1#ifndef DELTA_H 2#define DELTA_H 3 4/* handling of delta buffers */ 5extern void *diff_delta(void *from_buf, unsigned long from_size, 6 void *to_buf, unsigned long to_size, 7 unsigned long *delta_size, unsigned long max_size); 8extern void *patch_delta(void *src_buf, unsigned long src_size, 9 void *delta_buf, unsigned long delta_size, 10 unsigned long *dst_size); 11 12/* the smallest possible delta size is 2 bytes (empty to empty) */ 13#define DELTA_SIZE_MIN 2 14 15/* 16 * This must be called twice on the delta data buffer, first to get the 17 * expected reference buffer size, and again to get the result buffer size. 18 */ 19static inline unsigned long get_delta_hdr_size(const unsigned char **datap) 20{ 21 const unsigned char *data = *datap; 22 unsigned char cmd = *data++; 23 unsigned long size = cmd & ~0x80; 24 int i = 7; 25 while (cmd & 0x80) { 26 cmd = *data++; 27 size |= (cmd & ~0x80) << i; 28 i += 7; 29 } 30 *datap = data; 31 return size; 32} 33 34#endif