sl@0: /* inflate.c -- zlib interface to inflate modules
sl@0:  * Copyright (C) 1995-1998 Mark Adler
sl@0:  * For conditions of distribution and use, see copyright notice in zlib.h 
sl@0:  */
sl@0: 
sl@0: #include "zutil.h"
sl@0: #include "infblock.h"
sl@0: 
sl@0: struct inflate_blocks_state {int dummy;}; /* for buggy compilers */
sl@0: 
sl@0: typedef enum {
sl@0:       METHOD,   /* waiting for method byte */
sl@0:       FLAG,     /* waiting for flag byte */
sl@0:       DICT4,    /* four dictionary check bytes to go */
sl@0:       DICT3,    /* three dictionary check bytes to go */
sl@0:       DICT2,    /* two dictionary check bytes to go */
sl@0:       DICT1,    /* one dictionary check byte to go */
sl@0:       DICT0,    /* waiting for inflateSetDictionary */
sl@0:       BLOCKS,   /* decompressing blocks */
sl@0:       CHECK4,   /* four check bytes to go */
sl@0:       CHECK3,   /* three check bytes to go */
sl@0:       CHECK2,   /* two check bytes to go */
sl@0:       CHECK1,   /* one check byte to go */
sl@0:       DONE,     /* finished check, done */
sl@0:       BAD}      /* got an error--stay here */
sl@0: inflate_mode;
sl@0: 
sl@0: /* inflate private state */
sl@0: struct internal_state {
sl@0: 
sl@0:   /* mode */
sl@0:   inflate_mode  mode;   /* current inflate mode */
sl@0: 	
sl@0:   /* mode dependent information */
sl@0:   union {
sl@0:     uInt method;        /* if FLAGS, method byte */
sl@0:     struct {
sl@0:       uLong was;                /* computed check value */
sl@0:       uLong need;               /* stream check value */
sl@0:     } check;            /* if CHECK, check values to compare */
sl@0:     uInt marker;        /* if BAD, inflateSync's marker bytes count */
sl@0:   } sub;        /* submode */
sl@0: 
sl@0:   /* mode independent information */
sl@0:   int  nowrap;          /* flag for no wrapper */
sl@0:   uInt wbits;           /* log2(window size)  (8..15, defaults to 15) */
sl@0:   inflate_blocks_statef 
sl@0:     *blocks;            /* current inflate_blocks state */
sl@0: 
sl@0: };
sl@0: 
sl@0: 
sl@0: EXPORT_C int ZEXPORT inflateReset(
sl@0: z_streamp z)
sl@0: {
sl@0:   if (z == Z_NULL || z->state == Z_NULL)
sl@0:     return Z_STREAM_ERROR;
sl@0:   z->total_in = z->total_out = 0;
sl@0:   z->msg = Z_NULL;
sl@0:   z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
sl@0:   inflate_blocks_reset(z->state->blocks, z, Z_NULL);
sl@0:   Tracev((stderr, "inflate: reset\n"));
sl@0:   return Z_OK;
sl@0: }
sl@0: 
sl@0: 
sl@0: EXPORT_C int ZEXPORT inflateEnd(
sl@0: z_streamp z)
sl@0: {
sl@0:   if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
sl@0:     return Z_STREAM_ERROR;
sl@0:   if (z->state->blocks != Z_NULL)
sl@0:     inflate_blocks_free(z->state->blocks, z);
sl@0:   ZFREE(z, z->state);
sl@0:   z->state = Z_NULL;
sl@0:   Tracev((stderr, "inflate: end\n"));
sl@0:   return Z_OK;
sl@0: }
sl@0: 
sl@0: 
sl@0: EXPORT_C int ZEXPORT inflateInit2_(
sl@0: z_streamp z,
sl@0: int w,
sl@0: const char *version,
sl@0: int stream_size)
sl@0: {
sl@0:   if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
sl@0:       stream_size != sizeof(z_stream))
sl@0:       return Z_VERSION_ERROR;
sl@0: 
sl@0:   /* initialize state */
sl@0:   if (z == Z_NULL)
sl@0:     return Z_STREAM_ERROR;
sl@0:   z->msg = Z_NULL;
sl@0:   if (z->zalloc == Z_NULL)
sl@0:   {
sl@0:     z->zalloc = zcalloc;
sl@0:     z->opaque = (voidpf)0;
sl@0:   }
sl@0:   if (z->zfree == Z_NULL) z->zfree = zcfree;
sl@0:   if ((z->state = (struct internal_state FAR *)
sl@0:        ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
sl@0:     return Z_MEM_ERROR;
sl@0:   z->state->blocks = Z_NULL;
sl@0: 
sl@0:   /* handle undocumented nowrap option (no zlib header or check) */
sl@0:   z->state->nowrap = 0;
sl@0:   if (w < 0)
sl@0:   {
sl@0:     w = - w;
sl@0:     z->state->nowrap = 1;
sl@0:   }
sl@0: 
sl@0:   /* set window size */
sl@0:   if (w < 8 || w > 15)
sl@0:   {
sl@0:     inflateEnd(z);
