From 300cee673cd190b12dcb82641f3bab9a43cca6f2 Mon Sep 17 00:00:00 2001
From: Nick Bowler <draconx@gmail.com>
Date: Fri, 4 Jan 2008 16:33:42 -0500
Subject: [PATCH] Move reading of embedded palette header into lbximg_fopen().

---
 src/image.c  | 48 ++++++++++++++++++++++++------------------------
 src/image.h  |  2 +-
 src/lbximg.c | 10 +++++-----
 3 files changed, 30 insertions(+), 30 deletions(-)

diff --git a/src/image.c b/src/image.c
index 6c77ed3..fda9dfc 100644
--- a/src/image.c
+++ b/src/image.c
@@ -40,9 +40,10 @@ struct lbx_image {
 	uint16_t wtf1;
 	uint16_t frames, leadin;
 	uint16_t flags;
+	uint16_t palstart, palcount;
 
 	FILE *f;
-	long foff;
+	long foff, paloff;
 
 	int currentframe;
 	int currentx, currenty;
@@ -95,6 +96,24 @@ struct lbx_image *lbximg_fopen(FILE *f)
 		goto readerr;
 	new->foff += sizeof *new->offsets * (new->frames+1);
 
+	if (new->flags & FLAG_PALETTE) {
+		if (fread(&new->palstart, sizeof new->palstart, 1, f) != 1)
+			goto readerr;
+		if (fread(&new->palcount, sizeof new->palcount, 1, f) != 1)
+			goto readerr;
+
+		new->palstart = letohs(new->palstart);
+		new->palcount = letohs(new->palcount);
+		new->foff    += sizeof new->palstart + sizeof new->palcount;
+		new->paloff   = new->foff;
+
+		if (new->palstart + new->palcount > 256) {
+			lbx_errno = LBX_EFORMAT;
+			free(new);
+			return NULL;
+		}
+	}
+
 	return new;
 readerr:
 	if (feof(f)) {
@@ -303,38 +322,19 @@ int lbximg_loadpalette(FILE *f, struct lbx_colour palette[static 256])
 int
 lbximg_getpalette(struct lbx_image *img, struct lbx_colour palette[static 256])
 {
-	size_t hdrlen = 6*(sizeof img->wtf1)+(img->frames+1)*(sizeof *img->offsets);
 	unsigned int i;
 	size_t rc;
 
-	uint16_t start, count;
 	uint8_t  entry[4];
 
 	/* Do nothing if the image doesn't have embedded palette data. */
 	if (!(img->flags & FLAG_PALETTE))
 		return 0;
 
-	/* Palette data is located right after the header. */
-	if (_lbx_fseek(img->f, &img->foff, hdrlen) == -1)
+	if (_lbx_fseek(img->f, &img->foff, img->paloff) == -1)
 		return -1;
 	
-	/* Palette header */
-	if (fread(&start, sizeof start, 1, img->f) != 1) goto readerr;
-	if (fread(&count, sizeof count, 1, img->f) != 1) goto readerr;
-	start = letohs(start); img->foff += sizeof start;
-	count = letohs(count); img->foff += sizeof count;
-
-	if (start + count > 256) {
-		lbx_errno = LBX_EFORMAT;
-		return -1;
-	}
-
-	if (hdrlen + 2*sizeof start + count*sizeof entry > img->offsets[0]) {
-		lbx_errno = LBX_EFORMAT;
-		return -1;
-	}
-
-	for (i = 0; i < count; i++) {
+	for (i = 0; i < img->palcount; i++) {
 		rc = fread(entry, 1, sizeof entry, img->f);
 		img->foff += rc;
 
@@ -347,7 +347,7 @@ lbximg_getpalette(struct lbx_image *img, struct lbx_colour palette[static 256])
 			return -1;
 		}
 
-		palette[start + i] = (struct lbx_colour){
+		palette[img->palstart + i] = (struct lbx_colour){
 			.red   = entry[1] << 2,
 			.green = entry[2] << 2,
 			.blue  = entry[3] << 2,
@@ -366,7 +366,7 @@ void lbximg_getinfo(struct lbx_image *img, struct lbx_imginfo *info)
 		.width      = img->width,
 		.height     = img->height,
 		.nframes    = img->frames,
-		.haspalette = (_Bool)(img->flags & FLAG_PALETTE),
+		.palettesz  = (img->flags & FLAG_PALETTE) ? img->palcount : 0,
 	};
 
 	/* There seems to be two ways of specifying that an image loops. */
diff --git a/src/image.h b/src/image.h
index 3ef95ab..7f70b43 100644
--- a/src/image.h
+++ b/src/image.h
@@ -14,7 +14,7 @@ struct lbx_colour {
 struct lbx_imginfo {
 	unsigned int width, height;
 	unsigned int nframes, loopstart;
-	int haspalette;
+	int palettesz;
 	int looping;
 };
 
diff --git a/src/lbximg.c b/src/lbximg.c
index 730c0af..921d42b 100644
--- a/src/lbximg.c
+++ b/src/lbximg.c
@@ -224,7 +224,7 @@ static int loadoverride(FILE *f, struct lbx_colour palette[static 256])
 	}
 	lbximg_getinfo(overimg, &info);
 
-	if (!info.haspalette) {
+	if (!info.palettesz) {
 		errmsg("override image has no palette.\n", 0);
 		lbximg_close(overimg);
 		return -1;
@@ -256,7 +256,7 @@ static int loadpalette(LBX_IMG *img, struct lbx_imginfo *info,
 	}
 
 	/* For sanity. */
-	if (!palf && !info->haspalette && !override) {
+	if (!palf && !info->palettesz && !override) {
 		errmsg("no palette available.\n", 0);
 		return -1;
 	}
@@ -273,7 +273,7 @@ static int loadpalette(LBX_IMG *img, struct lbx_imginfo *info,
 	}
 
 	/* Read the embedded palette, if any. */
-	if (info->haspalette && lbximg_getpalette(img, palette) == -1) {
+	if (info->palettesz && lbximg_getpalette(img, palette) == -1) {
 		errmsg("error reading embedded palette: %s\n", lbx_strerror());
 		return -1;
 	}
@@ -433,8 +433,8 @@ int main(int argc, char **argv)
 
 		printf("%s is %ux%u LBX image, %u frame(s)%s%s\n",
 		       name, info.width, info.height, info.nframes,
-		       info.haspalette ? ", embedded palette" : "",
-		       info.looping    ? ", loops" : "");
+		       info.palettesz ? ", embedded palette" : "",
+		       info.looping   ? ", loops" : "");
 	}
 
 	switch (mode) {
-- 
2.43.2