pb.h

00001 #ifndef _PB_H_
00002 #define _PB_H_
00003 
00004 /* pb.h: Common parts for nanopb library.
00005  * Most of these are quite low-level stuff. For the high-level interface,
00006  * see pb_encode.h or pb_decode.h
00007  */
00008 
00009 #define NANOPB_VERSION nanopb-0.1.9
00010 
00011 #include <stdint.h>
00012 #include <stddef.h>
00013 #include <stdbool.h>
00014 
00015 #ifdef __GNUC__
00016 /* This just reduces memory requirements, but is not required. */
00017 #define pb_packed __attribute__((packed))
00018 #else
00019 #define pb_packed
00020 #endif
00021 
00022 /* Handly macro for suppressing unreferenced-parameter compiler warnings.    */
00023 #ifndef UNUSED
00024 #define UNUSED(x) (void)(x)
00025 #endif
00026 
00027 /* Compile-time assertion, used for checking compatible compilation options.
00028  * If this fails on your compiler for some reason, use #define STATIC_ASSERT
00029  * to disable it. */
00030 #ifndef STATIC_ASSERT
00031 #define STATIC_ASSERT(COND,MSG) typedef char STATIC_ASSERT_MSG(MSG, __LINE__, __COUNTER__)[(COND)?1:-1];
00032 #define STATIC_ASSERT_MSG(MSG, LINE, COUNTER) STATIC_ASSERT_MSG_(MSG, LINE, COUNTER)
00033 #define STATIC_ASSERT_MSG_(MSG, LINE, COUNTER) static_assertion_##MSG##LINE##COUNTER
00034 #endif
00035 
00036 /* Number of required fields to keep track of
00037  * (change here or on compiler command line). */
00038 #ifndef PB_MAX_REQUIRED_FIELDS
00039 #define PB_MAX_REQUIRED_FIELDS 64
00040 #endif
00041 
00042 #if PB_MAX_REQUIRED_FIELDS < 64
00043 #error You should not lower PB_MAX_REQUIRED_FIELDS from the default value (64).
00044 #endif
00045 
00046 /* List of possible field types. These are used in the autogenerated code.
00047  * Least-significant 4 bits tell the scalar type
00048  * Most-significant 4 bits specify repeated/required/packed etc.
00049  * 
00050  * INT32 and UINT32 are treated the same, as are (U)INT64 and (S)FIXED*
00051  * These types are simply casted to correct field type when they are
00052  * assigned to the memory pointer.
00053  * SINT* is different, though, because it is zig-zag coded.
00054  */
00055 
00056 typedef enum {
00057     /************************
00058      * Field contents types *
00059      ************************/
00060     
00061     /* Numeric types */
00062     PB_LTYPE_VARINT = 0x00, /* int32, uint32, int64, uint64, bool, enum */
00063     PB_LTYPE_SVARINT = 0x01, /* sint32, sint64 */
00064     PB_LTYPE_FIXED32 = 0x02, /* fixed32, sfixed32, float */
00065     PB_LTYPE_FIXED64 = 0x03, /* fixed64, sfixed64, double */
00066     
00067     /* Marker for last packable field type. */
00068     PB_LTYPE_LAST_PACKABLE = 0x03,
00069     
00070     /* Byte array with pre-allocated buffer.
00071      * data_size is the length of the allocated PB_BYTES_ARRAY structure. */
00072     PB_LTYPE_BYTES = 0x04,
00073     
00074     /* String with pre-allocated buffer.
00075      * data_size is the maximum length. */
00076     PB_LTYPE_STRING = 0x05,
00077     
00078     /* Submessage
00079      * submsg_fields is pointer to field descriptions */
00080     PB_LTYPE_SUBMESSAGE = 0x06,
00081     
00082     /* Number of declared LTYPES */
00083     PB_LTYPES_COUNT = 7,
00084     PB_LTYPE_MASK = 0x0F,
00085     
00086     /******************
00087      * Modifier flags *
00088      ******************/
00089     
00090     /* Just the basic, write data at data_offset */
00091     PB_HTYPE_REQUIRED = 0x00,
00092     
00093     /* Write true at size_offset */
00094     PB_HTYPE_OPTIONAL = 0x10,
00095     
00096     /* Read to pre-allocated array
00097      * Maximum number of entries is array_size,
00098      * actual number is stored at size_offset */
00099     PB_HTYPE_ARRAY = 0x20,
00100     
00101     /* Works for all required/optional/repeated fields.
00102      * data_offset points to pb_callback_t structure.
00103      * LTYPE should be valid or 0 (it is ignored, but
00104      * sometimes used to speculatively index an array). */
00105     PB_HTYPE_CALLBACK = 0x30,
00106     
00107     PB_HTYPE_MASK = 0xF0
00108 } pb_packed pb_type_t;
00109 
00110 #define PB_HTYPE(x) ((x) & PB_HTYPE_MASK)
00111 #define PB_LTYPE(x) ((x) & PB_LTYPE_MASK)
00112 
00113 /* This structure is used in auto-generated constants
00114  * to specify struct fields.
