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- Unit InfBlock;
-
- { infblock.h and
- infblock.c -- interpret and process block types to last block
- Copyright (C) 1995-1998 Mark Adler
-
- Pascal tranlastion
- Copyright (C) 1998 by Jacques Nomssi Nzali
- For conditions of distribution and use, see copyright notice in readme.txt
- }
-
- interface
-
- {$I zconf.inc}
-
- uses
- {$IFDEF DEBUG}
- strutils,
- {$ENDIF}
- zutil, zlib;
-
- function inflate_blocks_new(var z : z_stream;
- c : check_func; { check function }
- w : uInt { window size }
- ) : pInflate_blocks_state;
-
- function inflate_blocks (var s : inflate_blocks_state;
- var z : z_stream;
- r : int { initial return code }
- ) : int;
-
- procedure inflate_blocks_reset (var s : inflate_blocks_state;
- var z : z_stream;
- c : puLong); { check value on output }
-
-
- function inflate_blocks_free(s : pInflate_blocks_state;
- var z : z_stream) : int;
-
- procedure inflate_set_dictionary(var s : inflate_blocks_state;
- const d : array of byte; { dictionary }
- n : uInt); { dictionary length }
-
- function inflate_blocks_sync_point(var s : inflate_blocks_state) : int;
-
- implementation
-
- uses
- infcodes, inftrees, infutil;
-
- { Tables for deflate from PKZIP's appnote.txt. }
- Const
- border : Array [0..18] Of Word { Order of the bit length code lengths }
- = (16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15);
-
- { Notes beyond the 1.93a appnote.txt:
-
- 1. Distance pointers never point before the beginning of the output
- stream.
- 2. Distance pointers can point back across blocks, up to 32k away.
- 3. There is an implied maximum of 7 bits for the bit length table and
- 15 bits for the actual data.
- 4. If only one code exists, then it is encoded using one bit. (Zero
- would be more efficient, but perhaps a little confusing.) If two
- codes exist, they are coded using one bit each (0 and 1).
- 5. There is no way of sending zero distance codes--a dummy must be
- sent if there are none. (History: a pre 2.0 version of PKZIP would
- store blocks with no distance codes, but this was discovered to be
- too harsh a criterion.) Valid only for 1.93a. 2.04c does allow
- zero distance codes, which is sent as one code of zero bits in
- length.
- 6. There are up to 286 literal/length codes. Code 256 represents the
- end-of-block. Note however that the static length tree defines
- 288 codes just to fill out the Huffman codes. Codes 286 and 287
- cannot be used though, since there is no length base or extra bits
- defined for them. Similarily, there are up to 30 distance codes.
- However, static trees define 32 codes (all 5 bits) to fill out the
- Huffman codes, but the last two had better not show up in the data.
- 7. Unzip can check dynamic Huffman blocks for complete code sets.
- The exception is that a single code would not be complete (see #4).
- 8. The five bits following the block type is really the number of
- literal codes sent minus 257.
- 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
- (1+6+6). Therefore, to output three times the length, you output
- three codes (1+1+1), whereas to output four times the same length,
- you only need two codes (1+3). Hmm.
- 10. In the tree reconstruction algorithm, Code = Code + Increment
- only if BitLength(i) is not zero. (Pretty obvious.)
- 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19)
- 12. Note: length code 284 can represent 227-258, but length code 285
- really is 258. The last length deserves its own, short code
- since it gets used a lot in very redundant files. The length
- 258 is special since 258 - 3 (the min match length) is 255.
