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120 lines
3.4 KiB
C++
120 lines
3.4 KiB
C++
/* getline.c -- Replacement for GNU C library function getline
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Copyright (C) 1993, 1996, 2001-2002 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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USA. */
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/* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */
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/* Specification. */
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#include "getline.h"
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#include <stddef.h>
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#include <stdio.h>
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#include <string.h>
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#include <assert.h>
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/* Always add at least this many bytes when extending the buffer. */
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#define MIN_CHUNK 64
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/* Reads up to (and including) a TERMINATOR from STREAM into *LINEPTR + OFFSET
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(and null-terminate it). *LINEPTR is a pointer returned from new [] (or
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NULL), pointing to *N characters of space. It is realloc'd as
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necessary. Returns the number of characters read (not including the
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null terminator), or -1 on error or immediate EOF.
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NOTE: There is another getstr() function declared in <curses.h>. */
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static int
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getstr (char **lineptr, size_t *n, FILE *stream, char terminator, size_t offset)
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{
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size_t nchars_avail; /* Allocated but unused chars in *LINEPTR. */
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char *read_pos; /* Where we're reading into *LINEPTR. */
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if (!lineptr || !n || !stream)
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return -1;
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if (!*lineptr)
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{
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*n = MIN_CHUNK;
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*lineptr = new char[*n];
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}
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nchars_avail = *n - offset;
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read_pos = *lineptr + offset;
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for (;;)
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{
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register int c = getc (stream);
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/* We always want at least one char left in the buffer, since we
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always (unless we get an error while reading the first char)
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NUL-terminate the line buffer. */
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assert (*n - nchars_avail == (size_t) (read_pos - *lineptr));
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if (nchars_avail < 2)
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{
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if (*n > MIN_CHUNK)
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*n *= 2;
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else
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*n += MIN_CHUNK;
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nchars_avail = *n + *lineptr - read_pos;
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char *new_line = new char[*n];
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if (*lineptr)
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{
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memcpy (new_line, *lineptr, read_pos - *lineptr);
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delete[] *lineptr;
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}
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*lineptr = new_line;
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read_pos = *n - nchars_avail + *lineptr;
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assert (*n - nchars_avail == (size_t) (read_pos - *lineptr));
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}
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if (c == EOF || ferror (stream))
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{
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/* Return partial line, if any. */
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if (read_pos == *lineptr)
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return -1;
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else
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break;
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}
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*read_pos++ = c;
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nchars_avail--;
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if (c == terminator)
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/* Return the line. */
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break;
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}
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/* Done - NUL terminate and return the number of chars read. */
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*read_pos = '\0';
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return read_pos - (*lineptr + offset);
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}
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int
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get_line (char **lineptr, size_t *n, FILE *stream)
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{
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return getstr (lineptr, n, stream, '\n', 0);
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}
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int
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get_delim (char **lineptr, size_t *n, int delimiter, FILE *stream)
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{
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return getstr (lineptr, n, stream, delimiter, 0);
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}
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