@worker-tools/deno-kv-storage
Version:
An implementation of the StorageArea (1,2,3) interface for Deno with an extensible system for supporting various database backends.
79 lines • 2.31 kB
JavaScript
import SqliteError from "./error.js";
// Move string to C
export function setStr(wasm, str, closure) {
const bytes = new TextEncoder().encode(str);
const ptr = wasm.malloc(bytes.length + 1);
if (ptr === 0) {
throw new SqliteError("Out of memory.");
}
const mem = new Uint8Array(wasm.memory.buffer, ptr, bytes.length + 1);
mem.set(bytes);
mem[bytes.length] = 0; // \0 terminator
try {
closure(ptr);
wasm.free(ptr);
}
catch (error) {
wasm.free(ptr);
throw error;
}
}
// Move Uint8Array to C
export function setArr(wasm, arr, closure) {
const ptr = wasm.malloc(arr.length);
if (ptr === 0) {
throw new SqliteError("Out of memory.");
}
const mem = new Uint8Array(wasm.memory.buffer, ptr, arr.length);
mem.set(arr);
try {
closure(ptr);
wasm.free(ptr);
}
catch (error) {
wasm.free(ptr);
throw error;
}
}
// Read string from C
export function getStr(wasm, ptr) {
const len = wasm.str_len(ptr);
const bytes = new Uint8Array(wasm.memory.buffer, ptr, len);
if (len > 16) {
return new TextDecoder().decode(bytes);
}
else {
// This optimization is lifted from EMSCRIPTEN's glue code
let str = "";
let idx = 0;
while (idx < len) {
let u0 = bytes[idx++];
if (!(u0 & 0x80)) {
str += String.fromCharCode(u0);
continue;
}
const u1 = bytes[idx++] & 63;
if ((u0 & 0xE0) == 0xC0) {
str += String.fromCharCode(((u0 & 31) << 6) | u1);
continue;
}
const u2 = bytes[idx++] & 63;
if ((u0 & 0xF0) == 0xE0) {
u0 = ((u0 & 15) << 12) | (u1 << 6) | u2;
}
else {
// cut warning
u0 = ((u0 & 7) << 18) | (u1 << 12) | (u2 << 6) | (bytes[idx++] & 63);
}
if (u0 < 0x10000) {
str += String.fromCharCode(u0);
}
else {
const ch = u0 - 0x10000;
str += String.fromCharCode(0xD800 | (ch >> 10), 0xDC00 | (ch & 0x3FF));
}
}
return str;
}
}
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