57 lines
1.1 KiB
Go
57 lines
1.1 KiB
Go
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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// See page 97.
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//!+
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// Charcount computes counts of Unicode characters.
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package main
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import (
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"bufio"
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"fmt"
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"io"
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"os"
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"unicode"
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"unicode/utf8"
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)
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func main() {
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counts := make(map[rune]int) // counts of Unicode characters
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var utflen [utf8.UTFMax + 1]int // count of lengths of UTF-8 encodings
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invalid := 0 // count of invalid UTF-8 characters
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in := bufio.NewReader(os.Stdin)
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for {
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r, n, err := in.ReadRune() // returns rune, nbytes, error
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if err == io.EOF {
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break
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}
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if err != nil {
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fmt.Fprintf(os.Stderr, "charcount: %v\n", err)
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os.Exit(1)
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}
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if r == unicode.ReplacementChar && n == 1 {
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invalid++
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continue
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}
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counts[r]++
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utflen[n]++
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}
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fmt.Printf("rune\tcount\n")
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for c, n := range counts {
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fmt.Printf("%q\t%d\n", c, n)
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}
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fmt.Print("\nlen\tcount\n")
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for i, n := range utflen {
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if i > 0 {
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fmt.Printf("%d\t%d\n", i, n)
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}
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}
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if invalid > 0 {
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fmt.Printf("\n%d invalid UTF-8 characters\n", invalid)
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}
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}
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//!-
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