versions/v1_4_0/mynewt-core/encoding/tinycbor/include/tinycbor/extract_number_p.h

/****************************************************************************
**
** Copyright (C) 2015 Intel Corporation
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#define _BSD_SOURCE 1
#define _DEFAULT_SOURCE 1
#include "cbor.h"
#include "cborconstants_p.h"
#include "compilersupport_p.h"
#include <stdlib.h>

static inline uint16_t get16(const uint8_t *ptr)
{
    uint16_t result;
    memcpy(&result, ptr, sizeof(result));
    return cbor_ntohs(result);
}

static inline uint32_t get32(const uint8_t *ptr)
{
    uint32_t result;
    memcpy(&result, ptr, sizeof(result));
    return cbor_ntohl(result);
}

static inline uint64_t get64(const uint8_t *ptr)
{
    uint64_t result;
    memcpy(&result, ptr, sizeof(result));
    return cbor_ntohll(result);
}

static inline CborError extract_number(const CborParser *p, int *offset, uint64_t *len)
{
    uint8_t additional_information = p->d->get8(p->d, *offset) & SmallValueMask;
    ++*offset;
    *len = 1;
    if (additional_information < Value8Bit) {
        *len = additional_information;
        return CborNoError;
    }
    if (unlikely(additional_information > Value64Bit))
        return CborErrorIllegalNumber;

    size_t bytesNeeded = (size_t)(1 << (additional_information - Value8Bit));
    if (unlikely(bytesNeeded > (size_t)(p->end - *offset))) {
        return CborErrorUnexpectedEOF;
    } else if (bytesNeeded == 1) {
        *len = p->d->get8(p->d, *offset);
    } else if (bytesNeeded == 2) {
        *len =  p->d->get16(p->d, *offset);
    } else if (bytesNeeded == 4) {
        *len =  p->d->get32(p->d, *offset);
    } else {
        *len =  p->d->get64(p->d, *offset);
    }
    *offset += bytesNeeded;
    return CborNoError;
}