1 files changed, 130 insertions, 74 deletions

diff --git a/inflate.c b/inflate.c
index b76e246..bed4e54 100644
--- a/inflate.c
+++ b/inflate.c
@@ -15,38 +15,63 @@ struct internal_state {
   enum {
       METHOD,   /* waiting for method byte */
       FLAG,     /* waiting for flag byte */
-      START,    /* make new blocks state */
       BLOCKS,   /* decompressing blocks */
       CHECK4,   /* four check bytes to go */
       CHECK3,   /* three check bytes to go */
       CHECK2,   /* two check bytes to go */
       CHECK1,   /* one check byte to go */
       DONE,     /* finished check, done */
-      INF_ERROR}/* got an error--stay here */
+      BAD}      /* got an error--stay here */
     mode;               /* current inflate mode */
 
   /* mode dependent information */
   union {
     uInt method;        /* if FLAGS, method byte */
-    struct inflate_blocks_state
-      *blocks;          /* if BLOCKS, current state */
     struct {
-      uLong was;                /* computed check value */
-      uLong need;               /* stream check value */
-    } check;            /* if CHECK, check values to compare */
+      uLong was;                /* computed check value */
+      uLong need;               /* stream check value */
+    } check;            /* if CHECK, check values to compare */
+    uInt marker;        /* if BAD, inflateSync's marker bytes count */
   } sub;        /* submode */
 
   /* mode independent information */
   int  nowrap;          /* flag for no wrapper */
   uInt wbits;           /* log2(window size)  (8..15, defaults to 15) */
+  struct inflate_blocks_state
+    *blocks;            /* current inflate_blocks state */
 
 };
 
 
-int inflateInit(z)
+int inflateReset(z)
 z_stream *z;
 {
-    return inflateInit2(z, WBITS);
+  uLong c;
+
+  if (z == Z_NULL || z->state == Z_NULL)
+    return Z_STREAM_ERROR;
+  z->total_in = z->total_out = 0;
+  z->msg = Z_NULL;
+  z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
+  inflate_blocks_reset(z->state->blocks, z, &c);
+  Trace((stderr, "inflate: reset\n"));
+  return Z_OK;
+}
+
+
+int inflateEnd(z)
+z_stream *z;
+{
+  uLong c;
+
+  if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
+    return Z_STREAM_ERROR;
+  if (z->state->blocks != Z_NULL)
+    inflate_blocks_free(z->state->blocks, z, &c);
+  ZFREE(z, z->state);
+  z->state = Z_NULL;
+  Trace((stderr, "inflate: end\n"));
+  return Z_OK;
 }
 
 
@@ -59,12 +84,10 @@ int w;
     return Z_STREAM_ERROR;
   if (z->zalloc == Z_NULL) z->zalloc = zcalloc;
   if (z->zfree == Z_NULL) z->zfree = zcfree;
-  z->total_in = z->total_out = 0;
-  z->msg = Z_NULL;
   if ((z->state = (struct internal_state *)
        ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
     return Z_MEM_ERROR;
-  z->state->mode = METHOD;
+  z->state->blocks = Z_NULL;
 
   /* handle undocumented nowrap option (no zlib header or check) */
   z->state->nowrap = 0;
@@ -72,7 +95,6 @@ int w;
   {
     w = - w;
     z->state->nowrap = 1;
-    z->state->mode = START;
   }
 
   /* set window size */
@@ -81,20 +103,40 @@ int w;
     inflateEnd(z);
     return Z_STREAM_ERROR;
   }
-  z->state->wbits = w;
+  z->state->wbits = (uInt)w;
+
+  /* create inflate_blocks state */
+  if ((z->state->blocks =
+       inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, 1 << w))
+      == Z_NULL)
+  {
+    inflateEnd(z);
+    return Z_MEM_ERROR;
+  }
+  Trace((stderr, "inflate: allocated\n"));
+
+  /* reset state */
+  inflateReset(z);
   return Z_OK;
 }
 
 
+int inflateInit(z)
+z_stream *z;
+{
+  return inflateInit2(z, DEF_WBITS);
+}
+
+
+#define NEEDBYTE {if(z->avail_in==0)return r;r=Z_OK;}
 #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
 
 int inflate(z, f)
 z_stream *z;
 int f;
 {
-  int r = f; /* to avoid warning about unused f */
+  int r = f;    /* to avoid warning about unused f */
   uInt b;
-  uLong c;
 
