TrackOffical/node_modules/geotiff/dist-node/predictor.js

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.applyPredictor = void 0;
function decodeRowAcc(row, stride) {
    let length = row.length - stride;
    let offset = 0;
    do {
        for (let i = stride; i > 0; i--) {
            row[offset + stride] += row[offset];
            offset++;
        }
        length -= stride;
    } while (length > 0);
}
function decodeRowFloatingPoint(row, stride, bytesPerSample) {
    let index = 0;
    let count = row.length;
    const wc = count / bytesPerSample;
    while (count > stride) {
        for (let i = stride; i > 0; --i) {
            row[index + stride] += row[index];
            ++index;
        }
        count -= stride;
    }
    const copy = row.slice();
    for (let i = 0; i < wc; ++i) {
        for (let b = 0; b < bytesPerSample; ++b) {
            row[(bytesPerSample * i) + b] = copy[((bytesPerSample - b - 1) * wc) + i];
        }
    }
}
function applyPredictor(block, predictor, width, height, bitsPerSample, planarConfiguration) {
    if (!predictor || predictor === 1) {
        return block;
    }
    for (let i = 0; i < bitsPerSample.length; ++i) {
        if (bitsPerSample[i] % 8 !== 0) {
            throw new Error('When decoding with predictor, only multiple of 8 bits are supported.');
        }
        if (bitsPerSample[i] !== bitsPerSample[0]) {
            throw new Error('When decoding with predictor, all samples must have the same size.');
        }
    }
    const bytesPerSample = bitsPerSample[0] / 8;
    const stride = planarConfiguration === 2 ? 1 : bitsPerSample.length;
    for (let i = 0; i < height; ++i) {
        // Last strip will be truncated if height % stripHeight != 0
        if (i * stride * width * bytesPerSample >= block.byteLength) {
            break;
        }
        let row;
        if (predictor === 2) { // horizontal prediction
            switch (bitsPerSample[0]) {
                case 8:
                    row = new Uint8Array(block, i * stride * width * bytesPerSample, stride * width * bytesPerSample);
                    break;
                case 16:
                    row = new Uint16Array(block, i * stride * width * bytesPerSample, stride * width * bytesPerSample / 2);
                    break;
                case 32:
                    row = new Uint32Array(block, i * stride * width * bytesPerSample, stride * width * bytesPerSample / 4);
                    break;
                default:
                    throw new Error(`Predictor 2 not allowed with ${bitsPerSample[0]} bits per sample.`);
            }
            decodeRowAcc(row, stride, bytesPerSample);
        }
        else if (predictor === 3) { // horizontal floating point
            row = new Uint8Array(block, i * stride * width * bytesPerSample, stride * width * bytesPerSample);
            decodeRowFloatingPoint(row, stride, bytesPerSample);
        }
    }
    return block;
}
exports.applyPredictor = applyPredictor;
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