Fixes the srcwin_cksum_pos advancement, at least up through the 32bit

boundary.

Adds XD3_TOOFARBACK error code and XD3_INTERNAL for internal errors
where asserts won't do.

5 files changed, 142 insertions, 477 deletions

diff --git a/xdelta3/.gdb_history b/xdelta3/.gdb_history
deleted file mode 100755
index 72410e8..0000000
--- a/xdelta3/.gdb_history
+++ /dev/null
@@ -1,256 +0,0 @@
-run test
-i[
-up
-print tpos
-print recon_size
-break xdelta3-test.h:2323
-run
-s
-s
-n
-print input_size
-up
-up
-print delta
-print delta_size
-run -vv -f -s ~/Desktop/hello.c ~/Desktop/world.c hw
-up
-down
-break xdelta3-main.h:2252
-run
-s
-n
-c
-c
-c
-run -vv -f -s ~/Desktop/hello.c ~/Desktop/world.c hw
-run -vv -f -s testcase/6/source testcase/6/target
-break xdelta3.c:5792
-run
-up
-updown
-break xdelta3.c:3837
-run
-s
-n
-print matchoff
-print streamoff
-print tryblk
-print tryoff
-n
-n
-n
-print stream->match_maxfwd
-print stream->match_fwd
-print str->cublk
-print str->curblk
-print src->curblk
-print tryoff
-n
-n
-print tryoff
-n
-print tryoff
-print src->curblk[21]
-print stream->next_in[21]
-print src->curblk
-print stream->next_in
-break xdelta3.c:5726
-c
-n
-print stream->match_fwd
-n
-n
-n
-n
-n
-n
-s
-n
-n
-n
-n
-n
-n
-n
-step 1
-step 1
-run -s testcase/3/source.doc testcase/3/target.doc
-break xdelta3.c:2697
-run
-p blkno
-p source->blocks
-up
-run -s testcase/3/source.doc testcase/3/target.doc out
-run -s testcase/3/source.doc testcase/3/target.doc > /dev/null
-break xdelta3.c:5095
-run
-p logical_input_cksum_pos
-p stream->input_pos
-p stream->input_position
-p stream->srcwin_size
-p stream->total_in
-n
-p logical_input_cksum_pos
-p stream-srcwin_cksum_pos
-p stream->srcwin_cksum_pos
-n
-n
-n
-p stream->srcwin_size
-n
-n
-p blkno
-p blkoff
-p onblk
-n
-n
-n
-break xdelta3.c:5114
-c
-n
-k
-y
-step 1
-d
-break xdelta3.c:5103
-break xdelta3.c:5097
-run
-n
-p logical_input_cksum_pos
-p stream->srcwin_size
-c
-n
-p stream->srcwin_cksum_pos
-run
-n
-c
-fin
-up
-down
-c
-up
-break xdelta3.c:5131
-c
-n
-p diff
-p onblk
-n
-p onblk
-p blkoff
-p blkoff
-p stream->large_look
-k
-y
-c
-k
-break xdelta3.c:5103
-run -s testcase/3/source.doc testcase/3/target.doc
-n
-o ibbkj
-p onblk
-n
-p blkoff
-p onblk
-n
-p blkoff
-break xdelta3.c:5119
-c
-n
-p stream->input_position
-p stream->srcwin_cksum_pos
-p stream->stream->srcwin_size
-p stream->srcwin_size
-p logical_input_cksum_pos
-p *next_move_point
-c
-n
-p stream->input_position
-p logical_input_cksum_pos
-p logical_input_cksum_pos
-p stream->srcwin_cksum_pos
-d
-c
-run -s testcase/3/source.doc testcase/3/target.doc -o /tmp/foo12
-run -s testcase/3/source.doc testcase/3/target.doc >  /dev/null
-run -vv -s testcase/3/source.doc testcase/3/target.doc >  /dev/null
-k
-y
-run -vv -s testcase/3/source.doc testcase/3/target.doc
-run -vv -s testcase/3/source.doc testcase/3/target.doc
-run -vv -s testcase/3/source.doc testcase/3/target.doc > /dev/null
-up
-n
-fin
-n
-break xdelta3.c:5119
-c
-c
-p stream->srcwin_cksum_pos
-p logical_input_cksum_pos
-p stream->total_iun
-p stream->total_i
-p stream->total_in
-p stream->srcwin_cksum_pos
-k
-run -vv -s testcase/3/source.doc testcase/3/target.doc  /tmp/fdsfd
-kill
-run -vv -s testcase/3/source.doc testcase/3/target.doc > /dev/null
-run -vv -s testcase/3/source.doc testcase/3/target.doc > /dev/null
-y
-run
-run -vv -s testcase/3/source.doc testcase/3/target.doc > /dev/null
-run
-run -vv -s testcase/3/source.doc testcase/3/target.doc > /dev/null
-n
-fin
-n
-p blkoff
-p stream->large_look
-p onblk
-break xdelta3.c:5122
-c
-n
-p blkno
-p stream->srcwin_cksum_pos
-up
-down
-p blkno
-p blkno * (1 <<18)
-p stream->srcwin_cksum_pos
-c
-p blkno * (1 <<18)
-p blkno
-c
-n
-n
-p onblk
-n
-p onblk
-p diff
-p stream->srcwin_cksum_pos
-n
-c
-n
-p stream->srcwin_cksum_pos
-p blkno
-c
-n
-p blkno
-c
-n
-c
-n
-p stream->srcwin_cksum_pos
-p logical_input_cksum_pos
-n
-run -vv -s testcase/3/source.doc testcase/3/target.doc
-run -vv -s testcase/3/source.doc testcase/3/target.doc > /dev/null
-up
-break xdelta3.c:5123
-c
-break xdelta3.c:5097
-c
-p stream->srcwin_cksum_pos
-p stream->logical_input_pos
-p logical_input_cksum_pos
diff --git a/xdelta3/.xdelta3.prcs_aux b/xdelta3/.xdelta3.prcs_aux
deleted file mode 100755
index b30689c..0000000
--- a/xdelta3/.xdelta3.prcs_aux
+++ /dev/null
@@ -1,84 +0,0 @@
-;; This file is automatically generated, editing may cause PRCS to do
-;; REALLY bad things.
-(Created-By-Prcs-Version 1 3 3)
-(www/xdelta3.css 938 1085949140 b/26_xdelta3.cs 1.3)
-(analyze_pfx.py 1422 1022037044 12_analyze_pf 1.1)
-(badcopy.c 2622 1047759845 20_badcopy.c 1.1)
-(analyze_clen.py 1342 1021753567 14_analyze_cl 1.1)
-(save.regtest.bug1/input.4 19022 1055471779 b/16_input.4 1.1)
-(save.regtest.bug11/input.0 4 1055554284 b/8_input.0 1.1)
