1 files changed, 480 insertions, 313 deletions

diff --git a/rbutil/rbutilqt/mspack/lzxd.c b/rbutil/rbutilqt/mspack/lzxd.c
index 9b26bac3e0..88cfd90c2a 100644
--- a/rbutil/rbutilqt/mspack/lzxd.c
+++ b/rbutil/rbutilqt/mspack/lzxd.c
@@ -1,5 +1,5 @@
 /* This file is part of libmspack.
- * (C) 2003-2004 Stuart Caie.
+ * (C) 2003-2013 Stuart Caie.
  *
  * The LZX method was created by Jonathan Forbes and Tomi Poutanen, adapted
  * by Microsoft Corporation.
@@ -70,6 +70,10 @@
  * The maximum window size has increased from 2MB to 32MB. This also
  * increases the maximum number of position slots, etc.
  *
+ * If the match length is 257 (the maximum possible), this signals
+ * a further length decoding step, that allows for matches up to
+ * 33024 bytes long.
+ *
  * The format now allows for "reference data", supplied by the caller.
  * If match offsets go further back than the number of bytes
  * decompressed so far, that is them accessing the reference data.
@@ -79,11 +83,11 @@
 #define BITS_TYPE struct lzxd_stream
 #define BITS_VAR lzx
 #define BITS_ORDER_MSB
-#define READ_BYTES do {                 \
-    unsigned char b0, b1;               \
-    READ_IF_NEEDED; b0 = *i_ptr++;      \
-    READ_IF_NEEDED; b1 = *i_ptr++;      \
-    INJECT_BITS((b1 << 8) | b0, 16);    \
+#define READ_BYTES do {                 \
+    unsigned char b0, b1;               \
+    READ_IF_NEEDED; b0 = *i_ptr++;      \
+    READ_IF_NEEDED; b1 = *i_ptr++;      \
+    INJECT_BITS((b1 << 8) | b0, 16);    \
 } while (0)
 #include "readbits.h"
 
@@ -96,43 +100,43 @@
 #include "readhuff.h"
 
 /* BUILD_TABLE(tbl) builds a huffman lookup table from code lengths */
-#define BUILD_TABLE(tbl)                                                \
-    if (make_decode_table(MAXSYMBOLS(tbl), TABLEBITS(tbl),              \
-                          &HUFF_LEN(tbl,0), &HUFF_TABLE(tbl,0)))        \
-    {                                                                   \
-        D(("failed to build %s table", #tbl))                           \
-        return lzx->error = MSPACK_ERR_DECRUNCH;                        \
+#define BUILD_TABLE(tbl)                                                \
+    if (make_decode_table(MAXSYMBOLS(tbl), TABLEBITS(tbl),              \
+                          &HUFF_LEN(tbl,0), &HUFF_TABLE(tbl,0)))        \
+    {                                                                   \
+        D(("failed to build %s table", #tbl))                           \
+        return lzx->error = MSPACK_ERR_DECRUNCH;                        \
     }
 
-#define BUILD_TABLE_MAYBE_EMPTY(tbl) do {                               \
-    lzx->tbl##_empty = 0;                                               \
-    if (make_decode_table(MAXSYMBOLS(tbl), TABLEBITS(tbl),              \
-                          &HUFF_LEN(tbl,0), &HUFF_TABLE(tbl,0)))        \
-    {                                                                   \
-        for (i = 0; i < MAXSYMBOLS(tbl); i++) {                         \
-            if (HUFF_LEN(tbl, i) > 0) {                                 \
-                D(("failed to build %s table", #tbl))                   \
-                return lzx->error = MSPACK_ERR_DECRUNCH;                \
-            }                                                           \
-        }                                                               \
-        /* empty tree - allow it, but don't decode symbols with it */   \
-        lzx->tbl##_empty = 1;                                           \
-    }                                                                   \
+#define BUILD_TABLE_MAYBE_EMPTY(tbl) do {                               \
+    lzx->tbl##_empty = 0;                                               \
+    if (make_decode_table(MAXSYMBOLS(tbl), TABLEBITS(tbl),              \
+                          &HUFF_LEN(tbl,0), &HUFF_TABLE(tbl,0)))        \
+    {                                                                   \
+        for (i = 0; i < MAXSYMBOLS(tbl); i++) {                         \
+            if (HUFF_LEN(tbl, i) > 0) {                                 \
+                D(("failed to build %s table", #tbl))                   \
+                return lzx->error = MSPACK_ERR_DECRUNCH;                \
+            }                                                           \
+        }                                                               \
+        /* empty tree - allow it, but don't decode symbols with it */   \
+        lzx->tbl##_empty = 1;                                           \
+    }                                                                   \
 } while (0)
 
 /* READ_LENGTHS(tablename, first, last) reads in code lengths for symbols
  * first to last in the given table. The code lengths are stored in their
  * own special LZX way.
  */
-#define READ_LENGTHS(tbl, first, last) do {             \
-  STORE_BITS;                                           \
-  if (lzxd_read_lens(lzx, &HUFF_LEN(tbl, 0), (first),   \
-    (unsigned int)(last))) return lzx->error;           \
-  RESTORE_BITS;                                         \
+#define READ_LENGTHS(tbl, first, last) do {             \
+  STORE_BITS;                                           \
+  if (lzxd_read_lens(lzx, &HUFF_LEN(tbl, 0), (first),   \
+    (unsigned int)(last))) return lzx->error;           \
+  RESTORE_BITS;                                         \
 } while (0)
 
