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[Liborigin-devel] OPJU support
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From: Ivan K. <kry...@gm...> - 2019-08-24 17:40:04
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Dear liborigin maintainers, How different is the new OPJU format from OPJ? How much is known about it? I have noticed that the library checks for the new "CPYUA" header, but the OPJU files I have are impossible to parse, and a cursory glance at the files suggests that they are, indeed, very different. For example, there is far less 0x0a bytes in OPJU files than in corresponding OPJ files, and the encoding seems to be much more compact, although similar byte patterns crop up now and then: OPJ: 00170620 0A 63 6F 6C 28 43 4A 29 .........col(CJ) 00170630 2A 32 2E 33 30 33 2F 30 2E 30 33 00 00 0A 00 00 *2.303/0.03..... 00170640 00 00 0A 00 00 00 00 0A 6F 00 00 00 0A 00 00 06 ........o....... 00170650 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00170660 5C 8F C2 F5 28 5C EE 3F DB B6 6D DB B6 6D AB 3F \...(\.?..m..m.? 00170670 14 00 00 00 00 10 01 3E 00 3E 00 C2 FF C2 FF 00 .......>.>...... 00170680 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00170690 00 00 00 47 52 31 00 00 00 00 00 00 00 00 00 00 ...GR1.......... 001706A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 001706B0 00 00 00 00 00 00 00 00 00 00 00 00 0A 14 00 00 ................ 001706C0 00 0A ..col(CI)*2.303/ OPJU: 000FBE70 0A 63 6F 6C 28 43 4A 29 2A 32 2E 33 30 33 2F ..col(CJ)*2.303/ 000FBE80 30 2E 30 33 00 00 0A 00 00 00 00 0A 00 00 00 80 0.03............ 000FBE90 2C 03 00 00 06 8D 11 5C 8F C2 F5 28 5C EE 3F DB ,......\...(\.?. 000FBEA0 B6 6D DB B6 6D AB 3F 14 81 0A 10 01 3E 00 3E 00 .m..m.?.....>.>. 000FBEB0 C2 FF C2 FF 91 03 47 52 31 A5 01 08 90 00 00 14 ......GR1....... 000FBEC0 00 00 00 0A ....col(CI)*2.30 For example, some short strings are prefixed with their length instead of being surrounded by NUL bytes, like 0x03 "GR1" in the example above or 0x07 "Book2_B" elsewhere in the same file. The data might also be compressed, since gnuplot commands plot for [i=0:7] 'file.opju' binary array=(-1) format="%double" skip=i not or plot for [i=0:3] 'file.opju' binary array=(-1) format="%float" skip=i not don't seem to reveal any structure, unlike they did for OPJ files (in the latter case, if I know typical range of values stored in the file and set it manually before plotting, I can usually see the data as they appear in the file). Is there a known methodology one could use to adapt the parser for the new format? -- Best regards, Ivan |
