Hi,
This patch add a new module bufio, which reads block of data at a
time, and return the required range to the upper level. This is
extremely useful in modules like png, where data are normally read one
byte at a time.
To use buffered io service, just include header file <grub/bufio.h>,
and replace grub_file_open with grub_buffile_open.
Changelog:
2008-07-27 Bean <[EMAIL PROTECTED]>
* conf/common.rmk (pkglib_MODULES): Add bufio.mod.
(bufio_mod_SOURCES): New macro.
(bufio_mod_CFLAGS): Likewise.
(bufio_mod_LDFLAGS): Likewise.
* include/grub/bufio.h: New file.
* io/bufio.c: Likewise.
* video/png.c (grub_video_reader_png): Use grub_buffile_open to open
file.
* video/jpeg.c (grub_video_reader_jpeg): Likewise.
* video/tga.c (grub_video_reader_tga): Likewise.
--
Bean
diff --git a/conf/common.rmk b/conf/common.rmk
index 7db0b2a..3d3cd8a 100644
--- a/conf/common.rmk
+++ b/conf/common.rmk
@@ -382,7 +382,7 @@ crc_mod_CFLAGS = $(COMMON_CFLAGS)
crc_mod_LDFLAGS = $(COMMON_LDFLAGS)
# Misc.
-pkglib_MODULES += gzio.mod elf.mod
+pkglib_MODULES += gzio.mod bufio.mod elf.mod
# For elf.mod.
elf_mod_SOURCES = kern/elf.c
@@ -393,3 +393,8 @@ elf_mod_LDFLAGS = $(COMMON_LDFLAGS)
gzio_mod_SOURCES = io/gzio.c
gzio_mod_CFLAGS = $(COMMON_CFLAGS)
gzio_mod_LDFLAGS = $(COMMON_LDFLAGS)
+
+# For bufio.mod.
+bufio_mod_SOURCES = io/bufio.c
+bufio_mod_CFLAGS = $(COMMON_CFLAGS)
+bufio_mod_LDFLAGS = $(COMMON_LDFLAGS)
diff --git a/include/grub/bufio.h b/include/grub/bufio.h
new file mode 100644
index 0000000..5ca54dd
--- /dev/null
+++ b/include/grub/bufio.h
@@ -0,0 +1,28 @@
+/* bufio.h - prototypes for bufio */
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2008 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GRUB_BUFIO_H
+#define GRUB_BUFIO_H 1
+
+#include <grub/file.h>
+
+grub_file_t grub_bufio_open (grub_file_t io);
+grub_file_t grub_buffile_open (const char *name);
+
+#endif /* ! GRUB_BUFIO_H */
diff --git a/io/bufio.c b/io/bufio.c
new file mode 100644
index 0000000..34034b0
--- /dev/null
+++ b/io/bufio.c
@@ -0,0 +1,172 @@
+/* bufio.c - buffered io access */
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2008 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/err.h>
+#include <grub/types.h>
+#include <grub/mm.h>
+#include <grub/misc.h>
+#include <grub/fs.h>
+#include <grub/bufio.h>
+
+#define GRUB_BUFIO_BUFSIZE 8192
+
+struct grub_bufio
+{
+ grub_file_t file;
+ char buffer[GRUB_BUFIO_BUFSIZE];
+ grub_size_t length;
+};
+typedef struct grub_bufio *grub_bufio_t;
+
+static struct grub_fs grub_bufio_fs;
+
+grub_file_t
+grub_bufio_open (grub_file_t io)
+{
+ grub_file_t file;
+ grub_bufio_t bufio = 0;
+
+ file = (grub_file_t) grub_malloc (sizeof (*file));
+ if (! file)
+ return 0;
+
+ bufio = grub_malloc (sizeof (*bufio));
+ if (! bufio)
+ {
+ grub_free (file);
+ return 0;
+ }
+
+ grub_memset (bufio, 0, sizeof (*bufio));
+ bufio->file = io;
+ bufio->length = 1;
+
+ file->device = io->device;
+ file->offset = 0;
+ file->size = io->size;
+ file->data = bufio;
+ file->read_hook = 0;
+ file->fs = &grub_bufio_fs;
+
+ return file;
+}
+
+grub_file_t
+grub_buffile_open (const char *name)
+{
+ grub_file_t io, file;
+
+ io = grub_file_open (name);
+ if (! io)
+ return 0;
+
+ file = grub_bufio_open (io);
+ if (! file)
+ {
+ grub_file_close (io);
+ return 0;
+ }
+