-(save.regtest.bug8/input.0 203756 1055518432 28_input.0 1.1)
-(save.regtest.bug1/input.5 21597 1055471779 b/17_input.5 1.1)
-(save.regtest.bug6/input.20 1235 1055474005 39_input.20 1.1)
-(save.regtest.bug11/input.1 10 1055554284 b/7_input.1 1.1)
-(xdelta3-list.h 9892 1052598762 6_xdelta3-li 1.1)
-(save.regtest.bug8/input.1 203756 1055518493 29_input.1 1.1)
-(save.regtest.bug7/recon 51200 1055515262 36_recon 1.1)
-(save.regtest.bug6/input.21 952 1055474005 38_input.21 1.1)
-(save.regtest.bug6/recon 952 1055480638 37_recon 1.1)
-(save.regtest.bug11/recon.x 10 1055554520 b/5_recon.x 1.1)
-(vcdiff.ps 131548 1014968851 b/19_vcdiff.ps 1.1)
-(www/Xdelta3.html 3200 1058668417 b/24_Xdelta3.ht 1.1)
-(priorities.txt 339 1057496665 b/18_priorities 1.1)
-(draft-korn-vcdiff.txt 60706 1018424758 b/22_draft-korn 1.1)
-(dead.code 72096 1085893991 b/21_dead.code 1.2)
-(linkxd3lib.c 1113 1056324075 19_linkxd3lib 1.1)
-(www/xdelta3.html 4708 1085952599 b/24_Xdelta3.ht 1.4)
-(xdelta3-second.h 8228 1057405215 3_xdelta3-se 1.1)
-(testh.c 21 1042671351 17_testh.c 1.1)
-(save.regtest.bug6/input.0 920 1055474005 40_input.0 1.1)
-(save.regtest.bug12/output.x 705 1055556257 b/1_output.x 1.1)
-(save.regtest.bug8/core 1159168 1055529025 23_core 1.1)
-(save.regtest.bug9/foo,v 123233 1055532021 21_foo,vx 1.1)
-(xdelta3.c 201721 1085893369 16_xdelta3.c 1.3)
-(xdelta3-cfgs.h 2701 1057695639 9_xdelta3-cf 1.1)
-(save.regtest.bug10/input.0 53274 1055532189 b/14_input.0 1.1)
-(xdelta3-regtest.py 17976 1085947234 10_xdelta3-re 1.3)
-(save.regtest.bug10/input.1 74663 1055532189 b/13_input.1 1.1)
-(save.regtest.bug4/input.0 7571 1055461840 45_input.0 1.1)
-(save.regtest.bug12/xd3regtest.27181/output 2336 1055566927 b/0_output 1.1)
-(save.regtest.bug4/input.1 11312 1055461840 44_input.1 1.1)
-(save.regtest.bug7/core 1146880 1055522004 30_core 1.1)
-(xdelta3-main.h 79350 1085950532 5_xdelta3-ma 1.3)
-(xdelta3.h 41796 1084138546 1_xdelta3.h 1.2)
-(rcs_junk.cc 36315 1055086755 15_rcs_junk.c 1.1)
-(www/xdelta3-cmdline.html 5234 1085953288 b/25_xdelta3-cm 1.2)
-(save.regtest.bug7/input.0 7571 1055515262 34_input.0 1.1)
-(save.regtest.bug7/output 14276 1055515262 35_output 1.1)
-(save.regtest.bug2/input.0 2296 1055471815 49_input.0 1.1)
-(save.regtest.bug7/input.1 11312 1055515262 33_input.1 1.1)
-(www/xdelta3-api-guide.html 7553 1085953324 b/23_Xdelta3-ap 1.4)
-(save.regtest.bug8/input.0.xz 70595 1055518500 27_input.0.xz 1.1)
-(save.regtest.bug2/input.1 2521 1055471815 48_input.1 1.1)
-(save.regtest.bug9/foo2,v 123233 1055532069 22_foo2,vx 1.1)
-(xdelta3-python.h 1466 1055671733 4_xdelta3-py 1.1)
-(save.regtest.bug10/output 48388 1055532189 b/15_output 1.1)
-(save.regtest.bug10/output.x 48408 1055533319 b/12_output.x 1.1)
-(save.regtest.bug7/recon.x 11312 1055517553 31_recon.x 1.1)
-(save.regtest.bug11/recon 10 1055554284 b/10_recon 1.1)
-(save.regtest.bug8/input.1.xz 89734 1055518503 26_input.1.xz 1.1)
-(xdelta3-test.h 71959 1084138350 2_xdelta3-te 1.2)
-(save.regtest.bug10/recon.x 74655 1055533328 b/11_recon.x 1.1)
-(save.regtest.bug12/input.0 280 1055555649 b/3_input.0 1.1)
-(save.regtest.bug12/input.1 1155 1055555649 b/2_input.1 1.1)
-(draft-vcdiff-huffman.txt 2935 1021721074 b/20_draft-vcdi 1.1)
-(save.regtest.bug8/output.x.right 48221 1055520912 24_output.x.r 1.1)
-(save.regtest.bug5/input.0 7571 1055471668 43_input.0 1.1)
-(save.regtest.bug11/output.x 45 1055554519 b/6_output.x 1.1)
-(save.regtest.bug12/xd3regtest.27181/input.0 2521 1055566927 51_input.0 1.1)
-(save.regtest.bug5/input.1 11312 1055471668 42_input.1 1.1)
-(save.regtest.bug12/xd3regtest.27181/input.1 2296 1055566927 50_input.1 1.1)
-(setup.py 626 1055562104 11_setup.py 1.1)
-(Makefile 3840 1085893399 0_Makefile 1.3)
-(save.regtest.bug3/input.0 732 1055471934 47_input.0 1.1)
-(save.regtest.bug6/output 69 1055480559 41_output 1.1)
-(xdelta3-fgk.h 21496 1057610026 7_xdelta3-fg 1.1)
-(save.regtest.bug3/input.1 271 1055471934 46_input.1 1.1)
-(www/Xdelta3-api.html 6128 1058674572 b/23_Xdelta3-ap 1.1)
-(save.regtest.bug12/output 39 1055555649 b/4_output 1.1)
-(analyze_gp.py 7442 1022750342 13_analyze_gp 1.1)
-(save.regtest.bug11/output 45 1055554284 b/9_output 1.1)
-(save.regtest.bug7/output.x 14296 1055517870 32_output.x 1.1)
-(save.regtest.bug8/output.x 48225 1055530557 25_output.x 1.1)
-(show.c 647 1043318861 18_show.c 1.1)
-(xdelta3-djw.h 51152 1057610015 8_xdelta3-dj 1.1)
diff --git a/xdelta3/xdelta3-main.h b/xdelta3/xdelta3-main.h
index 29469c3..8fda5de 100755
--- a/xdelta3/xdelta3-main.h
+++ b/xdelta3/xdelta3-main.h
@@ -1804,7 +1804,7 @@ main_set_source (xd3_stream *stream, int cmd, main_file *sfile, xd3_source *sour
   if (option_verbose > 1) { XPR(NT "source window size: %u\n", option_srcwinsz); }
   if (option_verbose > 1) { XPR(NT "source block size: %u\n", source->blksize); }
   
