Share LZMS x86 filter between compressor and decompressor

[wimlib] / src / lzms-decompress.c

diff --git a/src/lzms-decompress.c b/src/lzms-decompress.c
index 40d35bf6e2610e945a1034f19dc303e40ffa7d2b..4d87e658fbc05e66983f9ba8c8a37834229afd27 100644 (file)
--- a/src/lzms-decompress.c
+++ b/src/lzms-decompress.c
@@ -1112,132 +1112,6 @@ lzms_decode_items(const u8 *cdata, size_t clen, u8 *ubuf, size_t ulen,
        return 0;
 }
 
        return 0;
 }
 

-static s32
-lzms_try_x86_translation(u8 *ubuf, s32 i, s32 num_op_bytes,
-                        s32 *closest_target_usage_p, s32 last_target_usages[],
-                        s32 max_trans_offset)
-{
-       u16 pos;
-
-       if (i - *closest_target_usage_p <= max_trans_offset) {
-               LZMS_DEBUG("Performed x86 translation at position %d "
-                          "(opcode 0x%02x)", i, ubuf[i]);
-               le32 *p32 = (le32*)&ubuf[i + num_op_bytes];
-               u32 n = le32_to_cpu(*p32);
-               *p32 = cpu_to_le32(n - i);
-       }
-
-       pos = i + le16_to_cpu(*(const le16*)&ubuf[i + num_op_bytes]);
-
-       i += num_op_bytes + sizeof(le32) - 1;
-
-       if (i - last_target_usages[pos] <= LZMS_X86_MAX_GOOD_TARGET_OFFSET)
-               *closest_target_usage_p = i;
-
-       last_target_usages[pos] = i;
-
-       return i + 1;
-}
-
-static s32
-lzms_process_x86_translation(u8 *ubuf, s32 i, s32 *closest_target_usage_p,
-                            s32 last_target_usages[])
-{
-       /* Switch on first byte of the opcode, assuming it is really an x86
-        * instruction.  */
-       switch (ubuf[i]) {
-       case 0x48:
-               if (ubuf[i + 1] == 0x8b) {
-                       if (ubuf[i + 2] == 0x5 || ubuf[i + 2] == 0xd) {
-                               /* Load relative (x86_64)  */
-                               return lzms_try_x86_translation(ubuf, i, 3,
-                                                               closest_target_usage_p,
-                                                               last_target_usages,
-                                                               LZMS_X86_MAX_TRANSLATION_OFFSET);
-                       }
-               } else if (ubuf[i + 1] == 0x8d) {
-                       if ((ubuf[i + 2] & 0x7) == 0x5) {
-                               /* Load effective address relative (x86_64)  */
-                               return lzms_try_x86_translation(ubuf, i, 3,
-                                                               closest_target_usage_p,
-                                                               last_target_usages,
-                                                               LZMS_X86_MAX_TRANSLATION_OFFSET);
-                       }
-               }
-               break;
-
-       case 0x4c:
-               if (ubuf[i + 1] == 0x8d) {
-                       if ((ubuf[i + 2] & 0x7) == 0x5) {
-                               /* Load effective address relative (x86_64)  */
-                               return lzms_try_x86_translation(ubuf, i, 3,
-                                                               closest_target_usage_p,
-                                                               last_target_usages,
-                                                               LZMS_X86_MAX_TRANSLATION_OFFSET);
-                       }
-               }
-               break;
-
-       case 0xe8:
-               /* Call relative  */
-               return lzms_try_x86_translation(ubuf, i, 1, closest_target_usage_p,
-                                               last_target_usages,
-                                               LZMS_X86_MAX_TRANSLATION_OFFSET / 2);
-
-       case 0xe9:
-               /* Jump relative  */
-               return i + 5;
-
-       case 0xf0:
-               if (ubuf[i + 1] == 0x83 && ubuf[i + 2] == 0x05) {
-                       /* Lock add relative  */
-                       return lzms_try_x86_translation(ubuf, i, 3,
-                                                       closest_target_usage_p,
-                                                       last_target_usages,
-                                                       LZMS_X86_MAX_TRANSLATION_OFFSET);
-               }
-               break;
-
-       case 0xff:
-               if (ubuf[i + 1] == 0x15) {
-                       /* Call indirect  */
-                       return lzms_try_x86_translation(ubuf, i, 2,
-                                                       closest_target_usage_p,
-                                                       last_target_usages,
-                                                       LZMS_X86_MAX_TRANSLATION_OFFSET);
-               }
-               break;
-       }
-       return i + 1;
-}
-
-/* Postprocess the uncompressed data by undoing the translation of relative
- * addresses embedded in x86 instructions into absolute addresses.
- *
- * There does not appear to be any way to check to see if this postprocessing
- * actually needs to be done (or to plug in alternate filters, like in LZMA),
- * and the corresponding preprocessing seems to be done unconditionally.  */
-static void
-lzms_postprocess_data(u8 *ubuf, s32 ulen, s32 *last_target_usages)
-{
-       /* Offset (from beginning of buffer) of the most recent reference to a
-        * seemingly valid target address.  */
-       s32 closest_target_usage = -LZMS_X86_MAX_TRANSLATION_OFFSET - 1;
-
-       /* Initialize the last_target_usages array.  Each entry will contain the
-        * offset (from beginning of buffer) of the most recently used target
-        * address beginning with two bytes equal to the array index.  */
-       for (s32 i = 0; i < 65536; i++)
-               last_target_usages[i] = -LZMS_X86_MAX_GOOD_TARGET_OFFSET - 1;
-
-       /* Check each byte in the buffer for an x86 opcode for which a
-        * translation may be possible.  No translations are done on any
-        * instructions starting in the last 11 bytes of the buffer.  */
-       for (s32 i = 0; i < ulen - 11; )
-               i = lzms_process_x86_translation(ubuf, i, &closest_target_usage,
-                                                last_target_usages);
-}
-

 static int
 lzms_decompress(const void *compressed_data, size_t compressed_size,
                void *uncompressed_data, size_t uncompressed_size, void *_ctx)
 static int
 lzms_decompress(const void *compressed_data, size_t compressed_size,
                void *uncompressed_data, size_t uncompressed_size, void *_ctx)


@@ -1281,8 +1155,8 @@ lzms_decompress(const void *compressed_data, size_t compressed_size,
                return -1;
 
        /* Postprocess the data.  */
                return -1;
 
        /* Postprocess the data.  */

-       lzms_postprocess_data(uncompressed_data, uncompressed_size,
-                             ctx->last_target_usages);
+       lzms_x86_filter(uncompressed_data, uncompressed_size,
+                       ctx->last_target_usages, true);

 
        LZMS_DEBUG("Decompression successful.");
        return 0;
 
        LZMS_DEBUG("Decompression successful.");
        return 0;