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add signed varint support to BIPF, allows to encode most pencil movem…
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…ents in 4 bytes instead of 10, change clip icon to pencil
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@tschudin
tschudin committed Jul 30, 2024
1 parent b207e89 commit b3fdeef
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Showing 6 changed files with 124 additions and 85 deletions.
3 changes: 1 addition & 2 deletions android/tinySSB/app/build.gradle
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Original file line number Diff line number Diff line change
Expand Up @@ -5,15 +5,14 @@ apply plugin: 'kotlin-kapt'
android {
namespace "tremolavossbol"
compileSdk 30
buildToolsVersion "30.0.3"

buildFeatures {
viewBinding = true
}

defaultConfig {
applicationId "nz.scuttlebutt.tremolavossbol"
minSdkVersion 26
minSdk 24
targetSdkVersion 30
versionCode 1
versionName "0.1"
Expand Down
105 changes: 59 additions & 46 deletions android/tinySSB/app/src/main/assets/web/bipf.js
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,13 @@ const BIPF_MATH_POW_5 = Math.pow(2, 5*7)
const BIPF_MATH_POW_6 = Math.pow(2, 6*7)
const BIPF_MATH_POW_7 = Math.pow(2, 7*7)

function bipf_fvdecode(buf, offset) {
function unzigzag(value) {
let s = value & 0x01;
value >>>= 1;
return s ? -value - 1 : value
}

function bipf_fvdecode(buf, offset, zigzag) {
offset = offset || 0

buf = new Uint8Array(buf)
Expand All @@ -51,56 +57,56 @@ function bipf_fvdecode(buf, offset) {
res += b & BIPF_REST
if (b < BIPF_MSB) {
bipf_fvdecode.bytes = 1
return res
return zigzag ? unzigzag(res) : res
}

b = buf[offset + 1]
res += (b & BIPF_REST) << 7
if (b < BIPF_MSB) {
bipf_fvdecode.bytes = 2
return res
return zigzag ? unzigzag(res) : res
}

b = buf[offset + 2]
res += (b & BIPF_REST) << 14
if (b < BIPF_MSB) {
bipf_fvdecode.bytes = 3
return res
return zigzag ? unzigzag(res) : res
}

b = buf[offset + 3]
res += (b & BIPF_REST) << 21
if (b < BIPF_MSB) {
bipf_fvdecode.bytes = 4
return res
return zigzag ? unzigzag(res) : res
}

b = buf[offset + 4]
res += (b & BIPF_REST) * BIPF_MATH_POW_4
if (b < BIPF_MSB) {
bipf_fvdecode.bytes = 5
return res
return zigzag ? unzigzag(res) : res
}

b = buf[offset + 5]
res += (b & BIPF_REST) * BIPF_MATH_POW_5
if (b < BIPF_MSB) {
bipf_fvdecode.bytes = 6
return res
return zigzag ? unzigzag(res) : res
}

b = buf[offset + 6]
res += (b & BIPF_REST) * BIPF_MATH_POW_6
if (b < BIPF_MSB) {
bipf_fvdecode.bytes = 7
return res
return zigzag ? unzigzag(res) : res
}

b = buf[offset + 7]
res += (b & BIPF_REST) * BIPF_MATH_POW_7
if (b < BIPF_MSB) {
bipf_fvdecode.bytes = 8
return res
return zigzag ? unzigzag(res) : res
}

bipf_fvdecode.bytes = 0
Expand All @@ -110,11 +116,13 @@ function bipf_fvdecode(buf, offset) {
var BIPF_MSBALL = ~BIPF_REST
var BIPF_INT31 = Math.pow(2, 31)

function bipf_fvencode(num, out, offset) {
function bipf_fvencode(num, out, offset, zigzag) {
if (Number.MAX_SAFE_INTEGER && num > Number.MAX_SAFE_INTEGER) {
bipf_fvencode.bytes = 0
throw new RangeError('Could not encode varint')
}
if (zigzag)
num = num >= 0 ? 2*num : (2 * -num) - 1 // zig-zag encoding of sign
// out = out || []
out = new Uint8Array(out)
offset = offset || 0
Expand Down Expand Up @@ -145,21 +153,21 @@ var BIFP_N7 = Math.pow(2, 49)
var BIFP_N8 = Math.pow(2, 56)
var BIFP_N9 = Math.pow(2, 63)