-  lru_size = (option_srcwinsz / source->blksize) + 1;
+  lru_size = (option_srcwinsz / source->blksize);
 
   XD3_ASSERT(lru_size <= 128);  /* TODO: fix performance here */
 
@@ -1862,7 +1862,7 @@ main_set_source (xd3_stream *stream, int cmd, main_file *sfile, xd3_source *sour
               source->curblkno = 0;
               source->onblk    = nread;
 
-              if (option_verbose > 1)
+              if (option_verbose > 2)
                 {
                   XPR(NT "source block 0 read (not compressed)\n");
                 }
@@ -1957,8 +1957,12 @@ main_getblk_func (xd3_stream *stream,
           lru_hits += 1;
           return 0;
         }
-      XD3_ASSERT (lru[idx].blkno == -1LL ||
-                  lru[idx].blkno == blkno - lru_size);
+
+      if (lru[idx].blkno != -1LL &&
+          lru[idx].blkno != blkno - lru_size)
+        {
+          return XD3_TOOFARBACK;
+        }
     }
   else
     {
@@ -2015,7 +2019,7 @@ main_getblk_func (xd3_stream *stream,
 
   main_blklru_list_push_back (& lru_list, blru);
 
-  if (option_verbose > 1)
+  if (option_verbose > 2)
     {
       if (blru->blkno != -1LL)
         {
@@ -2182,14 +2186,12 @@ main_input (xd3_cmd     cmd,
       {
         config.winsize = min (input_size, (xoff_t) option_winsize);
       }
-    config.winsize = xd3_round_blksize (config.winsize, MIN_BUFSIZE);
     config.winsize = max (config.winsize, MIN_BUFSIZE);
   }
   {
     /* Source blocksize is not user-settable, only option_srcwinsz is,
      * which determines the number of blocks. */
     source.blksize = XD3_DEFAULT_SRCBLKSZ;
-    option_srcwinsz = xd3_round_blksize(option_srcwinsz, MIN_BUFSIZE);
     option_srcwinsz = max(option_srcwinsz, MIN_BUFSIZE);
     config.srcwin_maxsz = option_srcwinsz;
   }
@@ -2391,34 +2393,34 @@ main_input (xd3_cmd     cmd,
                 if (option_verbose)
                   {
                     char rrateavg[32], wrateavg[32], tm[32];
-                    char rdb[32],  wdb[32],  sb[32];
-                    char trdb[32], twdb[32], tsb[32];
-                    char srcbuf[48], tsrcbuf[48];
+                    char rdb[32], wdb[32];
+                    char trdb[32], twdb[32];
                     long millis = get_millisecs_since ();
                     usize_t this_read = stream.total_in - last_total_in;
                     usize_t this_write = stream.total_out - last_total_out;
                     last_total_in = stream.total_in;
                     last_total_out = stream.total_out;
 
