kolibrios/programs/fs/kfar/trunk/zlib/deflate.inc
IgorA ccedb4ca44 new version 'longest_match'
git-svn-id: svn://kolibrios.org@6799 a494cfbc-eb01-0410-851d-a64ba20cac60
2016-12-16 09:36:51 +00:00

351 lines
11 KiB
PHP

; deflate.inc -- internal compression state
; Copyright (C) 1995-2012 Jean-loup Gailly
; For conditions of distribution and use, see copyright notice in zlib.inc
; WARNING: this file should *not* be used by applications. It is
; part of the implementation of the compression library and is
; subject to change. Applications should only use zlib.inc.
include 'zutil.inc'
; ===========================================================================
; Internal compression state.
LENGTH_CODES equ 29
; number of length codes, not counting the special END_BLOCK code
LITERALS equ 256
; number of literal bytes 0..255
L_CODES equ (LITERALS+1+LENGTH_CODES)
; number of Literal or Length codes, including the END_BLOCK code
D_CODES equ 30
; number of distance codes
BL_CODES equ 19
; number of codes used to transfer the bit lengths
HEAP_SIZE equ (2*L_CODES+1)
; maximum heap size
MAX_BITS equ 15
; All codes must not exceed MAX_BITS bits
Buf_size equ 16
; size of bit buffer in bi_buf
INIT_STATE equ 42
EXTRA_STATE equ 69
NAME_STATE equ 73
COMMENT_STATE equ 91
HCRC_STATE equ 103
BUSY_STATE equ 113
FINISH_STATE equ 800
; Stream status
; Data structure describing a single value and its code string.
struct ct_data
fc dw ? ;union
;uint_16 freq ;frequency count
;uint_16 code ;bit string
dale dw ? ;union
;uint_16 dad ;father node in Huffman tree
;uint_16 len ;length of bit string
ends
Freq equ ct_data.fc ;.freq
Code equ ct_data.fc ;.code
Dad equ ct_data.dale ;.dad
Len equ ct_data.dale ;.len
struct tree_desc
dyn_tree dd ? ;ct_data * ;the dynamic tree
max_code dd ? ;int ;largest code with non zero frequency
stat_desc dd ? ;static_tree_desc * ;the corresponding static tree
ends
; A Pos is an index in the character window. We use short instead of int to
; save space in the various tables. IPos is used only for parameter passing.
struct deflate_state ;internal_state
strm dd ? ;z_streamp ;pointer back to this zlib stream
status dd ? ;int ;as the name implies
pending_buf dd ? ;Bytef *;output still pending
pending_buf_size dd ? ;ulg ;size of pending_buf
pending_out dd ? ;Bytef * ;next pending byte to output to the stream
pending dd ? ;uInt ;nb of bytes in the pending buffer
wrap dd ? ;int ;bit 0 true for zlib, bit 1 true for gzip
gzhead dd ? ;gz_headerp ;gzip header information to write
gzindex dd ? ;uInt ;where in extra, name, or comment
method db ? ;Byte ;can only be DEFLATED
rb 3 ;for align
last_flush dd ? ;int ;value of flush param for previous deflate call
; used by deflate.asm:
w_size dd ? ;uInt ;LZ77 window size (32K by default)
w_bits dd ? ;uInt ;log2(w_size) (8..16)
w_mask dd ? ;uInt ;w_size - 1
window dd ? ;Bytef *
; Sliding window. Input bytes are read into the second half of the window,
; and move to the first half later to keep a dictionary of at least wSize
; bytes. With this organization, matches are limited to a distance of
; wSize-MAX_MATCH bytes, but this ensures that IO is always
; performed with a length multiple of the block size. Also, it limits
; the window size to 64K, which is quite useful on MSDOS.
; To do: use the user input buffer as sliding window.
window_size dd ? ;ulg
; Actual size of window: 2*wSize, except when the user input buffer
; is directly used as sliding window.
prev dd ? ;Posf *
; Link to older string with same hash index. To limit the size of this
; array to 64K, this link is maintained only for the last 32K strings.
