1// Copyright 2009 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// Simple file i/o and string manipulation, to avoid 6// depending on strconv and bufio and strings. 7 8package net 9 10import ( 11 "io" 12 "os" 13) 14 15type file struct { 16 file *os.File 17 data []byte 18 atEOF bool 19} 20 21func (f *file) close() { f.file.Close() } 22 23func (f *file) getLineFromData() (s string, ok bool) { 24 data := f.data 25 i := 0 26 for i = 0; i < len(data); i++ { 27 if data[i] == '\n' { 28 s = string(data[0:i]) 29 ok = true 30 // move data 31 i++ 32 n := len(data) - i 33 copy(data[0:], data[i:]) 34 f.data = data[0:n] 35 return 36 } 37 } 38 if f.atEOF && len(f.data) > 0 { 39 // EOF, return all we have 40 s = string(data) 41 f.data = f.data[0:0] 42 ok = true 43 } 44 return 45} 46 47func (f *file) readLine() (s string, ok bool) { 48 if s, ok = f.getLineFromData(); ok { 49 return 50 } 51 if len(f.data) < cap(f.data) { 52 ln := len(f.data) 53 n, err := io.ReadFull(f.file, f.data[ln:cap(f.data)]) 54 if n >= 0 { 55 f.data = f.data[0 : ln+n] 56 } 57 if err == io.EOF || err == io.ErrUnexpectedEOF { 58 f.atEOF = true 59 } 60 } 61 s, ok = f.getLineFromData() 62 return 63} 64 65func open(name string) (*file, error) { 66 fd, err := os.Open(name) 67 if err != nil { 68 return nil, err 69 } 70 return &file{fd, make([]byte, os.Getpagesize())[0:0], false}, nil 71} 72 73func byteIndex(s string, c byte) int { 74 for i := 0; i < len(s); i++ { 75 if s[i] == c { 76 return i 77 } 78 } 79 return -1 80} 81 82// Count occurrences in s of any bytes in t. 83func countAnyByte(s string, t string) int { 84 n := 0 85 for i := 0; i < len(s); i++ { 86 if byteIndex(t, s[i]) >= 0 { 87 n++ 88 } 89 } 90 return n 91} 92 93// Split s at any bytes in t. 94func splitAtBytes(s string, t string) []string { 95 a := make([]string, 1+countAnyByte(s, t)) 96 n := 0 97 last := 0 98 for i := 0; i < len(s); i++ { 99 if byteIndex(t, s[i]) >= 0 { 100 if last < i { 101 a[n] = string(s[last:i]) 102 n++ 103 } 104 last = i + 1 105 } 106 } 107 if last < len(s) { 108 a[n] = string(s[last:]) 109 n++ 110 } 111 return a[0:n] 112} 113 114func getFields(s string) []string { return splitAtBytes(s, " \r\t\n") } 115 116// Bigger than we need, not too big to worry about overflow 117const big = 0xFFFFFF 118 119// Decimal to integer starting at &s[i0]. 120// Returns number, new offset, success. 121func dtoi(s string, i0 int) (n int, i int, ok bool) { 122 n = 0 123 for i = i0; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ { 124 n = n*10 + int(s[i]-'0') 125 if n >= big { 126 return 0, i, false 127 } 128 } 129 if i == i0 { 130 return 0, i, false 131 } 132 return n, i, true 133} 134 135// Hexadecimal to integer starting at &s[i0]. 136// Returns number, new offset, success. 137func xtoi(s string, i0 int) (n int, i int, ok bool) { 138 n = 0 139 for i = i0; i < len(s); i++ { 140 if '0' <= s[i] && s[i] <= '9' { 141 n *= 16 142 n += int(s[i] - '0') 143 } else if 'a' <= s[i] && s[i] <= 'f' { 144 n *= 16 145 n += int(s[i]-'a') + 10 146 } else if 'A' <= s[i] && s[i] <= 'F' { 147 n *= 16 148 n += int(s[i]-'A') + 10 149 } else { 150 break 151 } 152 if n >= big { 153 return 0, i, false 154 } 155 } 156 if i == i0 { 157 return 0, i, false 158 } 159 return n, i, true 160} 161 162// xtoi2 converts the next two hex digits of s into a byte. 163// If s is longer than 2 bytes then the third byte must be e. 164// If the first two bytes of s are not hex digits or the third byte 165// does not match e, false is returned. 166func xtoi2(s string, e byte) (byte, bool) { 167 if len(s) > 2 && s[2] != e { 168 return 0, false 169 } 170 n, ei, ok := xtoi(s[:2], 0) 171 return byte(n), ok && ei == 2 172} 173 174// Integer to decimal. 175func itoa(i int) string { 176 var buf [30]byte 177 n := len(buf) 178 neg := false 179 if i < 0 { 180 i = -i 181 neg = true 182 } 183 ui := uint(i) 184 for ui > 0 || n == len(buf) { 185 n-- 186 buf[n] = byte('0' + ui%10) 187 ui /= 10 188 } 189 if neg { 190 n-- 191 buf[n] = '-' 192 } 193 return string(buf[n:]) 194} 195 196// Convert i to decimal string. 197func itod(i uint) string { 198 if i == 0 { 199 return "0" 200 } 201 202 // Assemble decimal in reverse order. 203 var b [32]byte 204 bp := len(b) 205 for ; i > 0; i /= 10 { 206 bp-- 207 b[bp] = byte(i%10) + '0' 208 } 209 210 return string(b[bp:]) 211} 212 213// Convert i to hexadecimal string. 214func itox(i uint, min int) string { 215 // Assemble hexadecimal in reverse order. 216 var b [32]byte 217 bp := len(b) 218 for ; i > 0 || min > 0; i /= 16 { 219 bp-- 220 b[bp] = "0123456789abcdef"[byte(i%16)] 221 min-- 222 } 223 224 return string(b[bp:]) 225} 226 227// Number of occurrences of b in s. 228func count(s string, b byte) int { 229 n := 0 230 for i := 0; i < len(s); i++ { 231 if s[i] == b { 232 n++ 233 } 234 } 235 return n 236} 237 238// Index of rightmost occurrence of b in s. 239func last(s string, b byte) int { 240 i := len(s) 241 for i--; i >= 0; i-- { 242 if s[i] == b { 243 break 244 } 245 } 246 return i 247} 248