-                    tsrcbuf[0] = srcbuf[0] = 0;
-                    if (used_source)
+                    if (option_verbose > 1)
                       {
-                        sprintf (srcbuf, ": src %s", main_format_bcnt (xd3_encoder_srclen (& stream), sb));
-                        sprintf (tsrcbuf, ": src %s", main_format_bcnt (stream.srcwin_cksum_pos, tsb));
-                      }
-                    /*if (stream.current_window >= option_first_window &&
-                          stream.current_window <= option_last_window)*/
-                      {
-                        XPR(NT "%"Q"u: in %s (%s): out %s (%s)%s: total in %s: out %s%s: %s\n",
+                        XPR(NT "%"Q"u: in %s (%s): out %s (%s): total in %s: out %s: %s\n",
                             stream.current_window,
                             main_format_bcnt (this_read, rdb),
                             main_format_rate (this_read, millis, rrateavg),
                             main_format_bcnt (this_write, wdb),
                             main_format_rate (this_write, millis, wrateavg),
-                            srcbuf,
                             main_format_bcnt (stream.total_in, trdb),
                             main_format_bcnt (stream.total_out, twdb),
-                            tsrcbuf,
+                            main_format_millis (millis, tm));
+                      }
+                    else
+                      {
+                        XPR(NT "%"Q"u: in %s: out %s: total in %s: out %s: %s\n",
+                            stream.current_window,
+                            main_format_bcnt (this_read, rdb),
+                            main_format_bcnt (this_write, wdb),
+                            main_format_bcnt (stream.total_in, trdb),
+                            main_format_bcnt (stream.total_out, twdb),
                             main_format_millis (millis, tm));
                       }
                   }
diff --git a/xdelta3/xdelta3.c b/xdelta3/xdelta3.c
index fb9a09f..a0c7a2a 100755
--- a/xdelta3/xdelta3.c
+++ b/xdelta3/xdelta3.c
@@ -654,6 +654,8 @@ const char* xd3_strerror (int ret)
     case XD3_GOTHEADER: return "XD3_GOTHEADER";
     case XD3_WINSTART: return "XD3_WINSTART";
     case XD3_WINFINISH: return "XD3_WINFINISH";
+    case XD3_TOOFARBACK: return "XD3_TOOFARBACK";
+    case XD3_INTERNAL: return "XD3_INTERNAL";
     }
   return strerror (ret);
 }
@@ -692,7 +694,7 @@ static const xd3_sec_type fgk_sec_type =
 #define IF_FGK(x)
 #define FGK_CASE(s) \
   s->msg = "unavailable secondary compressor: FGK Adaptive Huffman"; \
-  return EINVAL;
+  return XD3_INTERNAL;
 #endif
 
 #if SECONDARY_DJW
@@ -718,7 +720,7 @@ static const xd3_sec_type djw_sec_type =
 #define IF_DJW(x)
 #define DJW_CASE(s) \
   s->msg = "unavailable secondary compressor: DJW Static Huffman"; \
-  return EINVAL;
+  return XD3_INTERNAL;
 #endif
 
 /******************************************************************************************/
@@ -1337,7 +1339,7 @@ xd3_apply_table_string (xd3_stream *stream, const uint8_t *code_string)
               if (*code_string > XD3_CPY)
                 {
                   stream->msg = "invalid code-table opcode";
-                  return EINVAL;
+                  return XD3_INTERNAL;
                 }
               code_table[i].type1 = *code_string++;
               break;
@@ -1345,7 +1347,7 @@ xd3_apply_table_string (xd3_stream *stream, const uint8_t *code_string)
               if (*code_string > XD3_CPY)
                 {
                   stream->msg = "invalid code-table opcode";
-                  return EINVAL;
+                  return XD3_INTERNAL;
                 }
               code_table[i].type2 = *code_string++;
               break;
@@ -1353,7 +1355,7 @@ xd3_apply_table_string (xd3_stream *stream, const uint8_t *code_string)
               if (*code_string != 0 && code_table[i].type1 == XD3_NOOP)
                 {
                   stream->msg = "invalid code-table size";
-                  return EINVAL;
+                  return XD3_INTERNAL;
                 }
               code_table[i].size1 = *code_string++;
               break;
@@ -1361,7 +1363,7 @@ xd3_apply_table_string (xd3_stream *stream, const uint8_t *code_string)
               if (*code_string != 0 && code_table[i].type2 == XD3_NOOP)
                 {
                   stream->msg = "invalid code-table size";
-                  return EINVAL;
+                  return XD3_INTERNAL;
                 }
               code_table[i].size2 = *code_string++;
               break;
@@ -1369,12 +1371,12 @@ xd3_apply_table_string (xd3_stream *stream, const uint8_t *code_string)
               if (*code_string >= modes)
                 {
                   stream->msg = "invalid code-table mode";
-                  return EINVAL;
+                  return XD3_INTERNAL;
                 }
               if (*code_string != 0 && code_table[i].type1 != XD3_CPY)
                 {
                   stream->msg = "invalid code-table mode";
-                  return EINVAL;
+                  return XD3_INTERNAL;
                 }
               code_table[i].type1 += *code_string++;
               break;
@@ -1382,12 +1384,12 @@ xd3_apply_table_string (xd3_stream *stream, const uint8_t *code_string)
               if (*code_string >= modes)
                 {
                   stream->msg = "invalid code-table mode";
-                  return EINVAL;
+                  return XD3_INTERNAL;
                 }
               if (*code_string != 0 && code_table[i].type2 != XD3_CPY)
                 {
                   stream->msg = "invalid code-table mode";
-                  return EINVAL;
+                  return XD3_INTERNAL;
                 }
               code_table[i].type2 += *code_string++;
               break;
@@ -1432,7 +1434,7 @@ xd3_apply_table_encoding (xd3_stream *in_stream, const uint8_t *data, usize_t si
   if (code_size != sizeof (code_string))
     {
       stream.msg = "corrupt code-table encoding";
-      ret = EINVAL;
+      ret = XD3_INTERNAL;
       goto fail;
     }
 
@@ -1566,7 +1568,7 @@ xd3_check_pow2 (usize_t value, usize_t *logof)
         }
     }
 
