istream-lf: Cleanup & performance improvement.

memchr() is faster than lopping through the data ourself.

diff --git a/src/lib/istream-crlf.c b/src/lib/istream-crlf.c
index 3cd113c1d2219559d078f2bda704bfd12b00f8ef..e74bbba7231d84e94e01d34017b1360cd4f2d9c7 100644 (file)
--- a/src/lib/istream-crlf.c
+++ b/src/lib/istream-crlf.c
@@ -114,10 +114,10 @@ static ssize_t i_stream_crlf_read_crlf(struct istream_private *stream)
 static ssize_t i_stream_crlf_read_lf(struct istream_private *stream)
 {
        struct crlf_istream *cstream = (struct crlf_istream *)stream;
-       const unsigned char *data;
-       size_t i, dest, size;
+       const unsigned char *data, *p;
+       size_t i, dest, size, max;
        ssize_t ret;
-       int diff;
+       bool pending_cr;
 
        ret = i_stream_crlf_read_common(cstream);
        if (ret <= 0)
@@ -126,40 +126,44 @@ static ssize_t i_stream_crlf_read_lf(struct istream_private *stream)
        data = i_stream_get_data(stream->parent, &size);
 
        /* @UNSAFE */
+       /* \r\n -> \n
+          \r<anything> -> \r<anything>
+          \r\r\n -> \r\n */
        dest = stream->pos;
-       if (data[0] == '\n') {
-               stream->w_buffer[dest++] = '\n';
-               cstream->pending_cr = FALSE;
-       } else {
-               if (cstream->pending_cr) {
-                       /* CR without LF */
-                       stream->w_buffer[dest++] = '\r';
-                       if (dest == stream->buffer_size) {
-                               stream->pos++;
-                               cstream->pending_cr = FALSE;
-                               return 1;
-                       }
-               }
-               if (data[0] != '\r')
-                       stream->w_buffer[dest++] = data[0];
-       }
-
-       diff = 1;
-       for (i = 1; i < size && dest < stream->buffer_size; i++) {
+       pending_cr = cstream->pending_cr;
+       for (i = 0; i < size && dest < stream->buffer_size; ) {
                if (data[i] == '\r') {
-                       if (data[i-1] != '\r')
-                               continue;
-               } else if (data[i-1] == '\r' && data[i] != '\n') {
-                       stream->w_buffer[dest++] = '\r';
-                       if (dest == stream->buffer_size) {
-                               diff = 0;
-                               break;
+                       if (pending_cr) {
+                               /* \r\r */
+                               stream->w_buffer[dest++] = '\r';
+                       } else {
+                               pending_cr = TRUE;
                        }
+                       i++;
+               } else if (data[i] == '\n') {
+                       /* [\r]\n */
+                       pending_cr = FALSE;
+                       stream->w_buffer[dest++] = '\n';
+                       i++;
+               } else if (pending_cr) {
+                       /* \r<anything> */
+                       pending_cr = FALSE;
+                       stream->w_buffer[dest++] = '\r';
+               } else {
+                       /* copy everything until the next \r */
+                       max = I_MIN(size - i, stream->buffer_size - dest);
+                       p = memchr(data + i, '\r', max);
+                       if (p != NULL)
+                               max = p - (data+i);
+                       memcpy(stream->w_buffer + dest, data + i, max);
+                       dest += max;
+                       i += max;
                }
-
-               stream->w_buffer[dest++] = data[i];
        }
-       cstream->pending_cr = data[i-diff] == '\r';
+       i_assert(i <= size);
+       i_assert(dest <= stream->buffer_size);
+
+       cstream->pending_cr = pending_cr;
        i_stream_skip(stream->parent, i);
 
        ret = dest - stream->pos;