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September 2017 Update

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Ingy döt Net 2017-09-23 10:01:46 +02:00
parent bba7bfd280
commit ba8067c3b7
14570 changed files with 153136 additions and 63871 deletions
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342
Task/LZW-compression/C/lzw-compression.c
View file

@ -10,249 +10,249 @@
/* -------- aux stuff ---------- */
void* mem_alloc(size_t item_size, size_t n_item)
{
size_t *x = calloc(1, sizeof(size_t)*2 + n_item * item_size);
x[0] = item_size;
x[1] = n_item;
return x + 2;
size_t *x = calloc(1, sizeof(size_t)*2 + n_item * item_size);
x[0] = item_size;
x[1] = n_item;
return x + 2;
}
void* mem_extend(void *m, size_t new_n)
{
size_t *x = (size_t*)m - 2;
x = realloc(x, sizeof(size_t) * 2 + *x * new_n);
if (new_n > x[1])
memset((char*)(x + 2) + x[0] * x[1], 0, x[0] * (new_n - x[1]));
x[1] = new_n;
return x + 2;
size_t *x = (size_t*)m - 2;
x = realloc(x, sizeof(size_t) * 2 + *x * new_n);
if (new_n > x[1])
memset((char*)(x + 2) + x[0] * x[1], 0, x[0] * (new_n - x[1]));
x[1] = new_n;
return x + 2;
}
inline void _clear(void *m)
{
size_t *x = (size_t*)m - 2;
memset(m, 0, x[0] * x[1]);
size_t *x = (size_t*)m - 2;
memset(m, 0, x[0] * x[1]);
}
#define _new(type, n) mem_alloc(sizeof(type), n)
#define _del(m) { free((size_t*)(m) - 2); m = 0; }
#define _len(m) *((size_t*)m - 1)
#define _setsize(m, n) m = mem_extend(m, n)
#define _extend(m) m = mem_extend(m, _len(m) * 2)
#define _new(type, n) mem_alloc(sizeof(type), n)
#define _del(m) { free((size_t*)(m) - 2); m = 0; }
#define _len(m) *((size_t*)m - 1)
#define _setsize(m, n) m = mem_extend(m, n)
#define _extend(m) m = mem_extend(m, _len(m) * 2)
/* ----------- LZW stuff -------------- */
typedef uint8_t byte;
typedef uint16_t ushort;
#define M_CLR 256 /* clear table marker */
#define M_EOD 257 /* end-of-data marker */
#define M_NEW 258 /* new code index */
#define M_CLR 256 /* clear table marker */
#define M_EOD 257 /* end-of-data marker */
#define M_NEW 258 /* new code index */
/* encode and decode dictionary structures.
for encoding, entry at code index is a list of indices that follow current one,
i.e. if code 97 is 'a', code 387 is 'ab', and code 1022 is 'abc',
then dict[97].next['b'] = 387, dict[387].next['c'] = 1022, etc. */
typedef struct {
ushort next[256];
ushort next[256];
} lzw_enc_t;
/* for decoding, dictionary contains index of whatever prefix index plus trailing
byte. i.e. like previous example,
dict[1022] = { c: 'c', prev: 387 },
dict[387] = { c: 'b', prev: 97 },
dict[97] = { c: 'a', prev: 0 }
dict[1022] = { c: 'c', prev: 387 },
dict[387] = { c: 'b', prev: 97 },
dict[97] = { c: 'a', prev: 0 }
the "back" element is used for temporarily chaining indices when resolving
a code to bytes
*/
typedef struct {
ushort prev, back;
byte c;
ushort prev, back;
byte c;
} lzw_dec_t;
byte* lzw_encode(byte *in, int max_bits)
{
int len = _len(in), bits = 9, next_shift = 512;
ushort code, c, nc, next_code = M_NEW;
lzw_enc_t *d = _new(lzw_enc_t, 512);
int len = _len(in), bits = 9, next_shift = 512;
ushort code, c, nc, next_code = M_NEW;