-  return EINVAL;
+  return XD3_INTERNAL;
 }
 
 static usize_t
@@ -1862,7 +1864,7 @@ xd3_emit_bytes (xd3_stream     *stream,
       if (PART & OFLOW)                                                \
         {                                                              \
           stream->msg = "overflow in decode_integer";                  \
-          return EINVAL;                                               \
+          return XD3_INTERNAL;                                               \
         }                                                              \
                                                                        \
       PART = (PART << 7) | (next & 127);                               \
@@ -1888,13 +1890,13 @@ xd3_emit_bytes (xd3_stream     *stream,
       if (inp == max)                                                  \
         {                                                              \
           stream->msg = "end-of-input in read_integer";                \
-          return EINVAL;                                               \
+          return XD3_INTERNAL;                                               \
         }                                                              \
                                                                        \
       if (val & OFLOW)                                                 \
         {                                                              \
           stream->msg = "overflow in read_intger";                     \
-          return EINVAL;                                               \
+          return XD3_INTERNAL;                                               \
         }                                                              \
                                                                        \
       next = (*inp++);                                                 \
@@ -2171,7 +2173,7 @@ xd3_decode_address (xd3_stream *stream, usize_t here, uint mode, const uint8_t *
       if (*inpp == max)
         {
           stream->msg = "address underflow";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       mode -= same_start;
@@ -2484,7 +2486,7 @@ xd3_config_stream(xd3_stream *stream,
       (ret = xd3_check_pow2(XD3_ALLOCSIZE, NULL)))
     {
       stream->msg = "incorrect compilation: wrong integer sizes";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   /* Check/set secondary compressor. */
@@ -2494,7 +2496,7 @@ xd3_config_stream(xd3_stream *stream,
       if (stream->flags & XD3_SEC_OTHER)
         {
           stream->msg = "XD3_SEC flags require a secondary compressor type";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
       break;
     case XD3_SEC_FGK:
@@ -2503,7 +2505,7 @@ xd3_config_stream(xd3_stream *stream,
       DJW_CASE (stream);
     default:
       stream->msg = "too many secondary compressor types set";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   /* Check/set encoder code table. */
@@ -2521,7 +2523,7 @@ xd3_config_stream(xd3_stream *stream,
 #endif
   default:
     stream->msg = "alternate code table support was not compiled";
-    return EINVAL;
+    return XD3_INTERNAL;
   }
 
   /* Check sprevsz */
@@ -2534,7 +2536,7 @@ xd3_config_stream(xd3_stream *stream,
       if ((ret = xd3_check_pow2 (stream->sprevsz, NULL)))
         {
           stream->msg = "sprevsz is required to be a power of two";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       stream->sprevmask = stream->sprevsz - 1;
@@ -2557,7 +2559,7 @@ xd3_config_stream(xd3_stream *stream,
           config->srcwin_maxsz < stream->srcwin_size)
         {
           stream->msg = "invalid soft string-match config";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
       break;)
 
@@ -2566,7 +2568,7 @@ xd3_config_stream(xd3_stream *stream,
       IF_BUILD_FAST(case XD3_SMATCH_FAST: smatcher = & __smatcher_fast; break;)
     default:
       stream->msg = "invalid string match config type";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   stream->string_match  = smatcher->string_match;
@@ -2600,7 +2602,7 @@ xd3_getblk (xd3_stream *stream/*, xd3_source *source*/, xoff_t blkno)
   if (blkno >= source->blocks)
     {
       stream->msg = "source file too short";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   if (blkno != source->curblkno || source->curblk == NULL)
@@ -2626,7 +2628,7 @@ xd3_getblk (xd3_stream *stream/*, xd3_source *source*/, xoff_t blkno)
   if (source->onblk != xd3_bytes_on_srcblk (source, blkno))
     {
       stream->msg = "getblk returned short block";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   return 0;
@@ -2673,7 +2675,7 @@ xd3_close_stream (xd3_stream *stream)
       if (stream->enc_state != ENC_INPUT || stream->avail_in != 0)
         {
           stream->msg = "encoding is incomplete";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
     }
   else
@@ -2690,7 +2692,7 @@ xd3_close_stream (xd3_stream *stream)
         default:
           /* If decoding, should be ready for the next window. */
           stream->msg = "EOF in decode";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
     }
 
@@ -2709,7 +2711,7 @@ xd3_get_appheader (xd3_stream  *stream,
   if (stream->dec_state < DEC_WININD)
     {
       stream->msg = "application header not available";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   (*data) = stream->dec_appheader;
@@ -3640,7 +3642,7 @@ xd3_encode_input (xd3_stream *stream)
   if (stream->dec_state != 0)
     {
       stream->msg = "encoder/decoder transition";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   switch (stream->enc_state)
@@ -3781,7 +3783,7 @@ xd3_encode_input (xd3_stream *stream)
       if (stream->avail_out != 0)
         {
           stream->msg = "missed call to consume output";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       /* Continue outputting one buffer at a time, until the next is NULL. */
@@ -3813,7 +3815,7 @@ xd3_encode_input (xd3_stream *stream)
 
     default:
       stream->msg = "invalid state";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 }
 #endif /* XD3_ENCODER */
@@ -3853,7 +3855,7 @@ xd3_process_completely (xd3_stream    *stream,
         case XD3_GETSRCBLK:
           {
             stream->msg = "stream requires source input";
-            return EINVAL;
+            return XD3_INTERNAL;
           }
         case 0: /* there is no plain "success" return for xd3_encode/decode */
           XD3_ASSERT (ret != 0);
@@ -3947,7 +3949,7 @@ xd3_decode_setup_buffers (xd3_stream *stream)
       if (stream->dec_cpyoff < stream->dec_laststart)
         {
           stream->msg = "unsupported VCD_TARGET offset";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       /* See if the two windows are the same.  This indicates the first time VCD_TARGET is
@@ -4113,7 +4115,7 @@ xd3_decode_parse_halfinst (xd3_stream *stream, xd3_hinst *inst)
 
                             & inst->size)))
     {
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   /* For copy instructions, read address. */
@@ -4143,7 +4145,7 @@ xd3_decode_parse_halfinst (xd3_stream *stream, xd3_hinst *inst)
       if (inst->addr >= stream->dec_position)
         {
           stream->msg = "address too large";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       /* Check: a VCD_TARGET or VCD_SOURCE copy cannot exceed the remaining buffer space
@@ -4151,7 +4153,7 @@ xd3_decode_parse_halfinst (xd3_stream *stream, xd3_hinst *inst)
       if (inst->addr < stream->dec_cpylen && inst->addr + inst->size > stream->dec_cpylen)
         {
           stream->msg = "size too large";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
     }
   else
@@ -4183,7 +4185,7 @@ xd3_decode_parse_halfinst (xd3_stream *stream, xd3_hinst *inst)
   if (stream->dec_position + inst->size > stream->dec_maxpos)
     {
       stream->msg = "size too large";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   stream->dec_position += inst->size;
@@ -4200,7 +4202,7 @@ xd3_decode_instruction (xd3_stream *stream)
   if (stream->inst_sect.buf == stream->inst_sect.buf_max)
     {
       stream->msg = "instruction underflow";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   inst = &stream->code_table[*stream->inst_sect.buf++];
@@ -4241,7 +4243,7 @@ xd3_decode_output_halfinst (xd3_stream *stream, xd3_hinst *inst)
         if (stream->data_sect.buf == stream->data_sect.buf_max)
           {
             stream->msg = "data underflow";
-            return EINVAL;
+            return XD3_INTERNAL;
           }
 
