Реалізація ідеї арифметичного кодування, Детальна інформація

range = high – low

high = low + range*cum_freq[symbol - 1]

low = low + range*cum_freq[symbol]

return symbol

\x00D0enoiie 1. Inaaaeieiae a\x00F0eoiaoe/iiai eiaeoaaiiy oa aeaeiaeoaaiiy.

4. Caoaaaeaiiy aei \x00F0aae\x00B3caoe\x00B3?.

4.1 I\x00F0e\x00F0iuoaai\x00B3 ia\x00F0aaea/a \x00B3 io\x00F0eiaiiy \x00B3ioi\x00F0iaoe\x00B3?.

Iaaaaeaiee aeai\x00F0eoi eiaeoaaiiy i\x00B3/iai ia ia\x00F0aaea\x00BA aei iiaiiai caaa\x00F0oaiiy eiaeoaaiiy anueiai oaenoo, a oaeiae \x00B3 aeaeiaeoaaeueiee ia ii/eia\x00BA oeae i\x00F0ioean, iiee ia io\x00F0eia\x00BA noeniaiee oaeno oe\x00B3eeii. Aeey a\x00B3eueoino\x00B3 aeiaaee\x00B3a iaiao\x00B3aeai iiaoaiiee \x00F0aaeei aeeiiaiiy .

4.2 Aaaeaia aeei\x00F0enoaiiy oe\x00B3ei/eneaii? a\x00F0eoiaoeee.

Iio\x00F0\x00B3aia aeey i\x00F0aaenoaaeaiiy \x00B3ioa\x00F0aaeo [low; high] oi/i\x00B3noue c\x00F0inoa\x00BA \x00F0acii c aeiaaeeiith oaenoo. Iiaoaiia aeeiiaiiy aeiiiiaaa\x00BA ae\x00F0\x00B3oeoe oeth i\x00F0iaeaio, aea aeiaaa\x00BA i\x00F0e oeueiio oaaaeiiai iae\x00B3eo iiaeeeaiai ia\x00F0aiiaiaiiy oa a\x00B3ae’\x00BAiiiai ia\x00F0aiiaiaiiy.

4.3 Aoaeoeaia \x00F0aae\x00B3caoe\x00B3y iiaeae\x00B3.

\x00D0aae\x00B3caoe\x00B3y iiaeae\x00B3 iiaeiia i\x00B3i\x00B3i\x00B3coaaoe /an aecia/aiiy ianooiiiai neiaieo aeai\x00F0eoiii aeaeiaeoaaiiy. E\x00F0\x00B3i oiai, aaeaioeai\x00B3 iiaeae\x00B3 iiaeii\x00B3 oaeiae i\x00B3i\x00B3i\x00B3coaaoe /an, yeee aeiaaa\x00BAoueny aeey i\x00B3aeo\x00F0eiaiiy iaeiie/aieo /anoio.

5. \x00D0aae\x00B3caoe\x00B3y iiaeae\x00B3.

Naia \x00F0aae\x00B3caoe\x00B3y aoaea iaaiai\x00F0thaaoeny a ianooiiiio \x00F0icae\x00B3e\x00B3, a ooo o\x00F0aaa eeoa oi\x00F0eiooeny o\x00B3eueee \x00B3ioa\x00F0oaeno c iiaeaeeth. sse a\x00B3aeiii, aaeo i\x00F0aaenoaaey\x00BA niaith oe\x00B3ea /enei a\x00B3ae 0 aei 255 (oei char). Ooo ie i\x00F0aaenoaaey\x00BAii aaeo ye oe\x00B3ea /enei a\x00B3ae 1 aei 257 aeeth/ii (oei index), aea EOF o\x00F0aeoo\x00BAoueny ye 257-e neiaie. Aoei a aeia\x00F0a a\x00B3aeni\x00F0ooaaoe iiaeaeue a ii\x00F0yaeeo ciaioaiiy /anoio aeey i\x00B3i\x00B3i\x00B3caoe\x00B3? e\x00B3eueeino\x00B3 aeeiiaiiy oeeeeo aeaeiaeoaaiiy. Ia\x00F0aoai\x00F0aiiy c oeio char a index, oa iaaiaee, \x00F0aae\x00B3ciaaii ca aeiiiiiaith aeaio oaaeeoeue – index_to_char[] i char_to_index[]. A aaeaioeai\x00B3e iiaeae\x00B3 aeeiio\x00BAoueny ia\x00F0aeiaeoaaiiy, yea i\x00F0enaith\x00BA iae/ano\x00B3oei neiaieai iaeaiuee\x00B3 \x00B3iaeaene.

