I just had a chance to try this out and it looks good. I encoded a ~1MB string in ~1.8 seconds. The biggest time sink for me was now openpgp_cfb_encrypt as we might expect.
GPG didn't complain about the CRC generated, so I think the values are correct (but obviously didn't get to individually check all of them). Nice work, Carsten. I think between this and the other text optimizations, we've captured most of the "low hanging fruit" of optimizations which has provided speed ups of orders of magnitude, so that's good news. On Fri, Feb 17, 2012 at 11:33 AM, Carsten Wentzlow < [email protected]> wrote: > Hi! > ~~~ > > On 02/17/2012 04:13 PM, Carsten Wentzlow wrote: > > On 02/17/2012 03:28 PM, Sean Colyer wrote: > >> I was looking at the CRC24 method yesterday. So, I think the issue > comes from the fact that we're looping over lots of data, and looping 8 > times for each entry. I think what we need to do is build a lookup table > for CRC24. I was looking around to see if other CRC's had lookup tables or > other optimizations some of them do. http://wiki.osdev.org/CRC32Describes one > method for CRC32 that could be adjusted for building a > similar table for CRC24. > >> > >> Thoughts? > > Very good idea. This should speed up the calculation. > > > @Tankred: Could you please try again by replacing the createcrc24 function > at src/encoding/openpgp.encoding.asciiarmor.js with the following and > profile again: > > var crc_table = [ > 0x00000000, 0x00864cfb, 0x018ad50d, 0x010c99f6, 0x0393e6e1, 0x0315aa1a, > 0x021933ec, 0x029f7f17, 0x07a18139, 0x0727cdc2, 0x062b5434, 0x06ad18cf, > 0x043267d8, 0x04b42b23, 0x05b8b2d5, 0x053efe2e, 0x0fc54e89, 0x0f430272, > 0x0e4f9b84, 0x0ec9d77f, 0x0c56a868, 0x0cd0e493, 0x0ddc7d65, 0x0d5a319e, > 0x0864cfb0, 0x08e2834b, 0x09ee1abd, 0x09685646, 0x0bf72951, 0x0b7165aa, > 0x0a7dfc5c, 0x0afbb0a7, 0x1f0cd1e9, 0x1f8a9d12, 0x1e8604e4, 0x1e00481f, > 0x1c9f3708, 0x1c197bf3, 0x1d15e205, 0x1d93aefe, 0x18ad50d0, 0x182b1c2b, > 0x192785dd, 0x19a1c926, 0x1b3eb631, 0x1bb8faca, 0x1ab4633c, 0x1a322fc7, > 0x10c99f60, 0x104fd39b, 0x11434a6d, 0x11c50696, 0x135a7981, 0x13dc357a, > 0x12d0ac8c, 0x1256e077, 0x17681e59, 0x17ee52a2, 0x16e2cb54, 0x166487af, > 0x14fbf8b8, 0x147db443, 0x15712db5, 0x15f7614e, 0x3e19a3d2, 0x3e9fef29, > 0x3f9376df, 0x3f153a24, 0x3d8a4533, 0x3d0c09c8, 0x3c00903e, 0x3c86dcc5, > 0x39b822eb, 0x393e6e10, 0x3832f7e6, 0x38b4bb1d, 0x3a2bc40a, 0x3aad88f1, > 0x3ba11107, 0x3b275dfc, 0x31dced5b, 0x315aa1a0, > 0x30563856, 0x30d074ad, 0x324f0bba, 0x32c94741, 0x33c5deb7, 0x3343924c, > 0x367d6c62, 0x36fb2099, 0x37f7b96f, 0x3771f594, 0x35ee8a83, 0x3568c678, > 0x34645f8e, 0x34e21375, 0x2115723b, 0x21933ec0, 0x209fa736, 0x2019ebcd, > 0x228694da, 0x2200d821, 0x230c41d7, 0x238a0d2c, 0x26b4f302, 0x2632bff9, > 0x273e260f, 0x27b86af4, 0x252715e3, 0x25a15918, 0x24adc0ee, 0x242b8c15, > 0x2ed03cb2, 0x2e567049, 0x2f5ae9bf, 0x2fdca544, 0x2d43da53, 0x2dc596a8, > 0x2cc90f5e, 0x2c4f43a5, 0x2971bd8b, 0x29f7f170, 0x28fb6886, 0x287d247d, > 0x2ae25b6a, 0x2a641791, 0x2b688e67, 0x2beec29c, 0x7c3347a4, 0x7cb50b5f, > 0x7db992a9, 0x7d3fde52, 0x7fa0a145, 0x7f26edbe, 0x7e2a7448, 0x7eac38b3, > 0x7b92c69d, 0x7b148a66, 0x7a181390, 