rm_/lib/readtokens0.c

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2020-09-02 16:47:03 +08:00
/* readtokens0.c -- Read NUL-separated tokens from an input stream.
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Copyright (C) 2004, 2006, 2009-2022 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
Written by Jim Meyering. */
#include <config.h>
#include <stdlib.h>
#include "readtokens0.h"
#define obstack_chunk_alloc malloc
#define obstack_chunk_free free
void
readtokens0_init (struct Tokens *t)
{
t->n_tok = 0;
t->tok = NULL;
t->tok_len = NULL;
obstack_init (&t->o_data);
obstack_init (&t->o_tok);
obstack_init (&t->o_tok_len);
}
void
readtokens0_free (struct Tokens *t)
{
obstack_free (&t->o_data, NULL);
obstack_free (&t->o_tok, NULL);
obstack_free (&t->o_tok_len, NULL);
}
/* Finalize (in the obstack_finish sense) the current token
and record its pointer and length. */
static void
save_token (struct Tokens *t)
{
/* Don't count the trailing NUL byte in the length. */
size_t len = obstack_object_size (&t->o_data) - 1;
char const *s = obstack_finish (&t->o_data);
obstack_ptr_grow (&t->o_tok, s);
obstack_grow (&t->o_tok_len, &len, sizeof len);
t->n_tok++;
}
/* Read NUL-separated tokens from stream IN into T until EOF or error.
The final NUL is optional. Always append a NULL pointer to the
resulting list of token pointers, but that pointer isn't counted
via t->n_tok. Return true if successful. */
bool
readtokens0 (FILE *in, struct Tokens *t)
{
while (1)
{
int c = fgetc (in);
if (c == EOF)
{
size_t len = obstack_object_size (&t->o_data);
/* If the current object has nonzero length, then there
was no NUL byte at EOF -- or maybe there was an error,
in which case, we need to append a NUL byte to our buffer. */
if (len)
{
obstack_1grow (&t->o_data, '\0');
save_token (t);
}
break;
}
obstack_1grow (&t->o_data, c);
if (c == '\0')
save_token (t);
}
/* Add a NULL pointer at the end, in case the caller (like du)
requires an argv-style array of strings. */
obstack_ptr_grow (&t->o_tok, NULL);
t->tok = obstack_finish (&t->o_tok);
t->tok_len = obstack_finish (&t->o_tok_len);
return ! ferror (in);
}