lzw_enc_t *d = _new(lzw_enc_t, 512);
if (max_bits > 15) max_bits = 15;
if (max_bits < 9 ) max_bits = 12;
if (max_bits > 15) max_bits = 15;
if (max_bits < 9 ) max_bits = 12;
byte *out = _new(ushort, 4);
int out_len = 0, o_bits = 0;
uint32_t tmp = 0;
byte *out = _new(ushort, 4);
int out_len = 0, o_bits = 0;
uint32_t tmp = 0;
inline void write_bits(ushort x) {
tmp = (tmp << bits) | x;
o_bits += bits;
if (_len(out) <= out_len) _extend(out);
while (o_bits >= 8) {
o_bits -= 8;
out[out_len++] = tmp >> o_bits;
tmp &= (1 << o_bits) - 1;
}
}
inline void write_bits(ushort x) {
tmp = (tmp << bits) | x;
o_bits += bits;
if (_len(out) <= out_len) _extend(out);
while (o_bits >= 8) {
o_bits -= 8;
out[out_len++] = tmp >> o_bits;
tmp &= (1 << o_bits) - 1;
}
}
//write_bits(M_CLR);
for (code = *(in++); --len; ) {
c = *(in++);
if ((nc = d[code].next[c]))
code = nc;
else {
write_bits(code);
nc = d[code].next[c] = next_code++;
code = c;
}
//write_bits(M_CLR);
for (code = *(in++); --len; ) {
c = *(in++);
if ((nc = d[code].next[c]))
code = nc;
else {
write_bits(code);
nc = d[code].next[c] = next_code++;
code = c;
}
/* next new code would be too long for current table */
if (next_code == next_shift) {
/* either reset table back to 9 bits */
if (++bits > max_bits) {
/* table clear marker must occur before bit reset */
write_bits(M_CLR);
/* next new code would be too long for current table */
if (next_code == next_shift) {
/* either reset table back to 9 bits */
if (++bits > max_bits) {
/* table clear marker must occur before bit reset */
write_bits(M_CLR);
bits = 9;
next_shift = 512;
next_code = M_NEW;
_clear(d);
} else /* or extend table */
_setsize(d, next_shift *= 2);
}
}
bits = 9;
next_shift = 512;
next_code = M_NEW;
_clear(d);
} else /* or extend table */
_setsize(d, next_shift *= 2);
}
}
write_bits(code);
write_bits(M_EOD);
if (tmp) write_bits(tmp);
write_bits(code);
write_bits(M_EOD);
if (tmp) write_bits(tmp);
_del(d);
_del(d);
_setsize(out, out_len);
return out;
_setsize(out, out_len);
return out;
}
byte* lzw_decode(byte *in)
{
byte *out = _new(byte, 4);
int out_len = 0;
byte *out = _new(byte, 4);
int out_len = 0;
inline void write_out(byte c)
{
while (out_len >= _len(out)) _extend(out);
out[out_len++] = c;
}
inline void write_out(byte c)
{
while (out_len >= _len(out)) _extend(out);
out[out_len++] = c;
}
lzw_dec_t *d = _new(lzw_dec_t, 512);
int len, j, next_shift = 512, bits = 9, n_bits = 0;
ushort code, c, t, next_code = M_NEW;
lzw_dec_t *d = _new(lzw_dec_t, 512);
int len, j, next_shift = 512, bits = 9, n_bits = 0;
ushort code, c, t, next_code = M_NEW;
uint32_t tmp = 0;
inline void get_code() {
while(n_bits < bits) {
if (len > 0) {
len --;
tmp = (tmp << 8) | *(in++);
n_bits += 8;
} else {
tmp = tmp << (bits - n_bits);
n_bits = bits;
}
}
n_bits -= bits;
code = tmp >> n_bits;
tmp &= (1 << n_bits) - 1;
}
uint32_t tmp = 0;
inline void get_code() {
while(n_bits < bits) {
if (len > 0) {
len --;
tmp = (tmp << 8) | *(in++);
n_bits += 8;
} else {
tmp = tmp << (bits - n_bits);
n_bits = bits;
}
}
n_bits -= bits;
code = tmp >> n_bits;
tmp &= (1 << n_bits) - 1;
}
inline void clear_table() {
_clear(d);
