Source file src/pkg/index/suffixarray/gen.go

     1	// Copyright 2019 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	// +build ignore
     6	
     7	// Gen generates sais2.go by duplicating functions in sais.go
     8	// using different input types.
     9	// See the comment at the top of sais.go for details.
    10	package main
    11	
    12	import (
    13		"bytes"
    14		"io/ioutil"
    15		"log"
    16		"strings"
    17	)
    18	
    19	func main() {
    20		log.SetPrefix("gen: ")
    21		log.SetFlags(0)
    22	
    23		data, err := ioutil.ReadFile("sais.go")
    24		if err != nil {
    25			log.Fatal(err)
    26		}
    27	
    28		x := bytes.Index(data, []byte("\n\n"))
    29		if x < 0 {
    30			log.Fatal("cannot find blank line after copyright comment")
    31		}
    32	
    33		var buf bytes.Buffer
    34		buf.Write(data[:x])
    35		buf.WriteString("\n\n// Code generated by go generate; DO NOT EDIT.\n\npackage suffixarray\n")
    36	
    37		for {
    38			x := bytes.Index(data, []byte("\nfunc "))
    39			if x < 0 {
    40				break
    41			}
    42			data = data[x:]
    43			p := bytes.IndexByte(data, '(')
    44			if p < 0 {
    45				p = len(data)
    46			}
    47			name := string(data[len("\nfunc "):p])
    48	
    49			x = bytes.Index(data, []byte("\n}\n"))
    50			if x < 0 {
    51				log.Fatalf("cannot find end of func %s", name)
    52			}
    53			fn := string(data[:x+len("\n}\n")])
    54			data = data[x+len("\n}"):]
    55	
    56			if strings.HasSuffix(name, "_32") {
    57				buf.WriteString(fix32.Replace(fn))
    58			}
    59			if strings.HasSuffix(name, "_8_32") {
    60				// x_8_32 -> x_8_64 done above
    61				fn = fix8_32.Replace(stripByteOnly(fn))
    62				buf.WriteString(fn)
    63				buf.WriteString(fix32.Replace(fn))
    64			}
    65		}
    66	
    67		if err := ioutil.WriteFile("sais2.go", buf.Bytes(), 0666); err != nil {
    68			log.Fatal(err)
    69		}
    70	}
    71	
    72	var fix32 = strings.NewReplacer(
    73		"32", "64",
    74		"int32", "int64",
    75	)
    76	
    77	var fix8_32 = strings.NewReplacer(
    78		"_8_32", "_32",
    79		"byte", "int32",
    80	)
    81	
    82	func stripByteOnly(s string) string {
    83		lines := strings.SplitAfter(s, "\n")
    84		w := 0
    85		for _, line := range lines {
    86			if !strings.Contains(line, "256") && !strings.Contains(line, "byte-only") {
    87				lines[w] = line
    88				w++
    89			}
    90		}
    91		return strings.Join(lines[:w], "")
    92	}
    93	

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