Index: uspace/lib/libc/generic/io/io.c =================================================================== --- uspace/lib/libc/generic/io/io.c (revision a000878c0dee83a08f032207ffd800c201fca95b) +++ uspace/lib/libc/generic/io/io.c (revision 39e8406404efea86e341847c0720d5d65bed7959) @@ -46,4 +46,5 @@ #include +static void _ffillbuf(FILE *stream); static void _fflushbuf(FILE *stream); @@ -57,5 +58,7 @@ .buf = NULL, .buf_size = 0, - .buf_head = NULL + .buf_head = NULL, + .buf_tail = NULL, + .buf_state = _bs_empty }; @@ -69,5 +72,7 @@ .buf = NULL, .buf_size = BUFSIZ, - .buf_head = NULL + .buf_head = NULL, + .buf_tail = NULL, + .buf_state = _bs_empty }; @@ -81,5 +86,7 @@ .buf = NULL, .buf_size = 0, - .buf_head = NULL + .buf_head = NULL, + .buf_tail = NULL, + .buf_state = _bs_empty }; @@ -179,4 +186,6 @@ stream->buf_size = size; stream->buf_head = stream->buf; + stream->buf_tail = stream->buf; + stream->buf_state = _bs_empty; } @@ -210,4 +219,5 @@ stream->buf_head = stream->buf; + stream->buf_tail = stream->buf; return 0; } @@ -243,4 +253,5 @@ stream->klog = false; stream->phone = -1; + stream->need_sync = false; _setvbuf(stream); @@ -264,4 +275,5 @@ stream->klog = false; stream->phone = -1; + stream->need_sync = false; _setvbuf(stream); @@ -295,4 +307,5 @@ stream->klog = false; stream->phone = -1; + stream->need_sync = false; _setvbuf(stream); @@ -331,5 +344,5 @@ } -/** Read from a stream. +/** Read from a stream (unbuffered). * * @param buf Destination buffer. @@ -337,7 +350,6 @@ * @param nmemb Number of records to read. * @param stream Pointer to the stream. - * - */ -size_t fread(void *buf, size_t size, size_t nmemb, FILE *stream) + */ +static size_t _fread(void *buf, size_t size, size_t nmemb, FILE *stream) { size_t left, done; @@ -345,7 +357,4 @@ if (size == 0 || nmemb == 0) return 0; - - /* Make sure no data is pending write. */ - _fflushbuf(stream); left = size * nmemb; @@ -368,4 +377,11 @@ } +/** Write to a stream (unbuffered). + * + * @param buf Source buffer. + * @param size Size of each record. + * @param nmemb Number of records to write. + * @param stream Pointer to the stream. + */ static size_t _fwrite(const void *buf, size_t size, size_t nmemb, FILE *stream) { @@ -394,23 +410,125 @@ } } + + if (done > 0) + stream->need_sync = true; return (done / size); } -/** Drain stream buffer, do not sync stream. */ +/** Read some data in stream buffer. */ +static void _ffillbuf(FILE *stream) +{ + ssize_t rc; + + stream->buf_head = stream->buf_tail = stream->buf; + + rc = read(stream->fd, stream->buf, stream->buf_size); + if (rc < 0) { + stream->error = true; + return; + } + + if (rc == 0) { + stream->eof = true; + return; + } + + stream->buf_head += rc; + stream->buf_state = _bs_read; +} + +/** Write out stream buffer, do not sync stream. */ static void _fflushbuf(FILE *stream) { size_t bytes_used; - + if ((!stream->buf) || (stream->btype == _IONBF) || (stream->error)) return; - - bytes_used = stream->buf_head - stream->buf; + + bytes_used = stream->buf_head - stream->buf_tail; if (bytes_used == 0) return; - - (void) _fwrite(stream->buf, 1, bytes_used, stream); + + /* If buffer has prefetched read data, we need to seek back. */ + if (stream->buf_state == _bs_read) + lseek(stream->fd, - (ssize_t) bytes_used, SEEK_CUR); + + /* If buffer has unwritten data, we need to write them out. */ + if (stream->buf_state == _bs_write) + (void) _fwrite(stream->buf_tail, 1, bytes_used, stream); + stream->buf_head = stream->buf; -} + stream->buf_tail = stream->buf; + stream->buf_state = _bs_empty; +} + +/** Read from a stream. + * + * @param dest Destination buffer. + * @param size Size of each record. + * @param nmemb Number of records to read. + * @param stream Pointer to the stream. + * + */ +size_t fread(void *dest, size_t size, size_t nmemb, FILE *stream) +{ + uint8_t *dp; + size_t bytes_left; + size_t now; + size_t data_avail; + size_t total_read; + size_t i; + + if (size == 0 || nmemb == 0) + return 0; + + /* If not buffered stream, read in directly. */ + if (stream->btype == _IONBF) { + now = _fread(dest, size, nmemb, stream); + return now; + } + + /* Make sure no data is pending write. */ + if (stream->buf_state == _bs_write) + _fflushbuf(stream); + + /* Perform lazy allocation of stream buffer. */ + if (stream->buf == NULL) { + if (_fallocbuf(stream) != 0) + return 0; /* Errno set by _fallocbuf(). */ + } + + bytes_left = size * nmemb; + total_read = 0; + dp = (uint8_t *) dest; + + while ((!stream->error) && (!stream->eof) && (bytes_left > 0)) { + if (stream->buf_head == stream->buf_tail) + _ffillbuf(stream); + + if (stream->error || stream->eof) + break; + + data_avail = stream->buf_head - stream->buf_tail; + + if (bytes_left > data_avail) + now = data_avail; + else + now = bytes_left; + + for (i = 0; i < now; i++) { + dp[i] = stream->buf_tail[i]; + } + + dp += now; + stream->buf_tail += now; + bytes_left -= now; + total_read += now; + } + + return (total_read / size); +} + /** Write to a stream. @@ -442,5 +560,10 @@ return now; } - + + /* Make sure buffer contains no prefetched data. */ + if (stream->buf_state == _bs_read) + _fflushbuf(stream); + + /* Perform lazy allocation of stream buffer. */ if (stream->buf == NULL) { @@ -482,4 +605,7 @@ } + if (total_written > 0) + stream->buf_state = _bs_write; + if (need_flush) fflush(stream); @@ -570,12 +696,15 @@ int fseek(FILE *stream, off64_t offset, int whence) { - off64_t rc = lseek(stream->fd, offset, whence); + off64_t rc; + + _fflushbuf(stream); + + rc = lseek(stream->fd, offset, whence); if (rc == (off64_t) (-1)) { /* errno has been set by lseek64. */ return -1; } - + stream->eof = false; - return 0; } @@ -600,6 +729,12 @@ } - if (stream->fd >= 0) + if (stream->fd >= 0 && stream->need_sync) { + /** + * Better than syncing always, but probably still not the + * right thing to do. + */ + stream->need_sync = false; return fsync(stream->fd); + } return ENOENT; Index: uspace/lib/libc/include/stdio.h =================================================================== --- uspace/lib/libc/include/stdio.h (revision a000878c0dee83a08f032207ffd800c201fca95b) +++ uspace/lib/libc/include/stdio.h (revision 39e8406404efea86e341847c0720d5d65bed7959) @@ -75,4 +75,15 @@ }; +enum _buffer_state { + /** Buffer is empty */ + _bs_empty, + + /** Buffer contains data to be written */ + _bs_write, + + /** Buffer contains prefetched data for reading */ + _bs_read +}; + typedef struct { /** Linked list pointer. */ @@ -94,12 +105,27 @@ int phone; + /** + * Non-zero if the stream needs sync on fflush(). XXX change + * console semantics so that sync is not needed. + */ + int need_sync; + /** Buffering type */ enum _buffer_type btype; + /** Buffer */ uint8_t *buf; + /** Buffer size */ size_t buf_size; + + /** Buffer state */ + enum _buffer_state buf_state; + /** Buffer I/O pointer */ uint8_t *buf_head; + + /** Points to end of occupied space when in read mode. */ + uint8_t *buf_tail; } FILE;