
+// terms of the GNU General Public License, version 2.
+// See the 'LICENSE' file for more details.
+//-----------------------------------------------------------------------------
+/// \file  strbuf.h
+/// \brief string buffer library, for making chunks of many small strings
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// for simplicity's sake, the header is included in the size (keeps the allocation aligned!)
+struct strbuf_t
+{
+	UINT32 size;
+	char buf[];
+};
+
+strbuf_t *strbuf_alloc(void);
+UINT32 strbuf_append(strbuf_t **strbuf, const char *str);
+char *strbuf_get(strbuf_t *strbuf, UINT32 ofs);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/typedef.h b/src/typedef.h
index 467352019..312eaff03 100644
--- a/src/typedef.h
+++ b/src/typedef.h
@@ -393,6 +393,9 @@ TYPEDEF (vmode_t);
 // sounds.h
 TYPEDEF (sfxinfo_t);
 
+// strbuf.h
+TYPEDEF (strbuf_t);
+
 // taglist.h
 TYPEDEF (taglist_t);
 TYPEDEF (taggroup_t);