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1 /* line.c: return the next line from a file, or NULL. |
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2 |
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3 Copyright (C) 1992, 93 Free Software Foundation, Inc. |
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4 |
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5 This program is free software; you can redistribute it and/or modify |
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6 it under the terms of the GNU General Public License as published by |
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7 the Free Software Foundation; either version 2, or (at your option) |
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8 any later version. |
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9 |
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10 This program is distributed in the hope that it will be useful, |
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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13 GNU General Public License for more details. |
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14 |
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15 You should have received a copy of the GNU General Public License |
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16 along with this program; if not, write to the Free Software |
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17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
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18 |
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19 /* Don't include config.h or all our other usual includes, since |
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20 it's useful to just throw this file into other programs. */ |
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21 |
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22 #include <stdio.h> |
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23 extern void free (); |
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24 |
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25 /* From xmalloc.c and xrealloc.c. This saves having to include config.h. */ |
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26 extern void *xmalloc (), *xrealloc (); |
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27 |
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28 |
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29 /* Allocate in increments of this size. */ |
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30 #define BLOCK_SIZE 40 |
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31 |
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32 char * |
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33 read_line (f) |
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34 FILE *f; |
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35 { |
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36 int c; |
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37 unsigned limit = BLOCK_SIZE; |
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38 unsigned loc = 0; |
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39 char *line = xmalloc (limit); |
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40 |
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41 while ((c = getc (f)) != EOF && c != '\n') |
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42 { |
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43 line[loc] = c; |
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44 loc++; |
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45 |
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46 /* By testing after the assignment, we guarantee that we'll always |
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47 have space for the null we append below. We know we always |
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48 have room for the first char, since we start with BLOCK_SIZE. */ |
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49 if (loc == limit) |
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50 { |
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51 limit += BLOCK_SIZE; |
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52 line = xrealloc (line, limit); |
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53 } |
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54 } |
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55 |
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56 /* If we read anything, return it. This can't represent a last |
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57 ``line'' which doesn't end in a newline, but so what. */ |
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58 if (c != EOF) |
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59 { |
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60 /* Terminate the string. We can't represent nulls in the file, |
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61 either. Again, it doesn't matter. */ |
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62 line[loc] = 0; |
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63 } |
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64 else /* At end of file. */ |
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65 { |
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66 free (line); |
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67 line = NULL; |
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68 } |
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69 |
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70 return line; |
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71 } |
