POSIX GNU tar read support

- supporting tared csm.bin of Chasm: The Rift Remastered at https://store.steampowered.com/app/2061230/Chasm_The_Rift/
- Thanks to @sezero for OS/2 and Windows fixes

CMakeLists.txt

@@ -92,6 +92,7 @@ set(PHYSFS_SRCS
     src/physfs_archiver_qpak.c
     src/physfs_archiver_wad.c
     src/physfs_archiver_csm.c
+    src/physfs_archiver_tar.c
     src/physfs_archiver_zip.c
     src/physfs_archiver_slb.c
     src/physfs_archiver_iso9660.c
@@ -130,6 +131,11 @@ if(NOT PHYSFS_ARCHIVE_CSM)
     add_definitions(-DPHYSFS_SUPPORTS_CSM=0)
 endif()
 
+option(PHYSFS_ARCHIVE_TAR "Enable POSIX TAR / Chasm: The Rift [Demo] Remastered csm.bin support" TRUE)
+if(NOT PHYSFS_ARCHIVE_TAR)
+    add_definitions(-DPHYSFS_SUPPORTS_TAR=0)
+endif()
+
 option(PHYSFS_ARCHIVE_HOG "Enable Descent I/II HOG support" TRUE)
 if(NOT PHYSFS_ARCHIVE_HOG)
     add_definitions(-DPHYSFS_SUPPORTS_HOG=0)
@@ -325,6 +331,7 @@ message_bool_option("7zip support" PHYSFS_ARCHIVE_7Z)
 message_bool_option("GRP support" PHYSFS_ARCHIVE_GRP)
 message_bool_option("WAD support" PHYSFS_ARCHIVE_WAD)
 message_bool_option("CSM support" PHYSFS_ARCHIVE_CSM)
+message_bool_option("TAR support" PHYSFS_ARCHIVE_TAR)
 message_bool_option("HOG support" PHYSFS_ARCHIVE_HOG)
 message_bool_option("MVL support" PHYSFS_ARCHIVE_MVL)
 message_bool_option("QPAK support" PHYSFS_ARCHIVE_QPAK)

src/Makefile.os2

@@ -26,6 +26,7 @@ SRCS = physfs.c                   &
        physfs_archiver_slb.c      &
        physfs_archiver_iso9660.c  &
        physfs_archiver_csm.c      &
+       physfs_archiver_tar.c      &
        physfs_archiver_vdf.c
 
 

src/physfs.c

@@ -1191,6 +1191,9 @@ static int initStaticArchivers(void)
     #if PHYSFS_SUPPORTS_CSM
         REGISTER_STATIC_ARCHIVER(CSM);
     #endif
+    #if PHYSFS_SUPPORTS_TAR
+        REGISTER_STATIC_ARCHIVER(TAR);
+    #endif
     #if PHYSFS_SUPPORTS_SLB
         REGISTER_STATIC_ARCHIVER(SLB);
     #endif

