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![Werner Koch](/assets/img/avatar_default.png)
We better do this once and for all instead of cluttering all future commits with diffs of trailing white spaces. In the majority of cases blank or single lines are affected and thus this change won't disturb a git blame too much. For future commits the pre-commit scripts checks that this won't happen again.
229 lines
6.3 KiB
C
229 lines
6.3 KiB
C
/* b64dec.c - Simple Base64 decoder.
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* Copyright (C) 2008, 2011 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* 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.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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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, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <assert.h>
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#include "i18n.h"
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#include "util.h"
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/* The reverse base-64 list used for base-64 decoding. */
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static unsigned char const asctobin[128] =
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{
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0x3e, 0xff, 0xff, 0xff, 0x3f,
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0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
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0x3c, 0x3d, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
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0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
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0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
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0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
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0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
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0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
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0x31, 0x32, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff
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};
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enum decoder_states
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{
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s_init, s_idle, s_lfseen, s_begin,
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s_b64_0, s_b64_1, s_b64_2, s_b64_3,
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s_waitendtitle, s_waitend
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};
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/* Initialize the context for the base64 decoder. If TITLE is NULL a
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plain base64 decoding is done. If it is the empty string the
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decoder will skip everything until a "-----BEGIN " line has been
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seen, decoding ends at a "----END " line.
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Not yet implemented: If TITLE is either "PGP" or begins with "PGP "
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the PGP armor lines are skipped as well. */
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gpg_error_t
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b64dec_start (struct b64state *state, const char *title)
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{
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memset (state, 0, sizeof *state);
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if (title)
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{
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if (!strncmp (title, "PGP", 3) && (!title[3] || title[3] == ' '))
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state->lasterr = gpg_error (GPG_ERR_NOT_IMPLEMENTED);
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else
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{
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state->title = xtrystrdup (title);
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if (!state->title)
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state->lasterr = gpg_error_from_syserror ();
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else
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state->idx = s_init;
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}
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}
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else
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state->idx = s_b64_0;
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return state->lasterr;
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}
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/* Do in-place decoding of base-64 data of LENGTH in BUFFER. Stores the
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new length of the buffer at R_NBYTES. */
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gpg_error_t
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b64dec_proc (struct b64state *state, void *buffer, size_t length,
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size_t *r_nbytes)
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{
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enum decoder_states ds = state->idx;
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unsigned char val = state->radbuf[0];
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int pos = state->quad_count;
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char *d, *s;
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if (state->lasterr)
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return state->lasterr;
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if (state->stop_seen)
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{
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*r_nbytes = 0;
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state->lasterr = gpg_error (GPG_ERR_EOF);
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xfree (state->title);
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state->title = NULL;
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return state->lasterr;
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}
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for (s=d=buffer; length && !state->stop_seen; length--, s++)
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{
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switch (ds)
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{
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case s_idle:
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if (*s == '\n')
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{
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ds = s_lfseen;
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pos = 0;
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}
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break;
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case s_init:
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ds = s_lfseen;
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case s_lfseen:
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if (*s != "-----BEGIN "[pos])
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ds = s_idle;
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else if (pos == 10)
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ds = s_begin;
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else
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pos++;
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break;
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case s_begin:
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if (*s == '\n')
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ds = s_b64_0;
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break;
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case s_b64_0:
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case s_b64_1:
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case s_b64_2:
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case s_b64_3:
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{
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int c;
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if (*s == '-' && state->title)
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{
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/* Not a valid Base64 character: assume end
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header. */
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ds = s_waitend;
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}
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else if (*s == '=')
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{
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/* Pad character: stop */
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if (ds == s_b64_1)
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*d++ = val;
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ds = state->title? s_waitendtitle : s_waitend;
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}
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else if (*s == '\n' || *s == ' ' || *s == '\r' || *s == '\t')
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; /* Skip white spaces. */
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else if ( (*s & 0x80)
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|| (c = asctobin[*(unsigned char *)s]) == 255)
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{
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/* Skip invalid encodings. */
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state->invalid_encoding = 1;
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}
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else if (ds == s_b64_0)
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{
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val = c << 2;
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ds = s_b64_1;
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}
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else if (ds == s_b64_1)
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{
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val |= (c>>4)&3;
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*d++ = val;
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val = (c<<4)&0xf0;
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ds = s_b64_2;
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}
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else if (ds == s_b64_2)
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{
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val |= (c>>2)&15;
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*d++ = val;
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val = (c<<6)&0xc0;
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ds = s_b64_3;
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}
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else
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{
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val |= c&0x3f;
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*d++ = val;
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ds = s_b64_0;
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}
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}
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break;
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case s_waitendtitle:
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if (*s == '-')
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ds = s_waitend;
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break;
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case s_waitend:
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if ( *s == '\n')
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state->stop_seen = 1;
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break;
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default:
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BUG();
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}
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}
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state->idx = ds;
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state->radbuf[0] = val;
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state->quad_count = pos;
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*r_nbytes = (d -(char*) buffer);
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return 0;
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}
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/* This function needs to be called before releasing the decoder
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state. It may return an error code in case an encoding error has
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been found during decoding. */
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gpg_error_t
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b64dec_finish (struct b64state *state)
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{
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if (state->lasterr)
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return state->lasterr;
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xfree (state->title);
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state->title = NULL;
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return state->invalid_encoding? gpg_error(GPG_ERR_BAD_DATA): 0;
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}
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