libclammspack/mspack/mszipd.c
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 /* This file is part of libmspack.
  * (C) 2003-2010 Stuart Caie.
  *
  * The deflate method was created by Phil Katz. MSZIP is equivalent to the
  * deflate method.
  *
  * libmspack is free software; you can redistribute it and/or modify it under
  * the terms of the GNU Lesser General Public License (LGPL) version 2.1
  *
  * For further details, see the file COPYING.LIB distributed with libmspack
  */
 
 /* MS-ZIP decompression implementation. */
 
 #include <system.h>
 #include <mszip.h>
 
 /* import bit-reading macros and code */
 #define BITS_TYPE struct mszipd_stream
 #define BITS_VAR zip
 #define BITS_ORDER_LSB
 #define BITS_LSB_TABLE
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 #define READ_BYTES do {         \
     READ_IF_NEEDED;             \
     INJECT_BITS(*i_ptr++, 8);   \
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 } while (0)
 #include <readbits.h>
 
 /* import huffman macros and code */
 #define TABLEBITS(tbl)      MSZIP_##tbl##_TABLEBITS
 #define MAXSYMBOLS(tbl)     MSZIP_##tbl##_MAXSYMBOLS
 #define HUFF_TABLE(tbl,idx) zip->tbl##_table[idx]
 #define HUFF_LEN(tbl,idx)   zip->tbl##_len[idx]
 #define HUFF_ERROR          return INF_ERR_HUFFSYM
 #include <readhuff.h>
 
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 #define FLUSH_IF_NEEDED do {                            \
     if (zip->window_posn == MSZIP_FRAME_SIZE) {         \
         if (zip->flush_window(zip, MSZIP_FRAME_SIZE)) { \
             return INF_ERR_FLUSH;                       \
         }                                               \
         zip->window_posn = 0;                           \
     }                                                   \
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 } while (0)
 
 /* match lengths for literal codes 257.. 285 */
 static const unsigned short lit_lengths[29] = {
   3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27,
   31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258
 };
 
 /* match offsets for distance codes 0 .. 29 */
 static const unsigned short dist_offsets[30] = {
   1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385,
   513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577
 };
 
 /* extra bits required for literal codes 257.. 285 */
 static const unsigned char lit_extrabits[29] = {
   0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2,
   2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0
 };
 
 /* extra bits required for distance codes 0 .. 29 */
 static const unsigned char dist_extrabits[30] = {
   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
 };
 
 /* the order of the bit length Huffman code lengths */
 static const unsigned char bitlen_order[19] = {
   16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
 };
 
 /* inflate() error codes */
 #define INF_ERR_BLOCKTYPE   (-1)  /* unknown block type                      */
 #define INF_ERR_COMPLEMENT  (-2)  /* block size complement mismatch          */
 #define INF_ERR_FLUSH       (-3)  /* error from flush_window() callback      */
 #define INF_ERR_BITBUF      (-4)  /* too many bits in bit buffer             */
 #define INF_ERR_SYMLENS     (-5)  /* too many symbols in blocktype 2 header  */
 #define INF_ERR_BITLENTBL   (-6)  /* failed to build bitlens huffman table   */
 #define INF_ERR_LITERALTBL  (-7)  /* failed to build literals huffman table  */
 #define INF_ERR_DISTANCETBL (-8)  /* failed to build distance huffman table  */
 #define INF_ERR_BITOVERRUN  (-9)  /* bitlen RLE code goes over table size    */
 #define INF_ERR_BADBITLEN   (-10) /* invalid bit-length code                 */
 #define INF_ERR_LITCODE     (-11) /* out-of-range literal code               */
 #define INF_ERR_DISTCODE    (-12) /* out-of-range distance code              */
 #define INF_ERR_DISTANCE    (-13) /* somehow, distance is beyond 32k         */
 #define INF_ERR_HUFFSYM     (-14) /* out of bits decoding huffman symbol     */
 
 static int zip_read_lens(struct mszipd_stream *zip) {
   /* for the bit buffer and huffman decoding */
   register unsigned int bit_buffer;
   register int bits_left;
   unsigned char *i_ptr, *i_end;
 