 static int lzxd_read_lens(struct lzxd_stream *lzx, unsigned char *lens,
-                          unsigned int first, unsigned int last)
+                          unsigned int first, unsigned int last)
 {
   /* bit buffer and huffman symbol decode variables */
   register unsigned int bit_buffer;
@@ -189,27 +193,70 @@ static int lzxd_read_lens(struct lzxd_stream *lzx, unsigned char *lens,
  * a small 'position slot' number and a small offset from that slot are
  * encoded instead of one large offset.
  *
+ * The number of slots is decided by how many are needed to encode the
+ * largest offset for a given window size. This is easy when the gap between
+ * slots is less than 128Kb, it's a linear relationship. But when extra_bits
+ * reaches its limit of 17 (because LZX can only ensure reading 17 bits of
+ * data at a time), we can only jump 128Kb at a time and have to start
+ * using more and more position slots as each window size doubles.
+ *
  * position_base[] is an index to the position slot bases
  *
  * extra_bits[] states how many bits of offset-from-base data is needed.
  *
- * They are generated like so:
- * for (i = 0;        i < 4;  i++)  extra_bits[i] = 0;
- * for (i = 4, j = 0; i < 36; i+=2) extra_bits[i] = extra_bits[i+1] = j++;
- * for (i = 36;       i < 51; i++)  extra_bits[i] = 17;
- * for (i = 0, j = 0; i < 51; j += 1 << extra_bits[i++]) position_base[i] = j;
+ * They are calculated as follows:
+ * extra_bits[i] = 0 where i < 4
+ * extra_bits[i] = floor(i/2)-1 where i >= 4 && i < 36
+ * extra_bits[i] = 17 where i >= 36
+ * position_base[0] = 0
+ * position_base[i] = position_base[i-1] + (1 << extra_bits[i-1])
  */
-static const unsigned int position_base[51] = {
-  0, 1, 2, 3, 4, 6, 8, 12, 16, 24, 32, 48, 64, 96, 128, 192, 256,
-  384, 512, 768, 1024, 1536, 2048, 3072, 4096, 6144, 8192, 12288,
-  16384, 24576, 32768, 49152, 65536, 98304, 131072, 196608, 262144,
-  393216, 524288, 655360, 786432, 917504, 1048576, 1179648, 1310720,
-  1441792, 1572864, 1703936, 1835008, 1966080, 2097152
+static const unsigned int position_slots[11] = {
+    30, 32, 34, 36, 38, 42, 50, 66, 98, 162, 290
+};
+static const unsigned char extra_bits[36] = {
+    0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8,
+    9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16
 };
-static const unsigned char extra_bits[51] = {
-  0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8,
-  9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16,
-  17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17
+static const unsigned int position_base[290] = {
+    0, 1, 2, 3, 4, 6, 8, 12, 16, 24, 32, 48, 64, 96, 128, 192, 256, 384, 512,
+    768, 1024, 1536, 2048, 3072, 4096, 6144, 8192, 12288, 16384, 24576, 32768,
+    49152, 65536, 98304, 131072, 196608, 262144, 393216, 524288, 655360,
+    786432, 917504, 1048576, 1179648, 1310720, 1441792, 1572864, 1703936,
+    1835008, 1966080, 2097152, 2228224, 2359296, 2490368, 2621440, 2752512,
+    2883584, 3014656, 3145728, 3276800, 3407872, 3538944, 3670016, 3801088,
+    3932160, 4063232, 4194304, 4325376, 4456448, 4587520, 4718592, 4849664,
+    4980736, 5111808, 5242880, 5373952, 5505024, 5636096, 5767168, 5898240,
+    6029312, 6160384, 6291456, 6422528, 6553600, 6684672, 6815744, 6946816,
+    7077888, 7208960, 7340032, 7471104, 7602176, 7733248, 7864320, 7995392,
+    8126464, 8257536, 8388608, 8519680, 8650752, 8781824, 8912896, 9043968,
+    9175040, 9306112, 9437184, 9568256, 9699328, 9830400, 9961472, 10092544,
+    10223616, 10354688, 10485760, 10616832, 10747904, 10878976, 11010048,
+    11141120, 11272192, 11403264, 11534336, 11665408, 11796480, 11927552,
+    12058624, 12189696, 12320768, 12451840, 12582912, 12713984, 12845056,
+    12976128, 13107200, 13238272, 13369344, 13500416, 13631488, 13762560,
+    13893632, 14024704, 14155776, 14286848, 14417920, 14548992, 14680064,
+    14811136, 14942208, 15073280, 15204352, 15335424, 15466496, 15597568,
+    15728640, 15859712, 15990784, 16121856, 16252928, 16384000, 16515072,
+    16646144, 16777216, 16908288, 17039360, 17170432, 17301504, 17432576,
+    17563648, 17694720, 17825792, 17956864, 18087936, 18219008, 18350080,
+    18481152, 18612224, 18743296, 18874368, 19005440, 19136512, 19267584,
+    19398656, 19529728, 19660800, 19791872, 19922944, 20054016, 20185088,
+    20316160, 20447232, 20578304, 20709376, 20840448, 20971520, 21102592,
+    21233664, 21364736, 21495808, 21626880, 21757952, 21889024, 22020096,
+    22151168, 22282240, 22413312, 22544384, 22675456, 22806528, 22937600,
+    23068672, 23199744, 23330816, 23461888, 23592960, 23724032, 23855104,
+    23986176, 24117248, 24248320, 24379392, 24510464, 24641536, 24772608,
+    24903680, 25034752, 25165824, 25296896, 25427968, 25559040, 25690112,
+    25821184, 25952256, 26083328, 26214400, 26345472, 26476544, 26607616,
+    26738688, 26869760, 27000832, 27131904, 27262976, 27394048, 27525120,
+    27656192, 27787264, 27918336, 28049408, 28180480, 28311552, 28442624,
+    28573696, 28704768, 28835840, 28966912, 29097984, 29229056, 29360128,
+    29491200, 29622272, 29753344, 29884416, 30015488, 30146560, 30277632,
+    30408704, 30539776, 30670848, 30801920, 30932992, 31064064, 31195136,
+    31326208, 31457280, 31588352, 31719424, 31850496, 31981568, 32112640,
+    32243712, 32374784, 32505856, 32636928, 32768000, 32899072, 33030144,
+    33161216, 33292288, 33423360
 };
 
