X-Git-Url: http://git.draconx.ca/gitweb/liblbx.git/blobdiff_plain/2ec44cef64979d8e19eb66206c26a7bcad4bef8a..430be3ec2f86aec28fa21558b3141a2e28efd848:/src/image.c

diff --git a/src/image.c b/src/image.c
index b30f165..0caca96 100644
--- a/src/image.c
+++ b/src/image.c
@@ -39,6 +39,14 @@
 
 #define HDR_LEN 12
 
+/* States for image readout */
+enum {
+	READ_STATE_INIT,
+	READ_STATE_HEADER,
+	READ_STATE_DATA,
+	READ_STATE_DONE,
+};
+
 struct lbx_image_priv {
 	struct lbx_image pub;
 
@@ -52,8 +60,11 @@ struct lbx_image_priv {
 
 	long paloff;
 
+	/* State of frame readout */
+	unsigned currentx, currenty, currentn;
+	int read_state;
+
 	int currentframe;
-	int currentx, currenty;
 	unsigned char **framedata;
 	unsigned char **mask;
 
@@ -204,66 +215,26 @@ struct lbx_image *lbx_img_fopen(const char *file)
 
 static int _lbx_drawrow(struct lbx_image_priv *img)
 {
-	unsigned short length, offset;
-	unsigned char buf[4];
 	unsigned char *pos;
-	size_t rc;
+	unsigned x, y;
+	long rc;
 
 	assert(img->framedata);
 	assert(img->mask);
 
-	if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf)
-		goto readerr;
-
-	length = unpack_16_le(buf+0);
-	offset = unpack_16_le(buf+2);
-	if (length == 0 && offset == 1000)
+	rc = lbx_img_read_row_header(&img->pub, &x, &y);
+	if (rc == 0)
 		return 1;
-
-	/* Length of 0 increments Y position */
-	if (!length) {
-		if (offset > img->pub.height - img->currenty) {
-			lbx_error_raise(LBX_EFORMAT);
-			return -1;
-		}
-
-		img->currenty += offset;
-		img->currentx  = 0;
-		return 0;
-	}
-
-	/* Otherwise we read pixel data */
-	if (offset > img->pub.width - img->currentx) {
-		lbx_error_raise(LBX_EFORMAT);
+	else if (rc < 0)
 		return -1;
-	}
-	img->currentx += offset;
 
-	if (length > img->pub.width - img->currentx) {
-		lbx_error_raise(LBX_EFORMAT);
+	pos = &img->framedata[y][x];
+	rc = lbx_img_read_row_data(&img->pub, pos);
+	if (rc < 0)
 		return -1;
-	}
-
-	memset(&img->mask[img->currenty][img->currentx], 1, length);
-
-	pos = &img->framedata[img->currenty][img->currentx];
-	rc  = img->fops->read(pos, length, img->f);
-	img->currentx += rc;
-
-	if (rc < length)
-		goto readerr;
-
-	/* Skip padding byte, if any */
-	if (length % 2) {
-		if (img->fops->read(buf, 1, img->f) != 1)
-			goto readerr;
-	}
+	memset(&img->mask[y][x], 1, rc);
 
 	return 0;
-readerr:
-	if (img->fops->eof(img->f))
-		lbx_error_raise(LBX_EEOF);
-	return -1;
 }
 
 static unsigned char **allocframebuffer(size_t width, size_t height)
@@ -300,15 +271,154 @@ static unsigned char **allocframebuffer(size_t width, size_t height)
 	return new;
 }
 
