7zip reader: add support for zstandard compression in 7z archives

Zstandard support is not yet available in 7-Zip, though it is planned
for a future release:
https://sourceforge.net/p/sevenzip/feature-requests/1580/

The compression ID used here (4F71101) is copied from a popular 7-Zip
fork, which added ZSTD support back in 2017, and is mentioned in the
upstream 7-Zip ticket linked above:
https://github.com/mcmilk/7-Zip-zstd.git

Note that this does not add write support for Zstandard compression
in 7z archives.

Relates to #1656.

diff --git a/README.md b/README.md
index 4040762378714f35bfad14698838cb7847d9002f..37973be249129f2e47217a1e630d2d3fd969c8ad 100644 (file)
--- a/README.md
+++ b/README.md
@@ -87,7 +87,7 @@ Currently, the library automatically detects and reads the following formats:
   * ZIPX archives (with support for bzip2, ppmd8, lzma and xz compressed entries)
   * GNU and BSD 'ar' archives
   * 'mtree' format
-  * 7-Zip archives
+  * 7-Zip archives (including archives that use zstandard compression)
   * Microsoft CAB format
   * LHA and LZH archives
   * RAR and RAR 5.0 archives (with some limitations due to RAR's proprietary status)

diff --git a/libarchive/archive_read_support_format_7zip.c b/libarchive/archive_read_support_format_7zip.c
index 0ba4bee358b21067330465adb42c54dd90d5e41f..a0553c7eee505e5fc0fe1d74ddb6de3e48255abf 100644 (file)
--- a/libarchive/archive_read_support_format_7zip.c
+++ b/libarchive/archive_read_support_format_7zip.c
@@ -41,6 +41,9 @@ __FBSDID("$FreeBSD$");
 #ifdef HAVE_ZLIB_H
 #include <zlib.h>
 #endif
+#ifdef HAVE_ZSTD_H
+#include <zstd.h>
+#endif
 
 #include "archive.h"
 #include "archive_entry.h"
@@ -82,6 +85,8 @@ __FBSDID("$FreeBSD$");
 #define _7Z_ARMTHUMB   0x03030701
 #define _7Z_SPARC      0x03030805
 
+#define _7Z_ZSTD       0x4F71101 /* Copied from https://github.com/mcmilk/7-Zip-zstd.git */
+
 /*
  * 7-Zip header property IDs.
  */
@@ -277,6 +282,11 @@ struct _7zip {
 #ifdef HAVE_ZLIB_H
        z_stream                 stream;
        int                      stream_valid;
+#endif
+       /* Decoding Zstandard data. */
+#if HAVE_ZSTD_H
+       ZSTD_DStream             *zstd_dstream;
+       int                      zstdstream_valid;
 #endif
        /* Decoding PPMd data. */
        int                      ppmd7_stat;
@@ -1027,6 +1037,7 @@ init_decompression(struct archive_read *a, struct _7zip *zip,
        case _7Z_COPY:
        case _7Z_BZ2:
        case _7Z_DEFLATE:
+       case _7Z_ZSTD:
        case _7Z_PPMD:
                if (coder2 != NULL) {
                        if (coder2->codec != _7Z_X86 &&
@@ -1222,6 +1233,22 @@ init_decompression(struct archive_read *a, struct _7zip *zip,
                    "BZ2 codec is unsupported");
                return (ARCHIVE_FAILED);
 #endif
+       case _7Z_ZSTD:
+       {
+#if defined(HAVE_ZSTD_H)
+               if (zip->zstdstream_valid) {
+                       ZSTD_freeDStream(zip->zstd_dstream);
+                       zip->zstdstream_valid = 0;
+               }
+               zip->zstd_dstream = ZSTD_createDStream();
+               zip->zstdstream_valid = 1;
+               break;
+#else
+               archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
+                       "ZSTD codec is unsupported");
+               return (ARCHIVE_FAILED);
+#endif
+       }
        case _7Z_DEFLATE:
 #ifdef HAVE_ZLIB_H
                if (zip->stream_valid)
@@ -1487,6 +1514,22 @@ decompress(struct archive_read *a, struct _7zip *zip,
                t_avail_in = zip->stream.avail_in;
                t_avail_out = zip->stream.avail_out;
                break;
+#endif
+#ifdef HAVE_ZSTD_H
+       case _7Z_ZSTD:
+       {
+               ZSTD_inBuffer input = { t_next_in, t_avail_in, 0 }; // src, size, pos
+               ZSTD_outBuffer output = { t_next_out, t_avail_out, 0 }; // dst, size, pos
+
+               size_t const zret = ZSTD_decompressStream(zip->zstd_dstream, &output, &input);
+               if (ZSTD_isError(zret)) {
+                       archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, "Zstd decompression failed: %s", ZSTD_getErrorName(zret));
+                       return ARCHIVE_FAILED;
+               }
+               t_avail_in -= input.pos;
+               t_avail_out -= output.pos;
+               break;
+       }
 #endif
        case _7Z_PPMD:
        {