         /* TUNE: Probably want to eliminate memset/memcpy here */
@@ -4260,7 +4262,7 @@ xd3_decode_output_halfinst (xd3_stream *stream, xd3_hinst *inst)
         if (stream->data_sect.buf + take > stream->data_sect.buf_max)
           {
             stream->msg = "data underflow";
-            return EINVAL;
+            return XD3_INTERNAL;
           }
 
         memcpy (stream->next_out + stream->avail_out,
@@ -4318,6 +4320,7 @@ xd3_decode_output_halfinst (xd3_stream *stream, xd3_hinst *inst)
                 if ((ret = xd3_getblk (stream, block)))
                   {
                     /* could be a XD3_GETSRCBLK failure. */
+                    XD3_ASSERT(ret != XD3_TOOFARBACK);
                     return ret;
                   }
 
@@ -4328,7 +4331,7 @@ xd3_decode_output_halfinst (xd3_stream *stream, xd3_hinst *inst)
                 if ((source->onblk != blksize) && (blkoff + take > source->onblk))
                   {
                     stream->msg = "source file too short";
-                    return EINVAL;
+                    return XD3_INTERNAL;
 
                   }
 
@@ -4451,7 +4454,7 @@ xd3_decode_sections (xd3_stream *stream)
     {
     default:
       stream->msg = "internal error";
-      return EINVAL;
+      return XD3_INTERNAL;
 
     case DEC_DATA:
       if ((ret = xd3_decode_section (stream, & stream->data_sect, DEC_INST, copy))) { return ret; }
@@ -4527,19 +4530,19 @@ xd3_decode_emit (xd3_stream *stream)
     {
       IF_DEBUG1 (P(RINT "AVAIL_OUT(%d) != DEC_TGTLEN(%d)\n", stream->avail_out, stream->dec_tgtlen));
       stream->msg = "wrong window length";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   if (stream->data_sect.buf != stream->data_sect.buf_max)
     {
       stream->msg = "extra data section";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   if (stream->addr_sect.buf != stream->addr_sect.buf_max)
     {
       stream->msg = "extra address section";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   /* OPT: Should cksum computation be combined with the above loop? */
@@ -4551,7 +4554,7 @@ xd3_decode_emit (xd3_stream *stream)
       if (a32 != stream->dec_adler32)
         {
           stream->msg = "target window checksum mismatch";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
     }
 
@@ -4567,7 +4570,7 @@ xd3_decode_input (xd3_stream *stream)
   if (stream->enc_state != 0)
     {
       stream->msg = "encoder/decoder transition";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
 #define BYTE_CASE(expr,x,nstate)                                               \
@@ -4605,13 +4608,13 @@ xd3_decode_input (xd3_stream *stream)
             stream->dec_magic[2] != VCDIFF_MAGIC3)
           {
             stream->msg = "not a VCDIFF input";
-            return EINVAL;
+            return XD3_INTERNAL;
           }
 
         if (stream->dec_magic[3] != 0)
           {
             stream->msg = "VCDIFF input version > 0 is not supported";
-            return EINVAL;
+            return XD3_INTERNAL;
           }
 
         stream->dec_state = DEC_HDRIND;
@@ -4623,7 +4626,7 @@ xd3_decode_input (xd3_stream *stream)
         if ((stream->dec_hdr_ind & VCD_INVHDR) != 0)
           {
             stream->msg = "unrecognized header indicator bits set";
-            return EINVAL;
+            return XD3_INTERNAL;
           }
 
         stream->dec_state = DEC_SECONDID;
@@ -4643,7 +4646,7 @@ xd3_decode_input (xd3_stream *stream)
               DJW_CASE (stream);
             default:
               stream->msg = "unknown secondary compressor ID";
-              return EINVAL;
+              return XD3_INTERNAL;
             }
         }
 
@@ -4730,7 +4733,7 @@ xd3_decode_input (xd3_stream *stream)
         if (XOFF_T_OVERFLOW (stream->dec_winstart, stream->dec_tgtlen))
           {
             stream->msg = "decoder file offset overflow";
-            return EINVAL;
+            return XD3_INTERNAL;
           }
 
         stream->dec_winstart += stream->dec_tgtlen;
@@ -4738,7 +4741,7 @@ xd3_decode_input (xd3_stream *stream)
         if ((stream->dec_win_ind & VCD_INVWIN) != 0)
           {
             stream->msg = "unrecognized window indicator bits set";
-            return EINVAL;
+            return XD3_INTERNAL;
           }
 
         if ((ret = xd3_decode_init_window (stream))) { return ret; }
@@ -4765,7 +4768,7 @@ xd3_decode_input (xd3_stream *stream)
       if (XOFF_T_OVERFLOW (stream->dec_cpyoff, stream->dec_cpylen))
         {
           stream->msg = "decoder copy window overflows a file offset";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       /* Check copy window bounds: VCD_TARGET window may not exceed current position. */
@@ -4773,7 +4776,7 @@ xd3_decode_input (xd3_stream *stream)
           (stream->dec_cpyoff + (xoff_t) stream->dec_cpylen > stream->dec_winstart))
         {
           stream->msg = "VCD_TARGET window out of bounds";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
     case DEC_ENCLEN:
@@ -4789,14 +4792,14 @@ xd3_decode_input (xd3_stream *stream)
       if (USIZE_T_OVERFLOW (stream->dec_cpylen, stream->dec_tgtlen))
         {
           stream->msg = "decoder target window overflows a usize_t";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       /* Check for malicious files. */
       if (stream->dec_tgtlen > XD3_HARDMAXWINSIZE)
         {
           stream->msg = "hard window size exceeded";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       stream->dec_maxpos = stream->dec_cpylen + stream->dec_tgtlen;
@@ -4808,14 +4811,14 @@ xd3_decode_input (xd3_stream *stream)
       if ((stream->dec_del_ind & VCD_INVDEL) != 0)
         {
           stream->msg = "unrecognized delta indicator bits set";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       /* Delta indicator is only used with secondary compression. */
       if ((stream->dec_del_ind != 0) && (stream->sec_type == NULL))
         {
           stream->msg = "invalid delta indicator bits set";
-          return EINVAL;
+          return XD3_INTERNAL;
         }
 