 static void lzxd_reset_state(struct lzxd_stream *lzx) {
@@ -230,23 +277,37 @@ static void lzxd_reset_state(struct lzxd_stream *lzx) {
 /*-------- main LZX code --------*/
 
 struct lzxd_stream *lzxd_init(struct mspack_system *system,
-                              struct mspack_file *input,
-                              struct mspack_file *output,
-                              int window_bits,
-                              int reset_interval,
-                              int input_buffer_size,
-                              off_t output_length)
+                              struct mspack_file *input,
+                              struct mspack_file *output,
+                              int window_bits,
+                              int reset_interval,
+                              int input_buffer_size,
+                              off_t output_length,
+                              char is_delta)
 {
   unsigned int window_size = 1 << window_bits;
   struct lzxd_stream *lzx;
 
   if (!system) return NULL;
 
-  /* LZX supports window sizes of 2^15 (32Kb) through 2^21 (2Mb) */
-  if (window_bits < 15 || window_bits > 21) return NULL;
+  /* LZX DELTA window sizes are between 2^17 (128KiB) and 2^25 (32MiB),
+   * regular LZX windows are between 2^15 (32KiB) and 2^21 (2MiB)
+   */
+  if (is_delta) {
+      if (window_bits < 17 || window_bits > 25) return NULL;
+  }
+  else {
+      if (window_bits < 15 || window_bits > 21) return NULL;
+  }
 
+  if (reset_interval < 0 || output_length < 0) {
+      D(("reset interval or output length < 0"))
+      return NULL;
+  }
+
+  /* round up input buffer size to multiple of two */
   input_buffer_size = (input_buffer_size + 1) & -2;
-  if (!input_buffer_size) return NULL;
+  if (input_buffer_size < 2) return NULL;
 
   /* allocate decompression state */
   if (!(lzx = (struct lzxd_stream *) system->alloc(system, sizeof(struct lzxd_stream)))) {
@@ -272,6 +333,7 @@ struct lzxd_stream *lzxd_init(struct mspack_system *system,
 
   lzx->inbuf_size      = input_buffer_size;
   lzx->window_size     = 1 << window_bits;
+  lzx->ref_data_size   = 0;
   lzx->window_posn     = 0;
   lzx->frame_posn      = 0;
   lzx->frame           = 0;
@@ -280,11 +342,8 @@ struct lzxd_stream *lzxd_init(struct mspack_system *system,
   lzx->intel_curpos    = 0;
   lzx->intel_started   = 0;
   lzx->error           = MSPACK_ERR_OK;
-
-  /* window bits:    15  16  17  18  19  20  21
-   * position slots: 30  32  34  36  38  42  50  */
-  lzx->posn_slots      = ((window_bits == 21) ? 50 :
-                          ((window_bits == 20) ? 42 : (window_bits << 1)));
+  lzx->num_offsets     = position_slots[window_bits - 15] << 3;
+  lzx->is_delta        = is_delta;
 
   lzx->o_ptr = lzx->o_end = &lzx->e8_buf[0];
   lzxd_reset_state(lzx);
@@ -292,8 +351,44 @@ struct lzxd_stream *lzxd_init(struct mspack_system *system,
   return lzx;
 }
 
+int lzxd_set_reference_data(struct lzxd_stream *lzx,
+                            struct mspack_system *system,
+                            struct mspack_file *input,
+                            unsigned int length)
+{
+    if (!lzx) return MSPACK_ERR_ARGS;
+
+    if (!lzx->is_delta) {
+        D(("only LZX DELTA streams support reference data"))
+        return MSPACK_ERR_ARGS;
+    }
+    if (lzx->offset) {
+        D(("too late to set reference data after decoding starts"))
+        return MSPACK_ERR_ARGS;
+    }
+    if (length > lzx->window_size) {
+        D(("reference length (%u) is longer than the window", length))
+        return MSPACK_ERR_ARGS;
+    }
+    if (length > 0 && (!system || !input)) {
+        D(("length > 0 but no system or input"))
+        return MSPACK_ERR_ARGS;
+    }
+
+    lzx->ref_data_size = length;
+    if (length > 0) {
+        /* copy reference data */
+        unsigned char *pos = &lzx->window[lzx->window_size - length];
+        int bytes = system->read(input, pos, length);
+        /* length can't be more than 2^25, so no signedness problem */
+        if (bytes < (int)length) return MSPACK_ERR_READ;
+    }
+    lzx->ref_data_size = length;
+    return MSPACK_ERR_OK;
+}
+
 void lzxd_set_output_length(struct lzxd_stream *lzx, off_t out_bytes) {
-  if (lzx) lzx->length = out_bytes;
+  if (lzx && out_bytes > 0) lzx->length = out_bytes;
 }
 