   /* bitlen Huffman codes -- immediate lookup, 7 bit max code length */
   unsigned short bl_table[(1 << 7)];
   unsigned char bl_len[19];
 
   unsigned char lens[MSZIP_LITERAL_MAXSYMBOLS + MSZIP_DISTANCE_MAXSYMBOLS];
   unsigned int lit_codes, dist_codes, code, last_code=0, bitlen_codes, i, run;
 
   RESTORE_BITS;
 
   /* read the number of codes */
   READ_BITS(lit_codes,    5); lit_codes    += 257;
   READ_BITS(dist_codes,   5); dist_codes   += 1;
   READ_BITS(bitlen_codes, 4); bitlen_codes += 4;
   if (lit_codes  > MSZIP_LITERAL_MAXSYMBOLS)  return INF_ERR_SYMLENS;
   if (dist_codes > MSZIP_DISTANCE_MAXSYMBOLS) return INF_ERR_SYMLENS;
 
   /* read in the bit lengths in their unusual order */
   for (i = 0; i < bitlen_codes; i++) READ_BITS(bl_len[bitlen_order[i]], 3);
   while (i < 19) bl_len[bitlen_order[i++]] = 0;
 
   /* create decoding table with an immediate lookup */
   if (make_decode_table(19, 7, &bl_len[0], &bl_table[0])) {
     return INF_ERR_BITLENTBL;
   }
 
   /* read literal / distance code lengths */
   for (i = 0; i < (lit_codes + dist_codes); i++) {
     /* single-level huffman lookup */
     ENSURE_BITS(7);
     code = bl_table[PEEK_BITS(7)];
     REMOVE_BITS(bl_len[code]);
 
     if (code < 16) lens[i] = last_code = code;
     else {
       switch (code) {
       case 16: READ_BITS(run, 2); run += 3;  code = last_code; break;
       case 17: READ_BITS(run, 3); run += 3;  code = 0;         break;
       case 18: READ_BITS(run, 7); run += 11; code = 0;         break;
       default: D(("bad code!: %u", code)) return INF_ERR_BADBITLEN;
       }
       if ((i + run) > (lit_codes + dist_codes)) return INF_ERR_BITOVERRUN;
       while (run--) lens[i++] = code;
       i--;
     }
   }
 
   /* copy LITERAL code lengths and clear any remaining */
   i = lit_codes;
   zip->sys->copy(&lens[0], &zip->LITERAL_len[0], i);
   while (i < MSZIP_LITERAL_MAXSYMBOLS) zip->LITERAL_len[i++] = 0;
 
   i = dist_codes;
   zip->sys->copy(&lens[lit_codes], &zip->DISTANCE_len[0], i);
   while (i < MSZIP_DISTANCE_MAXSYMBOLS) zip->DISTANCE_len[i++] = 0;
 
   STORE_BITS;
   return 0;
 }
 
 /* a clean implementation of RFC 1951 / inflate */
 static int inflate(struct mszipd_stream *zip) {
   unsigned int last_block, block_type, distance, length, this_run, i;
 
   /* for the bit buffer and huffman decoding */
   register unsigned int bit_buffer;
   register int bits_left;
   register unsigned short sym;
   unsigned char *i_ptr, *i_end;
 
   RESTORE_BITS;
 
   do {
     /* read in last block bit */
     READ_BITS(last_block, 1);
 
     /* read in block type */
     READ_BITS(block_type, 2);
 
     if (block_type == 0) {
       /* uncompressed block */
       unsigned char lens_buf[4];
 
       /* go to byte boundary */
       i = bits_left & 7; REMOVE_BITS(i);
 
       /* read 4 bytes of data, emptying the bit-buffer if necessary */
       for (i = 0; (bits_left >= 8); i++) {
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         if (i == 4) return INF_ERR_BITBUF;
         lens_buf[i] = PEEK_BITS(8);
         REMOVE_BITS(8);
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       }
       if (bits_left != 0) return INF_ERR_BITBUF;
       while (i < 4) {
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         READ_IF_NEEDED;
         lens_buf[i++] = *i_ptr++;
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       }
 