for (j = 0; j < 256; j++) d[j].c = j;
next_code = M_NEW;
next_shift = 512;
bits = 9;
};
inline void clear_table() {
_clear(d);
for (j = 0; j < 256; j++) d[j].c = j;
next_code = M_NEW;
next_shift = 512;
bits = 9;
};
clear_table(); /* in case encoded bits didn't start with M_CLR */
for (len = _len(in); len;) {
get_code();
if (code == M_EOD) break;
if (code == M_CLR) {
clear_table();
continue;
}
clear_table(); /* in case encoded bits didn't start with M_CLR */
for (len = _len(in); len;) {
get_code();
if (code == M_EOD) break;
if (code == M_CLR) {
clear_table();
continue;
}
if (code >= next_code) {
fprintf(stderr, "Bad sequence\n");
_del(out);
goto bail;
}
if (code >= next_code) {
fprintf(stderr, "Bad sequence\n");
_del(out);
goto bail;
}
d[next_code].prev = c = code;
while (c > 255) {
t = d[c].prev; d[t].back = c; c = t;
}
d[next_code].prev = c = code;
while (c > 255) {
t = d[c].prev; d[t].back = c; c = t;
}
d[next_code - 1].c = c;
d[next_code - 1].c = c;
while (d[c].back) {
write_out(d[c].c);
t = d[c].back; d[c].back = 0; c = t;
}
write_out(d[c].c);
while (d[c].back) {
write_out(d[c].c);
t = d[c].back; d[c].back = 0; c = t;
}
write_out(d[c].c);
if (++next_code >= next_shift) {
if (++bits > 16) {
/* if input was correct, we'd have hit M_CLR before this */
fprintf(stderr, "Too many bits\n");
_del(out);
goto bail;
}
_setsize(d, next_shift *= 2);
}
}
if (++next_code >= next_shift) {
if (++bits > 16) {
/* if input was correct, we'd have hit M_CLR before this */
fprintf(stderr, "Too many bits\n");
_del(out);
goto bail;
}
_setsize(d, next_shift *= 2);
}
}
/* might be ok, so just whine, don't be drastic */
if (code != M_EOD) fputs("Bits did not end in EOD\n", stderr);
/* might be ok, so just whine, don't be drastic */
if (code != M_EOD) fputs("Bits did not end in EOD\n", stderr);
_setsize(out, out_len);
bail: _del(d);
return out;
_setsize(out, out_len);
bail: _del(d);
return out;
}
int main()
{
int i, fd = open("unixdict.txt", O_RDONLY);
int i, fd = open("unixdict.txt", O_RDONLY);
if (fd == -1) {
fprintf(stderr, "Can't read file\n");
return 1;
};
if (fd == -1) {
fprintf(stderr, "Can't read file\n");
return 1;
};
struct stat st;
fstat(fd, &st);
struct stat st;
fstat(fd, &st);
byte *in = _new(char, st.st_size);
read(fd, in, st.st_size);
_setsize(in, st.st_size);
close(fd);
byte *in = _new(char, st.st_size);
read(fd, in, st.st_size);
_setsize(in, st.st_size);
close(fd);
printf("input size: %d\n", _len(in));
printf("input size: %d\n", _len(in));
byte *enc = lzw_encode(in, 9);
printf("encoded size: %d\n", _len(enc));
byte *enc = lzw_encode(in, 9);
printf("encoded size: %d\n", _len(enc));
byte *dec = lzw_decode(enc);
printf("decoded size: %d\n", _len(dec));
byte *dec = lzw_decode(enc);
printf("decoded size: %d\n", _len(dec));
for (i = 0; i < _len(dec); i++)
if (dec[i] != in[i]) {
printf("bad decode at %d\n", i);
break;
}
for (i = 0; i < _len(dec); i++)
if (dec[i] != in[i]) {
printf("bad decode at %d\n", i);
break;
}
if (i == _len(dec)) printf("Decoded ok\n");
if (i == _len(dec)) printf("Decoded ok\n");
_del(in);
_del(enc);
_del(dec);
_del(in);
_del(enc);
_del(dec);
return 0;
return 0;
}

