60 lines
1.4 KiB
Go
60 lines
1.4 KiB
Go
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package main
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import (
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"fmt"
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"strconv"
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"strings"
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)
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// domain represents a domain log record
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type domain struct {
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name string
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visits int
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}
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// parser parses a log file and provides an iterator to iterate upon the domains
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//
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// the parser struct is carefully crafted to be usable using its zero values except the map field
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type parser struct {
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sum map[string]int // visits per unique domain
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domains []domain // unique domain names
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total int // total visits to all domains
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lines int // number of parsed lines (for the error messages)
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}
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// newParser creates and returns a new parser.
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func newParser() parser {
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return parser{sum: make(map[string]int)}
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}
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// parse parses the given text and returns a domain struct
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func parse(p parser, line string) (dom domain, err error) {
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fields := strings.Fields(line)
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if len(fields) != 2 {
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err = fmt.Errorf("wrong input: %v (line #%d)", fields, p.lines)
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return
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}
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name, visits := fields[0], fields[1]
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n, err := strconv.Atoi(visits)
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if n < 0 || err != nil {
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err = fmt.Errorf("wrong input: %q (line #%d)", visits, p.lines)
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return
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}
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return domain{name: name, visits: n}, nil
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}
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// push pushes the given domain to the internal list of domains.
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// it also increases the total visits for all the domains.
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func push(p parser, d domain) parser {
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if _, ok := p.sum[d.name]; !ok {
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p.domains = append(p.domains, d)
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}
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p.sum[d.name] += d.visits
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p.total += d.visits
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return p
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}
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