sl@0:     return Z_STREAM_ERROR;
sl@0:   }
sl@0:   z->state->wbits = (uInt)w;
sl@0: 
sl@0:   /* create inflate_blocks state */
sl@0:   if ((z->state->blocks =
sl@0:       inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
sl@0:       == Z_NULL)
sl@0:   {
sl@0:     inflateEnd(z);
sl@0:     return Z_MEM_ERROR;
sl@0:   }
sl@0:   Tracev((stderr, "inflate: allocated\n"));
sl@0: 
sl@0:   /* reset state */
sl@0:   inflateReset(z);
sl@0:   return Z_OK;
sl@0: }
sl@0: 
sl@0: 
sl@0: EXPORT_C int ZEXPORT inflateInit_(
sl@0: z_streamp z,
sl@0: const char *version,
sl@0: int stream_size)
sl@0: {
sl@0:   return inflateInit2_(z, DEF_WBITS, version, stream_size);
sl@0: }
sl@0: 
sl@0: 
sl@0: #define NEEDBYTE {if(z->avail_in==0)return r;r=f;}
sl@0: #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
sl@0: 
sl@0: EXPORT_C int ZEXPORT inflate(
sl@0: z_streamp z,
sl@0: int f)
sl@0: {
sl@0:   int r;
sl@0:   uInt b;
sl@0: 
sl@0:   if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL)
sl@0:     return Z_STREAM_ERROR;
sl@0:   f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
sl@0:   r = Z_BUF_ERROR;
sl@0: 
sl@0:   for (;;) switch (z->state->mode)
sl@0:   {
sl@0:     case METHOD:
sl@0:       NEEDBYTE
sl@0:       if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
sl@0:       {
sl@0:         z->state->mode = BAD;
sl@0:         z->msg = (char*)"unknown compression method";
sl@0:         z->state->sub.marker = 5;       /* can't try inflateSync */
sl@0:         break;
sl@0:       }
sl@0:       if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
sl@0:       {
sl@0:         z->state->mode = BAD;
sl@0:         z->msg = (char*)"invalid window size";
sl@0:         z->state->sub.marker = 5;       /* can't try inflateSync */
sl@0:         break;
sl@0:       }
sl@0:       z->state->mode = FLAG;
sl@0:     case FLAG:
sl@0:       NEEDBYTE
sl@0:       b = NEXTBYTE;
sl@0:       if (((z->state->sub.method << 8) + b) % 31)
sl@0:       {
sl@0:         z->state->mode = BAD;
sl@0:         z->msg = (char*)"incorrect header check";
sl@0:         z->state->sub.marker = 5;       /* can't try inflateSync */
sl@0:         break;
sl@0:       }
sl@0:       Tracev((stderr, "inflate: zlib header ok\n"));
sl@0:       if (!(b & PRESET_DICT))
sl@0:       {
sl@0:         z->state->mode = BLOCKS;
sl@0:         break;
sl@0:       }
sl@0:       z->state->mode = DICT4;
sl@0:     case DICT4:
sl@0:       NEEDBYTE
sl@0:       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
sl@0:       z->state->mode = DICT3;
sl@0:     case DICT3:
sl@0:       NEEDBYTE
sl@0:       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
sl@0:       z->state->mode = DICT2;
sl@0:     case DICT2:
sl@0:       NEEDBYTE
sl@0:       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
sl@0:       z->state->mode = DICT1;
sl@0:     case DICT1:
sl@0:       NEEDBYTE
sl@0:       z->state->sub.check.need += (uLong)NEXTBYTE;
sl@0:       z->adler = z->state->sub.check.need;
sl@0:       z->state->mode = DICT0;
sl@0:       return Z_NEED_DICT;
sl@0:     case DICT0:
sl@0:       z->state->mode = BAD;
sl@0:       z->msg = (char*)"need dictionary";
sl@0:       z->state->sub.marker = 0;       /* can try inflateSync */
sl@0:       return Z_STREAM_ERROR;
sl@0:     case BLOCKS:
sl@0:       r = inflate_blocks(z->state->blocks, z, r);
sl@0:       if (r == Z_DATA_ERROR)
sl@0:       {
sl@0:         z->state->mode = BAD;
sl@0:         z->state->sub.marker = 0;       /* can try inflateSync */
sl@0:         break;
sl@0:       }
sl@0:       if (r == Z_OK)
sl@0:         r = f;
sl@0:       if (r != Z_STREAM_END)
sl@0:         return r;
sl@0:       r = f;
sl@0:       inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
sl@0:       if (z->state->nowrap)
sl@0:       {
sl@0:         z->state->mode = DONE;
sl@0:         break;
sl@0:       }
sl@0:       z->state->mode = CHECK4;
sl@0:     case CHECK4:
sl@0:       NEEDBYTE
