diff options
Diffstat (limited to 'pb.h')
| -rw-r--r-- | pb.h | 162 |
1 files changed, 117 insertions, 45 deletions
@@ -3,19 +3,36 @@ #include <stdint.h> #include <stddef.h> // size_t +#include <stdbool.h> + +#ifdef __GNUC__ +// This just reduces memory requirements, but is not required. +#define pb_packed __attribute__((packed)) +#else +#define pb_packed +#endif /* Lightweight input stream. - * If buf is NULL, read but don't store bytes. */ + * If buf is NULL, read but don't store bytes. + * You have to provide a callback function for reading. + * You can use state to store your own data (e.g. buffer pointer), + * and rely on pb_read to verify that no-body reads past bytes_left. + * However, substreams may change bytes_left so don't use that to + * compute any pointers. + */ typedef struct _pb_istream_t pb_istream_t; struct _pb_istream_t { - bool (*callback)(pb_istream_t *stream, char *buf, size_t count); + bool (*callback)(pb_istream_t *stream, uint8_t *buf, size_t count); void *state; // Free field for use by callback implementation size_t bytes_left; }; -static inline bool pb_read(pb_istream_t *stream, char *buf, size_t count) +static inline bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count) { + if (stream->bytes_left < count) + return false; + bool status = stream->callback(stream, buf, count); stream->bytes_left -= count; return status; @@ -25,74 +42,129 @@ static inline bool pb_read(pb_istream_t *stream, char *buf, size_t count) typedef struct _pb_ostream_t pb_ostream_t; struct _pb_ostream_t { - bool (*callback)(pb_ostream_t *stream, const char *buf, size_t count); + bool (*callback)(pb_ostream_t *stream, const uint8_t *buf, size_t count); void *state; // Free field for use by callback implementation size_t bytes_written; }; -static inline bool pb_write(pb_ostream_t *stream, const char *buf, size_t count) +static inline bool pb_write(pb_ostream_t *stream, const uint8_t *buf, size_t count) { bool status = stream->callback(stream, buf, count); stream->bytes_written += count; return status; } -/* List of possible decode/encode action types */ +/* List of possible field types + * Least-significant 4 bits tell the scalar type + * Most-significant 4 bits specify repeated/required/packed etc. + * + * INT32 and UINT32 are treated the same, as are (U)INT64 and (S)FIXED* + * These types are simply casted to correct field type when they are + * assigned to the memory pointer. + * SINT* is different, though, because it is zig-zag coded. + */ typedef enum { - // Special case. Sets boolean field to true, continues parsing the data. - PB_ACT_HAS, - // Standard integer types - PB_ACT_UINT32, - PB_ACT_SINT32, - PB_ACT_INT32, - PB_ACT_FIXED32, - PB_ACT_SFIXED32, - PB_ACT_UINT64, - PB_ACT_SINT64, - PB_ACT_INT64, - PB_ACT_FIXED64, - PB_ACT_SFIXED64, - PB_ACT_BOOL, + PB_LTYPE_UINT32 = 0x00, + PB_LTYPE_INT32 = 0x00, + PB_LTYPE_SINT32 = 0x01, + PB_LTYPE_FIXED32 = 0x02, + PB_LTYPE_SFIXED32 = 0x02, + PB_LTYPE_UINT64 = 0x03, + PB_LTYPE_INT64 = 0x03, + PB_LTYPE_SINT64 = 0x04, + PB_LTYPE_FIXED64 = 0x05, + PB_LTYPE_SFIXED64 = 0x05, + PB_LTYPE_BOOL = 0x06, + PB_LTYPE_ENUM = 0x07, // Standard float types - PB_ACT_FLOAT, - PB_ACT_DOUBLE, + PB_LTYPE_FLOAT = 0x08, + PB_LTYPE_DOUBLE = 0x09, + + // Byte array with pre-allocated buffer. + // data_size is the length of the allocated PB_BYTES_ARRAY structure. + PB_LTYPE_BYTES = 0x0A, + + // String with pre-allocated buffer. + // data_size is the maximum length. + PB_LTYPE_STRING = 0x0B, - // Constant-sized array - PB_ACT_BYTES, + // Submessage + // submsg_fields is pointer to field descriptions + PB_LTYPE_SUBMESSAGE = 0x0C, - // Constant-sized array, with null termination - PB_ACT_STRING, + ///////////// + // Modifier flags - // Callback function pointer in field value - PB_ACT_SUBMESSAGE, + // Just the basic, write data at data_offset + PB_HTYPE_REQUIRED = 0x00, - PB_LAST_ACT -} pb_action_t; + // Write true at size_offset + PB_HTYPE_OPTIONAL = 0x10, + + // Read to pre-allocated array + // Maximum number of entries is array_size, + // actual number is stored at size_offset + PB_HTYPE_ARRAY = 0x20, + + // Works for all required/optional/repeated fields. + // data_offset points to pb_callback_t structure. + // LTYPE is ignored. + PB_HTYPE_CALLBACK = 0x30 +} pb_packed pb_type_t; -// This structure is used in constants to specify struct fields. -typedef struct { - int field_number; - uint16_t offset; - pb_action_t action; - uint8_t fieldsize; -} pb_field_t; +#define PB_HTYPE(x) ((x) & 0xF0) +#define PB_LTYPE(x) ((x) & 0x0F) + +/* This structure is used in auto-generated constants + * to specify struct fields. + * You can change field sizes here if you need structures + * larger than 256 bytes or field tags larger than 256. + * The compiler should complain if your .proto has such + * structures ("initializer too large for type"). + */ +typedef struct _pb_field_t pb_field_t; +struct _pb_field_t { + uint8_t tag; + pb_type_t type; + uint8_t data_offset; // Offset of actual data or array start + uint8_t size_offset; // Offset of array size or has-boolean + uint8_t data_size; // Data size in bytes for a single item + uint8_t array_size; // Maximum number of entries in array + + // Field definitions for submessage + // OR default value for all other non-array, non-callback types + // If null, then field will zeroed. + const void *ptr; +} pb_packed; #define PB_LAST_FIELD {0,0,0,0} -/* --- Types to use inside generated structures. --- */ +// This structure is used for 'bytes' arrays. +// It has the number of bytes in the beginning, and after that an array. +#define PB_BYTES_ARRAY(buffersize) \ +struct { \ + size_t size; \ + uint8_t bytes[buffersize]; \ +} -// Byte array and size word. -// Note: because of variable length array, this type cannot be directly used. -// Autogenerated code declares the same type of fields but with explicit length. -typedef struct { - size_t size; - char bytes[]; -} pb_bytearray_t; +typedef PB_BYTES_ARRAY(1) pb_bytes_array_t; // This structure is used for giving the callback function. +// +// The decoding callback will be given a limited-length stream +// If the wire type was string, the length is the length of the string. +// If the wire type was a varint/fixed32/fixed64, the length is the length +// of the actual value. +// The function may be called multiple times (especially for repeated types, +// but also otherwise if the message happens to contain the field multiple +// times.) +// +// The encoding callback will receive the actual output stream. +// It should write all the data in one call, including the field tag and +// wire type. It can write multiple fields. typedef struct _pb_callback_t pb_callback_t; struct _pb_callback_t { union { |