36
Task/LZW-compression/CoffeeScript/lzw-compression-1.coffee
View file

@ -1,36 +0,0 @@
lzw = (s) ->
dct = {} # map substrings to codes between 256 and 4096
stream = [] # array of compression results
# initialize basic ASCII characters
for code_num in [0..255]
c = String.fromCharCode(code_num)
dct[c] = code_num
code_num = 256
i = 0
while i < s.length
# Find word and new_word
# word = longest substr already encountered, or next character
# new_word = word plus next character, a new substr to encode
word = ''
j = i
while j < s.length
new_word = word + s[j]
break if !dct[new_word]
word = new_word
j += 1
# stream out the code for the substring
stream.push dct[word]
# build up our encoding dictionary
if code_num < 4096
dct[new_word] = code_num
code_num += 1
# advance thru the string
i += word.length
stream
console.log lzw "TOBEORNOTTOBEORTOBEORNOT"

17
Task/LZW-compression/CoffeeScript/lzw-compression-2.coffee
View file

@ -1,17 +0,0 @@
> coffee lzw.coffee
[ 84,
79,
66,
69,
79,
82,
78,
79,
84,
256,
258,
260,
265,
259,
261,
263 ]

204
Task/LZW-compression/Eiffel/lzw-compression.e
View file

@ -1,112 +1,112 @@
class
APPLICATION
APPLICATION
create
make
make
feature {NONE}
make
local
test: LINKED_LIST [INTEGER]
do
create test.make
test := compress ("TOBEORNOTTOBEORTOBEORNOT")
across
test as t
loop
io.put_string (t.item.out + " ")
end
io.new_line
io.put_string (decompress (test))
end
make
local
test: LINKED_LIST [INTEGER]
do
create test.make
test := compress ("TOBEORNOTTOBEORTOBEORNOT")
across
test as t
loop
io.put_string (t.item.out + " ")
end
io.new_line
io.put_string (decompress (test))
end
decompress (compressed: LINKED_LIST [INTEGER]): STRING
--Decompressed version of 'compressed'.
local
dictsize, i, k: INTEGER
dictionary: HASH_TABLE [STRING, INTEGER]
w, entry: STRING
char: CHARACTER_8
do
dictsize := 256
create dictionary.make (300)
create entry.make_empty
create Result.make_empty
from
i := 0
until
i > 256
loop
char := i.to_character_8
dictionary.put (char.out, i)
i := i + 1
end
w := compressed.first.to_character_8.out
compressed.go_i_th (1)
compressed.remove
Result := w
from
k := 1
until
k > compressed.count
loop
if attached dictionary.at (compressed [k]) as ata then
entry := ata
elseif compressed [k] = dictsize then
entry := w + w.at (1).out
else
io.put_string ("EXEPTION")
end
Result := Result + entry
dictsize := dictsize + 1
dictionary.put (w + entry.at (1).out, dictsize)
w := entry
k := k + 1
end
end
decompress (compressed: LINKED_LIST [INTEGER]): STRING
--Decompressed version of 'compressed'.
local
dictsize, i, k: INTEGER
dictionary: HASH_TABLE [STRING, INTEGER]
w, entry: STRING
char: CHARACTER_8
do
dictsize := 256
create dictionary.make (300)
create entry.make_empty
create Result.make_empty
from
i := 0
until
i > 256
loop
char := i.to_character_8
dictionary.put (char.out, i)
i := i + 1
end
w := compressed.first.to_character_8.out
compressed.go_i_th (1)
compressed.remove
Result := w
from
k := 1
until
k > compressed.count
loop
if attached dictionary.at (compressed [k]) as ata then
entry := ata
elseif compressed [k] = dictsize then
entry := w + w.at (1).out
else
io.put_string ("EXEPTION")
end
Result := Result + entry
dictsize := dictsize + 1
dictionary.put (w + entry.at (1).out, dictsize)
w := entry
k := k + 1
end
end
compress (uncompressed: STRING): LINKED_LIST [INTEGER]
-- Compressed version of 'uncompressed'.
local
dictsize: INTEGER
dictionary: HASH_TABLE [INTEGER, STRING]
i: INTEGER
w, wc: STRING
char: CHARACTER_8
do
dictsize := 256
create dictionary.make (256)
create w.make_empty
from
i := 0
until
i > 256
loop
char := i.to_character_8
dictionary.put (i, char.out)
i := i + 1
end
create Result.make
from
i := 1
until
i > uncompressed.count
loop
wc := w + uncompressed [i].out
if dictionary.has (wc) then
w := wc
else
Result.extend (dictionary.at (w))
dictSize := dictSize + 1
dictionary.put (dictSize, wc)
w := "" + uncompressed [i].out
end
i := i + 1
end
if w.count > 0 then
Result.extend (dictionary.at (w))
end
end
compress (uncompressed: STRING): LINKED_LIST [INTEGER]
-- Compressed version of 'uncompressed'.
local
dictsize: INTEGER
dictionary: HASH_TABLE [INTEGER, STRING]
i: INTEGER
w, wc: STRING
char: CHARACTER_8
do
dictsize := 256
create dictionary.make (256)
create w.make_empty
from
i := 0
until
i > 256
loop
char := i.to_character_8
dictionary.put (i, char.out)
i := i + 1
end
create Result.make
from
i := 1
until
i > uncompressed.count
loop
wc := w + uncompressed [i].out
if dictionary.has (wc) then
w := wc
else
Result.extend (dictionary.at (w))
dictSize := dictSize + 1
dictionary.put (dictSize, wc)
w := "" + uncompressed [i].out
end
i := i + 1
end
if w.count > 0 then
Result.extend (dictionary.at (w))
end
end
end

