src/lib-mail/istream-nonuls.c

/* Copyright (c) 2007-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "istream-private.h"
#include "istream-nonuls.h"

struct nonuls_istream {
    struct istream_private istream;
    char replace_chr;
};

static int i_stream_read_parent(struct istream_private *stream)
{
    ssize_t ret;

    if (i_stream_get_data_size(stream->parent) > 0)
        return 1;

    ret = i_stream_read_memarea(stream->parent);
    if (ret <= 0) {
        stream->istream.stream_errno = stream->parent->stream_errno;
        stream->istream.eof = stream->parent->eof;
        return ret;
    }
    i_assert(i_stream_get_data_size(stream->parent) != 0);
    return 1;
}

static ssize_t i_stream_nonuls_read(struct istream_private *stream)
{
    struct nonuls_istream *nstream = (struct nonuls_istream *)stream;
    const unsigned char *data, *p;
    size_t i, size, avail_size;
    int ret;

    if ((ret = i_stream_read_parent(stream)) <= 0)
        return ret;

    data = i_stream_get_data(stream->parent, &size);
    if (!i_stream_try_alloc(stream, size, &avail_size))
        return -2;
    if (size > avail_size)
        size = avail_size;
    i_assert(size > 0);

    p = memchr(data, '\0', size);
    if (p == NULL) {
        /* no NULs in this block */
        memcpy(stream->w_buffer+stream->pos, data, size);
    } else {
        i = p-data;
        memcpy(stream->w_buffer+stream->pos, data, i);
        for (; i < size; i++) {
            stream->w_buffer[stream->pos+i] = data[i] == '\0' ?
                nstream->replace_chr : data[i];
        }
    }
    stream->pos += size;
    i_stream_skip(stream->parent, size);
    return size;
}

struct istream *i_stream_create_nonuls(struct istream *input, char replace_chr)
{
    struct nonuls_istream *nstream;

    nstream = i_new(struct nonuls_istream, 1);
    nstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
    nstream->istream.stream_size_passthrough = TRUE;

    nstream->istream.read = i_stream_nonuls_read;

    nstream->istream.istream.readable_fd = FALSE;
    nstream->istream.istream.blocking = input->blocking;
    nstream->istream.istream.seekable = FALSE;
    nstream->replace_chr = replace_chr;
    return i_stream_create(&nstream->istream, input,
                   i_stream_get_fd(input), 0);
}