Add gzip support for cursors

The cursors used by twin compress well, so allow twin_cursor to load a
compressed cursor file when zlib is present. In both cases,
uncomressed cursors still work.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 50 insertions, 10 deletions

diff --git a/configure.ac b/configure.ac
index 6e1c323..dadcd78 100644
--- a/configure.ac
+++ b/configure.ac
@@ -81,6 +81,24 @@ AC_ARG_ENABLE(linux-mouse,
 		[Disable linux mouse support (default=enabled)]),
 	twin_mouse="$enableval", twin_mouse="yes")
 
+# zlib
+AC_ARG_ENABLE(zlib,
+	AC_HELP_STRING([--disable-zlib],
+		[Disable zlib support (default=enabled)]),
+	twin_zlib="$enableval", twin_zlib="yes")
+AH_TEMPLATE(HAVE_ZLIB, [Define if the zlib compression library is available])
+
+if test "x$twin_zlib" = "zlib"
+then
+        AC_CHECK_HEADER(zlib.h, twin_zlib="yes", twin_zlib="no")
+fi
+
+if test "x$twin_zlib" = "xyes"
+then
+	Z_LIBS=-lz
+	AC_DEFINE([HAVE_ZLIB])
+fi
+
 # png support
 AC_ARG_ENABLE(png,
 	AC_HELP_STRING([--disable-png],
@@ -156,13 +174,14 @@ AC_SUBST(ALTIVEC_CFLAGS)
 
 
 # TWIN_DEP_*FLAGS define all flags required by dependencies of libtwin
-TWIN_DEP_LDFLAGS="$X_LIBS $PNG_LIBS $JPEG_LIBS -lm"
+TWIN_DEP_LDFLAGS="$X_LIBS $PNG_LIBS $JPEG_LIBS $Z_LIBS -lm"
 TWIN_DEPCFLAGS="$X_CFLAGS $PNG_CFLAGS"
 AC_SUBST(TWIN_DEP_CFLAGS)
 AC_SUBST(TWIN_DEP_LDFLAGS)
 
 AM_CONDITIONAL(TWIN_X11, test x$twin_x11 = xyes)
 AM_CONDITIONAL(TWIN_FB, test x$twin_fb = xyes)
+AM_CONDITIONAL(TWIN_ZLIB, test x$twin_zlib = xyes)
 AM_CONDITIONAL(TWIN_PNG, test x$twin_png = xyes)
 AM_CONDITIONAL(TWIN_JPEG, test x$twin_jpeg = xyes)
 AM_CONDITIONAL(TWIN_TTF, test x$twin_ttf = xyes)
@@ -170,6 +189,7 @@ AM_CONDITIONAL(TWIN_MOUSE, test x$twin_mouse = xyes)
 
 AC_MSG_NOTICE([x11 support:    $twin_x11])
 AC_MSG_NOTICE([fbdev support:  $twin_fb])
+AC_MSG_NOTICE([zlib support:   $twin_zlib])
 AC_MSG_NOTICE([png support:    $twin_png])
 AC_MSG_NOTICE([jpeg support:   $twin_jpeg])
 AC_MSG_NOTICE([twin_ttf tool:  $twin_ttf])
diff --git a/libtwin/twin_cursor.c b/libtwin/twin_cursor.c
index f0e5fc3..aa7c710 100644
--- a/libtwin/twin_cursor.c
+++ b/libtwin/twin_cursor.c
@@ -19,6 +19,8 @@
  * Boston, MA 02111-1307, USA.
  */
 
+#include <twin_def.h>
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -31,6 +33,23 @@
 #include <byteswap.h>
 #include <endian.h>
 
+#ifdef HAVE_ZLIB
+#include <zlib.h>
+
+#define fdtype gzFile
+#define cursor_open(file) gzopen(file, "rb")
+#define cursor_read gzread
+#define cursor_seek gzseek
+#define cursor_close gzclose
+
+#else
+#define fdtype int
+#define cursor_open(file) open(file, O_RDONLY)
+#define cursor_read read
+#define cursor_seek lseek
+#define cursor_close close
+#endif
+
 #include "twin.h"
 
 /* Make something better here ! */
@@ -138,11 +157,11 @@ twin_pixmap_t *twin_get_default_cursor(int *hx, int *hy)
 #define XCURSOR_IMAGE_HEADER_LEN    (XCURSOR_CHUNK_HEADER_LEN + (5*4))
 #define XCURSOR_IMAGE_MAX_SIZE      0x7fff      /* 32767x32767 max cursor size */
 
-static inline int twin_read_header(int fd, uint32_t *buf, int size)
+static inline int twin_read_header(fdtype fd, uint32_t *buf, int size)
 {
 	int i, len;
 
-	len = read(fd, buf, size);
+	len = cursor_read(fd, buf, size);
 	if (len != size)
 		return 0;
 
@@ -156,11 +175,12 @@ static inline int twin_read_header(int fd, uint32_t *buf, int size)
 twin_pixmap_t *twin_load_X_cursor(const char *file, int index,
 				  int *hx, int *hy)
 {
-	int		fd, img, i, toccnt;
+	fdtype		fd;
+	int		img, i, toccnt;
 	uint32_t	buffer[32], filepos, size;
 	twin_pixmap_t	*cur = NULL;	
 
-	fd = open(file, O_RDONLY);
+	fd = cursor_open(file);
 	if (fd < 0)
 		return NULL;
 	if (!twin_read_header(fd, buffer, XCURSOR_FILE_HEADER_LEN))
@@ -178,7 +198,7 @@ twin_pixmap_t *twin_load_X_cursor(const char *file, int index,
 	toccnt = buffer[3];
 
 	/* seek to first toc entry (header len) */
-	lseek(fd, buffer[1] , SEEK_SET);
+	cursor_seek(fd, buffer[1] , SEEK_SET);
 
 	/* look for the index'th image in TOC */
 	img = 0;
@@ -197,7 +217,7 @@ twin_pixmap_t *twin_load_X_cursor(const char *file, int index,
 		goto bail;
 
 	/* seek to image header and read it */
-	lseek(fd, filepos, SEEK_SET);
+	cursor_seek(fd, filepos, SEEK_SET);
 	if (!twin_read_header(fd, buffer, XCURSOR_IMAGE_HEADER_LEN))
 		goto bail;
 
@@ -220,8 +240,8 @@ twin_pixmap_t *twin_load_X_cursor(const char *file, int index,
 
 	/* load pixels */
 	size = buffer[4] * buffer[5] * 4;
-	lseek(fd, filepos + buffer[0], SEEK_SET);
-	if (read(fd, cur->p.v, size) != size) {
+	cursor_seek(fd, filepos + buffer[0], SEEK_SET);
+	if (cursor_read(fd, cur->p.v, size) != size) {
 		twin_pixmap_destroy(cur);
 		goto bail;
 	}
@@ -232,7 +252,7 @@ twin_pixmap_t *twin_load_X_cursor(const char *file, int index,
 #endif
 
  bail:
-	close(fd);
+	cursor_close(fd);
 	return cur;
 }