 int lzxd_decompress(struct lzxd_stream *lzx, off_t out_bytes) {
@@ -304,7 +399,7 @@ int lzxd_decompress(struct lzxd_stream *lzx, off_t out_bytes) {
   register unsigned short sym;
 
   int match_length, length_footer, extra, verbatim_bits, bytes_todo;
-  int this_run, main_element, aligned_bits, j;
+  int this_run, main_element, aligned_bits, j, warned = 0;
   unsigned char *window, *runsrc, *rundest, buf[12];
   unsigned int frame_size=0, end_frame, match_offset, window_posn;
   unsigned int R0, R1, R2;
@@ -340,8 +435,12 @@ int lzxd_decompress(struct lzxd_stream *lzx, off_t out_bytes) {
     /* have we reached the reset interval? (if there is one?) */
     if (lzx->reset_interval && ((lzx->frame % lzx->reset_interval) == 0)) {
       if (lzx->block_remaining) {
-        D(("%d bytes remaining at reset interval", lzx->block_remaining))
-        return lzx->error = MSPACK_ERR_DECRUNCH;
+        /* this is a file format error, we can make a best effort to extract what we can */
+        D(("%d bytes remaining at reset interval", lzx->block_remaining))
+        if (!warned) {
+          lzx->sys->message(NULL, "WARNING; invalid reset interval detected during LZX decompression");
+          warned++;
+        }
       }
 
       /* re-read the intel header and reset the huffman lengths */
@@ -351,6 +450,12 @@ int lzxd_decompress(struct lzxd_stream *lzx, off_t out_bytes) {
       R2 = lzx->R2;
     }
 
+    /* LZX DELTA format has chunk_size, not present in LZX format */
+    if (lzx->is_delta) {
+      ENSURE_BITS(16);
+      REMOVE_BITS(16);
+    }
+
     /* read header if necessary */
     if (!lzx->header_read) {
       /* read 1 bit. if bit=0, intel filesize = 0.
@@ -373,62 +478,61 @@ int lzxd_decompress(struct lzxd_stream *lzx, off_t out_bytes) {
     while (bytes_todo > 0) {
       /* initialise new block, if one is needed */
       if (lzx->block_remaining == 0) {
-        /* realign if previous block was an odd-sized UNCOMPRESSED block */
-        if ((lzx->block_type == LZX_BLOCKTYPE_UNCOMPRESSED) &&
-            (lzx->block_length & 1))
-        {
-          READ_IF_NEEDED;
-          i_ptr++;
-        }
-
-        /* read block type (3 bits) and block length (24 bits) */
-        READ_BITS(lzx->block_type, 3);
-        READ_BITS(i, 16); READ_BITS(j, 8);
-        lzx->block_remaining = lzx->block_length = (i << 8) | j;
-        /*D(("new block t%d len %u", lzx->block_type, lzx->block_length))*/
-
-        /* read individual block headers */
-        switch (lzx->block_type) {
-        case LZX_BLOCKTYPE_ALIGNED:
-          /* read lengths of and build aligned huffman decoding tree */
-          for (i = 0; i < 8; i++) { READ_BITS(j, 3); lzx->ALIGNED_len[i] = j; }
-          BUILD_TABLE(ALIGNED);
-          /* no break -- rest of aligned header is same as verbatim */
-        case LZX_BLOCKTYPE_VERBATIM:
-          /* read lengths of and build main huffman decoding tree */
-          READ_LENGTHS(MAINTREE, 0, 256);
-          READ_LENGTHS(MAINTREE, 256, LZX_NUM_CHARS + (lzx->posn_slots << 3));
-          BUILD_TABLE(MAINTREE);
-          /* if the literal 0xE8 is anywhere in the block... */
-          if (lzx->MAINTREE_len[0xE8] != 0) lzx->intel_started = 1;
-          /* read lengths of and build lengths huffman decoding tree */
-          READ_LENGTHS(LENGTH, 0, LZX_NUM_SECONDARY_LENGTHS);