- 13. The literal/length and distance code bit lengths are read as a
- single stream of lengths. It is possible (and advantageous) for
- a repeat code (16, 17, or 18) to go across the boundary between
- the two sets of lengths. }
-
-
- procedure inflate_blocks_reset (var s : inflate_blocks_state;
- var z : z_stream;
- c : puLong); { check value on output }
- begin
- if (c <> Z_NULL) then
- c^ := s.check;
- if (s.mode = BTREE) or (s.mode = DTREE) then
- ZFREE(z, s.sub.trees.blens);
- if (s.mode = CODES) then
- inflate_codes_free(s.sub.decode.codes, z);
-
- s.mode := ZTYPE;
- s.bitk := 0;
- s.bitb := 0;
-
- s.write := s.window;
- s.read := s.window;
- if Assigned(s.checkfn) then
- begin
- s.check := s.checkfn(uLong(0), pBytef(NIL), 0);
- z.adler := s.check;
- end;
- {$IFDEF DEBUG}
- Tracev('inflate: blocks reset');
- {$ENDIF}
- end;
-
-
- function inflate_blocks_new(var z : z_stream;
- c : check_func; { check function }
- w : uInt { window size }
- ) : pInflate_blocks_state;
- var
- s : pInflate_blocks_state;
- begin
- s := pInflate_blocks_state( ZALLOC(z,1, sizeof(inflate_blocks_state)) );
- if (s = Z_NULL) then
- begin
- inflate_blocks_new := s;
- exit;
- end;
- s^.hufts := huft_ptr( ZALLOC(z, sizeof(inflate_huft), MANY) );
-
- if (s^.hufts = Z_NULL) then
- begin
- ZFREE(z, s);
- inflate_blocks_new := Z_NULL;
- exit;
- end;
-
- s^.window := pBytef( ZALLOC(z, 1, w) );
- if (s^.window = Z_NULL) then
- begin
- ZFREE(z, s^.hufts);
- ZFREE(z, s);
- inflate_blocks_new := Z_NULL;
- exit;
- end;
- s^.zend := s^.window;
- Inc(s^.zend, w);
- s^.checkfn := c;
- s^.mode := ZTYPE;
- {$IFDEF DEBUG}
- Tracev('inflate: blocks allocated');
- {$ENDIF}
- inflate_blocks_reset(s^, z, Z_NULL);
- inflate_blocks_new := s;
- end;
-
-
- function inflate_blocks (var s : inflate_blocks_state;
- var z : z_stream;
- r : int) : int; { initial return code }
- label
- start_btree, start_dtree,
- start_blkdone, start_dry,
- start_codes;
-
- var
- t : uInt; { temporary storage }
- b : uLong; { bit buffer }
- k : uInt; { bits in bit buffer }
- p : pBytef; { input data pointer }
- n : uInt; { bytes available there }
- q : pBytef; { output window write pointer }
- m : uInt; { bytes to end of window or read pointer }
- { fixed code blocks }
- var
- bl, bd : uInt;
- tl, td : pInflate_huft;
- var
- h : pInflate_huft;
- i, j, c : uInt;
- var
- cs : pInflate_codes_state;
- begin
- { copy input/output information to locals }
- p := z.next_in;
- n := z.avail_in;
- b := s.bitb;
- k := s.bitk;
- q := s.write;
- if ptr2int(q) < ptr2int(s.read) then
- m := uInt(ptr2int(s.read)-ptr2int(q)-1)
- else
- m := uInt(ptr2int(s.zend)-ptr2int(q));
-
- { decompress an inflated block }
-
-
- { process input based on current state }
- while True do
- Case s.mode of
- ZTYPE:
- begin
- {NEEDBITS(3);}
- while (k < 3) do
- begin
- {NEEDBYTE;}
- if (n <> 0) then
- r :=Z_OK
- else
- begin
- {UPDATE}
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p)-ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- Dec(n);
- b := b or (uLong(p^) shl k);
- Inc(p);
- Inc(k, 8);
- end;
-
- t := uInt(b) and 7;
- s.last := boolean(t and 1);
- case (t shr 1) of
- 0: { stored }
- begin
- {$IFDEF DEBUG}
- if s.last then
- Tracev('inflate: stored block (last)')
- else
- Tracev('inflate: stored block');
- {$ENDIF}
- {DUMPBITS(3);}
- b := b shr 3;
- Dec(k, 3);
-
- t := k and 7; { go to byte boundary }
- {DUMPBITS(t);}
- b := b shr t;
- Dec(k, t);
-
- s.mode := LENS; { get length of stored block }
- end;
- 1: { fixed }
- begin
- begin
- {$IFDEF DEBUG}
- if s.last then
- Tracev('inflate: fixed codes blocks (last)')
- else
- Tracev('inflate: fixed codes blocks');
- {$ENDIF}
