src/rt/RdataShare.h

/* RCSid $Id$ */
/*
 *  RdataShare.h
 *
 *      Radiance classes for interprocess data sharing
 *
 *      Errors end up calling error() from rterror.h, so
 *      checking return values is not normally needed.
 *
 *  Created by Greg Ward on 10/14/2024.
 */

#ifndef RdataShare_h
#define RdataShare_h

#include <sys/types.h>

/// Channel creation and i/o flags
enum {RDSexcl=1, RDSextend=2, RDSread=4, RDSwrite=8};

/*
 * When data sharing object is created, flag meanings are:
 *      RDSexcl =       Create a new file, or fail if it exists
 *      RDSextend =     Set data extent to match size parameter
 *      RDSread =       Data may be read
 *      RDSwrite =      Data may be written
 *
 * The RDSread flag should be given to GetMemory() if a data
 * read operation is desired.  Similarly, the RDSwrite flag
 * should be given when writing data in ReleaseMemory().
 * Memory-mapped files always read *and* write data if opened
 * in the appropriate mode.  (Beware that writing to read-only data
 * or reading write-only data will generate a system fault.)
 * The RDSextend flag may be given with RDSread in GetMemory()
 * and RDSwrite in ReleaseMemory() to allow the file size to
 * increase as needed for a given operation.
 * In some implementations, the RDSexcl flag may guarantee
 * data consistency by placing locks on the requested memory areas.
 * In such cases, it may make sense to include the RDSwrite flag
 * in GetMemory() calls if the intention is to write new results
 * in ReleaseMemory(), so an exclusive lock will be held.
 */

/// Data share object types returned by GetType()
enum RDSType {RDSTanonMap=1, RDSTfileMap, RDSTfile,
                RDSTcust1, RDSTcust2, RDSTcust3, RDSTcust4};

extern const char       RDSnoname[];

/// Abstract base class for shared memory object
class RdataShare {
protected:
        char *          chName;                 // channel name
        size_t          osiz;                   // current object size
        int             mode;                   // open mode
public:
                        RdataShare() {
                                chName = NULL; osiz = 0; mode = 0;
                        }
        virtual         ~RdataShare();
                        /// Get channel name, or RDSnoname if anonymous
        const char *    GetName() const {
                                return chName ? chName : RDSnoname;
                        }
                        /// Get R/W flags
        int             GetMode() const {
                                return mode & (RDSread|RDSwrite);
                        }
                        /// Get current object size
        size_t          GetSize() const {
                                return osiz;
                        }
                        /// Return data sharing type
        virtual RDSType GetType() const = 0;
                        /// Attempt to extend or shrink object (adjust if 0)
        virtual size_t  Resize(size_t new_siz = 0) = 0;
                        /// Get data buffer
        virtual void *  GetMemory(size_t offs, size_t len, int fl = RDSread) = 0;
                        /// Return data buffer
        virtual bool    ReleaseMemory(void *bp, int fl = RDSwrite) = 0;
};

/// Memory sharing implemented with mmap'ed file (or anonymous area)
class RdataShareMap : public RdataShare {
        void *          mmorg;                  // memory-mapped origin
        int             bufCount;               // count of allocated buffers
public:
                        RdataShareMap(const char *name, int flags, size_t siz = 0);
        virtual         ~RdataShareMap();
        RDSType         GetType() const {
                                return chName ? RDSTfileMap : RDSTanonMap;
                        }
        size_t          Resize(size_t new_siz = 0);
        void *          GetMemory(size_t offs, size_t len, int fl);
        bool            ReleaseMemory(void *dp, int fl);
};

struct RDSbuffer;       // Private struct for buffer list

/// Memory sharing implemented with simple file
class RdataShareFile : public RdataShare {
        int             fd;                     // open file descriptor
        RDSbuffer *     blist;                  // allocated buffer list
public:
                        RdataShareFile(const char *name, int flags, size_t siz = 0);
        virtual         ~RdataShareFile();
        RDSType         GetType() const {
                                return RDSTfile;
                        }
        size_t          Resize(size_t new_siz = 0);
        void *          GetMemory(size_t offs, size_t len, int fl);
        bool            ReleaseMemory(void *dp, int fl);
};