12
Task/LZW-compression/Erlang/lzw-compression.erl
View file

@ -7,7 +7,7 @@
test() ->
Str = "TOBEORNOTTOBEORTOBEORNOT",
[84,79,66,69,79,82,78,79,84,256,258,260,265,259,261,263] =
encode(Str),
encode(Str),
Str = decode(encode(Str)),
ok.
@ -24,11 +24,11 @@ encode([H|T], D, Free, Out) ->
find_match([H|T], L, LastVal, D, Free, Out) ->
case dict:find([H|L], D) of
{ok, Val} ->
find_match(T, [H|L], Val, D, Free, Out);
error ->
D1 = dict:store([H|L], Free, D),
encode([H|T], D1, Free+1, [LastVal|Out])
{ok, Val} ->
find_match(T, [H|L], Val, D, Free, Out);
error ->
D1 = dict:store([H|L], Free, D),
encode([H|T], D1, Free+1, [LastVal|Out])
end;
find_match([], _, LastVal, _, _, Out) ->
reverse([LastVal|Out]).

4
Task/LZW-compression/Forth/lzw-compression.fth
View file

@ -16,7 +16,7 @@ create w 256 allot \ counted string
: free-dict forth-wordlist set-current ;
: in-dict? ( key len -- ? ) \ can assume len > 1
: in-dict? ( key len -- ? ) \ can assume len > 1
dict search-wordlist dup if nip then ;
: lookup-dict ( key len -- symbol )
@ -83,7 +83,7 @@ create entry 256 allot
else
abort" bad symbol!"
then then
entry count type \ output
entry count type \ output
entry 1+ c@ w+c
w count add-symbol
entry count w place

16
Task/LZW-compression/Groovy/lzw-compression-1.groovy
View file

@ -1,5 +1,5 @@
def compress = { text ->
def dictionary = (1..255).inject([:]) { map, ch -> map."${(char)ch}" = ch; map }
def dictionary = (0..<256).inject([:]) { map, ch -> map."${(char)ch}" = ch; map }
def w = '', compressed = []
text.each { ch ->
def wc = "$w$ch"
@ -7,7 +7,7 @@ def compress = { text ->
w = wc
} else {
compressed << dictionary[w]
dictionary[wc] = dictionary.size() + 1
dictionary[wc] = dictionary.size()
w = "$ch"
}
}
@ -16,18 +16,22 @@ def compress = { text ->
}
def decompress = { compressed ->
def dictionary = (1..255).inject([:]) { map, ch -> map[ch] = "${(char)ch}"; map }
String w = "${(char)compressed.remove(0)}"
def dictionary = (0..<256).inject([:]) { map, ch -> map[ch] = "${(char)ch}"; map }
int dictSize = 128;
String w = "${(char)compressed[0]}"
StringBuffer result = new StringBuffer(w)
compressed.each { k ->
compressed.drop(1).each { k ->
String entry = dictionary[k]
if (!entry) {
if (k != dictionary.size()) throw new IllegalArgumentException("Bad compressed k $k")
entry = "$w${w[0]}"
}
result << entry
dictionary[dictionary.size() + 1] = "$w${entry[0]}"
dictionary[dictionary.size()] = "$w${entry[0]}"
w = entry
}
result.toString()
}

