63 lines
1.6 KiB
JavaScript
63 lines
1.6 KiB
JavaScript
function sumSysv(u8) {
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let crc = 0
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for (let i = 0; i < u8.length; i++) crc += u8[i]
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crc = (crc & 0xffff) + ((crc >> 16) & 0xffff)
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crc = (crc & 0xffff) + ((crc >> 16) & 0xffff)
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return crc & 0xffff
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}
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function sumBsd(u8) {
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let cksum = 0
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for (let i = 0; i < u8.length; i++) {
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cksum = (cksum >> 1) + ((cksum & 1) << 15)
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cksum = (cksum + u8[i]) & 0xffff
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}
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return cksum
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}
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async function run(ctx, argv) {
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let bsd = false
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const paths = []
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for (let i = 1; i < argv.length; i++) {
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const a = argv[i]
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if (a === '-h' || a === '--help') {
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ctx.console.log(
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'usage: sum [-r] [FILE]...\n' +
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' -r BSD algorithm (default is SysV / CRC16-style sum)'
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)
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ctx.exitCode = 0
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return
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}
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if (a === '-r') bsd = true
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else if (a.startsWith('-') && a !== '-') {
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ctx.console.error('sum: unsupported option ' + a)
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ctx.exitCode = 1
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return
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} else paths.push(a)
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}
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const b4 = ctx.b4a
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function one(name, buf) {
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const u8 = buf instanceof Uint8Array ? buf : new Uint8Array(buf)
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const blocks = Math.ceil(u8.length / 512) || 1
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const v = bsd ? sumBsd(u8) : sumSysv(u8)
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ctx.console.log(v + '\t' + blocks + '\t' + name)
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}
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if (!paths.length || (paths.length === 1 && paths[0] === '-')) {
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one('-', b4.from(bareStdin(ctx)))
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return
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}
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for (const p of paths) {
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if (p === '-') {
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one('-', b4.from(bareStdin(ctx)))
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continue
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}
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const b = await ctx.vfs.readFile(p)
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if (!b) {
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ctx.console.error('sum: ' + p + ': No such file')
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ctx.exitCode = 1
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continue
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}
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one(p, b)
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}
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}
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