114 lines
2.4 KiB
JavaScript
114 lines
2.4 KiB
JavaScript
/* Node.js 6.4.0 and up has full support */
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var hasFullSupport = (function () {
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try {
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if (!Buffer.isEncoding('latin1')) {
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return false
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}
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var buf = Buffer.alloc ? Buffer.alloc(4) : new Buffer(4)
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buf.fill('ab', 'ucs2')
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return (buf.toString('hex') === '61006200')
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} catch (_) {
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return false
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}
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}())
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function isSingleByte (val) {
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return (val.length === 1 && val.charCodeAt(0) < 256)
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}
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function fillWithNumber (buffer, val, start, end) {
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if (start < 0 || end > buffer.length) {
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throw new RangeError('Out of range index')
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}
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start = start >>> 0
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end = end === undefined ? buffer.length : end >>> 0
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if (end > start) {
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buffer.fill(val, start, end)
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}
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return buffer
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}
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function fillWithBuffer (buffer, val, start, end) {
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if (start < 0 || end > buffer.length) {
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throw new RangeError('Out of range index')
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}
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if (end <= start) {
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return buffer
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}
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start = start >>> 0
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end = end === undefined ? buffer.length : end >>> 0
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var pos = start
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var len = val.length
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while (pos <= (end - len)) {
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val.copy(buffer, pos)
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pos += len
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}
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if (pos !== end) {
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val.copy(buffer, pos, 0, end - pos)
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}
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return buffer
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}
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function fill (buffer, val, start, end, encoding) {
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if (hasFullSupport) {
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return buffer.fill(val, start, end, encoding)
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}
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if (typeof val === 'number') {
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return fillWithNumber(buffer, val, start, end)
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}
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if (typeof val === 'string') {
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if (typeof start === 'string') {
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encoding = start
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start = 0
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end = buffer.length
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} else if (typeof end === 'string') {
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encoding = end
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end = buffer.length
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}
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if (encoding !== undefined && typeof encoding !== 'string') {
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throw new TypeError('encoding must be a string')
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}
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if (encoding === 'latin1') {
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encoding = 'binary'
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}
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if (typeof encoding === 'string' && !Buffer.isEncoding(encoding)) {
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throw new TypeError('Unknown encoding: ' + encoding)
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}
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if (val === '') {
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return fillWithNumber(buffer, 0, start, end)
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}
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if (isSingleByte(val)) {
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return fillWithNumber(buffer, val.charCodeAt(0), start, end)
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}
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val = new Buffer(val, encoding)
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}
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if (Buffer.isBuffer(val)) {
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return fillWithBuffer(buffer, val, start, end)
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}
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// Other values (e.g. undefined, boolean, object) results in zero-fill
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return fillWithNumber(buffer, 0, start, end)
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}
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module.exports = fill
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