- inflate_trees_fixed(bl, bd, tl, td, z);
- s.sub.decode.codes := inflate_codes_new(bl, bd, tl, td, z);
- if (s.sub.decode.codes = Z_NULL) then
- begin
- r := Z_MEM_ERROR;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- end;
- {DUMPBITS(3);}
- b := b shr 3;
- Dec(k, 3);
-
- s.mode := CODES;
- end;
- 2: { dynamic }
- begin
- {$IFDEF DEBUG}
- if s.last then
- Tracev('inflate: dynamic codes block (last)')
- else
- Tracev('inflate: dynamic codes block');
- {$ENDIF}
- {DUMPBITS(3);}
- b := b shr 3;
- Dec(k, 3);
-
- s.mode := TABLE;
- end;
- 3:
- begin { illegal }
- {DUMPBITS(3);}
- b := b shr 3;
- Dec(k, 3);
-
- s.mode := BLKBAD;
- z.msg := 'invalid block type';
- r := Z_DATA_ERROR;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- end;
- end;
- LENS:
- begin
- {NEEDBITS(32);}
- while (k < 32) do
- begin
- {NEEDBYTE;}
- if (n <> 0) then
- r :=Z_OK
- else
- begin
- {UPDATE}
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p)-ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- Dec(n);
- b := b or (uLong(p^) shl k);
- Inc(p);
- Inc(k, 8);
- end;
-
- if (((not b) shr 16) and $ffff) <> (b and $ffff) then
- begin
- s.mode := BLKBAD;
- z.msg := 'invalid stored block lengths';
- r := Z_DATA_ERROR;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- s.sub.left := uInt(b) and $ffff;
- k := 0;
- b := 0; { dump bits }
- {$IFDEF DEBUG}
- Tracev('inflate: stored length '+IntToStr(s.sub.left));
- {$ENDIF}
- if s.sub.left <> 0 then
- s.mode := STORED
- else
- if s.last then
- s.mode := DRY
- else
- s.mode := ZTYPE;
- end;
- STORED:
- begin
- if (n = 0) then
- begin
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- {NEEDOUT}
- if (m = 0) then
- begin
- {WRAP}
- if (q = s.zend) and (s.read <> s.window) then
- begin
- q := s.window;
- if ptr2int(q) < ptr2int(s.read) then
- m := uInt(ptr2int(s.read)-ptr2int(q)-1)
- else
- m := uInt(ptr2int(s.zend)-ptr2int(q));
- end;
-
- if (m = 0) then
- begin
- {FLUSH}
- s.write := q;
- r := inflate_flush(s,z,r);
- q := s.write;
- if ptr2int(q) < ptr2int(s.read) then
- m := uInt(ptr2int(s.read)-ptr2int(q)-1)
- else
- m := uInt(ptr2int(s.zend)-ptr2int(q));
-
- {WRAP}
- if (q = s.zend) and (s.read <> s.window) then
- begin
- q := s.window;
- if ptr2int(q) < ptr2int(s.read) then
- m := uInt(ptr2int(s.read)-ptr2int(q)-1)
- else
- m := uInt(ptr2int(s.zend)-ptr2int(q));
- end;
-
- if (m = 0) then
- begin
- {UPDATE}
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p)-ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- end;
- end;
- r := Z_OK;
-
- t := s.sub.left;
- if (t > n) then
- t := n;
- if (t > m) then
- t := m;
- zmemcpy(q, p, t);
- Inc(p, t); Dec(n, t);
- Inc(q, t); Dec(m, t);
- Dec(s.sub.left, t);
- if (s.sub.left = 0) then
- begin
- {$IFDEF DEBUG}
- if (ptr2int(q) >= ptr2int(s.read)) then
- Tracev('inflate: stored end '+
- IntToStr(z.total_out + ptr2int(q) - ptr2int(s.read)) + ' total out')
- else
- Tracev('inflate: stored end '+
- IntToStr(z.total_out + ptr2int(s.zend) - ptr2int(s.read) +
- ptr2int(q) - ptr2int(s.window)) + ' total out');
- {$ENDIF}
- if s.last then
- s.mode := DRY
- else
- s.mode := ZTYPE;
- end;
- end;
- TABLE:
- begin
- {NEEDBITS(14);}
- while (k < 14) do
- begin
- {NEEDBYTE;}
- if (n <> 0) then
- r :=Z_OK
- else
- begin
- {UPDATE}
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p)-ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- Dec(n);
- b := b or (uLong(p^) shl k);
- Inc(p);
- Inc(k, 8);
- end;
-
- t := uInt(b) and $3fff;
- s.sub.trees.table := t;
- {$ifndef PKZIP_BUG_WORKAROUND}
- if ((t and $1f) > 29) or (((t shr 5) and $1f) > 29) then
- begin
- s.mode := BLKBAD;
- z.msg := 'too many length or distance symbols';
