diff options
author | Joshua Haberman <joshua@reverberate.org> | 2011-02-13 12:59:54 -0800 |
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committer | Joshua Haberman <joshua@reverberate.org> | 2011-02-13 12:59:54 -0800 |
commit | 6bdbb45e88e7b88b294dfb6e4cb493cbc3c8cf74 (patch) | |
tree | 0e00246fb124ebdf6a2210c816704c1d840e2138 /src/upb_decoder.h | |
parent | ee84a7da167d2211066c4a663d41febdf9544438 (diff) |
Merged core/ and stream/ -> src/. The split wasn't worth it.
Diffstat (limited to 'src/upb_decoder.h')
-rw-r--r-- | src/upb_decoder.h | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/src/upb_decoder.h b/src/upb_decoder.h new file mode 100644 index 0000000..1c62753 --- /dev/null +++ b/src/upb_decoder.h @@ -0,0 +1,86 @@ +/* + * 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_ */ |