bootsplash: Added support for 16/24/32bpp in one function

Specifically added support for 16 and 32bpp files, in addition to
24bpp.  The function bmp_show() in bmp.c has had the hardcoded check
for 24bpp replaced with a general bpp check that uses a % to check for
remainder, and returns 1 if the remainder is >0.  The previous method
for adjusting the BMP data (raw_data_format_adjust_24bpp) relied on a
preset 3*bytes_per_line_src, this has been changed and the
multiplication is now performed in the function's arguments. This
change still allows someone else to reuse the same function for
1/2/4bpp support if necessary. The file util.h has been modified to
reflect this decision.

The changes to raw_data_format_adjust() is based on an abandoned patch
by Gert Menke (submitted March 14, 2017), credit to them for that
change and the addition of *bpp to bmp_get_info().

Signed-off-by: Joseph S. Pacheco-Corwin <hammersamatom@gmail.com>

3 files changed, 13 insertions, 14 deletions

diff --git a/src/bmp.c b/src/bmp.c
index 96a2b3f2..fecc2953 100644
--- a/src/bmp.c
+++ b/src/bmp.c
@@ -56,10 +56,9 @@ typedef struct tagRGBQUAD {
 *   arrange horizontal pixel data, add extra space in the dest buffer
 *       for every line
 */
-static void raw_data_format_adjust_24bpp(u8 *src, u8 *dest, int width,
-                                        int height, int bytes_per_line_dest)
+static void raw_data_format_adjust(u8 *src, u8 *dest, int width,
+		int height, int bytes_per_line_src, int bytes_per_line_dest)
 {
-    int bytes_per_line_src = 3 * width;
     int i;
     for (i = 0 ; i < height ; i++) {
         memcpy(dest + i * bytes_per_line_dest,
@@ -95,22 +94,22 @@ int bmp_decode(struct bmp_decdata *bmp, unsigned char *data, int data_size)
 }
 
 /* get bmp properties */
-void bmp_get_size(struct bmp_decdata *bmp, int *width, int *height)
+void bmp_get_info(struct bmp_decdata *bmp, int *width, int *height, int *bpp)
 {
     *width = bmp->width;
     *height = bmp->height;
+    *bpp = bmp->bpp;
 }
 
 /* flush flat picture data to *pc */
-int bmp_show(struct bmp_decdata *bmp, unsigned char *pic, int width
-             , int height, int depth, int bytes_per_line_dest)
+int bmp_show(struct bmp_decdata *bmp, unsigned char *pic, int width,
+             int height, int depth, int bytes_per_line_dest)
 {
     if (bmp->datap == pic)
         return 0;
-    /* now only support 24bpp bmp file */
-    if ((depth == 24) && (bmp->bpp == 24)) {
-        raw_data_format_adjust_24bpp(bmp->datap, pic, width, height,
-                                        bytes_per_line_dest);
+    if ((depth == bmp->bpp) && (bmp->bpp%8 == 0)) {
+        raw_data_format_adjust(bmp->datap, pic, width, height,
+			(bmp->bpp/8)*width, bytes_per_line_dest);
         return 0;
     }
     return 1;
diff --git a/src/bootsplash.c b/src/bootsplash.c
index 165c98d0..538b316d 100644
--- a/src/bootsplash.c
+++ b/src/bootsplash.c
@@ -172,10 +172,10 @@ enable_bootsplash(void)
             dprintf(1, "bmp_decode failed with return code %d...\n", ret);
             goto done;
         }
-        bmp_get_size(bmp, &width, &height);
-        bpp_require = 24;
+        bmp_get_info(bmp, &width, &height, &bpp_require);
     }
-    /* jpeg would use 16 or 24 bpp video mode, BMP use 24bpp mode only */
+
+    // jpeg would use 16 or 24 bpp video mode, BMP uses 16/24/32 bpp mode.
 
     // Try to find a graphics mode with the corresponding dimensions.
     int videomode = find_videomode(vesa_info, mode_info, width, height,
diff --git a/src/util.h b/src/util.h
index 6dd080f6..9c068503 100644
--- a/src/util.h
+++ b/src/util.h
@@ -12,7 +12,7 @@ void handle_1553(struct bregs *regs);
 // bmp.c
 struct bmp_decdata *bmp_alloc(void);
 int bmp_decode(struct bmp_decdata *bmp, unsigned char *data, int data_size);
-void bmp_get_size(struct bmp_decdata *bmp, int *width, int *height);
+void bmp_get_info(struct bmp_decdata *bmp, int *width, int *height, int *bpp);
 int bmp_show(struct bmp_decdata *bmp, unsigned char *pic, int width
              , int height, int depth, int bytes_per_line_dest);