-          BUILD_TABLE_MAYBE_EMPTY(LENGTH);
-          break;
-
-        case LZX_BLOCKTYPE_UNCOMPRESSED:
-          /* because we can't assume otherwise */
-          lzx->intel_started = 1;
-
-          /* read 1-16 (not 0-15) bits to align to bytes */
-          ENSURE_BITS(16);
-          if (bits_left > 16) i_ptr -= 2;
-          bits_left = 0; bit_buffer = 0;
-
-          /* read 12 bytes of stored R0 / R1 / R2 values */
-          for (rundest = &buf[0], i = 0; i < 12; i++) {
-            READ_IF_NEEDED;
-            *rundest++ = *i_ptr++;
-          }
-          R0 = buf[0] | (buf[1] << 8) | (buf[2]  << 16) | (buf[3]  << 24);
-          R1 = buf[4] | (buf[5] << 8) | (buf[6]  << 16) | (buf[7]  << 24);
-          R2 = buf[8] | (buf[9] << 8) | (buf[10] << 16) | (buf[11] << 24);
-          break;
-
-        default:
-          D(("bad block type"))
-          return lzx->error = MSPACK_ERR_DECRUNCH;
-        }
+        /* realign if previous block was an odd-sized UNCOMPRESSED block */
+        if ((lzx->block_type == LZX_BLOCKTYPE_UNCOMPRESSED) &&
+            (lzx->block_length & 1))
+        {
+          READ_IF_NEEDED;
+          i_ptr++;
+        }
+
+        /* read block type (3 bits) and block length (24 bits) */
+        READ_BITS(lzx->block_type, 3);
+        READ_BITS(i, 16); READ_BITS(j, 8);
+        lzx->block_remaining = lzx->block_length = (i << 8) | j;
+        /*D(("new block t%d len %u", lzx->block_type, lzx->block_length))*/
+
+        /* read individual block headers */
+        switch (lzx->block_type) {
+        case LZX_BLOCKTYPE_ALIGNED:
+          /* read lengths of and build aligned huffman decoding tree */
+          for (i = 0; i < 8; i++) { READ_BITS(j, 3); lzx->ALIGNED_len[i] = j; }
+          BUILD_TABLE(ALIGNED);
+          /* rest of aligned header is same as verbatim */ /*@fallthrough@*/
+        case LZX_BLOCKTYPE_VERBATIM:
+          /* read lengths of and build main huffman decoding tree */
+          READ_LENGTHS(MAINTREE, 0, 256);
+          READ_LENGTHS(MAINTREE, 256, LZX_NUM_CHARS + lzx->num_offsets);
+          BUILD_TABLE(MAINTREE);
+          /* if the literal 0xE8 is anywhere in the block... */
+          if (lzx->MAINTREE_len[0xE8] != 0) lzx->intel_started = 1;
+          /* read lengths of and build lengths huffman decoding tree */
+          READ_LENGTHS(LENGTH, 0, LZX_NUM_SECONDARY_LENGTHS);
+          BUILD_TABLE_MAYBE_EMPTY(LENGTH);
+          break;
+
+        case LZX_BLOCKTYPE_UNCOMPRESSED:
+          /* because we can't assume otherwise */
+          lzx->intel_started = 1;
+
+          /* read 1-16 (not 0-15) bits to align to bytes */
+          if (bits_left == 0) ENSURE_BITS(16);
+          bits_left = 0; bit_buffer = 0;
+
+          /* read 12 bytes of stored R0 / R1 / R2 values */
+          for (rundest = &buf[0], i = 0; i < 12; i++) {
+            READ_IF_NEEDED;
+            *rundest++ = *i_ptr++;
+          }
+          R0 = buf[0] | (buf[1] << 8) | (buf[2]  << 16) | (buf[3]  << 24);
+          R1 = buf[4] | (buf[5] << 8) | (buf[6]  << 16) | (buf[7]  << 24);
+          R2 = buf[8] | (buf[9] << 8) | (buf[10] << 16) | (buf[11] << 24);
+          break;
+
+        default:
+          D(("bad block type"))
+          return lzx->error = MSPACK_ERR_DECRUNCH;
+        }
       }
 
