lzop: don't support ancient versions < 0.94 (15 Oct 1997)

0.94 came only 2 months after initial 0.90:

    0.90 (10 Aug 1997): First public release of lzop
    ...
    0.94 (15 Oct 1997): Header format change

function                                             old     new   delta
do_lzo_decompress                                    411     404      -7
f_read8                                               24       -     -24
f_read16                                              31       -     -31
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 0/1 up/down: 0/-62)             Total: -62 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/archival/lzop.c b/archival/lzop.c
index 419e1e21fdccbe3c6ff2f7a715bff7d37f7d2935..e724b9edf507704c971aaa935fe8b6fb269d9aa8 100644 (file)
--- a/archival/lzop.c
+++ b/archival/lzop.c
@@ -448,7 +448,7 @@ typedef struct header_t {
        uint16_t version_needed_to_extract_be16;
        uint8_t  method;
        uint8_t  level;
-       uint32_t flags32; /* be32 on disk, but we keep them in native order */
+       uint32_t flags32; /* be32 on disk, but we keep this field in native order */
        uint32_t mode_be32;
        uint32_t mtime_be32;
        uint32_t gmtdiff_be32;
@@ -577,18 +577,18 @@ static void f_read(void* buf, int cnt)
        xread(0, buf, cnt);
        add_bytes_to_chksum(buf, cnt);
 }
-static int f_read8(void)
-{
-       uint8_t v;
-       f_read(&v, 1);
-       return v;
-}
-static unsigned f_read16(void)
-{
-       uint16_t v;
-       f_read(&v, 2);
-       return ntohs(v);
-}
+//static int f_read8(void)
+//{
+//     uint8_t v;
+//     f_read(&v, 1);
+//     return v;
+//}
+//static unsigned f_read16(void)
+//{
+//     uint16_t v;
+//     f_read(&v, 2);
+//     return ntohs(v);
+//}
 static uint32_t f_read32(void)
 {
        uint32_t v;
@@ -928,66 +928,62 @@ static int read_header(header_t *h)
 {
        int l;
        uint32_t checksum;
+       /* As it stands now, only h->flags32 is used by our caller.
+        * Therefore we don't store many fields in h->FIELD.
+        */
        unsigned h_version;
-       uint8_t h_method, h_level;
+       unsigned h_version_needed_to_extract;
 
        init_chksum();
 
-       /* As it stands now, only h->flags32 is used by our caller.
-        * Therefore we don't store many fields in h->field.
+       /* We don't support versions < 0.94, since 0.94
+        * came only 2 months after 0.90:
+        * 0.90 (10 Aug 1997): First public release of lzop
+        * 0.94 (15 Oct 1997): Header format change
         */
-       h_version = f_read16();
-       if (h_version < 0x0900)
+
+       /* Read up to and including name length byte */
+       f_read(&h->version_be16, ((char*)&h->len_and_name[1]) - ((char*)&h->version_be16));
+
+       h_version = htons(h->version_be16);
+       if (h_version < 0x0940)
+               return 3;
+       h_version_needed_to_extract = htons(h->version_needed_to_extract_be16);
+       if (h_version_needed_to_extract > LZOP_VERSION)
+               return 16;
+       if (h_version_needed_to_extract < 0x0940)
                return 3;
-       /* UNUSED h->lib_version_be16 = */ f_read16();
-       if (h_version >= 0x0940) {
-               unsigned h_version_needed_to_extract = f_read16();
-               if (h_version_needed_to_extract > LZOP_VERSION)
-                       return 16;
-               if (h_version_needed_to_extract < 0x0900) /* first lzop version */
-                       return 3;
-       }
 
-       h_method = f_read8();
-       if (h_method <= 0)
+       if (h->method <= 0)
                return 14;
-       h_level = 0;
-       if (h_version >= 0x0940)
-               h_level = f_read8();
 
        /* former lzo_get_method(h): */
-       if (h_method == M_LZO1X_1) {
-               if (h_level == 0)
-                       h_level = 3;
-       } else if (h_method == M_LZO1X_1_15) {
-               if (h_level == 0)
-                       h_level = 1;
-       } else if (h_method == M_LZO1X_999) {
-               if (h_level == 0)
-                       h_level = 9;
+       if (h->method == M_LZO1X_1) {
+               if (h->level == 0)
+                       h->level = 3;
+       } else if (h->method == M_LZO1X_1_15) {
+               if (h->level == 0)
+                       h->level = 1;
+       } else if (h->method == M_LZO1X_999) {
+               if (h->level == 0)
+                       h->level = 9;
        } else
                return -1; /* not a LZO method */
        /* check compression level */
-       if (h_level < 1 || h_level > 9)
+       if (h->level < 1 || h->level > 9)
                return 15;
 
-       h->flags32 = f_read32();
+       h->flags32 = ntohl(h->flags32);
        if (h->flags32 & F_H_FILTER)
                return 16; /* filter not supported */
        /* check reserved flags */
        if (h->flags32 & F_RESERVED)
                return -13;
 
-       /* UNUSED h->mode = */ f_read32();
-       /* UNUSED h->mtime = */ f_read32();
-       if (h_version >= 0x0940)
-               /* UNUSED h->gmtdiff = */ f_read32();
-
-       l = f_read8();
-       /* UNUSED h->len_and_name[0] = l; */
-       /* UNUSED h->len_and_name[1+l] = 0; */
+       l = h->len_and_name[0];
        if (l > 0)
-               f_read(h->len_and_name+1, l);
+               /* UNUSED */ f_read(h->len_and_name+1, l);
+       /* UNUSED h->len_and_name[1+l] = 0; */
 
        checksum = chksum_getresult(h->flags32);
        if (f_read32() != checksum)
@@ -998,12 +994,13 @@ static int read_header(header_t *h)
                uint32_t extra_field_len;
                uint32_t extra_field_checksum;
                uint32_t k;
+               char dummy;
 
                /* note: the checksum also covers the length */
                init_chksum();
                extra_field_len = f_read32();
                for (k = 0; k < extra_field_len; k++)
-                       f_read8();
+                       f_read(&dummy, 1);
                checksum = chksum_getresult(h->flags32);
                extra_field_checksum = f_read32();
                if (extra_field_checksum != checksum)