sl@0:       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
sl@0:       z->state->mode = CHECK3;
sl@0:     case CHECK3:
sl@0:       NEEDBYTE
sl@0:       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
sl@0:       z->state->mode = CHECK2;
sl@0:     case CHECK2:
sl@0:       NEEDBYTE
sl@0:       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
sl@0:       z->state->mode = CHECK1;
sl@0:     case CHECK1:
sl@0:       NEEDBYTE
sl@0:       z->state->sub.check.need += (uLong)NEXTBYTE;
sl@0: 
sl@0:       if (z->state->sub.check.was != z->state->sub.check.need)
sl@0:       {
sl@0:         z->state->mode = BAD;
sl@0:         z->msg = (char*)"incorrect data check";
sl@0:         z->state->sub.marker = 5;       /* can't try inflateSync */
sl@0:         break;
sl@0:       }
sl@0:       Tracev((stderr, "inflate: zlib check ok\n"));
sl@0:       z->state->mode = DONE;
sl@0:     case DONE:
sl@0:       return Z_STREAM_END;
sl@0:     case BAD:
sl@0:       return Z_DATA_ERROR;
sl@0:     default:
sl@0:       return Z_STREAM_ERROR;
sl@0:   }
sl@0: #ifdef NEED_DUMMY_RETURN
sl@0:   return Z_STREAM_ERROR;  /* Some dumb compilers complain without this */
sl@0: #endif
sl@0: }
sl@0: 
sl@0: 
sl@0: EXPORT_C int ZEXPORT inflateSetDictionary(
sl@0: z_streamp z,
sl@0: const Bytef *dictionary,
sl@0: uInt  dictLength)
sl@0: {
sl@0:   uInt length = dictLength;
sl@0: 
sl@0:   if (z == Z_NULL || z->state == Z_NULL || z->state->mode != DICT0)
sl@0:     return Z_STREAM_ERROR;
sl@0: 
sl@0:   if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;
sl@0:   z->adler = 1L;
sl@0: 
sl@0:   if (length >= ((uInt)1<<z->state->wbits))
sl@0:   {
sl@0:     length = (1<<z->state->wbits)-1;
sl@0:     dictionary += dictLength - length;
sl@0:   }
sl@0:   inflate_set_dictionary(z->state->blocks, dictionary, length);
sl@0:   z->state->mode = BLOCKS;
sl@0:   return Z_OK;
sl@0: }
sl@0: 
sl@0: 
sl@0: EXPORT_C int ZEXPORT inflateSync(
sl@0: z_streamp z)
sl@0: {
sl@0:   uInt n;       /* number of bytes to look at */
sl@0:   Bytef *p;     /* pointer to bytes */
sl@0:   uInt m;       /* number of marker bytes found in a row */
sl@0:   uLong r, w;   /* temporaries to save total_in and total_out */
sl@0: 
sl@0:   /* set up */
sl@0:   if (z == Z_NULL || z->state == Z_NULL)
sl@0:     return Z_STREAM_ERROR;
sl@0:   if (z->state->mode != BAD)
sl@0:   {
sl@0:     z->state->mode = BAD;
sl@0:     z->state->sub.marker = 0;
sl@0:   }
sl@0:   if ((n = z->avail_in) == 0)
sl@0:     return Z_BUF_ERROR;
sl@0:   p = z->next_in;
sl@0:   m = z->state->sub.marker;
sl@0: 
sl@0:   /* search */
sl@0:   while (n && m < 4)
sl@0:   {
sl@0:     static const Byte mark[4] = {0, 0, 0xff, 0xff};
sl@0:     if (*p == mark[m])
sl@0:       m++;
sl@0:     else if (*p)
sl@0:       m = 0;
sl@0:     else
sl@0:       m = 4 - m;
sl@0:     p++, n--;
sl@0:   }
sl@0: 
sl@0:   /* restore */
sl@0:   z->total_in += p - z->next_in;
sl@0:   z->next_in = p;
sl@0:   z->avail_in = n;
sl@0:   z->state->sub.marker = m;
sl@0: 
sl@0:   /* return no joy or set up to restart on a new block */
sl@0:   if (m != 4)
sl@0:     return Z_DATA_ERROR;
sl@0:   r = z->total_in;  w = z->total_out;
sl@0:   inflateReset(z);
sl@0:   z->total_in = r;  z->total_out = w;
sl@0:   z->state->mode = BLOCKS;
sl@0:   return Z_OK;
sl@0: }
sl@0: 
sl@0: 
sl@0: /* Returns true if inflate is currently at the end of a block generated
sl@0:  * by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
sl@0:  * implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
sl@0:  * but removes the length bytes of the resulting empty stored block. When
sl@0:  * decompressing, PPP checks that at the end of input packet, inflate is
sl@0:  * waiting for these length bytes.
sl@0:  */
sl@0: EXPORT_C int ZEXPORT inflateSyncPoint(
sl@0: z_streamp z)
sl@0: {
sl@0:   if (z == Z_NULL || z->state == Z_NULL || z->state->blocks == Z_NULL)
sl@0:     return Z_STREAM_ERROR;
sl@0:   return inflate_blocks_sync_point(z->state->blocks);
sl@0: }