Eiia\x00B3\x00F0iino\x00B3 i\x00F0aaenoaaeythoueny a iiaeae\x00B3 ye oe\x00B3ei/enaeai\x00B3 e\x00B3/eeueieee /anoio, a iaeiie/oaai\x00B3 /anoioe caa\x00F0\x00B3aathoueny a ianea\x00B3 cum_freq[]. sse \x00B3 a iiia\x00F0aaeiueiio aeiaaeeo, oeae ianea – “cai\x00F0ioi\x00B3e”, \x00B3 e\x00B3/eeueiee caaaeueii? /anoioe, yeee aeei\x00F0enoiao\x00BAoueny aeey ii\x00F0iae\x00B3caoe\x00B3? an\x00B3o /anoio, \x00F0ici\x00B3uo\x00BAoueny a cum_freq[0]. Iaeiie/oaai\x00B3 /anoioe ia iiaeii\x00B3 ia\x00F0aaeuoaaoe anoaiiaeaiiee a Max_frequency iaeneioi, a \x00F0aae\x00B3caoe\x00B3y iiaeae\x00B3 iiaeiia caiia\x00B3aaoe ia\x00F0aiiaiaiith a\x00B3aeiia\x00B3aeiei iaooaaoaaiiyi. Iaiao\x00B3aeii oaeiae i\x00F0eiaeii\x00B3 ia 1 caaacia/eoe \x00F0\x00B3cieoeth i\x00B3ae aeaiia non\x00B3aeieie cia/aiiyie cum_freq[], a i\x00F0ioeaiiio aeiaaeeo neiaie, ui ia\x00F0aaeyaea\x00BAoueny, ia aoaea ia\x00F0aaeaiee.

6. Aeiaaaeaiiy i\x00F0aaeeueiino\x00B3 aeaeiaeoaaiiy.

Ia\x00F0aa\x00B3\x00F0eii i\x00F0aaeeuei\x00B3noue aecia/aiiy i\x00F0ioeaaeo\x00F0ith decode_symbol() ianooiiiai neiaieo. C inaaaeieiaeo ia \x00F0enoieo 1 c\x00F0icoi\x00B3ei, ui decode_symbol() iiaeiia aeei\x00F0enoiaoaaoe Value aeey iiooeo neiaiea, yeee i\x00F0e eiaeoaaii\x00B3 nei\x00F0ioea \x00F0iai/ee \x00B3ioa\x00F0aae oae, ui a\x00B3i i\x00F0iaeiaaeo\x00BA aeeth/aoe a naaa Value. A \x00F0iai/\x00B3e i\x00F0ia\x00F0ai\x00B3 a decode_symbol() aecia/a\x00BAoueny oaeee neiaie, aeey yeiai:

cum_freq [symbol] ( (((value – low +1)*cum_freq [0]–1)/(high – low + 1) ( < cum_freq [symbol - 1], aea ( ( icia/a\x00BA iia\x00F0aoe\x00B3th acyooy oe\x00B3ei? /anoeie – ae\x00B3eaiiy c a\x00B3aeeeaeaiiyi ae\x00F0iaiai? /anoeie. Iieacaii, ui oea ia\x00F0aaeaa/a\x00BA:

low + ( ((high - low + 1)*cum_freq [symbol]) / cum_freq [0] ( ( value ( low + ( ((high – low +1)*cum_freq [symbol - 1]) / cum_freq [0](, oaeei /eiii, ui value iaeaaeeoue iiaiio \x00B3ioa\x00F0aaeo, yeee ae\x00F0aoiao\x00BAoueny i\x00F0ioeaaeo\x00F0ith decode_symbol(). Oea aa\x00F0aioo\x00BA ei\x00F0aeoi\x00B3noue aecia/aiiy eiaeiiai neiaieo iia\x00F0aoe\x00B3\x00BAe aeaeiaeoaaiiy.