function bipf_fvencodingLength (value) {
if (value >= 0)
return (
value < BIFP_N1 ? 1
: value < BIFP_N2 ? 2
: value < BIFP_N3 ? 3
: value < BIFP_N4 ? 4
: value < BIFP_N5 ? 5
: value < BIFP_N6 ? 6
: value < BIFP_N7 ? 7
: value < BIFP_N8 ? 8
: value < BIFP_N9 ? 9
: 10
)
return -1 // FIXME: handle negative numbers
function bipf_fvencodingLength (value, zigzag) {
if (zigzag)
value = value >= 0 ? 2*value : (2 * -value) - 1 // zig-zag encoding of sign
return (
value < BIFP_N1 ? 1
: value < BIFP_N2 ? 2
: value < BIFP_N3 ? 3
: value < BIFP_N4 ? 4
: value < BIFP_N5 ? 5
: value < BIFP_N6 ? 6
: value < BIFP_N7 ? 7
: value < BIFP_N8 ? 8
: value < BIFP_N9 ? 9
: 10
)
}

// --- encode
Expand All @@ -177,9 +185,12 @@ const BIPF_encoders = [
return b.length
},
function Integer(i, buffer, start) {
let dv = new DataView(buffer);
dv.setInt32(start, i, true);
return 4
// let dv = new DataView(buffer);
// dv.setInt32(start, i, true);
// return 4
bipf_fvencode(i, buffer, start, true);
return bipf_fvencode.bytes;

},
function Double(d, buffer, start) {
let dv = new DataView(buffer);
Expand Down Expand Up @@ -216,20 +227,20 @@ const BIPF_encodingLengthers = [
return b.length
},
function Integer(i) {
// return bipf_fvencodingLength(i)
return 4
// return 4
return bipf_fvencodingLength(i, true);
},
function Double(d) {
return 8
},
function Array(a) {
var bytes = 0
for (var i = 0; i < a.length; i++) bytes += bipf_encodingLength(a[i])
for (var i = 0; i < a.length; i++) bytes += bipf_encodingLength(a[i], false)
return bytes
},
function Object(o) {
var bytes = 0
for (var k in o) bytes += bipf_encodingLength(k) + bipf_encodingLength(o[k])
for (var k in o) bytes += bipf_encodingLength(k) + bipf_encodingLength(o[k], false)
return bytes
},
function boolnull(b, buffer, start) {
Expand Down Expand Up @@ -258,7 +269,7 @@ function bipf_encodingLength(value) {
if (type === void 0) throw new Error('unknown type: ' + JSON.stringify(value))
if (type === BIPF_ALREADY_BIPF) return value.length
const len = BIPF_encodingLengthers[type](value)
return bipf_fvencodingLength(len << BIPF_TAG_SIZE) + len
return bipf_fvencodingLength(len << BIPF_TAG_SIZE, false) + len
}

function bipf_encode(value, buffer, start, _len) {
Expand All @@ -273,7 +284,7 @@ function bipf_encode(value, buffer, start, _len) {
// if(!buffer)
// buffer = Buffer.allocUnsafe(len)
//throw new Error('buffer must be provided')
bipf_fvencode((len << BIPF_TAG_SIZE) | type, buffer, start)
bipf_fvencode((len << BIPF_TAG_SIZE) | type, buffer, start, false)
const bytes = bipf_fvencode.bytes
return BIPF_encoders[type](value, buffer, start + bytes) + bytes
}
Expand All @@ -294,22 +305,22 @@ function bipf_isIdempotent(buffer) {
}

function bipf_getEncodedLength(buffer, start) {
return bipf_fvdecode(buffer, start) >> BIPF_TAG_SIZE
return bipf_fvdecode(buffer, start, false) >> BIPF_TAG_SIZE
}