81
Task/LZW-compression/JavaScript/lzw-compression-1.js
View file

@ -1,81 +0,0 @@
//LZW Compression/Decompression for Strings
var LZW = {
compress: function (uncompressed) {
"use strict";
// Build the dictionary.
var i,
dictionary = {},
c,
wc,
w = "",
result = [],
dictSize = 256;
for (i = 0; i < 256; i += 1) {
dictionary[String.fromCharCode(i)] = i;
}
for (i = 0; i < uncompressed.length; i += 1) {
c = uncompressed.charAt(i);
wc = w + c;
//Do not use dictionary[wc] because javascript arrays
//will return values for array['pop'], array['push'] etc
// if (dictionary[wc]) {
if (dictionary.hasOwnProperty(wc)) {
w = wc;
} else {
result.push(dictionary[w]);
// Add wc to the dictionary.
dictionary[wc] = dictSize++;
w = String(c);
}
}
// Output the code for w.
if (w !== "") {
result.push(dictionary[w]);
}
return result;
},
decompress: function (compressed) {
"use strict";
// Build the dictionary.
var i,
dictionary = [],
w,
result,
k,
entry = "",
dictSize = 256;
for (i = 0; i < 256; i += 1) {
dictionary[i] = String.fromCharCode(i);
}
w = String.fromCharCode(compressed[0]);
result = w;
for (i = 1; i < compressed.length; i += 1) {
k = compressed[i];
if (dictionary[k]) {
entry = dictionary[k];
} else {
if (k === dictSize) {
entry = w + w.charAt(0);
} else {
return null;
}
}
result += entry;
// Add w+entry[0] to the dictionary.
dictionary[dictSize++] = w + entry.charAt(0);
w = entry;
}
return result;
}
}, // For Test Purposes
comp = LZW.compress("TOBEORNOTTOBEORTOBEORNOT"),
decomp = LZW.decompress(comp);
document.write(comp + '<br>' + decomp);

2
Task/LZW-compression/JavaScript/lzw-compression-2.js
View file

@ -1,2 +0,0 @@
84,79,66,69,79,82,78,79,84,256,258,260,265,259,261,263
TOBEORNOTTOBEORTOBEORNOT

0
Task/LZW-compression/jq/lzw-compression-1.jq → Task/LZW-compression/Jq/lzw-compression-1.jq
View file

0
Task/LZW-compression/jq/lzw-compression-2.jq → Task/LZW-compression/Jq/lzw-compression-2.jq
View file

62
Task/LZW-compression/Kotlin/lzw-compression.kotlin Normal file
View file

@ -0,0 +1,62 @@
// version 1.1.2
object Lzw {
/** Compress a string to a list of output symbols. */
fun compress(uncompressed: String): MutableList<Int> {
// Build the dictionary.
var dictSize = 256
val dictionary = mutableMapOf<String, Int>()
(0 until dictSize).forEach { dictionary.put(it.toChar().toString(), it)}
var w = ""
val result = mutableListOf<Int>()
for (c in uncompressed) {
val wc = w + c
if (dictionary.containsKey(wc))
w = wc
else {
result.add(dictionary[w]!!)
// Add wc to the dictionary.
dictionary.put(wc, dictSize++)
w = c.toString()
}
}
// Output the code for w
if (!w.isEmpty()) result.add(dictionary[w]!!)
return result
}
/** Decompress a list of output symbols to a string. */
fun decompress(compressed: MutableList<Int>): String {
// Build the dictionary.
var dictSize = 256
val dictionary = mutableMapOf<Int, String>()
(0 until dictSize).forEach { dictionary.put(it, it.toChar().toString())}
var w = compressed.removeAt(0).toChar().toString()
val result = StringBuilder(w)
for (k in compressed) {
var entry: String
if (dictionary.containsKey(k))
entry = dictionary[k]!!
else if (k == dictSize)
entry = w + w[0]
else
throw IllegalArgumentException("Bad compressed k: $k")
result.append(entry)
// Add w + entry[0] to the dictionary.
dictionary.put(dictSize++, w + entry[0])
w = entry
}
return result.toString()
}
}
fun main(args: Array<String>) {
val compressed = Lzw.compress("TOBEORNOTTOBEORTOBEORNOT")
println(compressed)
val decompressed = Lzw.decompress(compressed)
println(decompressed)
}

2
Task/LZW-compression/PHP/lzw-compression.php
View file

@ -49,7 +49,7 @@ class LZW
}
}
$result .= $entry;
$dictionary[$dictSize++] = $w + $entry[0];
$dictionary[$dictSize++] = $w . $entry[0];
$w = $entry;
}
return $result;

