istream-base64-encoder.c revision 3785910c303507db5f629684e6dde2cc7f83668e
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen/* Copyright (c) 2003-2012 Dovecot authors, see the included COPYING file */
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen#include "lib.h"
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen#include "buffer.h"
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen#include "base64.h"
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen#include "istream-private.h"
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen#include "istream-base64-encoder.h"
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainenstruct base64_encoder_istream {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen struct istream_private istream;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen /* current encoded line length. */
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen unsigned int cur_line_len;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen unsigned int chars_per_line;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen bool crlf;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen};
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainenstatic int i_stream_read_parent(struct istream_private *stream)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen{
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen size_t size;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen ssize_t ret;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen size = i_stream_get_data_size(stream->parent);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (size >= 4)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return 1;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen /* we have less than one base64 block.
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen see if there is more data available. */
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen ret = i_stream_read(stream->parent);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (ret <= 0) {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen stream->istream.stream_errno = stream->parent->stream_errno;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen stream->istream.eof = stream->parent->eof;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return size > 0 ? 1 : ret;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen }
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen size = i_stream_get_data_size(stream->parent);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_assert(size != 0);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return 1;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen}
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainenstatic bool
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Siraineni_stream_base64_try_encode_line(struct base64_encoder_istream *bstream)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen{
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen struct istream_private *stream = &bstream->istream;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen const unsigned char *data;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen size_t size, avail, buffer_avail;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen buffer_t buf;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen data = i_stream_get_data(stream->parent, &size);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (size == 0)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return FALSE;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (bstream->cur_line_len == bstream->chars_per_line) {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen /* @UNSAFE: end of line, add newline */
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (!i_stream_get_buffer_space(stream,
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen bstream->crlf ? 2 : 1, &avail))
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return FALSE;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (bstream->crlf)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen stream->w_buffer[stream->pos++] = '\r';
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen stream->w_buffer[stream->pos++] = '\n';
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen bstream->cur_line_len = 0;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen }
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen (void)i_stream_get_buffer_space(stream, (size+2)/3*4, &avail);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen buffer_avail = stream->buffer_size - stream->pos;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if ((size + 2) / 3 * 4 > buffer_avail) {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen /* can't fit everything to destination buffer.
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen write as much as we can. */
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen size = (buffer_avail / 4) * 3;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen } else if (!stream->parent->eof && size % 3 != 0) {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen /* encode 3 chars at a time, so base64_encode() doesn't
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen add '=' characters in the middle of the stream */
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen size -= (size % 3);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen }
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (size == 0)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return FALSE;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (bstream->cur_line_len + (size+2)/3*4 > bstream->chars_per_line) {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen size = (bstream->chars_per_line - bstream->cur_line_len)/4 * 3;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_assert(size != 0);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen }
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen buffer_create_data(&buf, stream->w_buffer + stream->pos, buffer_avail);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen base64_encode(data, size, &buf);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_assert(buf.used > 0);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen bstream->cur_line_len += buf.used;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_assert(bstream->cur_line_len <= bstream->chars_per_line);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen stream->pos += buf.used;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_stream_skip(stream->parent, size);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return TRUE;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen}
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainenstatic ssize_t i_stream_base64_encoder_read(struct istream_private *stream)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen{
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen struct base64_encoder_istream *bstream =
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen (struct base64_encoder_istream *)stream;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen size_t pre_count, post_count, size;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen int ret;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen do {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen ret = i_stream_read_parent(stream);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (ret <= 0)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return ret;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen size = i_stream_get_data_size(stream->parent);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen } while (size < 4 && !stream->parent->eof);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen /* encode as many lines as fits into destination buffer */
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen pre_count = stream->pos - stream->skip;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen while (i_stream_base64_try_encode_line(bstream)) ;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen post_count = stream->pos - stream->skip;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (pre_count == post_count) {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_assert(stream->buffer_size - stream->pos < 4);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return -2;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen }
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_assert(post_count > pre_count);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return post_count - pre_count;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen}
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainenstatic const struct stat *
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Siraineni_stream_base64_encoder_stat(struct istream_private *stream, bool exact)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen{
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (exact) {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen /* too much trouble to implement until it's actually needed */
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_panic("istream-base64-encoder: "
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen "stat() doesn't support getting exact size");
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen }
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen return i_stream_stat(stream->parent, exact);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen}
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainenstatic void
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Siraineni_stream_base64_encoder_seek(struct istream_private *stream,
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen uoff_t v_offset, bool mark)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen{
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen struct base64_encoder_istream *bstream =
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen (struct base64_encoder_istream *)stream;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen if (v_offset < stream->istream.v_offset) {
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen /* seeking backwards - go back to beginning and seek
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen forward from there. */
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen stream->parent_expected_offset = stream->parent_start_offset;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen stream->skip = stream->pos = 0;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen stream->istream.v_offset = 0;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen bstream->cur_line_len = 0;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_stream_seek(stream->parent, 0);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen }
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_stream_default_seek(stream, v_offset, mark);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen}
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainenstruct istream *
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Siraineni_stream_create_base64_encoder(struct istream *input,
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen unsigned int chars_per_line, bool crlf)
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen{
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen struct base64_encoder_istream *bstream;
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen i_assert(chars_per_line % 4 == 0);
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen
4b7957c5e995f2c1820891d77a292a4886d52a43Timo Sirainen bstream = i_new(struct base64_encoder_istream, 1);
bstream->chars_per_line = chars_per_line;
bstream->crlf = crlf;
bstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
bstream->istream.parent = input;
bstream->istream.read = i_stream_base64_encoder_read;
bstream->istream.stat = i_stream_base64_encoder_stat;
bstream->istream.seek = i_stream_base64_encoder_seek;
bstream->istream.istream.readable_fd = FALSE;
bstream->istream.istream.blocking = input->blocking;
bstream->istream.istream.seekable = input->seekable;
return i_stream_create(&bstream->istream, input,
i_stream_get_fd(input));
}