       /* decode more of the block:
@@ -443,208 +547,270 @@ int lzxd_decompress(struct lzxd_stream *lzx, off_t out_bytes) {
       /* decode at least this_run bytes */
       switch (lzx->block_type) {
       case LZX_BLOCKTYPE_VERBATIM:
-        while (this_run > 0) {
-          READ_HUFFSYM(MAINTREE, main_element);
-          if (main_element < LZX_NUM_CHARS) {
-            /* literal: 0 to LZX_NUM_CHARS-1 */
-            window[window_posn++] = main_element;
-            this_run--;
-          }
-          else {
-            /* match: LZX_NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
-            main_element -= LZX_NUM_CHARS;
-
-            /* get match length */
-            match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
-            if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
-              if (lzx->LENGTH_empty) {
+        while (this_run > 0) {
+          READ_HUFFSYM(MAINTREE, main_element);
+          if (main_element < LZX_NUM_CHARS) {
+            /* literal: 0 to LZX_NUM_CHARS-1 */
+            window[window_posn++] = main_element;
+            this_run--;
+          }
+          else {
+            /* match: LZX_NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
+            main_element -= LZX_NUM_CHARS;
+
+            /* get match length */
+            match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
+            if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
+              if (lzx->LENGTH_empty) {
                 D(("LENGTH symbol needed but tree is empty"))
                 return lzx->error = MSPACK_ERR_DECRUNCH;
               }
-              READ_HUFFSYM(LENGTH, length_footer);
-              match_length += length_footer;
-            }
-            match_length += LZX_MIN_MATCH;
-          
-            /* get match offset */
-            switch ((match_offset = (main_element >> 3))) {
-            case 0: match_offset = R0;                                  break;
-            case 1: match_offset = R1; R1=R0;        R0 = match_offset; break;
-            case 2: match_offset = R2; R2=R0;        R0 = match_offset; break;
-            case 3: match_offset = 1;  R2=R1; R1=R0; R0 = match_offset; break;
-            default:
-              extra = extra_bits[match_offset];
-              READ_BITS(verbatim_bits, extra);
-              match_offset = position_base[match_offset] - 2 + verbatim_bits;
-              R2 = R1; R1 = R0; R0 = match_offset;
-            }
-
-            if ((window_posn + match_length) > lzx->window_size) {
-              D(("match ran over window wrap"))
-              return lzx->error = MSPACK_ERR_DECRUNCH;
-            }
-            
-            /* copy match */
-            rundest = &window[window_posn];
-            i = match_length;
-            /* does match offset wrap the window? */
-            if (match_offset > window_posn) {
-              /* j = length from match offset to end of window */
-              j = match_offset - window_posn;
-              if (j > (int) lzx->window_size) {
-                D(("match offset beyond window boundaries"))
-                return lzx->error = MSPACK_ERR_DECRUNCH;
-              }
-              runsrc = &window[lzx->window_size - j];
-              if (j < i) {
-                /* if match goes over the window edge, do two copy runs */
-                i -= j; while (j-- > 0) *rundest++ = *runsrc++;
-                runsrc = window;
-              }
-              while (i-- > 0) *rundest++ = *runsrc++;
-            }
-            else {
-              runsrc = rundest - match_offset;
-              while (i-- > 0) *rundest++ = *runsrc++;
-            }
-
-            this_run    -= match_length;
-            window_posn += match_length;
-          }
-        } /* while (this_run > 0) */
-        break;
+              READ_HUFFSYM(LENGTH, length_footer);
+              match_length += length_footer;
+            }
+            match_length += LZX_MIN_MATCH;
+
+            /* get match offset */
+            switch ((match_offset = (main_element >> 3))) {
+            case 0: match_offset = R0;                                  break;
+            case 1: match_offset = R1; R1=R0;        R0 = match_offset; break;
+            case 2: match_offset = R2; R2=R0;        R0 = match_offset; break;
+            case 3: match_offset = 1;  R2=R1; R1=R0; R0 = match_offset; break;
+            default:
+              extra = (match_offset >= 36) ? 17 : extra_bits[match_offset];
+              READ_BITS(verbatim_bits, extra);
+              match_offset = position_base[match_offset] - 2 + verbatim_bits;
+              R2 = R1; R1 = R0; R0 = match_offset;
+            }
+
+            /* LZX DELTA uses max match length to signal even longer match */
+            if (match_length == LZX_MAX_MATCH && lzx->is_delta) {
+                int extra_len = 0;
+                ENSURE_BITS(3); /* 4 entry huffman tree */
+                if (PEEK_BITS(1) == 0) {
+                    REMOVE_BITS(1); /* '0' -> 8 extra length bits */
+                    READ_BITS(extra_len, 8);
+                }
+                else if (PEEK_BITS(2) == 2) {
+                    REMOVE_BITS(2); /* '10' -> 10 extra length bits + 0x100 */
+                    READ_BITS(extra_len, 10);
+                    extra_len += 0x100;
+                }
+                else if (PEEK_BITS(3) == 6) {
+                    REMOVE_BITS(3); /* '110' -> 12 extra length bits + 0x500 */
+                    READ_BITS(extra_len, 12);
+                    extra_len += 0x500;
+                }
+                else {
+                    REMOVE_BITS(3); /* '111' -> 15 extra length bits */
+                    READ_BITS(extra_len, 15);
+                }
+                match_length += extra_len;
+            }
+
+            if ((window_posn + match_length) > lzx->window_size) {
+              D(("match ran over window wrap"))
+              return lzx->error = MSPACK_ERR_DECRUNCH;
+            }
+            
+            /* copy match */
+            rundest = &window[window_posn];
+            i = match_length;
+            /* does match offset wrap the window? */
+            if (match_offset > window_posn) {
+              if (match_offset > lzx->offset &&
+                  (match_offset - window_posn) > lzx->ref_data_size)
+              {
+                D(("match offset beyond LZX stream"))
+                return lzx->error = MSPACK_ERR_DECRUNCH;
+              }
+              /* j = length from match offset to end of window */
+              j = match_offset - window_posn;
+              if (j > (int) lzx->window_size) {
+                D(("match offset beyond window boundaries"))
+                return lzx->error = MSPACK_ERR_DECRUNCH;
+              }
+              runsrc = &window[lzx->window_size - j];
+              if (j < i) {
+                /* if match goes over the window edge, do two copy runs */
+                i -= j; while (j-- > 0) *rundest++ = *runsrc++;
+                runsrc = window;
+              }
+              while (i-- > 0) *rundest++ = *runsrc++;
+            }
+            else {
+              runsrc = rundest - match_offset;
+              while (i-- > 0) *rundest++ = *runsrc++;
+            }
+
+            this_run    -= match_length;
+            window_posn += match_length;
+          }
+        } /* while (this_run > 0) */
+        break;
 