   if (z == Z_NULL || z->next_in == Z_NULL)
     return Z_STREAM_ERROR;
@@ -102,77 +144,86 @@ int f;
   while (1) switch (z->state->mode)
   {
     case METHOD:
-      if (z->avail_in == 0) return r;  r = Z_OK;
+      NEEDBYTE
       if (((z->state->sub.method = NEXTBYTE) & 0xf != DEFLATED))
       {
-        z->state->mode = INF_ERROR;
+        z->state->mode = BAD;
         z->msg = "unknown compression method";
-        return Z_DATA_ERROR;
+        z->state->sub.marker = 5;       /* can't try inflateSync */
+        break;
       }
       if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
       {
-        z->state->mode = INF_ERROR;
+        z->state->mode = BAD;
         z->msg = "invalid window size";
-        return Z_DATA_ERROR;
+        z->state->sub.marker = 5;       /* can't try inflateSync */
+        break;
       }
       z->state->mode = FLAG;
     case FLAG:
-      if (z->avail_in == 0) return r;  r = Z_OK;
+      NEEDBYTE
       if ((b = NEXTBYTE) & 0x20)
       {
-        z->state->mode = INF_ERROR;
+        z->state->mode = BAD;
         z->msg = "invalid reserved bit";
-        return Z_DATA_ERROR;
+        z->state->sub.marker = 5;       /* can't try inflateSync */
+        break;
       }
       if (((z->state->sub.method << 8) + b) % 31)
       {
-        z->state->mode = INF_ERROR;
+        z->state->mode = BAD;
         z->msg = "incorrect header check";
-        return Z_DATA_ERROR;
+        z->state->sub.marker = 5;       /* can't try inflateSync */
+        break;
       }
-      z->state->mode = START;
-    case START:
-      if ((z->state->sub.blocks = inflate_blocks_new(z,
-         z->state->nowrap ? Z_NULL : adler32,
-         1<< z->state->wbits)) == Z_NULL)
-        return Z_MEM_ERROR;
+      Trace((stderr, "inflate: zlib header ok\n"));
       z->state->mode = BLOCKS;
     case BLOCKS:
-      if ((r = inflate_blocks(z->state->sub.blocks, z, r)) != Z_STREAM_END)
-        return r;
-      inflate_blocks_free(z->state->sub.blocks, z, &c);
+      r = inflate_blocks(z->state->blocks, z, r);
+      if (r == Z_DATA_ERROR)
+      {
+        z->state->mode = BAD;
+        z->state->sub.marker = 0;       /* can try inflateSync */
+        break;
+      }
+      if (r != Z_STREAM_END)
+        return r;
+      r = Z_OK;
+      inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
       if (z->state->nowrap)
       {
-      z->state->mode = DONE;
+        z->state->mode = DONE;
         break;
       }
-      z->state->sub.check.was = c;
       z->state->mode = CHECK4;
     case CHECK4:
-      if (z->avail_in == 0) return r;  r = Z_OK;
+      NEEDBYTE
       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
       z->state->mode = CHECK3;
     case CHECK3:
-      if (z->avail_in == 0) return r;  r = Z_OK;
+      NEEDBYTE
       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
       z->state->mode = CHECK2;
     case CHECK2:
-      if (z->avail_in == 0) return r;  r = Z_OK;
+      NEEDBYTE
       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
       z->state->mode = CHECK1;
     case CHECK1:
-      if (z->avail_in == 0) return r;  r = Z_OK;
+      NEEDBYTE
       z->state->sub.check.need += (uLong)NEXTBYTE;
+
       if (z->state->sub.check.was != z->state->sub.check.need)
       {
-        z->state->mode = INF_ERROR;
+        z->state->mode = BAD;
         z->msg = "incorrect data check";
-        return Z_DATA_ERROR;
+        z->state->sub.marker = 5;       /* can't try inflateSync */
+        break;
       }
+      Trace((stderr, "inflate: zlib check ok\n"));
       z->state->mode = DONE;
     case DONE:
       return Z_STREAM_END;
-    case INF_ERROR:
+    case BAD:
       return Z_DATA_ERROR;
     default:
       return Z_STREAM_ERROR;
@@ -180,41 +231,46 @@ int f;
 }
 
 
-int inflateEnd(z)
+int inflateSync(z)
 z_stream *z;
 {
-  uLong c;
+  uInt n;       /* number of bytes to look at */
+  Byte *p;      /* pointer to bytes */
+  uInt m;       /* number of marker bytes found in a row */
+  uLong r, w;   /* temporaries to save total_in and total_out */
 
-  if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
+  /* set up */
+  if (z == Z_NULL || z->state == Z_NULL)
     return Z_STREAM_ERROR;
-  if (z->state->mode == BLOCKS)
-    inflate_blocks_free(z->state->sub.blocks, z, &c);
-  ZFREE(z, z->state);
-  z->state = Z_NULL;
-  return Z_OK;
-}
-
-
-/* inflateSync not implemented yet--this just consumes input */
-int inflateSync(z)
-z_stream *z;
-{
-  if (z == Z_NULL) return Z_STREAM_ERROR;
-  if (z->avail_in == 0) return Z_BUF_ERROR;
-  do {
-    z->total_in++;
-  } while (--z->avail_in);
-  return Z_DATA_ERROR;
-}
+  if (z->state->mode != BAD)
+    z->state->sub.marker = 0;
+  if ((n = z->avail_in) == 0)
+    return Z_BUF_ERROR;
+  p = z->next_in;
+  m = z->state->sub.marker;
 
+  /* search */
+  while (n && m < 4)
+  {
+    if (*p == (m < 2 ? 0 : 0xff))
+      m++;
+    else if (*p || m > 2)
+      m = 0;
+    p++, n--;
+  }
 
-/* inflateReset not fully implemented yet--this frees and reallocates */
-int inflateReset(z)
-z_stream *z;
-{
-  int r;
+  /* restore */
+  z->total_in += p - z->next_in;
+  z->next_in = p;
+  z->avail_in = n;
+  z->state->sub.marker = m;
 
-  if ((r = inflateEnd(z)) != Z_OK)
-    return r;
-  return inflateInit(z);
+  /* return no joy or set up to restart on a new block */
+  if (m != 4)
+    return Z_DATA_ERROR;
+  r = z->total_in;  w = z->total_out;
+  inflateReset(z);
+  z->total_in = r;  z->total_out = w;
+  z->state->mode = BLOCKS;
+  return Z_OK;
 }