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• zlib へ行く。
  • 1 (2024-07-11 (木) 21:18:22)
  • 2 (2024-08-24 (土) 15:50:20)

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Compression

• http://www.zlib.net/
  • http://www.zlib.net/zlib_tech.html Technical Details

• http://oku.edu.mie-u.ac.jp/~okumura/compression/zlib.html zlib 入門
• http://dencha.ojaru.jp/programs/pg_filer_04_extra_03.html zlib1.2.2 FAQ 訳
• http://www.futomi.com/lecture/japanese/rfc1950.html RFC 1950 ZLIB Compressed Data Format Specification version 3.3 日本語訳

• Deflate (圧縮アルゴリズム)

実装比較†

• A comparison of Zlib implementations
  • http://www.htslib.org/benchmarks/zlib.html

• Improving zlib-cloudflare and comparing performance with other zlib forks
  • https://aws.amazon.com/jp/blogs/opensource/improving-zlib-cloudflare-and-comparing-performance-with-other-zlib-forks/

compress / uncompress†

compress†

compsize = ～; // 圧縮後のサイズより大きな値
compbuff = malloc(compsize);
int result = compress(compbuff, &compsize, origbuff, origsize);
if (result != Z_OK) {
    if (result == Z_MEM_ERROR) {
        fprintf(stderr, "compress: Z_MEM_ERROR: can't malloc\n");
    } else if (result == Z_BUF_ERROR) {
        fprintf(stderr, "compress: Z_BUF_ERROR: not enough buff size\n");
    }
    return 1; // FAILURE
}

uncompress†

origsize = ～;  // 伸張後のサイズより大きな値
origbuff = malloc(origsize);
int result = uncompress(origbuff, &origsize, compbuff, compsize);
if (result != Z_OK) {
    if (result == Z_MEM_ERROR) {
        fprintf(stderr, "uncompress: Z_MEM_ERROR: can't malloc\n");
    } else if (result == Z_BUF_ERROR) {
        fprintf(stderr, "uncompress: Z_BUF_ERROR: not enough buff size\n");
    }
    return 1; // FAILURE
}

inflate / defrate†

(予定)

発表スライド†

未圧縮形式と固定ハフマン

• http://www.slideshare.net/7shi/deflate

参考†

• http://tools.ietf.org/rfc/rfc1950.pdf
• http://tools.ietf.org/rfc/rfc1951.pdf
• http://tools.ietf.org/rfc/rfc1952.pdf
• PNG Deflate/Inflate 圧縮
  • http://www.sutv.zaq.ne.jp/linuz/tks/PngSpec1.2/PNG-Compression.html

• Zlib Flush Modes
• https://www.bolet.org/~pornin/deflate-flush.html

• カスタムハフマン (dynamic huffman)
  • http://d.hatena.ne.jp/n7shi/20110719/1311093479
• Zlib (Deflate のコンテナ)
  • http://www.futomi.com/lecture/japanese/rfc1950.html
• Deflate (圧縮の仕様
  • http://www.futomi.com/lecture/japanese/rfc1951.html)
• IO_Zlib 1.0.0 リリース (ハマりどころメモ)
  • http://d.hatena.ne.jp/yoya/20110726/io_zlib

• SWFバイナリ編集のススメ番外編 (zlib 伸張)
  • https://labs.gree.jp/blog/2012/01/4082/
  • https://labs.gree.jp/blog/2014/01/4530/

関連†

• Deflate
• PNG
• IO_Zlib

• LZFSE (Apple の圧縮技術)