       case LZX_BLOCKTYPE_ALIGNED:
-        while (this_run > 0) {
-          READ_HUFFSYM(MAINTREE, main_element);
-          if (main_element < LZX_NUM_CHARS) {
-            /* literal: 0 to LZX_NUM_CHARS-1 */
-            window[window_posn++] = main_element;
-            this_run--;
-          }
-          else {
-            /* match: LZX_NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
-            main_element -= LZX_NUM_CHARS;
-
-            /* get match length */
-            match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
-            if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
+        while (this_run > 0) {
+          READ_HUFFSYM(MAINTREE, main_element);
+          if (main_element < LZX_NUM_CHARS) {
+            /* literal: 0 to LZX_NUM_CHARS-1 */
+            window[window_posn++] = main_element;
+            this_run--;
+          }
+          else {
+            /* match: LZX_NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
+            main_element -= LZX_NUM_CHARS;
+
+            /* get match length */
+            match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
+            if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
               if (lzx->LENGTH_empty) {
                 D(("LENGTH symbol needed but tree is empty"))
                 return lzx->error = MSPACK_ERR_DECRUNCH;
               } 
-              READ_HUFFSYM(LENGTH, length_footer);
-              match_length += length_footer;
-            }
-            match_length += LZX_MIN_MATCH;
-
-            /* get match offset */
-            switch ((match_offset = (main_element >> 3))) {
-            case 0: match_offset = R0;                             break;
-            case 1: match_offset = R1; R1 = R0; R0 = match_offset; break;
-            case 2: match_offset = R2; R2 = R0; R0 = match_offset; break;
-            default:
-              extra = extra_bits[match_offset];
-              match_offset = position_base[match_offset] - 2;
-              if (extra > 3) {
-                /* verbatim and aligned bits */
-                extra -= 3;
-                READ_BITS(verbatim_bits, extra);
-                match_offset += (verbatim_bits << 3);
-                READ_HUFFSYM(ALIGNED, aligned_bits);
-                match_offset += aligned_bits;
-              }
-              else if (extra == 3) {
-                /* aligned bits only */
-                READ_HUFFSYM(ALIGNED, aligned_bits);
-                match_offset += aligned_bits;
-              }
-              else if (extra > 0) { /* extra==1, extra==2 */
-                /* verbatim bits only */
-                READ_BITS(verbatim_bits, extra);
-                match_offset += verbatim_bits;
-              }
-              else /* extra == 0 */ {
-                /* ??? not defined in LZX specification! */
-                match_offset = 1;
-              }
-              /* update repeated offset LRU queue */
-              R2 = R1; R1 = R0; R0 = match_offset;
-            }
-
-            if ((window_posn + match_length) > lzx->window_size) {
-              D(("match ran over window wrap"))
-              return lzx->error = MSPACK_ERR_DECRUNCH;
-            }
-
-            /* copy match */
-            rundest = &window[window_posn];
-            i = match_length;
-            /* does match offset wrap the window? */
-            if (match_offset > window_posn) {
-              /* j = length from match offset to end of window */
-              j = match_offset - window_posn;
-              if (j > (int) lzx->window_size) {
-                D(("match offset beyond window boundaries"))
-                return lzx->error = MSPACK_ERR_DECRUNCH;
-              }
-              runsrc = &window[lzx->window_size - j];
-              if (j < i) {
-                /* if match goes over the window edge, do two copy runs */
-                i -= j; while (j-- > 0) *rundest++ = *runsrc++;
-                runsrc = window;
-              }
-              while (i-- > 0) *rundest++ = *runsrc++;
-            }
-            else {
-              runsrc = rundest - match_offset;
-              while (i-- > 0) *rundest++ = *runsrc++;
-            }
-
-            this_run    -= match_length;
-            window_posn += match_length;
-          }
-        } /* while (this_run > 0) */
-        break;
+              READ_HUFFSYM(LENGTH, length_footer);
+              match_length += length_footer;
+            }
+            match_length += LZX_MIN_MATCH;
+
+            /* get match offset */
+            switch ((match_offset = (main_element >> 3))) {
+            case 0: match_offset = R0;                             break;
+            case 1: match_offset = R1; R1 = R0; R0 = match_offset; break;
+            case 2: match_offset = R2; R2 = R0; R0 = match_offset; break;
+            default:
+              extra = (match_offset >= 36) ? 17 : extra_bits[match_offset];
+              match_offset = position_base[match_offset] - 2;
+              if (extra > 3) {
+                /* verbatim and aligned bits */
+                extra -= 3;
+                READ_BITS(verbatim_bits, extra);
+                match_offset += (verbatim_bits << 3);
+                READ_HUFFSYM(ALIGNED, aligned_bits);
+                match_offset += aligned_bits;
+              }
+              else if (extra == 3) {
+                /* aligned bits only */
+                READ_HUFFSYM(ALIGNED, aligned_bits);
+                match_offset += aligned_bits;
+              }
+              else if (extra > 0) { /* extra==1, extra==2 */
+                /* verbatim bits only */
+                READ_BITS(verbatim_bits, extra);
+                match_offset += verbatim_bits;
+              }
+              else /* extra == 0 */ {
+                /* ??? not defined in LZX specification! */
+                match_offset = 1;
+              }
+              /* update repeated offset LRU queue */
+              R2 = R1; R1 = R0; R0 = match_offset;
+            }
+
+            /* LZX DELTA uses max match length to signal even longer match */
+            if (match_length == LZX_MAX_MATCH && lzx->is_delta) {
+                int extra_len = 0;
+                ENSURE_BITS(3); /* 4 entry huffman tree */
+                if (PEEK_BITS(1) == 0) {
+                    REMOVE_BITS(1); /* '0' -> 8 extra length bits */
+                    READ_BITS(extra_len, 8);
+                }
+                else if (PEEK_BITS(2) == 2) {
+                    REMOVE_BITS(2); /* '10' -> 10 extra length bits + 0x100 */
+                    READ_BITS(extra_len, 10);
+                    extra_len += 0x100;
+                }
+                else if (PEEK_BITS(3) == 6) {
+                    REMOVE_BITS(3); /* '110' -> 12 extra length bits + 0x500 */
+                    READ_BITS(extra_len, 12);
+                    extra_len += 0x500;
+                }
+                else {
+                    REMOVE_BITS(3); /* '111' -> 15 extra length bits */
+                    READ_BITS(extra_len, 15);
+                }
+                match_length += extra_len;
+            }
+
+            if ((window_posn + match_length) > lzx->window_size) {
+              D(("match ran over window wrap"))
+              return lzx->error = MSPACK_ERR_DECRUNCH;
+            }
+
+            /* copy match */
+            rundest = &window[window_posn];
+            i = match_length;
+            /* does match offset wrap the window? */
+            if (match_offset > window_posn) {
+              if (match_offset > lzx->offset &&
+                  (match_offset - window_posn) > lzx->ref_data_size)
+              {
+                D(("match offset beyond LZX stream"))
+                return lzx->error = MSPACK_ERR_DECRUNCH;
+              }
+              /* j = length from match offset to end of window */
+              j = match_offset - window_posn;
+              if (j > (int) lzx->window_size) {
+                D(("match offset beyond window boundaries"))
+                return lzx->error = MSPACK_ERR_DECRUNCH;
+              }
+              runsrc = &window[lzx->window_size - j];
+              if (j < i) {
+                /* if match goes over the window edge, do two copy runs */
+                i -= j; while (j-- > 0) *rundest++ = *runsrc++;
+                runsrc = window;
+              }
+              while (i-- > 0) *rundest++ = *runsrc++;
+            }
+            else {
+              runsrc = rundest - match_offset;
+              while (i-- > 0) *rundest++ = *runsrc++;
+            }
+
+            this_run    -= match_length;
+            window_posn += match_length;
+          }
+        } /* while (this_run > 0) */
+        break;
 
