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/*
* upb - a minimalist implementation of protocol buffers.
*
* upb_decoder implements a high performance, streaming decoder for protobuf
* data that works by implementing upb_src and getting its data from a
* upb_bytesrc.
*
* The decoder does not currently support non-blocking I/O, in the sense that
* if the bytesrc returns UPB_STATUS_TRYAGAIN it is not possible to resume the
* decoder when data becomes available again. Support for this could be added,
* but it would add complexity and perhaps cost efficiency also.
*
* Copyright (c) 2009-2010 Joshua Haberman. See LICENSE for details.
*/
#ifndef UPB_DECODER_H_
#define UPB_DECODER_H_
#include <stdbool.h>
#include <stdint.h>
#include "upb_def.h"
#include "upb_stream.h"
#ifdef __cplusplus
extern "C" {
#endif
/* upb_decoder *****************************************************************/
// The decoder keeps a stack with one entry per level of recursion.
// upb_decoder_frame is one frame of that stack.
typedef struct {
upb_msgdef *msgdef;
size_t end_offset; // For groups, 0.
} upb_decoder_frame;
struct _upb_decoder {
// Immutable state of the decoder.
upb_src src;
upb_dispatcher dispatcher;
upb_bytesrc *bytesrc;
upb_msgdef *toplevel_msgdef;
upb_decoder_frame stack[UPB_MAX_NESTING];
// Mutable state of the decoder.
// Where we will store any errors that occur.
upb_status *status;
// Stack entries store the offset where the submsg ends (for groups, 0).
upb_decoder_frame *top, *limit;
// Current input buffer.
upb_string *buf;
// Temporary string for passing to callbacks.
upb_string *tmp;
// The offset within the overall stream represented by the *beginning* of buf.
size_t buf_stream_offset;
};
// A upb_decoder decodes the binary protocol buffer format, writing the data it
// decodes to a upb_sink.
struct _upb_decoder;
typedef struct _upb_decoder upb_decoder;
// Allocates and frees a upb_decoder, respectively.
void upb_decoder_init(upb_decoder *d, upb_msgdef *md);
void upb_decoder_uninit(upb_decoder *d);
// Resets the internal state of an already-allocated decoder. This puts it in a
// state where it has not seen any data, and expects the next data to be from
// the beginning of a new protobuf. Parsers must be reset before they can be
// used. A decoder can be reset multiple times.
void upb_decoder_reset(upb_decoder *d, upb_bytesrc *bytesrc);
// Returns a upb_src pointer by which the decoder can be used. The returned
// upb_src is invalidated by upb_decoder_reset() or upb_decoder_free().
upb_src *upb_decoder_src(upb_decoder *d);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* UPB_DECODER_H_ */
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