src/lib/istream-crlf.c

	istream-crlf.c revision 42dbeeb3462895b03e7633dbc59e8e191199734b
/* Copyright (c) 2007 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "istream-internal.h"
#include "istream-crlf.h"

struct crlf_istream {
    struct istream_private istream;

    struct istream *input;
    char last_char;
    unsigned int crlf:1;
};

static void i_stream_crlf_destroy(struct iostream_private *stream)
{
    struct crlf_istream *cstream = (struct crlf_istream *)stream;

    i_stream_unref(&cstream->input);
}

static void
i_stream_crlf_set_max_buffer_size(struct iostream_private *stream,
                   size_t max_size)
{
    struct crlf_istream *cstream = (struct crlf_istream *)stream;

    cstream->istream.max_buffer_size = max_size;
    i_stream_set_max_buffer_size(cstream->input, max_size);
}

static ssize_t i_stream_crlf_read(struct istream_private *stream)
{
    struct crlf_istream *cstream = (struct crlf_istream *)stream;
    const unsigned char *data;
    size_t i, dest, size;
    ssize_t ret;

    data = i_stream_get_data(cstream->input, &size);
    if (size == 0) {
        ret = i_stream_read(cstream->input);
        if (ret <= 0 && (ret != -2 || stream->skip == 0)) {
            stream->istream.stream_errno =
                cstream->input->stream_errno;
            stream->istream.eof = cstream->input->eof;
            return ret;
        }
    }

    data = i_stream_get_data(cstream->input, &size);
    i_assert(size != 0);

    if (!i_stream_get_buffer_space(stream, size, NULL))
        return -2;

    /* @UNSAFE */
    dest = stream->pos;
    if (data[0] == '\n')
        i = 0;
    else {
        if (cstream->last_char == '\r') {
            /* CR without LF */
            stream->w_buffer[dest++] = '\r';
            if (dest == stream->buffer_size) {
                cstream->last_char = 0;
                return 1;
            }
        }
        if (data[0] != '\r')
            stream->w_buffer[dest++] = data[0];
        i = 1;
    }
    cstream->last_char = data[size-1];
    for (; i < size && dest < stream->buffer_size; i++) {
        if (data[i] <= '\r') {
            if (data[i] == '\n') {
                if (cstream->crlf) {
                    if (dest + 1 == stream->buffer_size)
                        break;
                    stream->w_buffer[dest++] = '\r';
                }
                stream->w_buffer[dest++] = '\n';
                continue;
            }
            if (data[i] == '\r' && data[i-1] != '\r')
                continue;
        }
        if (data[i-1] == '\r') {
            /* CR without LF */
            stream->w_buffer[dest++] = '\r';
            if (dest == stream->buffer_size) {
                cstream->last_char = 0;
                break;
            }
            if (data[i] == '\r')
                continue;
        }
        stream->w_buffer[dest++] = data[i];
    }
    i_stream_skip(cstream->input, i);

    ret = dest - stream->pos;
    if (ret == 0) {
        i_assert(cstream->last_char == '\r' && size == 1);
        return i_stream_crlf_read(stream);
    }
    stream->pos = dest;
    return ret;
}

static void ATTR_NORETURN
i_stream_crlf_seek(struct istream_private *stream ATTR_UNUSED,
           uoff_t v_offset ATTR_UNUSED, bool mark ATTR_UNUSED)
{
    i_panic("crlf-istream: seeking unsupported currently");
}

static const struct stat *
i_stream_crlf_stat(struct istream_private *stream, bool exact)
{
    struct crlf_istream *cstream = (struct crlf_istream *)stream;

    return i_stream_stat(cstream->input, exact);
}

static struct istream *
i_stream_create_crlf_full(struct istream *input, bool crlf)
{
    struct crlf_istream *cstream;

    i_stream_ref(input);

    cstream = i_new(struct crlf_istream, 1);
    cstream->input = input;
    cstream->crlf = crlf;
    cstream->istream.max_buffer_size = input->real_stream->max_buffer_size;

    cstream->istream.iostream.destroy = i_stream_crlf_destroy;
    cstream->istream.iostream.set_max_buffer_size =
        i_stream_crlf_set_max_buffer_size;

    cstream->istream.read = i_stream_crlf_read;
    cstream->istream.seek = i_stream_crlf_seek;
    cstream->istream.stat = i_stream_crlf_stat;

    cstream->istream.istream.blocking = input->blocking;
    cstream->istream.istream.seekable = input->seekable;
    return i_stream_create(&cstream->istream, i_stream_get_fd(input), 0);
}

struct istream *i_stream_create_crlf(struct istream *input)
{
    return i_stream_create_crlf_full(input, TRUE);
}

struct istream *i_stream_create_lf(struct istream *input)
{
    return i_stream_create_crlf_full(input, FALSE);
}