image-size
Version:
get dimensions of any image file
61 lines (58 loc) • 2.4 kB
JavaScript
;
// lib/types/utils.ts
var decoder = new TextDecoder();
var toUTF8String = (input, start = 0, end = input.length) => decoder.decode(input.slice(start, end));
var toHexString = (input, start = 0, end = input.length) => input.slice(start, end).reduce((memo, i) => memo + `0${i.toString(16)}`.slice(-2), "");
var getView = (input, offset) => new DataView(input.buffer, input.byteOffset + offset);
var readInt16LE = (input, offset = 0) => getView(input, offset).getInt16(0, true);
var readUInt16BE = (input, offset = 0) => getView(input, offset).getUint16(0, false);
var readUInt16LE = (input, offset = 0) => getView(input, offset).getUint16(0, true);
var readUInt24LE = (input, offset = 0) => {
const view = getView(input, offset);
return view.getUint16(0, true) + (view.getUint8(2) << 16);
};
var readInt32LE = (input, offset = 0) => getView(input, offset).getInt32(0, true);
var readUInt32BE = (input, offset = 0) => getView(input, offset).getUint32(0, false);
var readUInt32LE = (input, offset = 0) => getView(input, offset).getUint32(0, true);
var readUInt64 = (input, offset, isBigEndian) => getView(input, offset).getBigUint64(0, !isBigEndian);
var methods = {
readUInt16BE,
readUInt16LE,
readUInt32BE,
readUInt32LE
};
function readUInt(input, bits, offset = 0, isBigEndian = false) {
const endian = isBigEndian ? "BE" : "LE";
const methodName = `readUInt${bits}${endian}`;
return methods[methodName](input, offset);
}
function readBox(input, offset) {
if (input.length - offset < 4) return;
const boxSize = readUInt32BE(input, offset);
if (input.length - offset < boxSize) return;
return {
name: toUTF8String(input, 4 + offset, 8 + offset),
offset,
size: boxSize
};
}
function findBox(input, boxName, currentOffset) {
while (currentOffset < input.length) {
const box = readBox(input, currentOffset);
if (!box) break;
if (box.name === boxName) return box;
currentOffset += box.size > 0 ? box.size : 8;
}
}
exports.findBox = findBox;
exports.readInt16LE = readInt16LE;
exports.readInt32LE = readInt32LE;
exports.readUInt = readUInt;
exports.readUInt16BE = readUInt16BE;
exports.readUInt16LE = readUInt16LE;
exports.readUInt24LE = readUInt24LE;
exports.readUInt32BE = readUInt32BE;
exports.readUInt32LE = readUInt32LE;
exports.readUInt64 = readUInt64;
exports.toHexString = toHexString;
exports.toUTF8String = toUTF8String;