protobuf/upb/mini_table.h

/*
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 *
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 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
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 *       derived from this software without specific prior written permission.
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 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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#ifndef UPB_MINI_TABLE_H_
#define UPB_MINI_TABLE_H_

#include "upb/msg_internal.h"

// Must be last.
#include "upb/port_def.inc"

#ifdef __cplusplus
extern "C" {
#endif

const upb_MiniTable_Field* upb_MiniTable_FindFieldByNumber(
    const upb_MiniTable* table, uint32_t number);

typedef enum {
  kUpb_MessageModifier_DefaultIsPacked = 1,
  kUpb_MessageModifier_HasClosedEnums = 2,
  kUpb_MessageModifier_IsExtendable = 4,
  kUpb_MessageModifier_IsMapEntry = 8,
} kUpb_MessageModifier;

typedef enum {
  kUpb_FieldModifier_IsRepeated = 1,
  kUpb_FieldModifier_IsPacked = 2,
  kUpb_FieldModifier_IsProto3Singular = 4,
  kUpb_FieldModifier_IsRequired = 8,
} kUpb_FieldModifier;

/** upb_MtDataEncoder *********************************************************/

// Functions to encode a string in a format that can be loaded by
// upb_MiniTable_Build().

typedef struct {
  char* end;  // Limit of the buffer passed as a parameter.
  // Aliased to internal-only members in .cc.
  char internal[32];
} upb_MtDataEncoder;

// If the input buffer has at least this many bytes available, the encoder call
// is guaranteed to succeed (as long as field number order is maintained).
#define kUpb_MtDataEncoder_MinSize 16

// Encodes field/oneof information for a given message.  The sequence of calls
// should look like:
//
//   upb_MtDataEncoder e;
//   char buf[256];
//   char* ptr = buf;
//   e.end = ptr + sizeof(buf);
//   ptr = upb_MtDataEncoder_StartMessage(&e, ptr);
//   // Fields *must* be in field number order.
//   ptr = upb_MtDataEncoder_PutField(&e, ptr, ...);
//   ptr = upb_MtDataEncoder_PutField(&e, ptr, ...);
//   ptr = upb_MtDataEncoder_PutField(&e, ptr, ...);
//
//   // If oneofs are present.  Oneofs must be encoded after regular fields.
//   ptr = upb_MiniTable_StartOneof(&e, ptr)
//   ptr = upb_MiniTable_PutOneofField(&e, ptr, ...);
//   ptr = upb_MiniTable_PutOneofField(&e, ptr, ...);
//
//   ptr = upb_MiniTable_StartOneof(&e, ptr);
//   ptr = upb_MiniTable_PutOneofField(&e, ptr, ...);
//   ptr = upb_MiniTable_PutOneofField(&e, ptr, ...);
//
// Oneofs must be encoded after all regular fields.
char* upb_MtDataEncoder_StartMessage(upb_MtDataEncoder* e, char* buf,
                                     uint64_t msg_mod);
char* upb_MtDataEncoder_PutField(upb_MtDataEncoder* e, char* buf,
                                 upb_FieldType type, uint32_t field_num,
                                 uint64_t field_mod);
char* upb_MtDataEncoder_StartOneof(upb_MtDataEncoder* e, char* buf);
char* upb_MtDataEncoder_PutOneofField(upb_MtDataEncoder* e, char* buf,
                                      uint32_t field_num);


/** upb_MiniTable *************************************************************/

typedef enum {
  kUpb_MiniTablePlatform_32Bit,
  kUpb_MiniTablePlatform_64Bit,
  kUpb_MiniTablePlatform_Native =
      UPB_SIZE(kUpb_MiniTablePlatform_32Bit, kUpb_MiniTablePlatform_64Bit),
} upb_MiniTablePlatform;

// Builds a mini table from the data encoded in the buffer [data, len]. If any
// errors occur, returns NULL and sets a status message. In the success case,
// the caller must call upb_MiniTable_SetSub*() for all message or proto2 enum
// fields to link the table to the appropriate sub-tables.
upb_MiniTable* upb_MiniTable_Build(const char* data, size_t len,
                                   upb_MiniTablePlatform platform,
                                   upb_Arena* arena, upb_Status* status);
void upb_MiniTable_SetSubMessage(upb_MiniTable* table,
                                 upb_MiniTable_Field* field,
                                 const upb_MiniTable* sub);
void upb_MiniTable_SetSubEnum(upb_MiniTable* table,
                              upb_MiniTable_Field* field,
                              const upb_MiniTable_Enum* sub);

upb_MiniTable_Extension* upb_MiniTable_BuildExtensions(const char* data,
                                                       size_t len,
                                                       size_t* ext_count,
                                                       upb_Arena* arena,
                                                       upb_Status* status);
void upb_MiniTable_ResolveExtension(upb_MiniTable_Extension* ext,
                                    const upb_MiniTable* extendee,
                                    upb_MiniTable_Sub sub);

// Special-case functions for MessageSet layout and map entries.
upb_MiniTable* upb_MiniTable_BuildMessageSet(upb_MiniTablePlatform platform,
                                             upb_Arena* arena);
upb_MiniTable* upb_MiniTable_BuildMapEntry(upb_FieldType key_type,
                                           upb_FieldType value_type,
                                           upb_MiniTablePlatform platform,
                                           upb_Arena* arena);

// Like upb_MiniTable_Build(), but the user provides a buffer of layout data so
// it can be reused from call to call, avoiding repeated realloc()/free().
//
// The caller owns `*buf` both before and after the call, and must free() it
// when it is no longer in use.  The function will realloc() `*buf` as
// necessary, updating `*size` accordingly.
upb_MiniTable* upb_MiniTable_BuildWithBuf(const char* data, size_t len,
                                          upb_MiniTablePlatform platform,
                                          upb_Arena* arena, void** buf,
                                          size_t* buf_size, upb_Status* status);

#ifdef __cplusplus
}  /* extern "C" */
#endif

#include "upb/port_undef.inc"

#endif  /* UPB_MINI_TABLE_H_ */