- r := Z_DATA_ERROR;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- {$endif}
- t := 258 + (t and $1f) + ((t shr 5) and $1f);
- s.sub.trees.blens := puIntArray( ZALLOC(z, t, sizeof(uInt)) );
- if (s.sub.trees.blens = Z_NULL) then
- begin
- r := Z_MEM_ERROR;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- {DUMPBITS(14);}
- b := b shr 14;
- Dec(k, 14);
-
- s.sub.trees.index := 0;
- {$IFDEF DEBUG}
- Tracev('inflate: table sizes ok');
- {$ENDIF}
- s.mode := BTREE;
- { fall trough case is handled by the while }
- { try GOTO for speed - Nomssi }
- goto start_btree;
- end;
- BTREE:
- begin
- start_btree:
- while (s.sub.trees.index < 4 + (s.sub.trees.table shr 10)) do
- begin
- {NEEDBITS(3);}
- while (k < 3) do
- begin
- {NEEDBYTE;}
- if (n <> 0) then
- r :=Z_OK
- else
- begin
- {UPDATE}
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p)-ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- Dec(n);
- b := b or (uLong(p^) shl k);
- Inc(p);
- Inc(k, 8);
- end;
-
- s.sub.trees.blens^[border[s.sub.trees.index]] := uInt(b) and 7;
- Inc(s.sub.trees.index);
- {DUMPBITS(3);}
- b := b shr 3;
- Dec(k, 3);
- end;
- while (s.sub.trees.index < 19) do
- begin
- s.sub.trees.blens^[border[s.sub.trees.index]] := 0;
- Inc(s.sub.trees.index);
- end;
- s.sub.trees.bb := 7;
- t := inflate_trees_bits(s.sub.trees.blens^, s.sub.trees.bb,
- s.sub.trees.tb, s.hufts^, z);
- if (t <> Z_OK) then
- begin
- ZFREE(z, s.sub.trees.blens);
- r := t;
- if (r = Z_DATA_ERROR) then
- s.mode := BLKBAD;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- s.sub.trees.index := 0;
- {$IFDEF DEBUG}
- Tracev('inflate: bits tree ok');
- {$ENDIF}
- s.mode := DTREE;
- { fall through again }
- goto start_dtree;
- end;
- DTREE:
- begin
- start_dtree:
- while TRUE do
- begin
- t := s.sub.trees.table;
- if not (s.sub.trees.index < 258 +
- (t and $1f) + ((t shr 5) and $1f)) then
- break;
- t := s.sub.trees.bb;
- {NEEDBITS(t);}
- while (k < t) do
- begin
- {NEEDBYTE;}
- if (n <> 0) then
- r :=Z_OK
- else
- begin
- {UPDATE}
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p)-ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- Dec(n);
- b := b or (uLong(p^) shl k);
- Inc(p);
- Inc(k, 8);
- end;
-
- h := s.sub.trees.tb;
- Inc(h, uInt(b) and inflate_mask[t]);
- t := h^.Bits;
- c := h^.Base;
-
- if (c < 16) then
- begin
- {DUMPBITS(t);}
- b := b shr t;
- Dec(k, t);
-
- s.sub.trees.blens^[s.sub.trees.index] := c;
- Inc(s.sub.trees.index);
- end
- else { c = 16..18 }
- begin
- if c = 18 then
- begin
- i := 7;
- j := 11;
- end
- else
- begin
- i := c - 14;
- j := 3;
- end;
- {NEEDBITS(t + i);}
- while (k < t + i) do
- begin
- {NEEDBYTE;}
- if (n <> 0) then
- r :=Z_OK
- else
- begin
- {UPDATE}
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p)-ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- Dec(n);
- b := b or (uLong(p^) shl k);
- Inc(p);
- Inc(k, 8);
- end;
-
- {DUMPBITS(t);}
- b := b shr t;
- Dec(k, t);
-
- Inc(j, uInt(b) and inflate_mask[i]);
- {DUMPBITS(i);}
- b := b shr i;
- Dec(k, i);
-
- i := s.sub.trees.index;
- t := s.sub.trees.table;
- if (i + j > 258 + (t and $1f) + ((t shr 5) and $1f)) or
- ((c = 16) and (i < 1)) then
- begin
- ZFREE(z, s.sub.trees.blens);
- s.mode := BLKBAD;
- z.msg := 'invalid bit length repeat';
- r := Z_DATA_ERROR;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- if c = 16 then
- c := s.sub.trees.blens^[i - 1]
- else
- c := 0;
- repeat
- s.sub.trees.blens^[i] := c;
- Inc(i);
- Dec(j);
- until (j=0);
- s.sub.trees.index := i;
- end;
- end; { while }
- s.sub.trees.tb := Z_NULL;
- begin
- bl := 9; { must be <= 9 for lookahead assumptions }
- bd := 6; { must be <= 9 for lookahead assumptions }
- t := s.sub.trees.table;
