mirrors/PMTiles
1
0
Fork 0
mirror of https://github.com/protomaps/PMTiles.git synced 2026-02-04 10:51:07 +00:00
Code Issues Packages Projects Releases Wiki Activity

v3 js: varint routines [#41]

Browse Source
This commit is contained in:
Brandon Liu
2022-09-19 21:13:58 -07:00
parent 07eaf102a9
commit fbb0f4614c
2 changed files with 89 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
js/index.test.ts
View File

@@ -11,7 +11,13 @@ import {
createDirectory,
} from "./index";
import { Entry as EntryV3, zxyToTileId, tileIdToZxy, findTile } from "./v3";
import {
Entry as EntryV3,
zxyToTileId,
tileIdToZxy,
findTile,
readVarint,
} from "./v3";
test("stub data", (assertion) => {
let dataview = createDirectory([
@@ -148,6 +154,22 @@ test("convert spec v1 directory to spec v2 directory", (assertion) => {
assertion.ok(entry!.offset === 3);
});
test("varint", (assertion) => {
let b: BufferPosition = {
buf: new Uint8Array([0, 1, 127, 0xe5, 0x8e, 0x26]),
pos: 0,
};
assertion.eq(readVarint(b), 0);
assertion.eq(readVarint(b), 1);
assertion.eq(readVarint(b), 127);
assertion.eq(readVarint(b), 624485);
b = {
buf: new Uint8Array([0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0f]),
pos: 0,
};
assertion.eq(readVarint(b), 9007199254740991);
});
test("zxy to tile id", (assertion) => {
assertion.eq(zxyToTileId(0, 0, 0), 0);
assertion.eq(zxyToTileId(1, 0, 0), 1);
@@ -185,7 +207,9 @@ test("tile search for first entry == id", (assertion) => {
});
test("tile search for first entry == id", (assertion) => {
let entries: EntryV3[] = [{ tileId: 100, offset: 1, length: 1, runLength: 1 }];
let entries: EntryV3[] = [
{ tileId: 100, offset: 1, length: 1, runLength: 1 },
];
let entry = findTile(entries, 100)!;
assertion.eq(entry.offset, 1);
assertion.eq(entry.length, 1);
@@ -193,7 +217,9 @@ test("tile search for first entry == id", (assertion) => {
});
test("tile search for first entry == id", (assertion) => {
let entries: EntryV3[] = [{ tileId: 100, offset: 1, length: 1, runLength: 2 }];
let entries: EntryV3[] = [
{ tileId: 100, offset: 1, length: 1, runLength: 2 },
];
let entry = findTile(entries, 101)!;
assertion.eq(entry.offset, 1);
assertion.eq(entry.length, 1);
@@ -217,7 +243,9 @@ test("tile search for first entry == id", (assertion) => {
});
test("leaf search", (assertion) => {
let entries: EntryV3[] = [{ tileId: 100, offset: 1, length: 1, runLength: 0 }];
let entries: EntryV3[] = [
{ tileId: 100, offset: 1, length: 1, runLength: 0 },
];
let entry = findTile(entries, 150);
assertion.eq(entry!.offset, 1);
assertion.eq(entry!.length, 1);

58
js/v3.ts
View File

@@ -1,3 +1,60 @@
interface BufferPosition {
buf: Uint8Array;
pos: number;
}
function toNum(low: number, high: number): number {
return (high >>> 0) * 0x100000000 + (low >>> 0);
}
function readVarintRemainder(l: number, p: BufferPosition): number {
var buf = p.buf,
h,
b;
b = buf[p.pos++];
h = (b & 0x70) >> 4;
if (b < 0x80) return toNum(l, h);
b = buf[p.pos++];
h |= (b & 0x7f) << 3;
if (b < 0x80) return toNum(l, h);
b = buf[p.pos++];
h |= (b & 0x7f) << 10;
if (b < 0x80) return toNum(l, h);
b = buf[p.pos++];
h |= (b & 0x7f) << 17;
if (b < 0x80) return toNum(l, h);
b = buf[p.pos++];
h |= (b & 0x7f) << 24;
if (b < 0x80) return toNum(l, h);
b = buf[p.pos++];
h |= (b & 0x01) << 31;
if (b < 0x80) return toNum(l, h);
throw new Error("Expected varint not more than 10 bytes");
}
export function readVarint(p: BufferPosition): number {
var buf = p.buf,
val,
b;
b = buf[p.pos++];
val = b & 0x7f;
if (b < 0x80) return val;
b = buf[p.pos++];
val |= (b & 0x7f) << 7;
if (b < 0x80) return val;
b = buf[p.pos++];
val |= (b & 0x7f) << 14;
if (b < 0x80) return val;
b = buf[p.pos++];
val |= (b & 0x7f) << 21;
if (b < 0x80) return val;
b = buf[p.pos];
val |= (b & 0x0f) << 28;
return readVarintRemainder(val, p);
}
function rotate(n: number, xy: number[], rx: number, ry: number): void {
if (ry == 0) {
if (rx == 1) {
@@ -98,4 +155,3 @@ export function findTile(entries: Entry[], tileId: number): Entry | null {
}
return null;
}