1 files changed, 30 insertions, 33 deletions

diff --git a/image-parser.c b/image-parser.c
index cb385cc..b135101 100644
--- a/image-parser.c
+++ b/image-parser.c
@@ -16,24 +16,21 @@
 #include <sys/stat.h>
 #include <sys/mman.h>
 
-#define MAGIC 0xFEEDBABE
-
-struct Header { /* Big Endian */
-	uint32_t magic; /* 0xFEEDBABE */
-	uint32_t len; /* Length of file excluding header */
-	uint32_t checksum; /* 32-bit sum of all bytes in file and header, excluding checksum */
-	uint32_t counter; /* Unknown */
-	uint32_t start_offset; /* Unknown */
-	char name[0x80]; /* File name */
-} __attribute__((packed));
-
+#define RG_MAGIC 0xFEEDBABE
+#define HEADER_SIZE ( sizeof(uint32_t) * 5 + 0x80 )
 struct File {
-	struct Header header;
-	uint8_t *data;
-	uint32_t decompressed_size;
-	uint8_t *decompressed_data;
+	uint32_t magic;			/* FEEDBABE */
+	uint32_t size;			/* Length of file excluding header */
+	uint32_t checksum;		/* 32-bit sum of all bytes in file and header, excluding checksum */
+	uint32_t counter;		/* Unknown */
+	uint32_t start_offset;		/* Unknown */
+	char name[0x80];		/* Filename */
+	uint8_t *data;			/* Pointer to mmap'd or allocated data of file */
+	uint32_t decompressed_size;	/* Decompressed length of file */
+	uint8_t *decompressed_data;	/* Pointer to allocated decompressed data */
 };
 
+
 uint8_t* decompress_data(uint8_t *data, uint32_t compressed_length, uint32_t decompressed_length)
 {
 	uint8_t *decompressed_data;
@@ -81,7 +78,7 @@ uint32_t checksum(uint8_t *data, uint32_t length)
 
 	while (length--) {
 		/* The checksum does not include itself, so we skip that field. */
-		if (length >= offsetof(struct Header, checksum) && length < offsetof(struct Header, counter))
+		if (length >= 8 && length < 12)
 			continue;
 		sum += data[length];
 	}
@@ -91,33 +88,33 @@ uint32_t checksum(uint8_t *data, uint32_t length)
 
 bool read_file(uint8_t *data, struct File *file)
 {
-	memcpy(&file->header, data, sizeof(file->header));
-	file->header.magic = be32toh(file->header.magic);
-	file->header.len = be32toh(file->header.len);
-	file->header.checksum = be32toh(file->header.checksum);
-	file->header.counter = be32toh(file->header.counter);
-	file->header.start_offset = be32toh(file->header.start_offset);
-	file->header.name[0x7f] = '\0';
-
-	file->data = data + sizeof(file->header);
+	uint32_t *packed_integers = (uint32_t *)data;
+	file->magic = be32toh(packed_integers[0]);
+	file->size = be32toh(packed_integers[1]);
+	file->checksum = be32toh(packed_integers[2]);
+	file->counter = be32toh(packed_integers[3]);
+	file->start_offset = be32toh(packed_integers[4]);
+	memcpy(&file->name, &packed_integers[5], sizeof(file->name));
+	file->name[0x7f] = '\0';
+	file->data = data + HEADER_SIZE;
 	file->decompressed_data = NULL;
 	file->decompressed_size = 0;
-	if (!strcmp(file->header.name, "rg_conf")) {	
+	if (!strcmp(file->name, "rg_conf")) {	
 		/* When the file is gzipped, the length of the decompressed file is
 		 * the first four bytes in big endian. */
 		file->decompressed_size = be32toh(*((uint32_t *)file->data));
-		file->decompressed_data = decompress_data(file->data + sizeof(uint32_t), file->header.len - sizeof(uint32_t), file->decompressed_size);
+		file->decompressed_data = decompress_data(file->data + sizeof(uint32_t), file->size - sizeof(uint32_t), file->decompressed_size);
 		if (!file->decompressed_data)
 			file->decompressed_size = 0;
 	}
 
-	return file->header.magic == MAGIC && file->header.checksum == checksum(data, sizeof(file->header) + file->header.len);
+	return file->magic == RG_MAGIC && file->checksum == checksum(data, HEADER_SIZE + file->size);
 }
 
 void print_file(struct File *file, bool valid)
 {
-	printf("==== %s (%s) ====\n", file->header.name, valid ? "Valid Checksum" : "INVALID CHECKSUM");
-	printf("Length: %u bytes\n", file->header.len);
+	printf("==== %s (%s) ====\n", file->name, valid ? "Valid Checksum" : "INVALID CHECKSUM");
+	printf("Length: %u bytes\n", file->size);
 	if (file->decompressed_size)
 		printf("Decompressed Length: %u bytes\n", file->decompressed_size);
 }
@@ -128,7 +125,7 @@ void save_file(struct File *file, bool valid, uint32_t offset)
 	char *slash;
 	int fd;
 	
-	sprintf(filename, "%#.8x-%s%s", offset, file->header.name, valid ? "" : ".corrupt");
+	sprintf(filename, "%#.8x-%s%s", offset, file->name, valid ? "" : ".corrupt");
 	for (slash = filename; (slash = strchr(slash, '/')) != NULL; ++slash)
 		*slash = '_';
 
@@ -145,7 +142,7 @@ void save_file(struct File *file, bool valid, uint32_t offset)
 			exit(EXIT_FAILURE);
 		}
 	} else {
-		if (write(fd, file->data, file->header.len) < 0) {
+		if (write(fd, file->data, file->size) < 0) {
 			perror("write");
 			exit(EXIT_FAILURE);
 		}
@@ -184,7 +181,7 @@ int main(int argc, char *argv[])
 		return EXIT_FAILURE;
 	}
 
-	needle = htobe32(MAGIC);
+	needle = htobe32(RG_MAGIC);
 	next = data;
 	for (;;) {
 		next = memmem(next, sbuf.st_size - (next - data), &needle, sizeof(needle));