liblbx: Add support for "chunked" images.

[liblbx.git] / src / image.c

diff --git a/src/image.c b/src/image.c
index 76fbfed3528ccf2d8561c7ee1bf9502e7d6eef99..5f3a6e320c51f62010d12f24ac8fac28a0d9bd63 100644 (file)
--- a/src/image.c
+++ b/src/image.c
@@ -30,19 +30,20 @@
 #include "lbx.h"
 #include "image.h"
 
+#define FLAG_RAW       0x0100 /* Image is stored as a flat array of bytes. */
 #define FLAG_OVERWRITE 0x0400 /* Draw each frame on a clean slate (unsure). */
 #define FLAG_BUILDING  0x0800 /* Buildings have this, related to shadow? */
 #define FLAG_PALETTE   0x1000 /* Image contains embedded palette. */
 #define FLAG_LOOPING   0x2000 /* Loop over all frames in the image (unsure). */
 
-#define FLAG_ALL (FLAG_OVERWRITE|FLAG_BUILDING|FLAG_PALETTE|FLAG_LOOPING)
+#define FLAG_ALL (FLAG_RAW|FLAG_OVERWRITE|FLAG_BUILDING|FLAG_PALETTE|FLAG_LOOPING)
 
 #define HDR_LEN 12
 
 struct lbx_image {
        unsigned short width, height;
        unsigned short wtf, flags;
-       unsigned short frames, leadin;
+       unsigned char  frames, wtf2, leadin, chunk;
        unsigned short palstart, palcount;
 
        const struct lbx_file_ops *fops;
@@ -74,8 +75,10 @@ static struct lbx_image *lbximg_init(unsigned char hdr[static HDR_LEN])
                .width  = unpack_16_le(hdr+0),
                .height = unpack_16_le(hdr+2),
                .wtf    = unpack_16_le(hdr+4),
-               .frames = unpack_16_le(hdr+6),
-               .leadin = unpack_16_le(hdr+8),
+               .frames = hdr[6],
+               .wtf2   = hdr[7],
+               .leadin = hdr[8],
+               .chunk  = hdr[9],
                .flags  = unpack_16_le(hdr+10),
 
                .currentframe = -1,
@@ -108,11 +111,12 @@ struct lbx_image *lbximg_open(void *f, const struct lbx_file_ops *fops,
        /*
         * DEBUG ONLY.  These assertions exist to catch otherwise valid image
         * files which differ from what I believe to be true of all LBX images.
-        * If we never find any exceptions, we can replace the assertions with
-        * assumptions.
+        * When we can decode every image, then these assertions should be
+        * replaced with constraints.
         */
-       _lbx_assert(img->wtf == 0); /* version? */
-       _lbx_assert(img->frames > img->leadin); /* cmbtshp.lbx breaks this. */
+       _lbx_assert(img->wtf  == 0); /* version? */
+       _lbx_assert(img->wtf2 == 0); /* very likely is simply reserved. */
+       _lbx_assert(img->frames > img->leadin);
        _lbx_assert(!(img->flags & ~FLAG_ALL));
 
        /* Read all offsets.  Should be merged with identical code in lbx.c */
@@ -265,6 +269,33 @@ static unsigned char **allocframebuffer(size_t width, size_t height)
        return new;
 }
 
+static unsigned char **read_raw_frame(struct lbx_image *img, int frame)
+{
+       unsigned long size = img->width * img->height;
+
+       assert(img->flags & FLAG_RAW);
+
+       if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
+               lbx_errno = -errno;
+               return NULL;
+       }
+
+       if (img->fops->read(img->framedata[0], size, img->f) != size) {
+               lbx_errno = -errno;
+               if (img->fops->eof(img->f))
+                       lbx_errno = LBX_EEOF;
+               return NULL;
+       }
+       memset(img->mask[0], 1, size);
+
+       if (img->fops->tell(img->f) > img->offsets[frame+1]) {
+               lbx_errno = LBX_EFORMAT;
+               return NULL;
+       }
+
+       return img->framedata;
+}
+
 unsigned char **lbximg_getframe(struct lbx_image *img, int frame)
 {
        if (frame >= img->frames || frame < 0) {
@@ -284,7 +315,11 @@ unsigned char **lbximg_getframe(struct lbx_image *img, int frame)
                        return NULL;
        }
 
-       if (img->flags & FLAG_OVERWRITE) {
+       if (img->flags & FLAG_RAW)
+               return read_raw_frame(img, frame);
+
+       if ((img->flags & FLAG_OVERWRITE)
+            || (img->chunk && !(frame % img->chunk))) {
                /* Clear the slate. */
                img->currentframe = -1;
                memset(img->framedata[0], 0, img->width * img->height);
@@ -404,6 +439,7 @@ void lbximg_getinfo(struct lbx_image *img, struct lbx_imginfo *info)
                .width      = img->width,
                .height     = img->height,
                .nframes    = img->frames,
+               .chunk      = img->chunk,
                .palettesz  = (img->flags & FLAG_PALETTE) ? img->palcount : 0,
        };