- t := inflate_trees_dynamic(257 + (t and $1f),
- 1 + ((t shr 5) and $1f),
- s.sub.trees.blens^, bl, bd, tl, td, s.hufts^, z);
- ZFREE(z, s.sub.trees.blens);
- if (t <> Z_OK) then
- begin
- if (t = uInt(Z_DATA_ERROR)) then
- s.mode := BLKBAD;
- r := t;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- {$IFDEF DEBUG}
- Tracev('inflate: trees ok');
- {$ENDIF}
- { c renamed to cs }
- cs := inflate_codes_new(bl, bd, tl, td, z);
- if (cs = Z_NULL) then
- begin
- r := Z_MEM_ERROR;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- s.sub.decode.codes := cs;
- end;
- s.mode := CODES;
- { yet another falltrough }
- goto start_codes;
- end;
- CODES:
- begin
- start_codes:
- { update pointers }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
-
- r := inflate_codes(s, z, r);
- if (r <> Z_STREAM_END) then
- begin
- inflate_blocks := inflate_flush(s, z, r);
- exit;
- end;
- r := Z_OK;
- inflate_codes_free(s.sub.decode.codes, z);
- { load local pointers }
- p := z.next_in;
- n := z.avail_in;
- b := s.bitb;
- k := s.bitk;
- q := s.write;
- if ptr2int(q) < ptr2int(s.read) then
- m := uInt(ptr2int(s.read)-ptr2int(q)-1)
- else
- m := uInt(ptr2int(s.zend)-ptr2int(q));
- {$IFDEF DEBUG}
- if (ptr2int(q) >= ptr2int(s.read)) then
- Tracev('inflate: codes end '+
- IntToStr(z.total_out + ptr2int(q) - ptr2int(s.read)) + ' total out')
- else
- Tracev('inflate: codes end '+
- IntToStr(z.total_out + ptr2int(s.zend) - ptr2int(s.read) +
- ptr2int(q) - ptr2int(s.window)) + ' total out');
- {$ENDIF}
- if (not s.last) then
- begin
- s.mode := ZTYPE;
- continue; { break for switch statement in C-code }
- end;
- {$ifndef patch112}
- if (k > 7) then { return unused byte, if any }
- begin
- {$IFDEF DEBUG}
- Assert(k < 16, 'inflate_codes grabbed too many bytes');
- {$ENDIF}
- Dec(k, 8);
- Inc(n);
- Dec(p); { can always return one }
- end;
- {$endif}
- s.mode := DRY;
- { another falltrough }
- goto start_dry;
- end;
- DRY:
- begin
- start_dry:
- {FLUSH}
- s.write := q;
- r := inflate_flush(s,z,r);
- q := s.write;
-
- { not needed anymore, we are done:
- if ptr2int(q) < ptr2int(s.read) then
- m := uInt(ptr2int(s.read)-ptr2int(q)-1)
- else
- m := uInt(ptr2int(s.zend)-ptr2int(q));
- }
-
- if (s.read <> s.write) then
- begin
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- s.mode := BLKDONE;
- goto start_blkdone;
- end;
- BLKDONE:
- begin
- start_blkdone:
- r := Z_STREAM_END;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- BLKBAD:
- begin
- r := Z_DATA_ERROR;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- else
- begin
- r := Z_STREAM_ERROR;
- { update pointers and return }
- s.bitb := b;
- s.bitk := k;
- z.avail_in := n;
- Inc(z.total_in, ptr2int(p) - ptr2int(z.next_in));
- z.next_in := p;
- s.write := q;
- inflate_blocks := inflate_flush(s,z,r);
- exit;
- end;
- end; { Case s.mode of }
-
- end;
-
-
- function inflate_blocks_free(s : pInflate_blocks_state;
- var z : z_stream) : int;
- begin
- inflate_blocks_reset(s^, z, Z_NULL);
- ZFREE(z, s^.window);
- ZFREE(z, s^.hufts);
- ZFREE(z, s);
- {$IFDEF DEBUG}
- Trace('inflate: blocks freed');
- {$ENDIF}
- inflate_blocks_free := Z_OK;
- end;
-
-
- procedure inflate_set_dictionary(var s : inflate_blocks_state;
- const d : array of byte; { dictionary }
- n : uInt); { dictionary length }
- begin
- zmemcpy(s.window, pBytef(@d), n);
- s.write := s.window;
- Inc(s.write, n);
- s.read := s.write;
- end;
-
-
- { Returns true if inflate is currently at the end of a block generated
- by Z_SYNC_FLUSH or Z_FULL_FLUSH.
- IN assertion: s <> Z_NULL }
-
- function inflate_blocks_sync_point(var s : inflate_blocks_state) : int;
- begin
- inflate_blocks_sync_point := int(s.mode = LENS);
- end;
-
- end.