First version of decoding

git-svn-id: https://svn.kapsi.fi/jpa/nanopb@942 e3a754e5-d11d-0410-8d38-ebb782a927b9

1 files changed, 107 insertions, 0 deletions

diff --git a/pb.h b/pb.h
new file mode 100644
index 0000000..2cae75c
--- /dev/null
+++ b/pb.h
@@ -0,0 +1,107 @@
+#ifndef _PB_H_
+#define _PB_H_
+
+#include <stdint.h>
+#include <stddef.h> // size_t
+
+/* Lightweight input stream.
+ * If buf is NULL, read but don't store bytes. */
+typedef struct _pb_istream_t pb_istream_t;
+struct _pb_istream_t
+{
+    bool (*callback)(pb_istream_t *stream, char *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)
+{
+    bool status = stream->callback(stream, buf, count);
+    stream->bytes_left -= count;
+    return status;
+}
+
+/* Lightweight output stream. */
+typedef struct _pb_ostream_t pb_ostream_t;
+struct _pb_ostream_t
+{
+    bool (*callback)(pb_ostream_t *stream, const char *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)
+{
+    bool status = stream->callback(stream, buf, count);
+    stream->bytes_written += count;
+    return status;
+}
+
+/* List of possible decode/encode action types */
+
+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,
+    
+    // Standard float types
+    PB_ACT_FLOAT,
+    PB_ACT_DOUBLE,
+    
+    // Constant-sized array
+    PB_ACT_BYTES,
+    
+    // Constant-sized array, with null termination
+    PB_ACT_STRING,
+    
+    // Callback function pointer in field value
+    PB_ACT_SUBMESSAGE,
+    
+    PB_LAST_ACT
+} pb_action_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_LAST_FIELD {0,0,0,0}
+
+/* --- Types to use inside generated structures. --- */
+
+// 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;
+
+// This structure is used for giving the callback function.
+typedef struct _pb_callback_t pb_callback_t;
+struct _pb_callback_t {
+    union {
+        bool (*decode)(pb_istream_t *stream, const pb_field_t *field, void *arg);
+        bool (*encode)(pb_ostream_t *stream, const pb_field_t *field, void *arg);
+    } funcs;
+    
+    // Free arg for use by callback
+    void *arg;
+};
+
+#endif
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