; An index in this array is thus a window index modulo 32K.
head dd ? ;Posf * ;Heads of the hash chains or NIL.
ins_h dd ? ;uInt ;hash index of string to be inserted
hash_size dd ? ;uInt ;number of elements in hash table
hash_bits dd ? ;uInt ;log2(hash_size)
hash_mask dd ? ;uInt ;hash_size-1
hash_shift dd ? ;uInt
; Number of bits by which ins_h must be shifted at each input
; step. It must be such that after MIN_MATCH steps, the oldest
; byte no longer takes part in the hash key, that is:
; hash_shift * MIN_MATCH >= hash_bits
block_start dd ? ;long
; Window position at the beginning of the current output block. Gets
; negative when the window is moved backwards.
match_length dd ? ;uInt ;length of best match
prev_match dd ? ;IPos ;previous match
match_available dd ? ;int ;set if previous match exists
strstart dd ? ;uInt ;start of string to insert
match_start dd ? ;uInt ;start of matching string
lookahead dd ? ;uInt ;number of valid bytes ahead in window
prev_length dd ? ;uInt
; Length of the best match at previous step. Matches not greater than this
; are discarded. This is used in the lazy match evaluation.
max_chain_length dd ? ;uInt
; To speed up deflation, hash chains are never searched beyond this
; length. A higher limit improves compression ratio but degrades the
; speed.
max_lazy_match dd ? ;uInt
; Attempt to find a better match only when the current match is strictly
; smaller than this value. This mechanism is used only for compression
; levels >= 4.
level dw ? ;int ;compression level (1..9)
strategy dw ? ;int ;favor or force Huffman coding
good_match dd ? ;uInt
; Use a faster search when the previous match is longer than this
nice_match dd ? ;int ;Stop searching when current match exceeds this
; used by trees.asm:
; Didn't use ct_data typedef below to suppress compiler warning
dyn_ltree rb sizeof.ct_data * HEAP_SIZE ;literal and length tree
dyn_dtree rb sizeof.ct_data * (2*D_CODES+1) ;distance tree
bl_tree rb sizeof.ct_data * (2*BL_CODES+1) ;Huffman tree for bit lengths
l_desc tree_desc ;desc. for literal tree
d_desc tree_desc ;desc. for distance tree
bl_desc tree_desc ;desc. for bit length tree
bl_count rw MAX_BITS+1 ;uint_16[]
; number of codes at each bit length for an optimal tree
heap rw 2*L_CODES+1 ;int[] ;heap used to build the Huffman trees
heap_len dd ? ;int ;number of elements in the heap
heap_max dd ? ;int ;element of largest frequency
; The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
; The same heap array is used to build all trees.
depth rb ((2*L_CODES+1)+3) and (not 3) ;uch[]
; Depth of each subtree used as tie breaker for trees of equal frequency
l_buf dd ? ;uchf * ;buffer for literals or lengths
lit_bufsize dd ? ;uInt
; Size of match buffer for literals/lengths. There are 4 reasons for
; limiting lit_bufsize to 64K:
; - frequencies can be kept in 16 bit counters
; - if compression is not successful for the first block, all input
; data is still in the window so we can still emit a stored block even
; when input comes from standard input. (This can also be done for
; all blocks if lit_bufsize is not greater than 32K.)
; - if compression is not successful for a file smaller than 64K, we can
; even emit a stored file instead of a stored block (saving 5 bytes).
; This is applicable only for zip (not gzip or zlib).
; - creating new Huffman trees less frequently may not provide fast
; adaptation to changes in the input data statistics. (Take for
; example a binary file with poorly compressible code followed by
; a highly compressible string table.) Smaller buffer sizes give
; fast adaptation but have of course the overhead of transmitting
; trees more frequently.