#endif          // RdataShare_h
Revision:	2.1
Committed:	Tue Oct 29 00:36:54 2024 UTC (12 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad6R0, HEAD
Log Message:	feat(rxcontrib): First compiled version of rxcontrib tool to test new C++ classes
#	User	Rev	Content
1	greg	2.1	/* RCSid $Id$ */
2			/*
3			* RdataShare.h
4			*
5			* Radiance classes for interprocess data sharing
6			*
7			* Errors end up calling error() from rterror.h, so
8			* checking return values is not normally needed.
9			*
10			* Created by Greg Ward on 10/14/2024.
11			*/
12
13			#ifndef RdataShare_h
14			#define RdataShare_h
15
16			#include <sys/types.h>
17
18			/// Channel creation and i/o flags
19			enum {RDSexcl=1, RDSextend=2, RDSread=4, RDSwrite=8};
20
21			/*
22			* When data sharing object is created, flag meanings are:
23			* RDSexcl = Create a new file, or fail if it exists
24			* RDSextend = Set data extent to match size parameter
25			* RDSread = Data may be read
26			* RDSwrite = Data may be written
27			*
28			* The RDSread flag should be given to GetMemory() if a data
29			* read operation is desired. Similarly, the RDSwrite flag
30			* should be given when writing data in ReleaseMemory().
31			* Memory-mapped files always read and write data if opened
32			* in the appropriate mode. (Beware that writing to read-only data
33			* or reading write-only data will generate a system fault.)
34			* The RDSextend flag may be given with RDSread in GetMemory()
35			* and RDSwrite in ReleaseMemory() to allow the file size to
36			* increase as needed for a given operation.
37			* In some implementations, the RDSexcl flag may guarantee
38			* data consistency by placing locks on the requested memory areas.
39			* In such cases, it may make sense to include the RDSwrite flag
40			* in GetMemory() calls if the intention is to write new results
41			* in ReleaseMemory(), so an exclusive lock will be held.
42			*/
43
44			/// Data share object types returned by GetType()
45			enum RDSType {RDSTanonMap=1, RDSTfileMap, RDSTfile,
46			RDSTcust1, RDSTcust2, RDSTcust3, RDSTcust4};
47
48			extern const char RDSnoname[];
49
50			/// Abstract base class for shared memory object
51			class RdataShare {
52			protected:
53			char * chName; // channel name
54			size_t osiz; // current object size
55			int mode; // open mode
56			public:
57			RdataShare() {
58			chName = NULL; osiz = 0; mode = 0;
59			}
60			virtual ~RdataShare();
61			/// Get channel name, or RDSnoname if anonymous
62			const char * GetName() const {
63			return chName ? chName : RDSnoname;
64			}
65			/// Get R/W flags
66			int GetMode() const {
67			return mode & (RDSread\|RDSwrite);
68			}
69			/// Get current object size
70			size_t GetSize() const {
71			return osiz;
72			}
73			/// Return data sharing type
74			virtual RDSType GetType() const = 0;
75			/// Attempt to extend or shrink object (adjust if 0)
76			virtual size_t Resize(size_t new_siz = 0) = 0;
77			/// Get data buffer
78			virtual void * GetMemory(size_t offs, size_t len, int fl = RDSread) = 0;
79			/// Return data buffer
80			virtual bool ReleaseMemory(void *bp, int fl = RDSwrite) = 0;
81			};
82
83			/// Memory sharing implemented with mmap'ed file (or anonymous area)
84			class RdataShareMap : public RdataShare {
85			void * mmorg; // memory-mapped origin
86			int bufCount; // count of allocated buffers
87			public:
88			RdataShareMap(const char *name, int flags, size_t siz = 0);
89			virtual ~RdataShareMap();
90			RDSType GetType() const {
91			return chName ? RDSTfileMap : RDSTanonMap;
92			}
93			size_t Resize(size_t new_siz = 0);
94			void * GetMemory(size_t offs, size_t len, int fl);
95			bool ReleaseMemory(void *dp, int fl);
96			};
97
98			struct RDSbuffer; // Private struct for buffer list
99
100			/// Memory sharing implemented with simple file
101			class RdataShareFile : public RdataShare {
102			int fd; // open file descriptor
103			RDSbuffer * blist; // allocated buffer list
104			public:
105			RdataShareFile(const char *name, int flags, size_t siz = 0);
106			virtual ~RdataShareFile();
107			RDSType GetType() const {
108			return RDSTfile;
109			}
110			size_t Resize(size_t new_siz = 0);
111			void * GetMemory(size_t offs, size_t len, int fl);
112			bool ReleaseMemory(void *dp, int fl);
113			};
114
115			#endif // RdataShare_h