0x7a9e5f6b, 0x7801207c, 0x78876c87, > 0x798bf571, 0x790db98a, 0x73f6092d, 0x737045d6, 0x727cdc20, 0x72fa90db, > 0x7065efcc, 0x70e3a337, 0x71ef3ac1, 0x7169763a, 0x74578814, 0x74d1c4ef, > 0x75dd5d19, 0x755b11e2, 0x77c46ef5, 0x7742220e, 0x764ebbf8, 0x76c8f703, > 0x633f964d, 0x63b9dab6, 0x62b54340, 0x62330fbb, > 0x60ac70ac, 0x602a3c57, 0x6126a5a1, 0x61a0e95a, 0x649e1774, 0x64185b8f, > 0x6514c279, 0x65928e82, 0x670df195, 0x678bbd6e, 0x66872498, 0x66016863, > 0x6cfad8c4, 0x6c7c943f, 0x6d700dc9, 0x6df64132, 0x6f693e25, 0x6fef72de, > 0x6ee3eb28, 0x6e65a7d3, 0x6b5b59fd, 0x6bdd1506, 0x6ad18cf0, 0x6a57c00b, > 0x68c8bf1c, 0x684ef3e7, 0x69426a11, 0x69c426ea, 0x422ae476, 0x42aca88d, > 0x43a0317b, 0x43267d80, 0x41b90297, 0x413f4e6c, 0x4033d79a, 0x40b59b61, > 0x458b654f, 0x450d29b4, 0x4401b042, 0x4487fcb9, 0x461883ae, 0x469ecf55, > 0x479256a3, 0x47141a58, 0x4defaaff, 0x4d69e604, 0x4c657ff2, 0x4ce33309, > 0x4e7c4c1e, 0x4efa00e5, 0x4ff69913, 0x4f70d5e8, 0x4a4e2bc6, 0x4ac8673d, > 0x4bc4fecb, 0x4b42b230, 0x49ddcd27, 0x495b81dc, 0x4857182a, 0x48d154d1, > 0x5d26359f, 0x5da07964, 0x5cace092, 0x5c2aac69, 0x5eb5d37e, 0x5e339f85, > 0x5f3f0673, 0x5fb94a88, 0x5a87b4a6, 0x5a01f85d, 0x5b0d61ab, 0x5b8b2d50, > 0x59145247, 0x59921ebc, 0x589e874a, 0x5818cbb1, 0x52e37b16, 0x526537ed, > 0x5369ae1b, 0x53efe2e0, 0x51709df7, 0x51f6d10c, > 0x50fa48fa, 0x507c0401, 0x5542fa2f, 0x55c4b6d4, 0x54c82f22, 0x544e63d9, > 0x56d11cce, 0x56575035, 0x575bc9c3, 0x57dd8538]; > > function createcrc24(input) { > var crc = 0xB704CE; > var index = 0; > > while((input.length - index) > 16) { > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index)) & > 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+1)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+2)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+3)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+4)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+5)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+6)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+7)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+8)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+9)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+10)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+11)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+12)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+13)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+14)) > & 0xff]; > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index+15)) > & 0xff]; > index += 16; > } > > for(var j = index; j < input.length; j++) { > crc = (crc << 8) ^ crc_table[((crc >> 16) ^ input.charCodeAt(index++)) > & 0xff] > } > return crc & 0xffffff; > } > > regards, > carsten > > -- > > Recurity Labs GmbH | Carsten Wentzlow > http://www.recurity-labs.com | [email protected] > Wrangelstrasse 4 | Fon: +49 30 69539993-0 > 10997 Berlin | Mobil: +49 163 7007430 > Germany | PGP: AF3F 4C6C F80A 7C76 7DDE > | 39BF 83DD 3803 E163 4F45 > HRB 105213 B, Amtsgericht Charlottenburg, GF Felix Lindner > > > > _______________________________________________ > > http://openpgpjs.org >
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