7. I\x00F0iaeaia ia\x00F0aiiaiaiiy \x00B3 caaa\x00F0oaiiy eiaeoaaiiy.

7.1 A\x00B3ae’\x00BAiia ia\x00F0aiiaiaiiy.

sse iieacaii a inaaaeieiae\x00B3, a\x00F0\x00B3oiaoe/ia eiaeoaaiiy i\x00F0aoeth\x00BA ca aeiiiiiaith ianooaaoaaiiy iaeiie/aieo eiia\x00B3\x00F0iinoae, ye\x00B3 iaaeathoueny iiaeaeth a \x00B3ioa\x00F0aae\x00B3 [low; high] aeey eiaeiiai neiaieo, ui ia\x00F0aaea\x00BAoueny. I\x00F0eionoeii, ui low i high oae aeecuee\x00B3 iaeei aei iaeiiai, ui iia\x00F0aoe\x00B3y ianooaaoaaiiy i\x00F0ecaiaeeoue iaea\x00F0aeai\x00B3 a\x00B3ae iiaeae\x00B3 \x00F0\x00B3ci\x00B3 neiaiee aei iaeiiai oe\x00B3eiai /enea, yea aoiaeeoue a [low; high]. A oaeiio aeiaaeeo iiaeaeueoa eiaeoaaiiy i\x00F0iaeiaaeoaaoe iaiiaeeeai. Oiio eiaeoaaeueiee iiaeiai ne\x00B3aeeoaaoe ca oei, uia \x00B3ioa\x00F0aae [low; high] caaaeaee aoa aeineoue oe\x00F0ieei. Iaei\x00F0ino\x00B3oei caniaii aeey oeueiai \x00BA caaacia/aiiy oe\x00F0eie \x00B3ioa\x00F0aaeo ia iaioae Max_frequency – iaeneiaeueiiai cia/aiiy noie an\x00B3o iaeiie/oaaieo /anoio.

I\x00F0iaeaia a\x00B3ae’\x00BAiiiai ia\x00F0aiiaiaiiy \x00F0icaeyaea\x00BAoueny o\x00B3eueee a\x00B3aeiinii eiaeoaaeueieea, oiio ui i\x00F0e aeaeiaeoaaii\x00B3 eiaeiiai neiaieo i\x00F0ioean e\x00F0ieo\x00BA ca iia\x00F0aoe\x00B3\x00BAe eiaeoaaiiy, \x00B3 a\x00B3ae’iia ia\x00F0aiiaiaiiy ia aeieeia, yeui aeeiio\x00BAoueny oaea naia ianooaaoaaiiy c oeie ae naieie oiiaaie.

7.2 Ia\x00F0aiiaiaiiy.

Oaia\x00F0 \x00F0icaeyiaii iiaeeea\x00B3noue ia\x00F0aiiaiaiiy i\x00F0e oe\x00B3ei/eneaiiio iiiaeaii\x00B3. Ia\x00F0aiiaiaiiy ia aeieeia, yeui aeiaooie range*Max_frequency ai\x00B3uo\x00BAoueny a oe\x00B3ea neiai, ai iaeiie/ai\x00B3 /anoioe ia iiaeooue ia\x00F0aaeuoaaoe Max_frequency. Range ia\x00BA iaea\x00B3eueoa cia/aiiy a Top_Value + 1, oiio iaeneiaeueii iiaeeeaee aeiaooie \x00BA 2^16*(2^14 – 1), yea iaioa 2^30. Aeey aecia/aiiy code_value oa range aeei\x00F0enoaiee oei long, uia caaacia/eoe 32-o a\x00B3oiao oi/i\x00B3noue a\x00F0eoiaoe/ieo ia/eneaiue.

7.3 Caaa\x00F0oaiiy eiaeoaaiiy.

I\x00F0e caaa\x00F0oai\x00B3 i\x00F0ioeano eiaeoaaiiy iaiao\x00B3aeii iineaoe oi\x00B3eaeueiee oa\x00F0i\x00B3iaeueiee neiaie (EOF-neiaie), a iio\x00B3i iineaoe aeinoaoith e\x00B3euee\x00B3nouea\x00B3o\x00B3a aeey aa\x00F0aio\x00B3? oiai, ui caeiaeiaaiee \x00F0yaeie iio\x00F0aieoue a i\x00B3aenoieiaee \x00F0iai/ee \x00B3ioa\x00F0aae. *a\x00F0ac oa, ui i\x00F0ioeaaeo\x00F0a done_encoding() iiaea aooe “aiaaiaia”, ui low i high iaiaaeai\x00B3 aai oae, ui:

low < First_qtr < Half ( high, aai

low < Half < Third_qtr ( high,

oi cia/aiith o\x00F0aaa ia\x00F0aaeaoe 01 aai 10 a\x00B3aeiia\x00B3aeii, aeey aeaeaeaiiy iaaecia/aiino\x00B3, yea caeeoeeanue. Oaeei /eiii EOF oi\x00B3eaeueii aecia/a\x00BAoueny inoaii\x00B3ie ia\x00F0aaeaieie a\x00B3oaie.