+ return file;
+}
+
+static grub_ssize_t
+grub_bufio_read (grub_file_t file, char *buf, grub_size_t len)
+{
+ grub_size_t res = len;
+ grub_bufio_t bufio = file->data;
+ grub_size_t pos = file->offset & (GRUB_BUFIO_BUFSIZE - 1);
+
+ if (bufio->file->offset - bufio->length == file->offset - pos)
+ {
+ grub_size_t n;
+
+ n = bufio->length - pos;
+ if (n < len)
+ n = len;
+
+ grub_memcpy (buf, &bufio->buffer[pos], n);
+ len -= n;
+
+ if (! len)
+ return res;
+
+ buf += n;
+ pos = 0;
+ }
+ else
+ bufio->file->offset = file->offset - pos;
+
+ while (pos + len >= GRUB_BUFIO_BUFSIZE)
+ {
+ grub_size_t n;
+
+ n = GRUB_BUFIO_BUFSIZE - pos;
+ bufio->file->offset += pos;
+ bufio->file->fs->read (bufio->file, buf, n);
+ if (grub_errno)
+ return -1;
+
+ buf += n;
+ len -= n;
+ pos = 0;
+ }
+
+ if (! len)
+ {
+ bufio->length = 1;
+ return res;
+ }
+
+ bufio->length = bufio->file->size - bufio->file->offset;
+ if (bufio->length > GRUB_BUFIO_BUFSIZE)
+ bufio->length = GRUB_BUFIO_BUFSIZE;
+
+ bufio->file->fs->read (bufio->file, bufio->buffer, bufio->length);
+ if (grub_errno)
+ return -1;
+
+ grub_memcpy (buf, &bufio->buffer[pos], len);
+
+ return res;
+}
+
+static grub_err_t
+grub_bufio_close (grub_file_t file)
+{
+ grub_bufio_t bufio = file->data;
+
+ grub_file_close (bufio->file);
+ grub_free (bufio);
+
+ file->device = 0;
+
+ return grub_errno;
+}
+
+static struct grub_fs grub_bufio_fs =
+ {
+ .name = "bufio",
+ .dir = 0,
+ .open = 0,
+ .read = grub_bufio_read,
+ .close = grub_bufio_close,
+ .label = 0,
+ .next = 0
+ };
diff --git a/video/readers/jpeg.c b/video/readers/jpeg.c
index 8a4f803..bec084e 100644
--- a/video/readers/jpeg.c
+++ b/video/readers/jpeg.c
@@ -23,7 +23,7 @@
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/arg.h>
-#include <grub/file.h>
+#include <grub/bufio.h>
/* Uncomment following define to enable JPEG debug. */
//#define JPEG_DEBUG
@@ -664,7 +664,7 @@ grub_video_reader_jpeg (struct grub_video_bitmap **bitmap,
grub_file_t file;
struct grub_jpeg_data *data;
- file = grub_file_open (filename);
+ file = grub_buffile_open (filename);
if (!file)
return grub_errno;
diff --git a/video/readers/png.c b/video/readers/png.c
index 9dac4b6..ce38f9f 100644
--- a/video/readers/png.c
+++ b/video/readers/png.c
@@ -23,7 +23,7 @@
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/arg.h>
-#include <grub/file.h>
+#include <grub/bufio.h>
/* Uncomment following define to enable PNG debug. */
//#define PNG_DEBUG
@@ -840,7 +840,7 @@ grub_video_reader_png (struct grub_video_bitmap **bitmap,
grub_file_t file;
struct grub_png_data *data;
- file = grub_file_open (filename);
+ file = grub_buffile_open (filename);
if (!file)
return grub_errno;
diff --git a/video/readers/tga.c b/video/readers/tga.c
index 7b944b0..0fe785f 100644
--- a/video/readers/tga.c
+++ b/video/readers/tga.c
@@ -23,7 +23,7 @@
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/arg.h>
-#include <grub/file.h>
+#include <grub/bufio.h>
/* Uncomment following define to enable TGA debug. */
//#define TGA_DEBUG
@@ -319,7 +319,7 @@ grub_video_reader_tga (struct grub_video_bitmap **bitmap,
struct grub_tga_header header;
int has_alpha;
- file = grub_file_open (filename);
+ file = grub_buffile_open (filename);
if (! file)
return grub_errno;
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