Added specification document

For covering all the technical bits

lfs_util.h

@@ -12,7 +12,8 @@
 #include <stdio.h>
 
 
-// Builtin functions
+// Builtin functions, these may be replaced by more
+// efficient implementations in the system
 static inline uint32_t lfs_max(uint32_t a, uint32_t b) {
     return (a > b) ? a : b;
 }
@@ -33,10 +34,12 @@ static inline int lfs_scmp(uint32_t a, uint32_t b) {
     return (int)(unsigned)(a - b);
 }
 
+// CRC-32 with polynomial = 0x04c11db7
 void lfs_crc(uint32_t *crc, const void *buffer, size_t size);
 
 
-// Logging functions
+// Logging functions, these may be replaced by system-specific
+// logging functions
 #define LFS_DEBUG(fmt, ...) printf("lfs debug: " fmt "\n", __VA_ARGS__)
 #define LFS_WARN(fmt, ...)  printf("lfs warn: " fmt "\n", __VA_ARGS__)
 #define LFS_ERROR(fmt, ...) printf("lfs error: " fmt "\n", __VA_ARGS__)