1 /* getline.c -- Replacement for GNU C library function getline 2 3 Copyright (C) 1993 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or 6 modify it under the terms of the GNU General Public License as 7 published by the Free Software Foundation; either version 2 of the 8 License, or (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, but 11 WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 General Public License for more details. */ 14 15 /* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */ 16 17 #ifdef HAVE_CONFIG_H 18 #include <config.h> 19 #endif 20 21 #include <sys/types.h> 22 #include <stdio.h> 23 #include <assert.h> 24 #include <errno.h> 25 #include "getline.h" 26 27 #if STDC_HEADERS 28 #include <stdlib.h> 29 #else 30 char *malloc (), *realloc (); 31 #endif 32 33 /* Always add at least this many bytes when extending the buffer. */ 34 #define MIN_CHUNK 64 35 36 /* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR 37 + OFFSET (and null-terminate it). If LIMIT is non-negative, then 38 read no more than LIMIT chars. 39 40 *LINEPTR is a pointer returned from malloc (or NULL), pointing to 41 *N characters of space. It is realloc'd as necessary. 42 43 Return the number of characters read (not including the null 44 terminator), or -1 on error or EOF. On a -1 return, the caller 45 should check feof(), if not then errno has been set to indicate the 46 error. */ 47 48 int 49 getstr (lineptr, n, stream, terminator, offset, limit) 50 char **lineptr; 51 size_t *n; 52 FILE *stream; 53 char terminator; 54 int offset; 55 int limit; 56 { 57 int nchars_avail; /* Allocated but unused chars in *LINEPTR. */ 58 char *read_pos; /* Where we're reading into *LINEPTR. */ 59 int ret; 60 61 if (!lineptr || !n || !stream) 62 { 63 errno = EINVAL; 64 return -1; 65 } 66 67 if (!*lineptr) 68 { 69 *n = MIN_CHUNK; 70 *lineptr = malloc (*n); 71 if (!*lineptr) 72 { 73 errno = ENOMEM; 74 return -1; 75 } 76 } 77 78 nchars_avail = *n - offset; 79 read_pos = *lineptr + offset; 80 81 for (;;) 82 { 83 int save_errno; 84 register int c; 85 86 if (limit == 0) 87 break; 88 else 89 { 90 c = getc (stream); 91 92 /* If limit is negative, then we shouldn't pay attention to 93 it, so decrement only if positive. */ 94 if (limit > 0) 95 limit--; 96 } 97 98 save_errno = errno; 99 100 /* We always want at least one char left in the buffer, since we 101 always (unless we get an error while reading the first char) 102 NUL-terminate the line buffer. */ 103 104 assert((*lineptr + *n) == (read_pos + nchars_avail)); 105 if (nchars_avail < 2) 106 { 107 if (*n > MIN_CHUNK) 108 *n *= 2; 109 else 110 *n += MIN_CHUNK; 111 112 nchars_avail = *n + *lineptr - read_pos; 113 *lineptr = realloc (*lineptr, *n); 114 if (!*lineptr) 115 { 116 errno = ENOMEM; 117 return -1; 118 } 119 read_pos = *n - nchars_avail + *lineptr; 120 assert((*lineptr + *n) == (read_pos + nchars_avail)); 121 } 122 123 if (ferror (stream)) 124 { 125 /* Might like to return partial line, but there is no 126 place for us to store errno. And we don't want to just 127 lose errno. */ 128 errno = save_errno; 129 return -1; 130 } 131 132 if (c == EOF) 133 { 134 /* Return partial line, if any. */ 135 if (read_pos == *lineptr) 136 return -1; 137 else 138 break; 139 } 140 141 *read_pos++ = c; 142 nchars_avail--; 143 144 if (c == terminator) 145 /* Return the line. */ 146 break; 147 } 148 149 /* Done - NUL terminate and return the number of chars read. */ 150 *read_pos = '\0'; 151 152 ret = read_pos - (*lineptr + offset); 153 return ret; 154 } 155 156 int 157 getline (lineptr, n, stream) 158 char **lineptr; 159 size_t *n; 160 FILE *stream; 161 { 162 return getstr (lineptr, n, stream, '\n', 0, GETLINE_NO_LIMIT); 163 } 164 165 int 166 getline_safe (lineptr, n, stream, limit) 167 char **lineptr; 168 size_t *n; 169 FILE *stream; 170 int limit; 171 { 172 return getstr (lineptr, n, stream, '\n', 0, limit); 173 } 174