mikecarper
59b0ab93d0
Deduplicate validation and preserve the published preference bytes and transactional saves. Correct Ikoka Handheld Companion flash bounds and document QSPI Room migration. Qualify STM32 and RAK4631 at the full 1.18.0.1 release version length.
73 lines
2.6 KiB
C++
73 lines
2.6 KiB
C++
#pragma once
|
|
|
|
#include "CompanionTrafficPrefs.h"
|
|
#include <float.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
|
|
namespace mesh { namespace companion { namespace timezone {
|
|
|
|
// Optional footer after all existing preference fields and PMO/TXR footers.
|
|
// Integer-only images retain their exact published bytes and lengths.
|
|
static constexpr size_t FooterSize = 10;
|
|
|
|
// All supported preference ABIs use IEEE binary32. Checking its bits avoids
|
|
// duplicated soft-float comparisons on small ARM targets and remains strict
|
|
// when a board's compiler enables finite-math optimizations.
|
|
#if defined(__GNUC__)
|
|
__attribute__((noinline))
|
|
#endif
|
|
inline bool valid(float hours) {
|
|
static_assert(sizeof(float) == sizeof(uint32_t) && FLT_RADIX == 2
|
|
&& FLT_MANT_DIG == 24 && FLT_MAX_EXP == 128, "IEEE binary32 timezone");
|
|
uint32_t bits;
|
|
memcpy(&bits, &hours, sizeof(bits));
|
|
// Positive binary32 bits are ordered numerically. For negative values,
|
|
// their magnitude is ordered likewise above the sign bit. The thresholds
|
|
// are exactly -12 and +14; either sign of NaN/infinity exceeds its limit.
|
|
return bits <= ((bits & 0x80000000UL) ? 0xc1400000UL : 0x41600000UL);
|
|
}
|
|
|
|
inline bool fractional(float hours) {
|
|
return valid(hours) && hours != static_cast<int8_t>(hours);
|
|
}
|
|
|
|
inline void encodeFooter(uint8_t out[FooterSize], float hours) {
|
|
static_assert(sizeof(float) == sizeof(uint32_t), "32-bit timezone float");
|
|
out[0] = 'T'; out[1] = 'Z'; out[2] = 'F'; out[3] = 1;
|
|
#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
|
|
memcpy(out + 4, &hours, sizeof(hours));
|
|
#else
|
|
uint32_t bits;
|
|
memcpy(&bits, &hours, sizeof(bits));
|
|
for (unsigned i = 0; i < 4; ++i) out[4 + i] = uint8_t(bits >> (8 * i));
|
|
#endif
|
|
const uint16_t crc = traffic::checksum(out, 8);
|
|
out[8] = uint8_t(crc >> 8); out[9] = uint8_t(crc);
|
|
}
|
|
|
|
inline bool decodeFooter(const uint8_t* in, size_t size, float& hours) {
|
|
if (!in || size != FooterSize) return false;
|
|
#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
|
|
uint32_t magic;
|
|
memcpy(&magic, in, sizeof(magic));
|
|
if (magic != 0x01465a54UL) return false; // TZF, version 1
|
|
#else
|
|
if (memcmp(in, "TZF\1", 4) != 0) return false;
|
|
#endif
|
|
if (traffic::checksum(in, 8) != uint16_t((in[8] << 8) | in[9])) return false;
|
|
float decoded;
|
|
#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
|
|
memcpy(&decoded, in + 4, sizeof(decoded));
|
|
#else
|
|
uint32_t bits = 0;
|
|
for (unsigned i = 0; i < 4; ++i) bits |= uint32_t(in[4 + i]) << (8 * i);
|
|
memcpy(&decoded, &bits, sizeof(decoded));
|
|
#endif
|
|
if (!valid(decoded)) return false;
|
|
hours = decoded;
|
|
return true;
|
|
}
|
|
|
|
} } } // namespace mesh::companion::timezone
|