       /* get the length and its complement */
       length = lens_buf[0] | (lens_buf[1] << 8);
       i      = lens_buf[2] | (lens_buf[3] << 8);
       if (length != (~i & 0xFFFF)) return INF_ERR_COMPLEMENT;
 
       /* read and copy the uncompressed data into the window */
       while (length > 0) {
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         READ_IF_NEEDED;
 
         this_run = length;
         if (this_run > (unsigned int)(i_end - i_ptr)) this_run = i_end - i_ptr;
         if (this_run > (MSZIP_FRAME_SIZE - zip->window_posn))
           this_run = MSZIP_FRAME_SIZE - zip->window_posn;
 
         zip->sys->copy(i_ptr, &zip->window[zip->window_posn], this_run);
         zip->window_posn += this_run;
         i_ptr    += this_run;
         length   -= this_run;
         FLUSH_IF_NEEDED;
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       }
     }
     else if ((block_type == 1) || (block_type == 2)) {
       /* Huffman-compressed LZ77 block */
       unsigned int match_posn, code;
 
       if (block_type == 1) {
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         /* block with fixed Huffman codes */
         i = 0;
         while (i < 144) zip->LITERAL_len[i++] = 8;
         while (i < 256) zip->LITERAL_len[i++] = 9;
         while (i < 280) zip->LITERAL_len[i++] = 7;
         while (i < 288) zip->LITERAL_len[i++] = 8;
         for (i = 0; i < 32; i++) zip->DISTANCE_len[i] = 5;
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       }
       else {
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         /* block with dynamic Huffman codes */
         STORE_BITS;
         if ((i = zip_read_lens(zip))) return i;
         RESTORE_BITS;
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       }
 
       /* now huffman lengths are read for either kind of block, 
        * create huffman decoding tables */
       if (make_decode_table(MSZIP_LITERAL_MAXSYMBOLS, MSZIP_LITERAL_TABLEBITS,
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                             &zip->LITERAL_len[0], &zip->LITERAL_table[0]))
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       {
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         return INF_ERR_LITERALTBL;
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       }
 
       if (make_decode_table(MSZIP_DISTANCE_MAXSYMBOLS,MSZIP_DISTANCE_TABLEBITS,
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                             &zip->DISTANCE_len[0], &zip->DISTANCE_table[0]))
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       {
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         return INF_ERR_DISTANCETBL;
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       }
 
       /* decode forever until end of block code */
       for (;;) {
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         READ_HUFFSYM(LITERAL, code);
         if (code < 256) {
           zip->window[zip->window_posn++] = (unsigned char) code;
           FLUSH_IF_NEEDED;
         }
         else if (code == 256) {
           /* END OF BLOCK CODE: loop break point */
           break;
         }
         else {
           code -= 257; /* codes 257-285 are matches */
           if (code >= 29) return INF_ERR_LITCODE; /* codes 286-287 are illegal */
           READ_BITS_T(length, lit_extrabits[code]);
           length += lit_lengths[code];
 
           READ_HUFFSYM(DISTANCE, code);
           if (code >= 30) return INF_ERR_DISTCODE;
           READ_BITS_T(distance, dist_extrabits[code]);
           distance += dist_offsets[code];
 
           /* match position is window position minus distance. If distance
            * is more than window position numerically, it must 'wrap
            * around' the frame size. */ 
           match_posn = ((distance > zip->window_posn) ? MSZIP_FRAME_SIZE : 0)
             + zip->window_posn - distance;
 