00115  * You can change field sizes if you need structures
00116  * larger than 256 bytes or field tags larger than 256.
00117  * The compiler should complain if your .proto has such
00118  * structures. Fix that by defining PB_FIELD_16BIT or
00119  * PB_FIELD_32BIT.
00120  */
00121 typedef struct _pb_field_t pb_field_t;
00122 struct _pb_field_t {
00123 
00124 #if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)
00125     uint8_t tag;
00126     pb_type_t type;
00127     uint8_t data_offset; /* Offset of field data, relative to previous field. */
00128     int8_t size_offset; /* Offset of array size or has-boolean, relative to data */
00129     uint8_t data_size; /* Data size in bytes for a single item */
00130     uint8_t array_size; /* Maximum number of entries in array */
00131 #elif defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)
00132     uint16_t tag;
00133     pb_type_t type;
00134     uint8_t data_offset;
00135     int8_t size_offset;
00136     uint16_t data_size;
00137     uint16_t array_size;
00138 #else
00139     uint32_t tag;
00140     pb_type_t type;
00141     uint8_t data_offset;
00142     int8_t size_offset;
00143     uint32_t data_size;
00144     uint32_t array_size;
00145 #endif
00146     
00147     /* Field definitions for submessage
00148      * OR default value for all other non-array, non-callback types
00149      * If null, then field will zeroed. */
00150     const void *ptr;
00151 } pb_packed;
00152 
00153 /* This structure is used for 'bytes' arrays.
00154  * It has the number of bytes in the beginning, and after that an array.
00155  * Note that actual structs used will have a different length of bytes array.
00156  */
00157 struct _pb_bytes_array_t {
00158     size_t size;
00159     uint8_t bytes[1];
00160 };
00161 
00162 typedef struct _pb_bytes_array_t pb_bytes_array_t;
00163 
00164 /* This structure is used for giving the callback function.
00165  * It is stored in the message structure and filled in by the method that
00166  * calls pb_decode.
00167  *
00168  * The decoding callback will be given a limited-length stream
00169  * If the wire type was string, the length is the length of the string.
00170  * If the wire type was a varint/fixed32/fixed64, the length is the length
00171  * of the actual value.
00172  * The function may be called multiple times (especially for repeated types,
00173  * but also otherwise if the message happens to contain the field multiple
00174  * times.)
00175  *
00176  * The encoding callback will receive the actual output stream.
00177  * It should write all the data in one call, including the field tag and
00178  * wire type. It can write multiple fields.
00179  *
00180  * The callback can be null if you want to skip a field.
00181  */
00182 typedef struct _pb_istream_t pb_istream_t;
00183 typedef struct _pb_ostream_t pb_ostream_t;
00184 typedef struct _pb_callback_t pb_callback_t;
00185 struct _pb_callback_t {
00186     union {
00187         bool (*decode)(pb_istream_t *stream, const pb_field_t *field, void *arg);
00188         bool (*encode)(pb_ostream_t *stream, const pb_field_t *field, const void *arg);
00189     } funcs;
00190     
00191     /* Free arg for use by callback */
00192     void *arg;
00193 };
00194 
00195 /* Wire types. Library user needs these only in encoder callbacks. */
00196 typedef enum {
00197     PB_WT_VARINT = 0,
00198     PB_WT_64BIT  = 1,
00199     PB_WT_STRING = 2,
00200     PB_WT_32BIT  = 5
00201 } pb_wire_type_t;
00202 
00203 /* These macros are used to declare pb_field_t's in the constant array. */
00204 #define pb_membersize(st, m) (sizeof ((st*)0)->m)
00205 #define pb_arraysize(st, m) (pb_membersize(st, m) / pb_membersize(st, m[0]))
00206 #define pb_delta(st, m1, m2) ((int)offsetof(st, m1) - (int)offsetof(st, m2))
00207 #define pb_delta_end(st, m1, m2) (offsetof(st, m1) - offsetof(st, m2) - pb_membersize(st, m2))
00208 #define PB_LAST_FIELD {0,(pb_type_t) 0,0,0,0,0,0}
00209 
00210 /* These macros are used for giving out error messages.
00211  * They are mostly a debugging aid; the main error information
00212  * is the true/false return value from functions.
00213  * Some code space can be saved by disabling the error
00214  * messages if not used.
00215  */
00216 #ifdef PB_NO_ERRMSG
00217 #define PB_RETURN_ERROR(stream,msg) return false
00218 #define PB_GET_ERROR(stream) "(errmsg disabled)"
00219 #else
00220 #define PB_RETURN_ERROR(stream,msg) \
00221     do {\
00222         if ((stream)->errmsg == NULL) \
00223             (stream)->errmsg = (msg); \
00224         return false; \
00225     } while(0)
00226 #define PB_GET_ERROR(stream) ((stream)->errmsg ? (stream)->errmsg : "(none)")
00227 #endif
00228 
00229 #endif