38
Task/LZW-compression/Perl-6/lzw-compression.pl6
View file

@ -4,17 +4,17 @@ sub compress(Str $uncompressed --> Seq) {
my $w = "";
gather {
for $uncompressed.comb -> $c {
my $wc = $w ~ $c;
if %dictionary{$wc}:exists { $w = $wc }
else {
take %dictionary{$w};
%dictionary{$wc} = +%dictionary;
$w = $c;
}
}
for $uncompressed.comb -> $c {
my $wc = $w ~ $c;
if %dictionary{$wc}:exists { $w = $wc }
else {
take %dictionary{$w};
%dictionary{$wc} = +%dictionary;
$w = $c;
}
}
take %dictionary{$w} if $w.chars;
take %dictionary{$w} if $w.chars;
}
}
@ -24,16 +24,16 @@ sub decompress(@compressed --> Str) {
my $w = shift @compressed;
join '', gather {
take $w;
for @compressed -> $k {
my $entry;
if %dictionary{$k}:exists { take $entry = %dictionary{$k} }
elsif $k == $dict-size { take $entry = $w ~ $w.substr(0,1) }
else { die "Bad compressed k: $k" }
take $w;
for @compressed -> $k {
my $entry;
if %dictionary{$k}:exists { take $entry = %dictionary{$k} }
elsif $k == $dict-size { take $entry = $w ~ $w.substr(0,1) }
else { die "Bad compressed k: $k" }
%dictionary{$dict-size++} = $w ~ $entry.substr(0,1);
$w = $entry;
}
%dictionary{$dict-size++} = $w ~ $entry.substr(0,1);
$w = $entry;
}
}
}

57
Task/LZW-compression/Phix/lzw-compression.phix Normal file
View file

@ -0,0 +1,57 @@
function compress(string uncompressed)
integer dict = new_dict()
sequence result = {}
integer dictSize = 255, c
string word = ""
for i=0 to 255 do
setd(""&i,i,dict)
end for
for i=1 to length(uncompressed) do
c = uncompressed[i]
if getd_index(word&c,dict) then
word &= c
else
result &= getd(word,dict)
dictSize += 1
setd(word&c,dictSize,dict)
word = ""&c
end if
end for
if word!="" then
result &= getd(word,dict)
end if
destroy_dict(dict)
return result
end function
function decompress(sequence compressed)
integer dict = new_dict()
integer dictSize = 255, k, ki
string dent = "", result = "", word = ""
for i=0 to 255 do
setd(i,""&i,dict)
end for
for i=1 to length(compressed) do
k = compressed[i]
ki = getd_index(k,dict)
if ki then
dent = getd_by_index(ki,dict)
elsif k=dictSize then
dent = word&word[1]
else
return {NULL,i}
end if
result &= dent
setd(dictSize,word&dent[1],dict)
dictSize += 1
word = dent
end for
destroy_dict(dict)
return result
end function
constant example = "TOBEORNOTTOBEORTOBEORNOT"
sequence com = compress(example)
--?com
pp(com)
?decompress(com)

6
Task/LZW-compression/Python/lzw-compression.py
View file

@ -31,13 +31,13 @@ def decompress(compressed):
# Build the dictionary.
dict_size = 256
dictionary = dict((chr(i), chr(i)) for i in xrange(dict_size))
# in Python 3: dictionary = {chr(i): chr(i) for i in range(dict_size)}
dictionary = dict((i, chr(i)) for i in xrange(dict_size))
# in Python 3: dictionary = {i: chr(i) for i in range(dict_size)}
# use StringIO, otherwise this becomes O(N^2)
# due to string concatenation in a loop
result = StringIO()
w = compressed.pop(0)
w = chr(compressed.pop(0))
result.write(w)
for k in compressed:
if k in dictionary:

105
Task/LZW-compression/REALbasic/lzw-compression.realbasic Normal file
View file

@ -0,0 +1,105 @@
Function compress(str as String) As String
Dim i as integer
Dim w as String = ""
Dim c as String
Dim strLen as Integer
Dim wc as string
Dim dic() as string
Dim result() as string
Dim lookup as integer
Dim startPos as integer = 0
Dim combined as String
strLen = len(str)
dic = populateDictionary
for i = 1 to strLen
c = str.mid(i, 1)
wc = w + c
startPos = getStartPos(wc)
lookup = findArrayPos(dic, wc, startPos)
if (lookup <> -1) then
w = wc
Else
startPos = getStartPos(w)
lookup = findArrayPos(dic, w, startPos)
if lookup <> -1 then
result.Append(lookup.ToText)
end if
dic.append(wc)
w = c
end if
next i
if (w <> "") then
startPos = getStartPos(w)
lookup = findArrayPos(dic, w, startPos)
result.Append(lookup.ToText)
end if
return join(result, ",")
End Function
Function decompress(str as string) As string
dim comStr() as string
dim w as string
dim result as string
dim comStrLen as integer
dim entry as string
dim dic() as string
dim i as integer
comStr = str.Split(",")
comStrLen = comStr.Ubound
dic = populateDictionary
w = chr(val(comStr(0)))
result = w
for i = 1 to comStrLen
entry = dic(val(comStr(i)))
result = result + entry
dic.append(w + entry.mid(1,1))
w = entry
next i
return result
End Function
Private Function findArrayPos(arr() as String, search as String, start as integer) As Integer
dim arraySize as Integer
dim arrayPosition as Integer = -1
dim i as Integer
arraySize = UBound(arr)
for i = start to arraySize
if (strcomp(arr(i), search, 0) = 0) then
arrayPosition = i
exit
end if
next i
return arrayPosition
End Function
Private Function getStartPos(str as String) As integer
if (len(str) = 1) then
return 0
else
return 255
end if
End Function
Private Function populateDictionary() As string()
dim dic() as string
dim i as integer
for i = 0 to 255
dic.append(Chr(i))
next i
return dic
End Function

4
Task/LZW-compression/Scheme/lzw-compression.ss
View file

@ -69,8 +69,8 @@
(set! dictionary
(append dictionary
(list (string-append
(list-ref dictionary k)
(string (string-ref (list-ref dictionary kn) 0)))))))))
(list-ref dictionary k)
(string (string-ref (list-ref dictionary kn) 0)))))))))
;; Build the resulting string
(set! result (string-append result (list-ref dictionary k)))

26
Task/LZW-compression/Sidef/lzw-compression.sidef
View file

@ -1,14 +1,14 @@
# Compress a string to a list of output symbols.
func compress(String uncompressed) -> Array {
 
# Build the dictionary.
var dict_size = 256
var dictionary = Hash()
 
for i in range(dict_size) {
dictionary{i.chr} = i.chr
}
 
var w = ''
var result = []
uncompressed.each { |c|
@ -23,26 +23,26 @@ func compress(String uncompressed) -> Array {
w = c
}
}
 
# Output the code for w.
if (w != '') {
if (w != '') {
result << dictionary{w}
}
 
return result
}
 
# Decompress a list of output ks to a string.
func decompress(Array compressed) -> String {
 
# Build the dictionary.
var dict_size = 256
var dictionary = Hash()
 
for i in range(dict_size) {
dictionary{i.chr} = i.chr
}
 
var w = compressed.shift
var result = w
compressed.each { |k|
@ -55,16 +55,16 @@ func decompress(Array compressed) -> String {
die "Bad compressed k: #{k}"
}
result += entry
 
# Add w+entry[0] to the dictionary.
dictionary{dict_size} = w+entry.first
dict_size++
 
w = entry
}
return result
}
 
# How to use:
var compressed = compress('TOBEORNOTTOBEORTOBEORNOT')
say compressed.join(' ')

28
Task/LZW-compression/Zkl/lzw-compression-1.zkl Normal file
View file

@ -0,0 +1,28 @@
fcn lzwCompress(uncompressed){ // text-->list of 12 bit ints
dictionary:=(256).pump(Dictionary(),fcn(n){ return(n.toChar(),n) });
w,compressed:="",List();
foreach c in (uncompressed){
wc:=w+c;
if(dictionary.holds(wc)) w=wc;
else{
compressed.append(dictionary[w]); // 12 bits
dictionary[wc]=dictionary.len();
w=c;
}
}
if(w) compressed.append(dictionary[w]);
compressed
}
fcn lzwUncompress(compressed){ // compressed data-->text
dictionary:=(256).pump(Dictionary(),fcn(n){ return(n,n.toChar()) });
w,decommpressed:=dictionary[compressed[0]],Data(Void,w);
foreach k in (compressed[1,*]){
if(dictionary.holds(k)) entry:=dictionary[k];
else if(k==dictionary.len()) entry:=w+w[0];
else throw(Exception.ValueError("Invalid compressed data"));
decommpressed.append(entry);
dictionary.add(dictionary.len(),w+entry[0]);
w=entry;
}
decommpressed.text
}

4
Task/LZW-compression/Zkl/lzw-compression-2.zkl Normal file
View file

@ -0,0 +1,4 @@
compressed:=lzwCompress("TOBEORNOTTOBEORTOBEORNOT");
compressed.toString(*).println();
lzwUncompress(compressed).println();