function bipf_getEncodedType(buffer, start) {
return bipf_fvdecode(buffer, start) & BIPF_TAG_MASK
return bipf_fvdecode(buffer, start, false) & BIPF_TAG_MASK
}

function bipf_allocAndEncode(value) {
const len = bipf_encodingLength(value)
const len = bipf_encodingLength(value, false)
const buffer = Buffer.allocUnsafe(len)
bipf_encode(value, buffer, 0)
return buffer
}

function bipf_allocAndEncodeIdempotent(value) {
const len = bipf_encodingLength(value)
const len = bipf_encodingLength(value, false)
const buffer = Buffer.allocUnsafe(len)
bipf_encodeIdempotent(value, buffer, 0)
return buffer
Expand All @@ -327,8 +338,9 @@ function bipf_decodeBuffer(buffer, start, length) {
}

function bipf_decodeInteger(buf, start, length) {
let dv = new DataView(buf);
return dv.getInt32(start, true); //TODO: encode in minimum bytes
// let dv = new DataView(buf);
// return dv.getInt32(start, true); //TODO: encode in minimum bytes
return bipf_fvdecode(buf, start, true);
}

function bipf_decodeDouble(buffer, start, length) {
Expand All @@ -339,7 +351,7 @@ function bipf_decodeDouble(buffer, start, length) {
function bipf_decodeArray(buffer, start, length) {
const a = []
for (let c = 0; c < length; ) {
const tag = bipf_fvdecode(buffer, start + c)
const tag = bipf_fvdecode(buffer, start + c, false)
const type = tag & BIPF_TAG_MASK
if (type === 7) throw new Error('reserved type')
const len = tag >> BIPF_TAG_SIZE
Expand All @@ -354,15 +366,15 @@ function bipf_decodeArray(buffer, start, length) {
function bipf_decodeObject(buffer, start, length) {
const o = {}
for (let c = 0; c < length; ) {
const tag = bipf_fvdecode(buffer, start + c)
const tag = bipf_fvdecode(buffer, start + c, false)
// JavaScript only allows string-valued and Symbol keys for objects
if (tag & BIPF_TAG_MASK) throw new Error('required type:string')
const len = tag >> BIPF_TAG_SIZE
c += bipf_fvdecode.bytes
const key = bipf_decodeString(buffer, start + c, len)
c += len

const tag2 = bipf_fvdecode(buffer, start + c)
const tag2 = bipf_fvdecode(buffer, start + c, false)
const type2 = tag2 & BIPF_TAG_MASK
if (type2 === 7) throw new Error('reserved type:value')
const len2 = tag2 >> BIPF_TAG_SIZE
Expand Down Expand Up @@ -404,7 +416,7 @@ function bipf_decodeType(type, buffer, start, len) {

function bipf_decode(buffer, start) {
start = start | 0
const tag = bipf_fvdecode(buffer, start)
const tag = bipf_fvdecode(buffer, start, false)
const type = tag & BIPF_TAG_MASK
const len = tag >> BIPF_TAG_SIZE
const bytes = bipf_fvdecode.bytes
Expand Down Expand Up @@ -444,7 +456,7 @@ const isObject = (object) => {
}
function testEncodeDecode(value) {
const buf = new ArrayBuffer(bipf_encodingLength(value))
const buf = new ArrayBuffer(bipf_encodingLength(value, false))
const len = bipf_encode(value, buf, 0)
console.log('in:', JSON.stringify(value), '--> encoded:', buf.slice(0, len))
//''+jsonString to get 'undefined' string.
Expand Down Expand Up @@ -491,9 +503,11 @@ pkg = {
}
testEncodeDecode(100)
testEncodeDecode(63)
testEncodeDecode(0)
testEncodeDecode(1)
testEncodeDecode(-1)
testEncodeDecode(-63)
testEncodeDecode(-100)
testEncodeDecode(123.456)
testEncodeDecode(2147483647)
Expand All @@ -514,7 +528,6 @@ testEncodeDecode({ foo: true })
// testEncodeDecode([-1, { foo: true }, Buffer.from('deadbeef', 'hex')])
testEncodeDecode(pkg)
testEncodeDecode({ 1: true })
*/

// eof
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