       /* Section lengths */
@@ -4856,7 +4859,7 @@ xd3_decode_input (xd3_stream *stream)
         if (stream->dec_enclen != enclen_check)
           {
             stream->msg = "incorrect encoding length (redundent)";
-            return EINVAL;
+            return XD3_INTERNAL;
           }
       }
 
@@ -4882,7 +4885,7 @@ xd3_decode_input (xd3_stream *stream)
           if (src == NULL)
             {
               stream->msg = "source input required";
-              return EINVAL;
+              return XD3_INTERNAL;
             }
 
           src->cpyoff_blocks = stream->dec_cpyoff / src->blksize;
@@ -4925,7 +4928,7 @@ xd3_decode_input (xd3_stream *stream)
 
     default:
       stream->msg = "invalid state";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 }
 
@@ -4998,8 +5001,7 @@ xd3_string_match_init (xd3_stream *stream)
 static int
 xd3_srcwin_move_point (xd3_stream *stream, usize_t *next_move_point)
 {
-  // The input offset at which the source should ideally be scanned
-  xoff_t logical_input_cksum_pos = stream->total_in + pos_in + stream->srcwin_size;
+  xoff_t logical_input_cksum_pos;
 
   if (stream->srcwin_cksum_pos >= stream->src->size)
     {
@@ -5007,27 +5009,32 @@ xd3_srcwin_move_point (xd3_stream *stream, usize_t *next_move_point)
       return 0;
     }
 
+  /* Begin by advancing at twice the input rate, up to half the maximum window size. */
+  logical_input_cksum_pos = min((stream->total_in + pos_in) * 2,
+                                (stream->total_in + pos_in) + (stream->srcwin_maxsz / 2));
+
+  /* If srcwin_cksum_pos is already greater, wait until the difference is met. */
   if (stream->srcwin_cksum_pos > logical_input_cksum_pos)
     {
-      *next_move_point = stream->srcwin_cksum_pos - logical_input_cksum_pos;
+      *next_move_point = pos_in +
+        (usize_t)(stream->srcwin_cksum_pos - logical_input_cksum_pos);
       return 0;
     }
 
-  IF_DEBUG1 (P(RINT "[move_p1] size=%d T=%"Q"d S=%"Q"d\n", stream->srcwin_size,
-               stream->total_in + pos_in, stream->srcwin_cksum_pos));
-
-  *next_move_point = pos_in + stream->srcwin_size;
+  /* If the stream has matched beyond the srcwin_cksum_pos (good), we shouldn't
+   * begin reading so far back. */
+  int diff = logical_input_cksum_pos - stream->srcwin_cksum_pos;
 
-  if (stream->srcwin_cksum_pos == 0)
+  if (diff > stream->srcwin_size)
     {
-      // Two windows to start with
-      logical_input_cksum_pos += stream->srcwin_size;
+      stream->srcwin_cksum_pos = stream->total_in + pos_in - stream->srcwin_size;
+      diff = logical_input_cksum_pos - stream->srcwin_cksum_pos;
     }
-  else
+
+  if (diff < stream->srcwin_size)
     {
-      // Otherwise double and add
-      stream->srcwin_size = min(stream->srcwin_maxsz, stream->srcwin_size * 2);
-      logical_input_cksum_pos += stream->srcwin_size;
+      /* Advance a minimum of srcwin_size bytes */
+      logical_input_cksum_pos = stream->srcwin_cksum_pos + stream->srcwin_size;
     }
 
   while (stream->srcwin_cksum_pos < logical_input_cksum_pos &&
@@ -5038,6 +5045,9 @@ xd3_srcwin_move_point (xd3_stream *stream, usize_t *next_move_point)
       usize_t onblk = xd3_bytes_on_srcblk (stream->src, blkno);
       int ret;
 
+      diff = logical_input_cksum_pos - stream->srcwin_cksum_pos;
+      onblk = min(onblk, blkoff + diff);
+
       if (blkoff + stream->large_look >= onblk)
         {
           /* Next block */
@@ -5045,16 +5055,20 @@ xd3_srcwin_move_point (xd3_stream *stream, usize_t *next_move_point)
           continue;
         }
 
+      IF_DEBUG1 (P(RINT "[move_p1] T=%"Q"u S=%"Q"u\n", 
+                   stream->total_in + pos_in,
+                   stream->srcwin_cksum_pos));
+
       if ((ret = xd3_getblk (stream, blkno)))
         {
+          if (ret == XD3_TOOFARBACK)
+            {
+              ret = XD3_INTERNAL;
+            }
           return ret;
         }
 
-      usize_t diff = logical_input_cksum_pos - stream->srcwin_cksum_pos;
-
-      onblk = min(onblk, diff + blkoff + stream->large_look);
-
-      while (blkoff + stream->large_look <= onblk)
+      while (blkoff + stream->large_look < onblk)
         {
           uint32_t cksum = xd3_lcksum (stream->src->curblk + blkoff, stream->large_look);
           usize_t hval = xd3_checksum_hash (& stream->large_hash, cksum);
@@ -5065,10 +5079,14 @@ xd3_srcwin_move_point (xd3_stream *stream, usize_t *next_move_point)
           stream->srcwin_cksum_pos += stream->large_step;
           IF_DEBUG (stream->large_ckcnt += 1);
         }
-    }
 
