Restructure encoders

Drop minor efficiency in favor of code clarity

Author: dingosky

src/lib/encoder/safe32.ts

@@ -1,39 +1,43 @@
-import { PuidEncoder } from "../../types/puid"
+import { PuidEncoder } from '../../types/puid'
+
+// n: 012 3456 7 8 901 2 34 567 8 9 0 123 4 567 890 1
+// c: 234 6789 b d fgh j mn pqr t B D FGH J LMN PQR T
 
 export default (): PuidEncoder => {
   const two = '2'.charCodeAt(0)
-  const six = '6'.charCodeAt(0) - 3
+  const six = '6'.charCodeAt(0)
   const b = 'b'.charCodeAt(0)
   const d = 'd'.charCodeAt(0)
-  const f = 'f'.charCodeAt(0) - 9
+  const f = 'f'.charCodeAt(0)
   const j = 'j'.charCodeAt(0)
-  const m = 'm'.charCodeAt(0) - 13
-  const p = 'p'.charCodeAt(0) - 15
+  const m = 'm'.charCodeAt(0)
+  const p = 'p'.charCodeAt(0)
   const t = 't'.charCodeAt(0)
   const B = 'B'.charCodeAt(0)
   const D = 'D'.charCodeAt(0)
-  const F = 'F'.charCodeAt(0) - 21
+  const F = 'F'.charCodeAt(0)
   const J = 'J'.charCodeAt(0)
-  const L = 'L'.charCodeAt(0) - 25
-  const P = 'P'.charCodeAt(0) - 28
+  const L = 'L'.charCodeAt(0)
+  const P = 'P'.charCodeAt(0)
   const T = 'T'.charCodeAt(0)
 
   return (n: number) => {
     if (n < 3) return n + two
-    if (n < 7) return n + six
+    if (n < 7) return n - 3 + six
     if (n === 7) return b
     if (n === 8) return d
-    if (n < 12) return n + f
+    if (n < 12) return n - 9 + f
     if (n === 12) return j
-    if (n < 15) return n + m
-    if (n < 18) return n + p
+    if (n < 15) return n - 13 + m
+    if (n < 18) return n - 15 + p
     if (n === 18) return t
     if (n === 19) return B
     if (n === 20) return D
-    if (n < 24) return n + F
+    if (n < 24) return n - 21 + F
     if (n === 24) return J
-    if (n < 28) return n + L
-    if (n < 31) return n + P
-    return T
+    if (n < 28) return n - 25 + L
+    if (n < 31) return n - 28 + P
+    if (n === 31) return T
+    return NaN
   }
 }

src/lib/encoder/safe64.ts

@@ -1,17 +1,21 @@
-import { PuidEncoder } from "../../types/puid"
+import { PuidEncoder } from '../../types/puid'
+
+// n: 01234567890123456789012345 67890123456789012345678901 2345678901 2 3
+// c: ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789 - _
 
 export default (): PuidEncoder => {
-  const upper = 'A'.charCodeAt(0)
-  const lower = 'a'.charCodeAt(0) - 26
-  const decimal = '0'.charCodeAt(0) - 52 
+  const A = 'A'.charCodeAt(0)
+  const a = 'a'.charCodeAt(0)
+  const zero = '0'.charCodeAt(0)
   const hyphen = '-'.charCodeAt(0)
   const underscore = '_'.charCodeAt(0)
 
   return (n: number) => {
-    if (n < 26) return n + upper
-    if (n < 52) return n + lower
-    if (n < 62) return n + decimal
+    if (n < 26) return n + A
+    if (n < 52) return n - 26 + a
+    if (n < 62) return n - 52 + zero
     if (n === 62) return hyphen
-    return underscore
+    if (n === 63) return underscore
+    return NaN
   }
 }

src/lib/encoder/safeAscii.ts

@@ -1,20 +1,21 @@
 import { PuidEncoder } from '../../types/puid'
 
+// n: 0 1234 5678901234567890123456789012345678901234567890123456 789 012345678901234567890123456789
+// c: ! #$%& ()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[ ]^_ abcdefghijklmnopqrstuvwxyz{|}~
+
 export default (): PuidEncoder => {
   const bang = '!'.charCodeAt(0)
-  const ampersand = '&'.charCodeAt(0) - 4
-  const openSquareBracket = '['.charCodeAt(0) - 56
-  const underscore = '_'.charCodeAt(0) - 59
-  const a = 'a'.charCodeAt(0) - 60
-  const tilde = '~'.charCodeAt(0)
+  const hash = '#'.charCodeAt(0)
+  const openParen = '('.charCodeAt(0)
+  const closeSquareBracket = ']'.charCodeAt(0)
+  const a = 'a'.charCodeAt(0)
 
   return (n: number) => {
     if (n === 0) return bang
-    if (n < 5) return n + ampersand
-    if (n < 57) return n + openSquareBracket
-    if (n < 60) return n + underscore
-    if (n < 90) return n + a
-    // CxInc throw
-    return tilde
+    if (n < 5) return n - 1 + hash
+    if (n < 57) return n - 5 + openParen
+    if (n < 60) return n - 57 + closeSquareBracket
+    if (n < 90) return n - 60 + a
+    return NaN
   }
 }

src/lib/encoder/symbol.ts

@@ -1,21 +1,25 @@
-import { PuidEncoder } from "../../types/puid"
+import { PuidEncoder } from '../../types/puid'
+
+// n: 0 1234 56789012 3456789 0 123 4567
+// c: ! #$%& ()*+,-./ :;<=>?@ [ ]^_ {|}~
 
 export default (): PuidEncoder => {
   const bang = '!'.charCodeAt(0)
-  const hash = '#'.charCodeAt(0) - 1
-  const openParen = '('.charCodeAt(0) - 5
-  const colon = ':'.charCodeAt(0) - 13
+  const hash = '#'.charCodeAt(0)
+  const openParen = '('.charCodeAt(0)
+  const colon = ':'.charCodeAt(0)
   const openSquareBracket = '['.charCodeAt(0)
-  const closeSquareBracket = ']'.charCodeAt(0) - 21
-  const openCurlyBracket = '{'.charCodeAt(0) - 24
+  const closeSquareBracket = ']'.charCodeAt(0)
+  const openCurlyBracket = '{'.charCodeAt(0)
 
   return (n: number) => {
     if (n === 0) return bang
-    if (n < 5) return n + hash
-    if (n < 13) return n + openParen
-    if (n < 20) return n + colon
+    if (n < 5) return n - 1 + hash
+    if (n < 13) return n - 5 + openParen
+    if (n < 20) return n - 13 + colon
     if (n === 20) return openSquareBracket
-    if (n < 24) return n + closeSquareBracket
-    return n + openCurlyBracket
+    if (n < 24) return n - 21 + closeSquareBracket
+    if (n < 28) return n - 24 + openCurlyBracket
+    return NaN
   }
 }