29:null 2a:["$","title",null,{"children":"Biased Fractional Indexing | Irakli Gozalishvili | Observable"}] 2f:T5c3,/** * @param {Uint8Array} bias - The bias to be used when inserting, derived from the item to be inserted. * @param {object} at * @param {string} [at.before] - Position of the element before insertion. * @param {string} [at.after] - Position of the element after the insertion. */ insert = (bias, { before = "", after = "" } = {}) => { const minDigit = "0".charCodeAt(0); const maxDigit = "9".charCodeAt(0); let foundDifference = false; let result = ""; let i = 0; // Compute a 32-bit bias value from the last 4 bytes of the bias array let biasValue = // ((bias[bias.length - 4] << 24) | // (bias[bias.length - 3] << 16) | // (bias[bias.length - 2] << 8) | // bias[bias.length - 1]) (bias.at() + bias.at(-2) + bias.at(-1)) % 0x1000; while (true) { const digitBefore = i < before.length ? before.charCodeAt(i) : minDigit; const digitAfter = !foundDifference && i < after.length ? after.charCodeAt(i) : maxDigit + 1; const pick = (digitBefore + digitAfter) >>> 1; result += String.fromCharCode(pick); if (pick <= digitBefore) { if (digitBefore < digitAfter) { foundDifference = true; } i += 1; continue; } result += "_"; while (biasValue > 0) { const base = maxDigit - minDigit + 1; const mod = biasValue % base; biasValue = (biasValue - mod) / base; result += String.fromCharCode(minDigit + mod); } return result; } }30:[] 2d:{"id":"67c2f69243c725fd","slug":null,"title":"Biased Fractional Indexing","thumbnail":"55bf50f83b92e4a4af1c43036ea1cab9bcb73eb5dd20920bd3090b8ed8336b61","access_level":"public","create_time":"$D2024-10-07T12:16:27.033Z","update_time":"$D2024-10-08T19:31:36.394Z","view_time":null,"first_public_time":"$D2024-10-07T12:16:27.033Z","fork":false,"stars":0,"starred":false,"owner":{"type":"team","id":"b5b68141c8cf6180","login":"gozala","name":"Irakli Gozalishvili","avatar_url":"https://avatars-next.observableusercontent.com/0117298600419b54ef5a1d77c46951e7418985d103a10ee32ca5047157ea0924","tier":"starter_2024"},"version":204,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"e9e28faabc1f7da7","login":"gozala","name":"Irakli Gozalishvili","avatar_url":"https://avatars-next.observableusercontent.com/0117298600419b54ef5a1d77c46951e7418985d103a10ee32ca5047157ea0924","tier":null}],"members":[{"type":"team","id":"b5b68141c8cf6180","login":"gozala","name":"Irakli Gozalishvili","avatar_url":"https://avatars-next.observableusercontent.com/0117298600419b54ef5a1d77c46951e7418985d103a10ee32ca5047157ea0924","tier":"starter_2024","role":"editor"},{"type":"individual","id":"e9e28faabc1f7da7","login":"gozala","name":"Irakli Gozalishvili","avatar_url":"https://avatars-next.observableusercontent.com/0117298600419b54ef5a1d77c46951e7418985d103a10ee32ca5047157ea0924","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"subscribed":null,"forks":1,"collection":null,"type":"notebook","body":{"title":"Biased Fractional Indexing","cells":[{"id":0,"value":"# Biased Fractional Indexing","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":143,"value":"toJSON = (position) => {\n const length = position[0];\n const major = position.subarray(1, length);\n const minor = position.subarray(length + 1);\n\n return { major, minor };\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":161,"value":"class Position extends Uint8Array {\n static get zero() {\n return new this([127, 0]);\n }\n static get min() {\n return new this(128).fill(0);\n }\n static get max() {\n return new this(1 + 255).fill(255);\n }\n\n get major() {\n return this[0];\n }\n get minor() {\n return new Uint8Array(this.buffer, 1, this.major);\n }\n get patch() {\n return new Uint8Array(this.buffer, this.major + 1);\n }\n toString() {\n return toString(this);\n }\n get [Symbol.toStringTag]() {\n return `.${toString(this)}`;\n }\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":169,"value":"/**\n * @param {Position} position\n */\ntoString = (position) => {\n const digits = [];\n for (const byte of position) {\n digits.push(String.fromCharCode(byte));\n }\n return digits.join(\"\");\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":171,"value":"/**\n * @param {string} source\n */\nfromString = (source) => {\n const position = new Position(source.length);\n let offset = 0;\n for (const digit of source) {\n const code = digit.charCodeAt(0);\n // ⚠️ If the code is out of the single byte range it will be truncated to\n // max value.\n position[offset] = code > 255 ? 255 : code;\n offset++;\n }\n\n return position;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":180,"value":"BASE_62 = \"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz\"","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":164,"value":"Position.zero","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":187,"value":"[\"a\".charCodeAt(\"a\"), \"z\".charCodeAt(\"z\")]","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":191,"value":"[\"A\".charCodeAt(\"A\"), \"Z\".charCodeAt(\"Z\")]","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":194,"value":"[\"0\".charCodeAt(0), \"9\".charCodeAt(0)]","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":5,"value":"$2f","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":50,"value":"0x1000","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":10,"value":"bias(new Uint16Array(refer(\"chr\").buffer))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":99,"value":"base64.baseEncode(refer(\"test me now\").subarray(-3))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":83,"value":"bias = (source) => {\n const minDigit = \"0\".charCodeAt(0);\n const maxDigit = \"9\".charCodeAt(0);\n\n let result = \"\";\n let biasValue = source.at(-1) % 0x1000;\n while (biasValue > 0) {\n const base = maxDigit - minDigit + 1;\n const mod = biasValue % base;\n biasValue = (biasValue - mod) / base;\n result += String.fromCharCode(minDigit + mod);\n }\n\n return result;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":109,"value":"base58btc.baseEncode(toVarint(1589))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":115,"value":"base58btc.baseEncode(toVarint(2))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":119,"value":"base58btc.baseEncode(toVarint(1590 )) < base58btc.baseEncode(toVarint(1589))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":107,"value":"toVarint = (n) => varint.encodeTo(n, new Uint8Array(varint.encodingLength(n)))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":137,"value":"toKey = (n) => base58btc.baseEncode(toVarint(n))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":129,"value":"toKey(256)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":140,"value":"toKey(255) < toKey(256)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":149,"value":"charvise.encode([0, 1])","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":158,"value":"charvise.encode([102323, 13690])","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":145,"value":"charvise = import(\"https://esm.sh/charwise\")","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":12,"value":"import { refer } from \"@gozala/merkle-references\"","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":96,"value":"import { varint, base64, base58btc } from \"@gozala/ipld\"","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W30","stdlib":"1","titling":"auto"}} 2e:"$2d:body"