Implemented function that correctly acquires TextureBatchDescriptors

src/devil1tex.c

@@ -2,15 +2,6 @@
 #include <stdio.h>
 #include <string.h>
 
-// get texture pack header
-void gettph (struct TexturePack *tp, const char *filedata) {
-// Assume the Texture Pack Header is already allocated memory.
-    if (tp != NULL && filedata != NULL) {
-        memcpy(tp, filedata, sizeof(struct TexturePack));
-    }
-    return;
-}
-
 void printtph (struct TexturePack *tp) {
     if (tp != NULL) { 
         printf("id: \t %c %c %c %c \n", tp -> id[3], 
@@ -24,31 +15,43 @@ void printtph (struct TexturePack *tp) {
     return;
 }
 
+void printtbd(struct TextureBatchDescriptor *bd) {
+    if (bd != NULL) {
+        printf("batch index: \t %i \n", bd -> batchIdx);
+        printf("hash: \t %u \n",        bd -> hash);
+        printf("textures: \t %i\n",     bd -> texNumber);
+    }
+}
+
 // get texture pack descriptors
-void gettbd (struct TextureBatchDescriptor *tbd,
-               struct TexturePack* tph,
-               const char *filedata,
-               unsigned int filesize) {
-    if (tbd == NULL || tph == NULL || filedata == NULL) {
-        // any of these being null will cause segmentation fault.
+void gettbd (struct TextureBatchDescriptor **descriptors,
+             const char *filedata,
+             unsigned int filesize) {
+    if (descriptors == NULL || filedata == NULL || filesize <= 0) {
         return;
     }
-    // do some checks regarding the header
-    if (tph -> firstBatchOffset >= filesize || 
-        tph -> firstBatchOffset <= 0) {
+    struct TexturePack *tp = NULL;
+    tp = (struct TexturePack*)filedata;
+    if (filesize <= (sizeof(struct TextureBatchDescriptor) 
+                    * tp -> batchNumber 
+                    + sizeof(struct TexturePack))){
+        fprintf(stderr, 
+                "File Error: file size to struct sizes ratio.\n");
         return;
     }
-    unsigned int index = tph -> firstBatchOffset;
+    unsigned int index = sizeof(struct TexturePack);
     // Batch Descriptors are structured one after another.
     // therefore the next one is at
     // current index + sizeof(TextureBatchDescriptor)
     unsigned int i = 0;
     do {
-        index += (sizeof(struct TextureBatchDescriptor) * i);
+        index = sizeof(struct TextureBatchDescriptor) * i 
+                + sizeof(struct TexturePack);
         printf("batch descriptor start: %x\n", index);
-        tbd = (struct TextureBatchDescriptor*)(filedata + index);
-        // <do something with the batch descriptor found>
-    } while(i < (tph -> batchNumber));
+        descriptors[i] = (struct TextureBatchDescriptor*)
+                            (filedata + index);
+        i++;
+    } while(i < (tp -> batchNumber));
     return;
 }