; - I can't count above 4
last_lit dd ? ;uInt ;running index in l_buf
d_buf dd ? ;uint_16p
; Buffer for distances. To simplify the code, d_buf and l_buf have
; the same number of elements. To use different lengths, an extra flag
; array would be necessary.
opt_len dd ? ;ulg ;bit length of current block with optimal trees
static_len dd ? ;ulg ;bit length of current block with static trees
matches dd ? ;uInt ;number of string matches in current block
insert dd ? ;uInt ;bytes at end of window left to insert
if DEBUG eq 1
compressed_len dd ? ;ulg ;total bit length of compressed file mod 2^32
bits_sent dd ? ;ulg ;bit length of compressed data sent mod 2^32
end if
bi_buf dw ? ;uint_16
; Output buffer. bits are inserted starting at the bottom (least
; significant bits).
bi_valid dd ? ;int
; Number of valid bits in bi_buf. All bits above the last valid bit
; are always zero.
high_water dd ? ;ulg
; High water mark offset in window for initialized bytes -- bytes above
; this are set to zero in order to avoid memory check warnings when
; longest match routines access bytes past the input. This is then
; updated to the new high water mark.
ends
deflate_state.max_insert_length equ deflate_state.max_lazy_match
; Insert new strings in the hash table only if the match length is not
; greater than this length. This saves time but degrades compression.
; max_insert_length is used only for compression levels <= 3.
; Output a byte on the stream.
; IN assertion: there is enough room in pending_buf.
macro put_byte s, c
{
movzx eax,word[s+deflate_state.pending]
add eax,[s+deflate_state.pending_buf]
mov byte[eax],c
inc word[s+deflate_state.pending]
}
macro put_dword s, d
{
zlib_debug '(%d)',d
movzx eax,word[s+deflate_state.pending]
add eax,[s+deflate_state.pending_buf]
mov dword[eax],d
add word[s+deflate_state.pending],4
}
MIN_LOOKAHEAD equ (MAX_MATCH+MIN_MATCH+1)
; Minimum amount of lookahead, except at the end of the input file.
; See deflate.asm for comments about the MIN_MATCH+1.
macro MAX_DIST s
{
mov eax,[s+deflate_state.w_size]
sub eax,MIN_LOOKAHEAD
}
; In order to simplify the code, particularly on 16 bit machines, match
; distances are limited to MAX_DIST instead of WSIZE.
WIN_INIT equ MAX_MATCH
; Number of bytes after end of data in window to initialize in order to avoid
; memory checker errors from longest match routines
macro d_code dist
{
;if (dist < 256) _dist_code[dist]
;else _dist_code[ 256+(dist>>7) ]
local .end0
mov eax,dist
cmp eax,256
jl .end0
shr eax,7
add eax,256
.end0:
movzx eax,byte[eax+_dist_code]
}
; Mapping from a distance to a distance code. dist is the distance - 1 and
; must not have side effects. _dist_code[256] and _dist_code[257] are never
; used.
macro _tr_tally_lit s, c, flush
{
local .end0
if DEBUG eq 0
; Inline versions of _tr_tally for speed:
if c eq eax
else
mov eax,c
end if
push ecx
mov ecx,[s+deflate_state.last_lit]
shl ecx,1
add ecx,[s+deflate_state.d_buf]
mov word[ecx],0
mov ecx,[s+deflate_state.last_lit]
add ecx,[s+deflate_state.l_buf]
mov byte[ecx],al
inc dword[s+deflate_state.last_lit]
and eax,0xff
imul eax,sizeof.ct_data
add eax,s
inc word[eax+deflate_state.dyn_ltree+Freq]
xor eax,eax
mov ecx,[s+deflate_state.lit_bufsize]
dec ecx
cmp [s+deflate_state.last_lit],ecx
jne .end0
inc eax ;flush = (..==..)
.end0:
mov flush, eax
pop ecx
else
stdcall _tr_tally, s, 0, c
mov flush, eax
end if
}
macro _tr_tally_dist s, distance, length, flush
{
if 0 ;;;DEBUG eq 0
push ecx
; uch len = (length)
if distance eq eax
else
mov eax,distance
end if
mov ecx,[s+deflate_state.last_lit]
shl ecx,1
add ecx,[s+deflate_state.d_buf]
mov word[ecx],ax
mov ecx,[s+deflate_state.last_lit]
add ecx,[s+deflate_state.l_buf]
mov byte[ecx],length
inc dword[s+deflate_state.last_lit]
dec eax
; s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++;
; s->dyn_dtree[d_code(dist)].Freq++;
; flush = (s->last_lit == s->lit_bufsize-1);
pop ecx
else
stdcall _tr_tally, s, distance, length
mov flush, eax
end if
}