@khoohaoyit/image-size/dist/formats/pnm.js

A stream based image size extractor in Node

"use strict";
var __await = (this && this.__await) || function (v) { return this instanceof __await ? (this.v = v, this) : new __await(v); }
var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
    var g = generator.apply(thisArg, _arguments || []), i, q = [];
    return i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i;
    function verb(n) { if (g[n]) i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; }
    function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
    function step(r) { r.value instanceof __await ? Promise.resolve(r.value.v).then(fulfill, reject) : settle(q[0][2], r); }
    function fulfill(value) { resume("next", value); }
    function reject(value) { resume("throw", value); }
    function settle(f, v) { if (f(v), q.shift(), q.length) resume(q[0][0], q[0][1]); }
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.extractPnmSize = void 0;
exports.extractPnmSize = function (stream) {
    return __asyncGenerator(this, arguments, function* () {
        const signature = yield __await(stream.readString(0, 2));
        if (PNMTypes[signature] === undefined)
            return yield __await(void 0);
        let width, height;
        loop: for (let offset = 3; width === undefined || height === undefined; ++offset) {
            const lineBuffers = [];
            for (; true; ++offset) {
                const buf = yield __await(stream.read(offset, 1));
                if (buf.indexOf('\n') === 0)
                    break;
                lineBuffers.push(buf);
            }
            const line = Buffer.concat(lineBuffers) + '';
            if (line.startsWith('#')) // comment
                continue;
            if (signature !== 'P7') { // pam
                [width, height] = line
                    .split(' ')
                    .map(val => +val);
                break;
            }
            const [type, value] = line.split(' ');
            switch (type) {
                default:
                    break;
                case 'ENDHDR':
                    break loop;
                case 'WIDTH':
                    {
                        width = +value;
                    }
                    break;
                case 'HEIGHT':
                    {
                        height = +value;
                    }
                    break;
            }
        }
        if (width === undefined || height === undefined)
            return yield __await(void 0);
        return yield __await(yield yield __await({ width, height }));
    });
};
const PNMTypes = {
    P1: 'pbm/ascii',
    P2: 'pgm/ascii',
    P3: 'ppm/ascii',
    P4: 'pbm',
    P5: 'pgm',
    P6: 'ppm',
    P7: 'pam',
    PF: 'pfm',
};
/*

ppm file format specification
 -> https://netpbm.sourceforge.net/doc/ppm.html

*/