include/libbej/bej_common.h

#pragma once

#include <stdbool.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C"
{
#endif

/**
 * @brief Use this value to indicate that the dictonary needs to be traversed
 * starting at the first property of the dictionary.
 */
#define BEJ_DICTIONARY_START_AT_HEAD 0

/**
 * @brief If expr is non zero, return with that value.
 */
#ifndef RETURN_IF_IERROR
#define RETURN_IF_IERROR(expr)                                                 \
    do                                                                         \
    {                                                                          \
        int __status = (expr);                                                 \
        if (__status != 0)                                                     \
        {                                                                      \
            return __status;                                                   \
        }                                                                      \
    } while (0)
#endif

/**
 * @brief Check a given varable is NULL. If it is NULL, this will return with
 * bejErrorNullParameter. If the variable is not NULL, this will not return.
 */
#define NULL_CHECK(param, structStr)                                           \
    do                                                                         \
    {                                                                          \
        if ((param) == NULL)                                                   \
        {                                                                      \
            fprintf(stderr, "nullCheck: %s cannot be null\n", structStr);      \
            return bejErrorNullParameter;                                      \
        }                                                                      \
    } while (0)

/**
 * @brief RDE BEJ decoding errors.
 */
enum BejError
{
    bejErrorNoError = 0,
    bejErrorUnknown,
    bejErrorInvalidSize,
    bejErrorNotSuppoted,
    bejErrorUnknownProperty,
    bejErrorInvalidSchemaType,
    bejErrorInvalidPropertyOffset,
    bejErrorNullParameter,
};

/**
 * @brief BEJ schema classes.
 */
enum BejSchemaClass
{
    bejMajorSchemaClass = 0,
    bejEventSchemaClass = 1,
    bejAnnotationSchemaClass = 2,
    bejCollectionMemberTypeSchemaClass = 3,
    bejErrorSchemaClass = 4,
};

/**
 * @brief BEJ data types supported in BEJ version 0xF1F0F000.
 */
enum BejPrincipalDataType
{
    bejSet = 0,
    bejArray = 1,
    bejNull = 2,
    bejInteger = 3,
    bejEnum = 4,
    bejString = 5,
    bejReal = 6,
    bejBoolean = 7,
    bejBytestring = 8,
    bejChoice = 9,
    bejPropertyAnnotation = 10,
    bejPrincipalDataReserved1 = 11,
    bejPrincipalDataReserved2 = 12,
    bejPrincipalDataReserved3 = 13,
    bejResourceLink = 14,
    bejResourceLinkExpansion = 15,
};

/**
 * @brief Format BEJ tuple.
 */
struct BejTupleF
{
    uint8_t deferredBinding:1;
    uint8_t readOnlyProperty:1;
    uint8_t nullableProperty:1;
    uint8_t reserved:1;
    enum BejPrincipalDataType principalDataType:4;
} __attribute__((__packed__));

/**
 * @brief Sequence Number BEJ tuple.
 */
struct BejTupleS
{
    uint8_t schema;
    // Dictionaries contain 16bit sequence numbers. So allocating 16bits for
    // the sequence number here.
    uint16_t sequenceNumber;
};

/**
 * @brief Represent offsets of Format, Value Length and Value of a SFLV
 * tuple.
 */
struct BejSFLVOffset
{
    uint32_t formatOffset;
    uint32_t valueLenNnintOffset;
    uint32_t valueOffset;
};

/**
 * @brief Fields in Bej Real data type.
 */
struct BejReal
{
    // Number bytes in exp.
    uint8_t expLen;
    int64_t whole;
    uint64_t zeroCount;
    uint64_t fract;
    int64_t exp;
};

/**
 * @brief SFLV BEJ tuple infomation.
 */
struct BejSFLV
{
    struct BejTupleS tupleS;
    struct BejTupleF format;
    // Value portion size in bytes.
    uint32_t valueLength;
    // Value end-offset with respect to the begining of the encoded stream.
    uint32_t valueEndOffset;
    // Pointer to the value.
    const uint8_t* value;
};

/**
 * @brief bejEncoding PLDM data type header.
 */
struct BejPldmBlockHeader
{
    uint32_t bejVersion;
    uint16_t reserved;
    uint8_t schemaClass;
} __attribute__((__packed__));

/**
 * @brief Points to dictionaries used for encoding and decoding.
 */
struct BejDictionaries
{
    const uint8_t* schemaDictionary;
    const uint8_t* annotationDictionary;
    const uint8_t* errorDictionary;
};

/**
 * @brief Callbacks to a stack that can store pointers.
 */
struct BejPointerStackCallback
{
    /**
     * @brief A context for the stack.
     */
    void* stackContext;

    /**
     * @brief Return true if the stack is empty.
     */
    bool (*stackEmpty)(void* stackContext);

    /**
     * @brief View the pointer at the top of the stack. If the stack is
     * empty, this will return NULL.
     */
    void* (*stackPeek)(void* stackContext);

    /**
     * @brief Returns and removes the top most pointer from the stack. The
     * Client of the libbej is responsible for destroying the memory used
     * for storing the removed pointer (not the memory pointed by the
     * pointer).
     */
    void* (*stackPop)(void* stackContext);

    /**
     * @brief Push a pointer into the stack. Returns 0 if the operation is
     * successful. Client of this API is responsible for allocating memory
     * for storing the new pointer.
     */
    int (*stackPush)(void* p, void* stackContext);

    /**
     * @brief Delete the stack.
     */
    void (*deleteStack)(void* stackContext);
};

/**
 * @brief Get the unsigned integer value from provided bytes.
 *
 * @param[in] bytes - valid pointer to a byte stream in little-endian
 * format.
 * @param[in] numOfBytes - number of bytes belongs to the value. Maximum
 * number of bytes supported is 8. If numOfBytes > 8, the result is
 * undefined.
 * @return unsigend 64bit representation of the value.
 */
uint64_t bejGetUnsignedInteger(const uint8_t* bytes, uint8_t numOfBytes);

/**
 * @brief Get the value from nnint type.
 *
 * @param[in] nnint - nnint should be pointing to a valid nnint.
 * @return unsigend 64bit representation of the value.
 */
uint64_t bejGetNnint(const uint8_t* nnint);

/**
 * @brief Get the size of the complete nnint.
 *
 * @param[in] nnint - pointer to a valid nnint.
 * @return size of the complete nnint.
 */
uint8_t bejGetNnintSize(const uint8_t* nnint);

/**
 * @brief Get the bytes needed represent the value as a bejInteger.
 *
 * This will return the number of bytes needed to encode the signed value
 * into a bejInteger type.
 *
 * @param val - signed value needed to encode.
 * @return size of the bejInteger.
 */
uint8_t bejIntLengthOfValue(int64_t val);

/**
 * @brief Get the total bytes needed to encode an unsigned value using nnint
 * format.
 *
 * @param[in] val - unsigned value needed to encode.
 * @return size of the nnint value.
 */
uint8_t bejNnintEncodingSizeOfUInt(uint64_t val);

/**
 * @brief Get the length field value of the unsigned value nnint encoding.
 *
 * @param val - unsigned value needed to encode.
 * @return value of the length field in the encoded nnint.
 */
uint8_t bejNnintLengthFieldOfUInt(uint64_t val);

#ifdef __cplusplus
}
#endif