A checksum of a store's reading, so a reply that brings nothing new costs no flash write. More...

#include <stddef.h>
#include <stdint.h>

Macros
#define	STORE_READING_SIZE(state, stamp)
	How many leading bytes of a store's blob are the reading, which is everything before its sync time.

Functions
uint32_t	store_sum (const void *bytes, size_t size)
	Sums a run of bytes, so two readings can be compared without keeping both.

Detailed Description

A checksum of a store's reading, so a reply that brings nothing new costs no flash write.

Every reply stamps a fresh sync time, so the saved blob always differs from the last one even when every reading in it is the same. A store sums only the part before its sync time, keeps that sum, and skips the write when the next one matches. Four bytes a store is far cheaper in RAM than a second copy of the blob.

Macros

Functions

Detailed Description