Fixes for issue 94.

3 files changed, 23 insertions, 25 deletions

diff --git a/xdelta3/xdelta3-decode.h b/xdelta3/xdelta3-decode.h
index ff5e999..542b6aa 100644
--- a/xdelta3/xdelta3-decode.h
+++ b/xdelta3/xdelta3-decode.h
@@ -904,7 +904,8 @@ xd3_decode_input (xd3_stream *stream)
             }
         }
 
-      stream->dec_hdrsize = stream->total_in;
+      /* xoff_t -> usize_t is safe because this is the first block. */
+      stream->dec_hdrsize = (usize_t) stream->total_in;
       stream->dec_state = DEC_WININD;
 
     case DEC_WININD:
diff --git a/xdelta3/xdelta3.c b/xdelta3/xdelta3.c
index 868c2ca..435e8d8 100644
--- a/xdelta3/xdelta3.c
+++ b/xdelta3/xdelta3.c
@@ -2583,17 +2583,16 @@ xd3_set_source (xd3_stream *stream,
 
   // If src->blksize is a power-of-two, xd3_blksize_div() will use
   // shift and mask rather than divide.  Check that here.
-  if (xd3_check_pow2 (src->blksize, &shiftby) == 0)
-    {
-      src->shiftby = shiftby;
-      src->maskby = (1 << shiftby) - 1;
-    }
-  else
+  if (!xd3_check_pow2 (src->blksize, &shiftby) == 0)
     {
+      int check;
       src->blksize = xd3_pow2_roundup(src->blksize);
-      xd3_check_pow2 (src->blksize, &shiftby);
+      check = xd3_check_pow2 (src->blksize, &shiftby);
+      XD3_ASSERT (check == 0);
     }
 
+  src->shiftby = shiftby;
+  src->maskby = (1 << shiftby) - 1;
   return 0;
 }
 
@@ -2777,14 +2776,14 @@ xd3_iopt_finish_encoding (xd3_stream *stream, xd3_rinst *inst)
                 XD3_ASSERT (inst->addr + inst->size <= src->srcbase + src->srclen);
                 addr = (inst->addr - src->srcbase);
                 stream->n_scpy += 1;
-                stream->l_scpy += inst->size;
+                stream->l_scpy += (xoff_t) inst->size;
               }
             else
               {
                 /* with source window: target copy address is offset by taroff. */
                 addr = stream->taroff + (usize_t) inst->addr;
                 stream->n_tcpy += 1;
-                stream->l_tcpy += inst->size;
+                stream->l_tcpy += (xoff_t) inst->size;
               }
           }
         else
@@ -3483,10 +3482,11 @@ xd3_emit_hdr (xd3_stream *stream)
           a32 = stream->recode_adler32;
         }
 
-      send[0] = (a32 >> 24);
-      send[1] = (a32 >> 16);
-      send[2] = (a32 >> 8);
-      send[3] = (a32 & 0xff);
+      /* Four bytes. */
+      send[0] = (uint8_t) (a32 >> 24);
+      send[1] = (uint8_t) (a32 >> 16);
+      send[2] = (uint8_t) (a32 >> 8);
+      send[3] = (uint8_t) (a32 & 0x000000FFU);
 
       if ((ret = xd3_emit_bytes (stream, & HDR_TAIL (stream), send, 4)))
         {
@@ -4374,7 +4374,7 @@ xd3_source_match_setup (xd3_stream *stream, xoff_t srcpos)
        * src->size/srcpos values and take the min. */
       if (srcpos < (xoff_t) stream->match_maxback)
         {
-          stream->match_maxback = srcpos;
+          stream->match_maxback = (usize_t) srcpos;
         }
 
       if (stream->src->eof_known)
@@ -4383,7 +4383,7 @@ xd3_source_match_setup (xd3_stream *stream, xoff_t srcpos)
 
           if (srcavail < (xoff_t) stream->match_maxfwd)
             {
-              stream->match_maxfwd = srcavail;
+              stream->match_maxfwd = (usize_t) srcavail;
             }
         }
 
diff --git a/xdelta3/xdelta3.h b/xdelta3/xdelta3.h
index ac5720f..c2741dd 100644
--- a/xdelta3/xdelta3.h
+++ b/xdelta3/xdelta3.h
@@ -1289,7 +1289,7 @@ void xd3_set_flags (xd3_stream *stream, int flags)
 }
 
 /* Gives some extra information about the latest library error, if any
-   is known. */
+ * is known. */
 static inline
 const char* xd3_errstring (xd3_stream  *stream)
 {
@@ -1297,19 +1297,16 @@ const char* xd3_errstring (xd3_stream  *stream)
 }
 
 
-/* 64-bit divisions are expensive.  on a 32bit platform, these show in
- * a profile as __udivdi3().  these are all the xoff_t divisions: */
+/* 64-bit divisions are expensive, which is why we require a power-of-2
+ * block size.  To relax this restriction is relatively easy, see the history 
+ * for this method.  gcc users should not see __udivdi3() in xd3_ profiles. */
 static inline
 void xd3_blksize_div (const xoff_t offset,
                       const xd3_source *source,
                       xoff_t *blkno,
                       usize_t *blkoff) {
-  *blkno = source->maskby ?
-    (offset >> source->shiftby) :
-    (offset / source->blksize);
-  *blkoff = source->maskby ?
-    (offset & source->maskby) :
-    (offset - *blkno * source->blksize);
+  *blkno = (xoff_t) (offset >> source->shiftby);
+  *blkoff = (usize_t) (offset & source->maskby);
 }
 
 #endif /* _XDELTA3_H_ */