-  IF_DEBUG1 (P(RINT "[move_p2] size=%d T=%"Q"d S=%"Q"d next_move=%d\n", stream->srcwin_size,
-               stream->total_in + pos_in, stream->srcwin_cksum_pos, *next_move_point));
+      IF_DEBUG1 (P(RINT "[move_p2] T=%"Q"u S=%"Q"u\n", 
+                   stream->total_in + pos_in,
+                   stream->srcwin_cksum_pos));
+
+    }
+  *next_move_point = pos_in +
+    (usize_t)(stream->srcwin_cksum_pos - logical_input_cksum_pos);
 
   return 0;
 }
@@ -5082,10 +5100,6 @@ xd3_srcwin_setup (xd3_stream *stream)
   xd3_source *src = stream->src;
   xoff_t length;
 
-  IF_DEBUG1 (P(RINT "[srcwin setup:%"Q"u] iopt buffer %s\n",
-                stream->current_window,
-                stream->enc_state < ENC_FLUSH ? "overflow" : "fit"));
-
   /* Check the undecided state. */
   XD3_ASSERT (src->srclen == 0 && src->srcbase == 0);
 
@@ -5108,7 +5122,7 @@ xd3_srcwin_setup (xd3_stream *stream)
   if (length > (xoff_t) USIZE_T_MAX)
     {
       stream->msg = "source window length overflow (not 64bit)";
-      return EINVAL;
+      return XD3_INTERNAL;
     }
 
   /* If ENC_FLUSH, then we know the exact source window to use because no more copies can
@@ -5133,10 +5147,6 @@ xd3_srcwin_setup (xd3_stream *stream)
 
   XD3_ASSERT (src->srclen);
  done:
-  IF_DEBUG1 (P(RINT "[srcwin setup:%"Q"u] base %"Q"u size %u\n",
-                      stream->current_window,
-                      src->srcbase,
-                      src->srclen));
   /* Set the taroff.  This convenience variable is used even when stream->src == NULL. */
   stream->taroff = src->srclen;
   return 0;
@@ -5152,28 +5162,12 @@ xd3_source_match_setup (xd3_stream *stream, xoff_t srcpos)
 {
   xd3_source *src = stream->src;
   usize_t greedy_or_not;
-  xoff_t farthest_src;
 
   stream->match_maxback = 0;
   stream->match_maxfwd  = 0;
   stream->match_back    = 0;
   stream->match_fwd     = 0;
 
-  farthest_src = max(stream->srcwin_cksum_pos, srcpos);
-
-  XD3_ASSERT (stream->srcwin_maxsz > src->blksize);
-
-  /* This prevents the encoder from seeking back more than srcwin_maxsz.  Using
-   * srcwin_maxsz is incorrect.  TODO: Possibly an new option here, how far back to
-   * seek? */
-  if (max_in == 0 ||
-      farthest_src - srcpos > stream->srcwin_maxsz - src->blksize)
-    {
-      goto bad;  // TODO! Note: this prevents catching the TODO/bug below
-    }
-
-  /* TODO: check for boundary crossing */
-
   /* Going backwards, the 1.5-pass algorithm allows some already-matched input may be
    * covered by a longer source match.  The greedy algorithm does not allow this. */
   if (stream->flags & XD3_BEGREEDY)
@@ -5299,6 +5293,12 @@ xd3_source_extend_match (xd3_stream *stream)
 
           if ((ret = xd3_getblk (stream, tryblk)))
             {
+              /* if search went too far back, continue forward. */
+              if (ret == XD3_TOOFARBACK)
+                {
+                  break;
+                }
+                
               /* could be a XD3_GETSRCBLK failure. */
               return ret;
             }
@@ -5334,6 +5334,13 @@ xd3_source_extend_match (xd3_stream *stream)
     {
       if ((ret = xd3_getblk (stream, tryblk)))
         {
+          /* if search went too far back, continue forward. */
+          if (ret == XD3_TOOFARBACK)
+            {
+              break;
+            }
+
+          /* could be a XD3_GETSRCBLK failure. */
           return ret;
         }
 
@@ -5753,12 +5760,6 @@ XD3_TEMPLATE(xd3_string_match_) (xd3_stream *stream)
   /* If there is not enough input remaining for any kind of match, skip it. */
   if (pos_in + SLOOK > max_in) { goto loopnomore; }
 
-  IF_DEBUG1 ({
-    static int x = 0;
-    P(RINT "[string match:%d] pos_in %d; \n",
-       x++, pos_in);
-  });
-
   /* Now reset the incremental loop state: */
 
   /* The min_match variable is updated to avoid matching the same lazy match over and over
diff --git a/xdelta3/xdelta3.h b/xdelta3/xdelta3.h
index a35c9b0..eb11141 100755
--- a/xdelta3/xdelta3.h
+++ b/xdelta3/xdelta3.h
@@ -47,7 +47,7 @@
 /* The source window starts with only a few checksums, then doubles up to
  * XD3_DEFAULT_MAX_CKSUM_ADVANCE. */
 #ifndef XD3_DEFAULT_START_CKSUM_ADVANCE
-#define XD3_DEFAULT_START_CKSUM_ADVANCE 1024
+#define XD3_DEFAULT_START_CKSUM_ADVANCE (1U << 14)
 #endif
 
 /* TODO: There is no command-line flag to set this value. */
@@ -295,6 +295,8 @@ typedef enum {
   XD3_WINSTART  = -17707, /* notification: returned before a window is processed, giving a
                            * chance to XD3_SKIP_WINDOW or not XD3_SKIP_EMIT that window. */
   XD3_WINFINISH = -17708, /* notification: returned after encode/decode & output for a window */
+  XD3_TOOFARBACK = -17709, /* (encoder only) may be returned by getblk() if the block is too old */
+  XD3_INTERNAL = -17710, /* internal error */
 
 } xd3_rvalues;