+int lbx_img_seek(struct lbx_image *pub, unsigned frame)
+{
+	struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
+
+	if (frame >= pub->frames) {
+		lbx_error_raise(LBX_EINVAL);
+		return -1;
+	}
+
+	if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
+		return -1;
+	}
+
+	if (!(img->flags & FLAG_RAW)) {
+		unsigned char buf[4];
+
+		/* Read frame header */
+		if (img->fops->read(buf, 4, img->f) != 4) {
+			if (img->fops->eof(img->f))
+				lbx_error_raise(LBX_EEOF);
+			return -1;
+		}
+
+		if (unpack_16_le(buf) != 1) {
+			lbx_error_raise(LBX_EFORMAT);
+			return -1;
+		}
+
+		img->currentx = 0;
+		img->currenty = unpack_16_le(buf+2);
+		if (img->currenty > img->pub.height) {
+			lbx_error_raise(LBX_EFORMAT);
+			return -1;
+		}
+	}
+
+	img->read_state = READ_STATE_HEADER;
+	return 0;
+}
+
+long lbx_img_read_row_header(struct lbx_image *pub, unsigned *x, unsigned *y)
+{
+	struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
+	unsigned short length, offset;
+	unsigned char buf[4];
+
+	if (img->read_state != READ_STATE_HEADER) {
+		lbx_error_raise(LBX_EINVAL);
+		return -1;
+	}
+
+	/* Raw images have no row headers */
+	if (img->flags & FLAG_RAW) {
+		img->currentn = img->pub.width;
+		*y = img->currenty++;
+		*x = 0;
+
+		if (*y < img->pub.height) {
+			img->read_state = READ_STATE_DATA;
+			return img->currentn;
+		} else {
+			img->read_state = READ_STATE_DONE;
+			return 0;
+		}
+	}
+
+	do {
+		if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf) {
+			if (img->fops->eof(img->f))
+				lbx_error_raise(LBX_EEOF);
+			return -1;
+		}
+
+		length = unpack_16_le(buf+0);
+		offset = unpack_16_le(buf+2);
+
+		if (length == 0) {
+			if (offset == 1000) {
+				img->read_state = READ_STATE_DONE;
+				return 0;
+			} else if (offset > img->pub.height - img->currenty) {
+				lbx_error_raise(LBX_EFORMAT);
+				return -1;
+			}
+
+			img->currenty += offset;
+			img->currentx  = 0;
+		}
+	} while (length == 0);
+
+	if (offset > img->pub.width - img->currentx) {
+		lbx_error_raise(LBX_EFORMAT);
+		return -1;
+	}
+	img->currentx += offset;
+
+	if (length > img->pub.width - img->currentx) {
+		lbx_error_raise(LBX_EFORMAT);
+		return -1;
+	}
+	img->currentn = length;
+
+	img->read_state = READ_STATE_DATA;
+	*x = img->currentx;
+	*y = img->currenty;
+
+	return img->currentn;
+}
+
+long lbx_img_read_row_data(struct lbx_image *pub, void *buf)
+{
+	struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
+
+	if (img->read_state != READ_STATE_DATA) {
+		lbx_error_raise(LBX_EINVAL);
+		return -1;
+	}
+
+	if (img->fops->read(buf, img->currentn, img->f) != img->currentn) {
+		if (img->fops->eof(img->f))
+			lbx_error_raise(LBX_EEOF);
+		return -1;
+	}
+
+	if (!(img->flags & FLAG_RAW)) {
+		/* Skip padding byte, if any */
+		if (img->currentn % 2) {
+			if (img->fops->seek(img->f, 1, SEEK_CUR))
+				return -1;
+		}
+	}
+
+	img->read_state = READ_STATE_HEADER;
+	img->currentx += img->currentn;
+
+	return img->currentn;
+}
+
 static unsigned char **read_raw_frame(struct lbx_image_priv *img, int frame)
 {
 	unsigned long size = img->pub.width * img->pub.height;
+	int rc;
 
 	assert(img->flags & FLAG_RAW);
 
-	if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
+	rc = lbx_img_seek(&img->pub, frame);
+	if (rc < 0)
 		return NULL;
-	}
 
 	if (img->fops->read(img->framedata[0], size, img->f) != size) {
 		if (img->fops->eof(img->f))
@@ -373,28 +483,9 @@ unsigned char **lbx_img_getframe(struct lbx_image *pub, int frame)
 	if (img->currentframe != frame) {
 		int rc;
 
-		if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
-			return NULL;
-		}
-
-		/* Read frame header */
-		if (img->fops->read(buf, 4, img->f) != 4) {
-			if (img->fops->eof(img->f))
-				lbx_error_raise(LBX_EEOF);
-			return NULL;
-		}
-
-		if (unpack_16_le(buf) != 1) {
-			lbx_error_raise(LBX_EFORMAT);
-			return NULL;
-		}
-
-		img->currentx = 0;
-		img->currenty = unpack_16_le(buf+2);
-		if (img->currenty > img->pub.height) {
-			lbx_error_raise(LBX_EFORMAT);
+		rc = lbx_img_seek(pub, frame);
+		if (rc < 0)
 			return NULL;
-		}
 
 		do {
 			rc = _lbx_drawrow(img);