1/* getline.c -- Replacement for GNU C library function getline 2 3 Copyright (C) 1993, 1996, 2001-2002 Free Software Foundation, Inc. 4 5 This program is free software: you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 17 18/* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */ 19 20/* Specification. */ 21#include "getline.h" 22 23#include <stddef.h> 24#include <stdio.h> 25#include <string.h> 26#include <assert.h> 27 28/* Always add at least this many bytes when extending the buffer. */ 29#define MIN_CHUNK 64 30 31/* Reads up to (and including) a TERMINATOR from STREAM into *LINEPTR + OFFSET 32 (and null-terminate it). *LINEPTR is a pointer returned from new [] (or 33 NULL), pointing to *N characters of space. It is realloc'd as 34 necessary. Returns the number of characters read (not including the 35 null terminator), or -1 on error or immediate EOF. 36 NOTE: There is another getstr() function declared in <curses.h>. */ 37 38static int 39getstr (char **lineptr, size_t *n, FILE *stream, char terminator, size_t offset) 40{ 41 size_t nchars_avail; /* Allocated but unused chars in *LINEPTR. */ 42 char *read_pos; /* Where we're reading into *LINEPTR. */ 43 44 if (!lineptr || !n || !stream) 45 return -1; 46 47 if (!*lineptr) 48 { 49 *n = MIN_CHUNK; 50 *lineptr = new char[*n]; 51 } 52 53 nchars_avail = *n - offset; 54 read_pos = *lineptr + offset; 55 56 for (;;) 57 { 58 register int c = getc (stream); 59 60 /* We always want at least one char left in the buffer, since we 61 always (unless we get an error while reading the first char) 62 NUL-terminate the line buffer. */ 63 64 assert (*n - nchars_avail == (size_t) (read_pos - *lineptr)); 65 if (nchars_avail < 2) 66 { 67 if (*n > MIN_CHUNK) 68 *n *= 2; 69 else 70 *n += MIN_CHUNK; 71 72 nchars_avail = *n + *lineptr - read_pos; 73 char *new_line = new char[*n]; 74 if (*lineptr) 75 { 76 memcpy (new_line, *lineptr, read_pos - *lineptr); 77 delete[] *lineptr; 78 } 79 *lineptr = new_line; 80 read_pos = *n - nchars_avail + *lineptr; 81 assert (*n - nchars_avail == (size_t) (read_pos - *lineptr)); 82 } 83 84 if (c == EOF || ferror (stream)) 85 { 86 /* Return partial line, if any. */ 87 if (read_pos == *lineptr) 88 return -1; 89 else 90 break; 91 } 92 93 *read_pos++ = c; 94 nchars_avail--; 95 96 if (c == terminator) 97 /* Return the line. */ 98 break; 99 } 100 101 /* Done - NUL terminate and return the number of chars read. */ 102 *read_pos = '\0'; 103 104 return read_pos - (*lineptr + offset); 105} 106 107int 108get_line (char **lineptr, size_t *n, FILE *stream) 109{ 110 return getstr (lineptr, n, stream, '\n', 0); 111} 112 113int 114get_delim (char **lineptr, size_t *n, int delimiter, FILE *stream) 115{ 116 return getstr (lineptr, n, stream, delimiter, 0); 117} 118