src/physfs_archiver_tar.c

@@ -0,0 +1,109 @@
+/*
+ * tar support routines for PhysicsFS.
+ *
+ * Please see the file LICENSE.txt in the source's root directory.
+ *
+ * based on code by Uli Köhler: https://techoverflow.net/2013/03/29/reading-tar-files-in-c/
+ */
+
+#define __PHYSICSFS_INTERNAL__
+#include "physfs_internal.h"
+
+#if PHYSFS_SUPPORTS_TAR
+#include "physfs_tar.h"
+
+static bool TAR_loadEntries(PHYSFS_Io *io, void *arc)
+{
+	union block zero_block;
+	union block current_block;
+	PHYSFS_uint64 count = 0;
+	bool long_name = false;
+
+	memset(zero_block.buffer, 0, sizeof(BLOCKSIZE));
+	memset(current_block.buffer, 0, sizeof(BLOCKSIZE));
+
+	/* read header block until zero-only terminated block */
+	for(; __PHYSFS_readAll(io, current_block.buffer, BLOCKSIZE); count++)
+	{
+		if( memcmp(current_block.buffer, zero_block.buffer, BLOCKSIZE) == 0 )
+			return true;
+
+		/* verify magic */
+		switch(TAR_magic(&current_block))
+		{
+			case POSIX_FORMAT:
+				TAR_posix_block(io, arc, &current_block, &count, &long_name);
+				break;
+			case OLDGNU_FORMAT:
+				break;
+			case GNU_FORMAT:
+				break;
+			case V7_FORMAT:
+				break;
+			case USTAR_FORMAT:
+				break;
+			case STAR_FORMAT:
+				break;
+			default:
+				break;
+		}
+	}
+
+	return false;
+}
+
+static void *TAR_openArchive(PHYSFS_Io *io, const char *name,
+                              int forWriting, int *claimed)
+{
+    void *unpkarc = NULL;
+    union block first;
+    enum archive_format format;
+
+    assert(io != NULL);  /* shouldn't ever happen. */
+
+    BAIL_IF(forWriting, PHYSFS_ERR_READ_ONLY, NULL);
+
+    BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, first.buffer, BLOCKSIZE), NULL);
+    format = TAR_magic(&first);
+    io->seek(io, 0);
+    *claimed = format == DEFAULT_FORMAT ? 0 : 1;
+
+    unpkarc = UNPK_openArchive(io, 0, 1);
+    BAIL_IF_ERRPASS(!unpkarc, NULL);
+
+    if (!TAR_loadEntries(io, unpkarc))
+    {
+        UNPK_abandonArchive(unpkarc);
+        return NULL;
+    } /* if */
+
+
+    return unpkarc;
+} /* TAR_openArchive */
+
+
+const PHYSFS_Archiver __PHYSFS_Archiver_TAR =
+{
+    CURRENT_PHYSFS_ARCHIVER_API_VERSION,
+    {
+        "TAR",
+        "POSIX tar archives / Chasm: the Rift Remastered",
+        "Jon Daniel <[email protected]>",
+	"http://www.gnu.org/software/tar/",
+        0,
+    },
+    TAR_openArchive,
+    UNPK_enumerate,
+    UNPK_openRead,
+    UNPK_openWrite,
+    UNPK_openAppend,
+    UNPK_remove,
+    UNPK_mkdir,
+    UNPK_stat,
+    UNPK_closeArchive
+};
+
+#endif  /* defined PHYSFS_SUPPORTS_TAR */
+
+/* end of physfs_archiver_tar.c ... */
+

src/physfs_internal.h

@@ -89,6 +89,7 @@ extern const PHYSFS_Archiver __PHYSFS_Archiver_HOG;
 extern const PHYSFS_Archiver __PHYSFS_Archiver_MVL;
 extern const PHYSFS_Archiver __PHYSFS_Archiver_WAD;
 extern const PHYSFS_Archiver __PHYSFS_Archiver_CSM;
+extern const PHYSFS_Archiver __PHYSFS_Archiver_TAR;
 extern const PHYSFS_Archiver __PHYSFS_Archiver_SLB;
 extern const PHYSFS_Archiver __PHYSFS_Archiver_ISO9660;
 extern const PHYSFS_Archiver __PHYSFS_Archiver_VDF;
@@ -204,6 +205,9 @@ void __PHYSFS_smallFree(void *ptr);
 #ifndef PHYSFS_SUPPORTS_CSM
 #define PHYSFS_SUPPORTS_CSM PHYSFS_SUPPORTS_DEFAULT
 #endif
+#ifndef PHYSFS_SUPPORTS_TAR
+#define PHYSFS_SUPPORTS_TAR PHYSFS_SUPPORTS_DEFAULT
+#endif
 #ifndef PHYSFS_SUPPORTS_QPAK
 #define PHYSFS_SUPPORTS_QPAK PHYSFS_SUPPORTS_DEFAULT
 #endif