1/* readtokens.c -- Functions for reading tokens from an input stream. 2 3 Copyright (C) 1990-1991, 1999-2004, 2006, 2009-2010 Free Software 4 Foundation, Inc. 5 6 This program is free software: you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program. If not, see <http://www.gnu.org/licenses/>. 18 19 Written by Jim Meyering. */ 20 21/* This almost supercedes xreadline stuff -- using delim="\n" 22 gives the same functionality, except that these functions 23 would never return empty lines. */ 24 25#include <config.h> 26 27#include "readtokens.h" 28 29#include <stdio.h> 30#include <stdlib.h> 31#include <string.h> 32#include <stdbool.h> 33 34#include "xalloc.h" 35 36#if USE_UNLOCKED_IO 37# include "unlocked-io.h" 38#endif 39 40/* Initialize a tokenbuffer. */ 41 42void 43init_tokenbuffer (token_buffer *tokenbuffer) 44{ 45 tokenbuffer->size = 0; 46 tokenbuffer->buffer = NULL; 47} 48 49/* Read a token from STREAM into TOKENBUFFER. 50 A token is delimited by any of the N_DELIM bytes in DELIM. 51 Upon return, the token is in tokenbuffer->buffer and 52 has a trailing '\0' instead of any original delimiter. 53 The function value is the length of the token not including 54 the final '\0'. Upon EOF (i.e. on the call after the last 55 token is read) or error, return -1 without modifying tokenbuffer. 56 The EOF and error conditions may be distinguished in the caller 57 by testing ferror (STREAM). 58 59 This function works properly on lines containing NUL bytes 60 and on files do not end with a delimiter. */ 61 62size_t 63readtoken (FILE *stream, 64 const char *delim, 65 size_t n_delim, 66 token_buffer *tokenbuffer) 67{ 68 char *p; 69 int c; 70 size_t i, n; 71 static const char *saved_delim = NULL; 72 static char isdelim[256]; 73 bool same_delimiters; 74 75 if (delim == NULL && saved_delim == NULL) 76 abort (); 77 78 same_delimiters = false; 79 if (delim != saved_delim && saved_delim != NULL) 80 { 81 same_delimiters = true; 82 for (i = 0; i < n_delim; i++) 83 { 84 if (delim[i] != saved_delim[i]) 85 { 86 same_delimiters = false; 87 break; 88 } 89 } 90 } 91 92 if (!same_delimiters) 93 { 94 size_t j; 95 saved_delim = delim; 96 memset (isdelim, 0, sizeof isdelim); 97 for (j = 0; j < n_delim; j++) 98 { 99 unsigned char ch = delim[j]; 100 isdelim[ch] = 1; 101 } 102 } 103 104 /* FIXME: don't fool with this caching. Use strchr instead. */ 105 /* skip over any leading delimiters */ 106 for (c = getc (stream); c >= 0 && isdelim[c]; c = getc (stream)) 107 { 108 /* empty */ 109 } 110 111 p = tokenbuffer->buffer; 112 n = tokenbuffer->size; 113 i = 0; 114 for (;;) 115 { 116 if (c < 0 && i == 0) 117 return -1; 118 119 if (i == n) 120 p = x2nrealloc (p, &n, sizeof *p); 121 122 if (c < 0) 123 { 124 p[i] = 0; 125 break; 126 } 127 if (isdelim[c]) 128 { 129 p[i] = 0; 130 break; 131 } 132 p[i++] = c; 133 c = getc (stream); 134 } 135 136 tokenbuffer->buffer = p; 137 tokenbuffer->size = n; 138 return i; 139} 140 141/* Build a NULL-terminated array of pointers to tokens 142 read from STREAM. Return the number of tokens read. 143 All storage is obtained through calls to xmalloc-like functions. 144 145 %%% Question: is it worth it to do a single 146 %%% realloc() of `tokens' just before returning? */ 147 148size_t 149readtokens (FILE *stream, 150 size_t projected_n_tokens, 151 const char *delim, 152 size_t n_delim, 153 char ***tokens_out, 154 size_t **token_lengths) 155{ 156 token_buffer tb, *token = &tb; 157 char **tokens; 158 size_t *lengths; 159 size_t sz; 160 size_t n_tokens; 161 162 if (projected_n_tokens == 0) 163 projected_n_tokens = 64; 164 else 165 projected_n_tokens++; /* add one for trailing NULL pointer */ 166 167 sz = projected_n_tokens; 168 tokens = xnmalloc (sz, sizeof *tokens); 169 lengths = xnmalloc (sz, sizeof *lengths); 170 171 n_tokens = 0; 172 init_tokenbuffer (token); 173 for (;;) 174 { 175 char *tmp; 176 size_t token_length = readtoken (stream, delim, n_delim, token); 177 if (n_tokens >= sz) 178 { 179 tokens = x2nrealloc (tokens, &sz, sizeof *tokens); 180 lengths = xnrealloc (lengths, sz, sizeof *lengths); 181 } 182 183 if (token_length == (size_t) -1) 184 { 185 /* don't increment n_tokens for NULL entry */ 186 tokens[n_tokens] = NULL; 187 lengths[n_tokens] = 0; 188 break; 189 } 190 tmp = xnmalloc (token_length + 1, sizeof *tmp); 191 lengths[n_tokens] = token_length; 192 tokens[n_tokens] = memcpy (tmp, token->buffer, token_length + 1); 193 n_tokens++; 194 } 195 196 free (token->buffer); 197 *tokens_out = tokens; 198 if (token_lengths != NULL) 199 *token_lengths = lengths; 200 return n_tokens; 201} 202