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/* Copyright (c) 2003-2018 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "buffer.h"
#include "base64.h"
#include "istream-private.h"
#include "istream-base64.h"
struct base64_encoder_istream {
struct istream_private istream;
struct base64_encoder encoder;
};
static int i_stream_read_parent(struct istream_private *stream)
{
size_t size;
ssize_t ret;
size = i_stream_get_data_size(stream->parent);
if (size > 0)
return 1;
ret = i_stream_read_memarea(stream->parent);
if (ret <= 0) {
stream->istream.stream_errno = stream->parent->stream_errno;
return ret;
}
size = i_stream_get_data_size(stream->parent);
i_assert(size != 0);
return 1;
}
static int
i_stream_base64_try_encode(struct base64_encoder_istream *bstream)
{
struct istream_private *stream = &bstream->istream;
struct base64_encoder *b64enc = &bstream->encoder;
const unsigned char *data;
size_t size, pos, out_size, avail;
buffer_t buf;
data = i_stream_get_data(stream->parent, &size);
if (size == 0)
return 0;
out_size = base64_encode_get_size(b64enc, size);
if (!i_stream_try_alloc(stream, out_size, &avail))
return -2;
buffer_create_from_data(&buf, stream->w_buffer + stream->pos, avail);
base64_encode_more(b64enc, data, size, &pos, &buf);
i_assert(buf.used > 0);
stream->pos += buf.used;
i_stream_skip(stream->parent, pos);
return 1;
}
static int
i_stream_base64_finish_encode(struct base64_encoder_istream *bstream)
{
struct istream_private *stream = &bstream->istream;
struct base64_encoder *b64enc = &bstream->encoder;
size_t out_size, buffer_avail;
buffer_t buf;
out_size = base64_encode_get_size(b64enc, 0);
if (out_size == 0) {
if (base64_encode_finish(b64enc, NULL))
stream->istream.eof = TRUE;
return 1;
}
if (!i_stream_try_alloc(stream, out_size, &buffer_avail))
return -2;
buffer_create_from_data(&buf, stream->w_buffer + stream->pos,
buffer_avail);
if (base64_encode_finish(b64enc, &buf))
stream->istream.eof = TRUE;
i_assert(buf.used > 0);
stream->pos += buf.used;
return 1;
}
static ssize_t i_stream_base64_encoder_read(struct istream_private *stream)
{
struct base64_encoder_istream *bstream =
container_of(stream, struct base64_encoder_istream, istream);
size_t pre_count, post_count;
int ret;
if (base64_encode_is_finished(&bstream->encoder)) {
stream->istream.eof = TRUE;
return -1;
}
pre_count = post_count = 0;
do {
ret = i_stream_read_parent(stream);
if (ret == 0)
return 0;
if (ret < 0) {
if (stream->istream.stream_errno != 0)
return -1;
if (i_stream_get_data_size(stream->parent) == 0)
break;
/* add the final partial block */
}
/* encode as many lines as fits into destination buffer */
pre_count = stream->pos - stream->skip;
while ((ret = i_stream_base64_try_encode(bstream)) > 0) ;
post_count = stream->pos - stream->skip;
} while (ret == 0 && pre_count == post_count);
if (ret == -2) {
if (pre_count == post_count)
return -2;
} else if (ret < 0) {
if (i_stream_get_data_size(stream->parent) == 0) {
i_assert(post_count == pre_count);
pre_count = stream->pos - stream->skip;
ret = i_stream_base64_finish_encode(bstream);
post_count = stream->pos - stream->skip;
if (ret <= 0)
return ret;
}
if (pre_count == post_count) {
stream->istream.eof = TRUE;
return -1;
}
}
i_assert(post_count > pre_count);
return post_count - pre_count;
}
static void
i_stream_base64_encoder_seek(struct istream_private *stream,
uoff_t v_offset, bool mark)
{
struct base64_encoder_istream *bstream =
container_of(stream, struct base64_encoder_istream, istream);
if (v_offset < stream->istream.v_offset) {
/* seeking backwards - go back to beginning and seek
forward from there. */
stream->parent_expected_offset = stream->parent_start_offset;
stream->skip = stream->pos = 0;
stream->istream.v_offset = 0;
i_stream_seek(stream->parent, 0);
base64_encode_reset(&bstream->encoder);
}
i_stream_default_seek_nonseekable(stream, v_offset, mark);
}
static int
i_stream_base64_encoder_stat(struct istream_private *stream,
bool exact ATTR_UNUSED)
{
struct base64_encoder_istream *bstream =
container_of(stream, struct base64_encoder_istream, istream);
const struct stat *st;
if (i_stream_stat(stream->parent, exact, &st) < 0) {
stream->istream.stream_errno = stream->parent->stream_errno;
return -1;
}
stream->statbuf = *st;
if (st->st_size == 0)
return 0;
stream->statbuf.st_size =
base64_get_full_encoded_size(&bstream->encoder, st->st_size);
return 0;
}
static struct istream *
i_stream_create_base64_encoder_common(const struct base64_scheme *b64,
struct istream *input,
unsigned int chars_per_line, bool crlf)
{
struct base64_encoder_istream *bstream;
enum base64_encode_flags b64_flags = 0;
i_assert(chars_per_line % 4 == 0);
bstream = i_new(struct base64_encoder_istream, 1);
bstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
bstream->istream.read = i_stream_base64_encoder_read;
bstream->istream.seek = i_stream_base64_encoder_seek;
bstream->istream.stat = i_stream_base64_encoder_stat;
bstream->istream.istream.readable_fd = FALSE;
bstream->istream.istream.blocking = input->blocking;
bstream->istream.istream.seekable = input->seekable;
if (crlf)
b64_flags |= BASE64_ENCODE_FLAG_CRLF;
base64_encode_init(&bstream->encoder, b64, b64_flags, chars_per_line);
return i_stream_create(&bstream->istream, input,
i_stream_get_fd(input), 0);
}
struct istream *
i_stream_create_base64_encoder(struct istream *input,
unsigned int chars_per_line, bool crlf)
{
return i_stream_create_base64_encoder_common(&base64_scheme, input,
chars_per_line, crlf);
}
struct istream *
i_stream_create_base64url_encoder(struct istream *input,
unsigned int chars_per_line, bool crlf)
{
return i_stream_create_base64_encoder_common(&base64url_scheme, input,
chars_per_line, crlf);
}
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