       case LZX_BLOCKTYPE_UNCOMPRESSED:
-        /* as this_run is limited not to wrap a frame, this also means it
-         * won't wrap the window (as the window is a multiple of 32k) */
-        rundest = &window[window_posn];
-        window_posn += this_run;
-        while (this_run > 0) {
-          if ((i = i_end - i_ptr) == 0) {
-            READ_IF_NEEDED;
-          }
-          else {
-            if (i > this_run) i = this_run;
-            lzx->sys->copy(i_ptr, rundest, (size_t) i);
-            rundest  += i;
-            i_ptr    += i;
-            this_run -= i;
-          }
-        }
-        break;
+        /* as this_run is limited not to wrap a frame, this also means it
+         * won't wrap the window (as the window is a multiple of 32k) */
+        rundest = &window[window_posn];
+        window_posn += this_run;
+        while (this_run > 0) {
+          if ((i = i_end - i_ptr) == 0) {
+            READ_IF_NEEDED;
+          }
+          else {
+            if (i > this_run) i = this_run;
+            lzx->sys->copy(i_ptr, rundest, (size_t) i);
+            rundest  += i;
+            i_ptr    += i;
+            this_run -= i;
+          }
+        }
+        break;
 
       default:
-        return lzx->error = MSPACK_ERR_DECRUNCH; /* might as well */
+        return lzx->error = MSPACK_ERR_DECRUNCH; /* might as well */
       }
 
       /* did the final match overrun our desired this_run length? */
       if (this_run < 0) {
-        if ((unsigned int)(-this_run) > lzx->block_remaining) {
-          D(("overrun went past end of block by %d (%d remaining)",
-             -this_run, lzx->block_remaining ))
-          return lzx->error = MSPACK_ERR_DECRUNCH;
-        }
-        lzx->block_remaining -= -this_run;
+        if ((unsigned int)(-this_run) > lzx->block_remaining) {
+          D(("overrun went past end of block by %d (%d remaining)",
+             -this_run, lzx->block_remaining ))
+          return lzx->error = MSPACK_ERR_DECRUNCH;
+        }
+        lzx->block_remaining -= -this_run;
       }
     } /* while (bytes_todo > 0) */
 
     /* streams don't extend over frame boundaries */
     if ((window_posn - lzx->frame_posn) != frame_size) {
       D(("decode beyond output frame limits! %d != %d",
-         window_posn - lzx->frame_posn, frame_size))
+         window_posn - lzx->frame_posn, frame_size))
       return lzx->error = MSPACK_ERR_DECRUNCH;
     }
 
@@ -654,13 +820,14 @@ int lzxd_decompress(struct lzxd_stream *lzx, off_t out_bytes) {
 
     /* check that we've used all of the previous frame first */
     if (lzx->o_ptr != lzx->o_end) {
-      D(("%ld avail bytes, new %d frame", lzx->o_end-lzx->o_ptr, frame_size))
+      D(("%ld avail bytes, new %d frame",
+          (long)(lzx->o_end - lzx->o_ptr), frame_size))
       return lzx->error = MSPACK_ERR_DECRUNCH;
     }
 
     /* does this intel block _really_ need decoding? */
     if (lzx->intel_started && lzx->intel_filesize &&
-        (lzx->frame <= 32768) && (frame_size > 10))
+        (lzx->frame <= 32768) && (frame_size > 10))
     {
       unsigned char *data    = &lzx->e8_buf[0];
       unsigned char *dataend = &lzx->e8_buf[frame_size - 10];
@@ -673,17 +840,17 @@ int lzxd_decompress(struct lzxd_stream *lzx, off_t out_bytes) {
       lzx->sys->copy(&lzx->window[lzx->frame_posn], data, frame_size);
 
       while (data < dataend) {
-        if (*data++ != 0xE8) { curpos++; continue; }
-        abs_off = data[0] | (data[1]<<8) | (data[2]<<16) | (data[3]<<24);
-        if ((abs_off >= -curpos) && (abs_off < filesize)) {
-          rel_off = (abs_off >= 0) ? abs_off - curpos : abs_off + filesize;
-          data[0] = (unsigned char) rel_off;
-          data[1] = (unsigned char) (rel_off >> 8);
-          data[2] = (unsigned char) (rel_off >> 16);
-          data[3] = (unsigned char) (rel_off >> 24);
-        }
-        data += 4;
-        curpos += 5;
+        if (*data++ != 0xE8) { curpos++; continue; }
+        abs_off = data[0] | (data[1]<<8) | (data[2]<<16) | (data[3]<<24);
+        if ((abs_off >= -curpos) && (abs_off < filesize)) {
+          rel_off = (abs_off >= 0) ? abs_off - curpos : abs_off + filesize;
+          data[0] = (unsigned char) rel_off;
+          data[1] = (unsigned char) (rel_off >> 8);
+          data[2] = (unsigned char) (rel_off >> 16);
+          data[3] = (unsigned char) (rel_off >> 24);
+        }
+        data += 4;
+        curpos += 5;
       }
       lzx->intel_curpos += frame_size;
     }