           /* copy match */
           if (length < 12) {
             /* short match, use slower loop but no loop setup code */
             while (length--) {
               zip->window[zip->window_posn++] = zip->window[match_posn++];
               match_posn &= MSZIP_FRAME_SIZE - 1;
               FLUSH_IF_NEEDED;
             }
           }
           else {
             /* longer match, use faster loop but with setup expense */
             unsigned char *runsrc, *rundest;
             do {
               this_run = length;
               if ((match_posn + this_run) > MSZIP_FRAME_SIZE)
                 this_run = MSZIP_FRAME_SIZE - match_posn;
               if ((zip->window_posn + this_run) > MSZIP_FRAME_SIZE)
                 this_run = MSZIP_FRAME_SIZE - zip->window_posn;
 
               rundest = &zip->window[zip->window_posn]; zip->window_posn += this_run;
               runsrc  = &zip->window[match_posn];  match_posn  += this_run;
               length -= this_run;
               while (this_run--) *rundest++ = *runsrc++;
               if (match_posn == MSZIP_FRAME_SIZE) match_posn = 0;
               FLUSH_IF_NEEDED;
             } while (length > 0);
           }
 
         } /* else (code >= 257) */
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       } /* for(;;) -- break point at 'code == 256' */
     }
     else {
       /* block_type == 3 -- bad block type */
       return INF_ERR_BLOCKTYPE;
     }
   } while (!last_block);
 
   /* flush the remaining data */
   if (zip->window_posn) {
     if (zip->flush_window(zip, zip->window_posn)) return INF_ERR_FLUSH;
   }
   STORE_BITS;
 
   /* return success */
   return 0;
 }
 
 /* inflate() calls this whenever the window should be flushed. As
  * MSZIP only expands to the size of the window, the implementation used
  * simply keeps track of the amount of data flushed, and if more than 32k
  * is flushed, an error is raised.
  */  
 static int mszipd_flush_window(struct mszipd_stream *zip,
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                                unsigned int data_flushed)
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 {
   zip->bytes_output += data_flushed;
   if (zip->bytes_output > MSZIP_FRAME_SIZE) {
     D(("overflow: %u bytes flushed, total is now %u",
        data_flushed, zip->bytes_output))
     return 1;
   }
   return 0;
 }
 
 struct mszipd_stream *mszipd_init(struct mspack_system *system,
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                                   struct mspack_file *input,
                                   struct mspack_file *output,
                                   int input_buffer_size,
                                   int repair_mode)
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 {
   struct mszipd_stream *zip;
 
   if (!system) return NULL;
 
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   /* round up input buffer size to multiple of two */
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   input_buffer_size = (input_buffer_size + 1) & -2;
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   if (input_buffer_size < 2) return NULL;
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   /* allocate decompression state */
   if (!(zip = (struct mszipd_stream *) system->alloc(system, sizeof(struct mszipd_stream)))) {
     return NULL;
   }
 
   /* allocate input buffer */
   zip->inbuf  = (unsigned char *) system->alloc(system, (size_t) input_buffer_size);
   if (!zip->inbuf) {
     system->free(zip);
     return NULL;
   }
 
   /* initialise decompression state */
   zip->sys             = system;
   zip->input           = input;
   zip->output          = output;
   zip->inbuf_size      = input_buffer_size;
   zip->input_end       = 0;
   zip->error           = MSPACK_ERR_OK;
   zip->repair_mode     = repair_mode;
   zip->flush_window    = &mszipd_flush_window;
 
   zip->i_ptr = zip->i_end = &zip->inbuf[0];
   zip->o_ptr = zip->o_end = NULL;
   zip->bit_buffer = 0; zip->bits_left = 0;
   return zip;
 }
 
 int mszipd_decompress(struct mszipd_stream *zip, off_t out_bytes) {
   /* for the bit buffer */
   register unsigned int bit_buffer;
   register int bits_left;
   unsigned char *i_ptr, *i_end;
 
   int i, state, error;
 
   /* easy answers */
   if (!zip || (out_bytes < 0)) return MSPACK_ERR_ARGS;
   if (zip->error) return zip->error;
 
