7zip reader: add 7z ARM filter support for copy/bzip2/deflate/zstd

This makes the new test_read_format_7zip_zstd_arm test pass. I expect
that the other compression algorithms in this group should also work
now.

diff --git a/libarchive/archive_read_support_format_7zip.c b/libarchive/archive_read_support_format_7zip.c
index a0553c7eee505e5fc0fe1d74ddb6de3e48255abf..df6f035ed782af369bf2acb0d73e3a2b3eb07e5e 100644 (file)
--- a/libarchive/archive_read_support_format_7zip.c
+++ b/libarchive/archive_read_support_format_7zip.c
@@ -407,6 +407,8 @@ static int  setup_decode_folder(struct archive_read *, struct _7z_folder *,
                    int);
 static void    x86_Init(struct _7zip *);
 static size_t  x86_Convert(struct _7zip *, uint8_t *, size_t);
+static void    arm_Init(struct _7zip *);
+static size_t  arm_Convert(struct _7zip *, uint8_t *, size_t);
 static ssize_t         Bcj2_Decode(struct _7zip *, uint8_t *, size_t);
 
 
@@ -1041,7 +1043,8 @@ init_decompression(struct archive_read *a, struct _7zip *zip,
        case _7Z_PPMD:
                if (coder2 != NULL) {
                        if (coder2->codec != _7Z_X86 &&
-                           coder2->codec != _7Z_X86_BCJ2) {
+                           coder2->codec != _7Z_X86_BCJ2 &&
+                           coder2->codec != _7Z_ARM) {
                                archive_set_error(&a->archive,
                                    ARCHIVE_ERRNO_MISC,
                                    "Unsupported filter %lx for %lx",
@@ -1052,6 +1055,8 @@ init_decompression(struct archive_read *a, struct _7zip *zip,
                        zip->bcj_state = 0;
                        if (coder2->codec == _7Z_X86)
                                x86_Init(zip);
+                       else if (coder2->codec == _7Z_ARM)
+                               arm_Init(zip);
                }
                break;
        default:
@@ -1615,16 +1620,21 @@ decompress(struct archive_read *a, struct _7zip *zip,
        /*
         * Decord BCJ.
         */
-       if (zip->codec != _7Z_LZMA2 && zip->codec2 == _7Z_X86) {
-               size_t l = x86_Convert(zip, buff, *outbytes);
-               zip->odd_bcj_size = *outbytes - l;
-               if (zip->odd_bcj_size > 0 && zip->odd_bcj_size <= 4 &&
-                   o_avail_in && ret != ARCHIVE_EOF) {
-                       memcpy(zip->odd_bcj, ((unsigned char *)buff) + l,
-                           zip->odd_bcj_size);
-                       *outbytes = l;
-               } else
-                       zip->odd_bcj_size = 0;
+       if (zip->codec != _7Z_LZMA2 && (zip->codec2 == _7Z_X86 || zip->codec2 == _7Z_ARM)) {
+               if (zip->codec2 == _7Z_X86) {
+                       size_t l = x86_Convert(zip, buff, *outbytes);
+
+                       zip->odd_bcj_size = *outbytes - l;
+                       if (zip->odd_bcj_size > 0 && zip->odd_bcj_size <= 4 &&
+                       o_avail_in && ret != ARCHIVE_EOF) {
+                               memcpy(zip->odd_bcj, ((unsigned char *)buff) + l,
+                               zip->odd_bcj_size);
+                               *outbytes = l;
+                       } else
+                               zip->odd_bcj_size = 0;
+               } else { // zip->codec2 == _7Z_ARM
+                       *outbytes = arm_Convert(zip, buff, *outbytes);
+               }
        }
 
        /*
@@ -3770,6 +3780,53 @@ x86_Convert(struct _7zip *zip, uint8_t *data, size_t size)
        return (bufferPos);
 }
 
+static void
+arm_Init(struct _7zip *zip)
+{
+       zip->bcj_ip = 8;
+}
+
+static size_t
+arm_Convert(struct _7zip *zip, uint8_t *buf, size_t size)
+{
+       // This function was adapted from
+       // static size_t bcj_arm(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
+       // in https://git.tukaani.org/xz-embedded.git
+
+       /*
+        * Branch/Call/Jump (BCJ) filter decoders
+        *
+        * Authors: Lasse Collin <lasse.collin@tukaani.org>
+        *          Igor Pavlov <https://7-zip.org/>
+        *
+        * This file has been put into the public domain.
+        * You can do whatever you want with this file.
+        */
+
+       size_t i;
+       uint32_t addr;
+
+       for (i = 0; i + 4 <= size; i += 4) {
+               if (buf[i + 3] == 0xEB) {
+                       // Calculate the transformed addr.
+                       addr = (uint32_t)buf[i] | ((uint32_t)buf[i + 1] << 8)
+                               | ((uint32_t)buf[i + 2] << 16);
+                       addr <<= 2;
+                       addr -= zip->bcj_ip + (uint32_t)i;
+                       addr >>= 2;
+
+                       // Store the transformed addr in buf.
+                       buf[i] = (uint8_t)addr;
+                       buf[i + 1] = (uint8_t)(addr >> 8);
+                       buf[i + 2] = (uint8_t)(addr >> 16);
+               }
+       }
+
+       zip->bcj_ip += i;
+
+       return i;
+}
+
 /*
  * Brought from LZMA SDK.
  *