Add lzma decompression support (Christoph Biedl)

diff --git a/src/compress.c b/src/compress.c
index 95e42a24dd5229af8ae50b77a1d7258e9a7648ab..316a165a8718e573d6b1d78330269e929d9eeb9d 100644 (file)
--- a/src/compress.c
+++ b/src/compress.c
@@ -35,7 +35,7 @@
 #include "file.h"
 
 #ifndef lint
-FILE_RCSID("@(#)$File: compress.c,v 1.121 2019/05/07 02:27:11 christos Exp $")
+FILE_RCSID("@(#)$File: compress.c,v 1.122 2019/07/18 15:43:54 christos Exp $")
 #endif
 
 #include "magic.h"
@@ -113,6 +113,16 @@ zlibcmp(const unsigned char *buf)
 }
 #endif
 
+static int
+lzmacmp(const unsigned char *buf)
+{
+       if (buf[0] != 0x5d || buf[1] || buf[2])
+               return 0;
+       if (buf[12] && buf[12] != 0xff)
+               return 0;
+       return 1;
+}
+
 #define gzip_flags "-cd"
 #define lrzip_flags "-do"
 #define lzip_flags gzip_flags
@@ -147,29 +157,30 @@ static const char *zstd_args[] = {
 
 private const struct {
        const void *magic;
-       size_t maglen;
+       int maglen;
        const char **argv;
        void *unused;
 } compr[] = {
-       { "\037\235",   2, gzip_args, NULL },           /* compressed */
+       { "\037\235",   2, gzip_args, NULL },           /* 0, compressed */
        /* Uncompress can get stuck; so use gzip first if we have it
         * Idea from Damien Clark, thanks! */
-       { "\037\235",   2, uncompress_args, NULL },     /* compressed */
-       { "\037\213",   2, gzip_args, do_zlib },        /* gzipped */
-       { "\037\236",   2, gzip_args, NULL },           /* frozen */
-       { "\037\240",   2, gzip_args, NULL },           /* SCO LZH */
+       { "\037\235",   2, uncompress_args, NULL },     /* 1, compressed */
+       { "\037\213",   2, gzip_args, do_zlib },        /* 2, gzipped */
+       { "\037\236",   2, gzip_args, NULL },           /* 3, frozen */
+       { "\037\240",   2, gzip_args, NULL },           /* 4, SCO LZH */
        /* the standard pack utilities do not accept standard input */
-       { "\037\036",   2, gzip_args, NULL },           /* packed */
-       { "PK\3\4",     4, gzip_args, NULL },           /* pkzipped, */
+       { "\037\036",   2, gzip_args, NULL },           /* 5, packed */
+       { "PK\3\4",     4, gzip_args, NULL },           /* 6, pkzipped, */
        /* ...only first file examined */
-       { "BZh",        3, bzip2_args, do_bzlib },      /* bzip2-ed */
-       { "LZIP",       4, lzip_args, NULL },           /* lzip-ed */
-       { "\3757zXZ\0", 6, xz_args, NULL },             /* XZ Utils */
-       { "LRZI",       4, lrzip_args, NULL },  /* LRZIP */
-       { "\004\"M\030",4, lz4_args, NULL },            /* LZ4 */
-       { "\x28\xB5\x2F\xFD", 4, zstd_args, NULL },     /* zstd */
+       { "BZh",        3, bzip2_args, do_bzlib },      /* 7, bzip2-ed */
+       { "LZIP",       4, lzip_args, NULL },           /* 8, lzip-ed */
+       { "\3757zXZ\0", 6, xz_args, NULL },             /* 9, XZ Utils */
+       { "LRZI",       4, lrzip_args, NULL },  /* 10, LRZIP */
+       { "\004\"M\030",4, lz4_args, NULL },            /* 11, LZ4 */
+       { "\x28\xB5\x2F\xFD", 4, zstd_args, NULL },     /* 12, zstd */
+       { RCAST(const void *, lzmacmp), -13, xz_args, NULL },   /* 13, lzma */
 #ifdef ZLIBSUPPORT
-       { RCAST(const void *, zlibcmp), 0, zlib_args, NULL },   /* zlib */
+       { RCAST(const void *, zlibcmp), -2, zlib_args, NULL },  /* 14, zlib */
 #endif
 };
 
@@ -234,15 +245,15 @@ file_zmagic(struct magic_set *ms, const struct buffer *b, const char *name)
 
        for (i = 0; i < ncompr; i++) {
                int zm;
-               if (nbytes < compr[i].maglen)
+               if (nbytes < CAST(size_t, abs(compr[i].maglen)))
                        continue;
-#ifdef ZLIBSUPPORT
-               if (compr[i].maglen == 0)
+               if (compr[i].maglen < 0) {
                        zm = (RCAST(int (*)(const unsigned char *),
                            CCAST(void *, compr[i].magic)))(buf);
-               else
-#endif
-                       zm = memcmp(buf, compr[i].magic, compr[i].maglen) == 0;
+               } else {
+                       zm = memcmp(buf, compr[i].magic,
+                           CAST(size_t, compr[i].maglen)) == 0;
+               }
 
                if (!zm)
                        continue;