   /* flush out any stored-up bytes before we begin */
   i = zip->o_end - zip->o_ptr;
   if ((off_t) i > out_bytes) i = (int) out_bytes;
   if (i) {
     if (zip->sys->write(zip->output, zip->o_ptr, i) != i) {
       return zip->error = MSPACK_ERR_WRITE;
     }
     zip->o_ptr  += i;
     out_bytes   -= i;
   }
   if (out_bytes == 0) return MSPACK_ERR_OK;
 
 
   while (out_bytes > 0) {
     /* unpack another block */
     RESTORE_BITS;
 
     /* skip to next read 'CK' header */
     i = bits_left & 7; REMOVE_BITS(i); /* align to bytestream */
     state = 0;
     do {
       READ_BITS(i, 8);
       if (i == 'C') state = 1;
       else if ((state == 1) && (i == 'K')) state = 2;
       else state = 0;
     } while (state != 2);
 
     /* inflate a block, repair and realign if necessary */
     zip->window_posn = 0;
     zip->bytes_output = 0;
     STORE_BITS;
     if ((error = inflate(zip))) {
       D(("inflate error %d", error))
       if (zip->repair_mode) {
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         /* recover partially-inflated buffers */
         if (zip->bytes_output == 0 && zip->window_posn > 0) {
           zip->flush_window(zip, zip->window_posn);
         }
         zip->sys->message(NULL, "MSZIP error, %u bytes of data lost.",
                           MSZIP_FRAME_SIZE - zip->bytes_output);
         for (i = zip->bytes_output; i < MSZIP_FRAME_SIZE; i++) {
           zip->window[i] = '\0';
         }
         zip->bytes_output = MSZIP_FRAME_SIZE;
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       }
       else {
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         return zip->error = (error > 0) ? error : MSPACK_ERR_DECRUNCH;
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       }
     }
     zip->o_ptr = &zip->window[0];
     zip->o_end = &zip->o_ptr[zip->bytes_output];
 
     /* write a frame */
     i = (out_bytes < (off_t)zip->bytes_output) ?
       (int)out_bytes : zip->bytes_output;
     if (zip->sys->write(zip->output, zip->o_ptr, i) != i) {
       return zip->error = MSPACK_ERR_WRITE;
     }
 
     /* mspack errors (i.e. read errors) are fatal and can't be recovered */
     if ((error > 0) && zip->repair_mode) return error;
 
     zip->o_ptr  += i;
     out_bytes   -= i;
   }
 
   if (out_bytes) {
     D(("bytes left to output"))
     return zip->error = MSPACK_ERR_DECRUNCH;
   }
   return MSPACK_ERR_OK;
 }
 
 int mszipd_decompress_kwaj(struct mszipd_stream *zip) {
     /* for the bit buffer */
     register unsigned int bit_buffer;
     register int bits_left;
     unsigned char *i_ptr, *i_end;
 
     int i, error, block_len;
 
     /* unpack blocks until block_len == 0 */
     for (;;) {
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         RESTORE_BITS;
 
         /* align to bytestream, read block_len */
         i = bits_left & 7; REMOVE_BITS(i);
         READ_BITS(block_len, 8);
         READ_BITS(i, 8); block_len |= i << 8;
 
         if (block_len == 0) break;
 
         /* read "CK" header */
         READ_BITS(i, 8); if (i != 'C') return MSPACK_ERR_DATAFORMAT;
         READ_BITS(i, 8); if (i != 'K') return MSPACK_ERR_DATAFORMAT;
 
         /* inflate block */
         zip->window_posn = 0;
         zip->bytes_output = 0;
         STORE_BITS;
         if ((error = inflate(zip))) {
             D(("inflate error %d", error))
             return zip->error = (error > 0) ? error : MSPACK_ERR_DECRUNCH;
         }
 
         /* write inflated block */
         if (zip->sys->write(zip->output, &zip->window[0], zip->bytes_output)
             != zip->bytes_output) return zip->error = MSPACK_ERR_WRITE;
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     }
     return MSPACK_ERR_OK;
 }
 
 void mszipd_free(struct mszipd_stream *zip) {
   struct mspack_system *sys;
   if (zip) {
     sys = zip->sys;
     sys->free(zip->inbuf);
     sys->free(zip);
   }
 }