utpersist.h

DataDraw is an ultra-fast persistent database for high performance programs written in C. It s so fa

/*
 * This file was written by Bill Cox.  It is hereby placed into the public domain.
 */

/* These are the commands supported in the recentChanges.  The high bit of a command byte is used
 * to indicate that the command is an undo command, rather than a redo command. */
typedef enum {
    UT_TRANSACTION_COMPLETE = 0, /* TRANSACTION_COMPLETE <32-bit checksum> */
    UT_WRITE_FIELD = 1, /* WRITE_FIELD <16-bit field #> <object number> <value> */
    UT_WRITE_ARRAY = 2, /* WRITE_ARRAY <16-bit field #> <32-bit index> <32-bit numValues> <values> */
    UT_WRITE_GLOBAL = 3, /* WRITE_GLOBAL <8-bit moduleID> <16-bit offset> <8-bit numBytes> <values> */
    UT_RESIZE_FIELD = 4 /* RESIZE_FIELD <16-bit field #> <64-bit size> */
} utCommandType;

/* This is the maximum header size of a command needed to determine it's size */
#define UT_COMMAND_MAX_HEADER_SIZE 11

typedef struct utModuleStruct *utModule;
typedef struct utClassStruct *utClass;
typedef struct utFieldStruct *utField;
typedef struct utTransactionStruct *utTransaction;
typedef struct utEnumStruct *utEnum;
typedef struct utEntryStruct *utEntry;
typedef struct utUnionStruct *utUnion;
typedef struct utUnionCaseStruct *utUnionCase;

struct utModuleStruct {
    char *prefix;
    uint32 hashValue;
    uint32 globalSize;
    void *globalData;
    uint16 firstFieldIndex, numFields;
    uint16 firstClassIndex, numClasses;
    uint16 firstEnumIndex, numEnums;
    void (*start)(void);
    void (*stop)(void);
    bool initialized;
};

extern struct utModuleStruct *utModules;
extern uint8 utAllocatedModules, utUsedModules;

utModule utFindModule(char *prefix);

struct utClassStruct {
    char *name;
    uint32 firstFieldIndex, numFields, numHiddenFields;
    uint64 (*constructor)(void);
    void (*destructor)(uint64 objectNumber);
    void *numUsedPtr;
    void *numAllocatedPtr;
    void *firstFreePtr;
    uint16 nextFreeFieldIndex;
    uint8 moduleIndex, referenceSize;
};

extern struct utClassStruct *utClasses;
extern uint16 utAllocatedClasses, utUsedClasses;

struct utFieldStruct {
    char *name;
    void *arrayPtr;
    uint32 size;
    utFieldType type;
    char *destName;
    uint32 *numUsedPtr; /* Only for arrays */
    uint32 *numAllocatedPtr; /* Only for arrays */
    void *(*getValues)(uint64 objectNumber, uint32 *numValues);
    void *(*allocValues)(uint64 objectNumber, uint32 numValues);
    uint16 classIndex;
    uint16 unionIndex; /* Only for unions */
    bool array;
    bool hidden; /* Only true for fields tracking array properties, or if declared hidden */
};

extern struct utFieldStruct *utFields;
extern uint16 utAllocatedFields, utUsedFields;
utField utFindField(utClass theClass, char *name);

struct utTransactionStruct {
    uint32 position; /* Position in recent changes file, or in utCommandBuffer if not persistent */
    uint32 length;
};

extern struct utTransactionStruct *utTransactions;
extern uint32 utUsedTransactions, utAllocatedTransactions;

struct utEnumStruct {
    uint16 firstEntryIndex, numEntries;
    char *name;
};

extern struct utEnumStruct *utEnums;
extern uint16 utAllocatedEnums, utUsedEnums;

struct utEntryStruct {
    char *name;
    uint32 value;
};

extern struct utEntryStruct *utEntries;
extern uint16 utAllocatedEntries, utUsedEntries;

struct utUnionStruct {
    uint16 fieldIndex;
    uint16 switchFieldIndex;
    uint16 firstUnionCaseIndex, numUnionCases;
};

extern struct utUnionStruct *utUnions;
extern uint16 utAllocatedUnions, utUsedUnions;

struct utUnionCaseStruct {
    uint32 value;
    utFieldType type;
    uint32 size;
};

extern struct utUnionCaseStruct *utUnionCases;
extern uint16 utAllocatedUnionCases, utUsedUnionCases;

/* Some utilities */
uint64 utFindIntValue(void *values, uint8 size);

/* This keeps us from writing the the unopened changes file before starting persistence */
extern bool utPersistenceInitialized;
extern char *utDatabaseDirectory;
extern bool utUseTextDatabaseFormat;