Improvements, array support

git-svn-id: https://svn.kapsi.fi/jpa/nanopb@943 e3a754e5-d11d-0410-8d38-ebb782a927b9

1 files changed, 117 insertions, 45 deletions

diff --git a/pb.h b/pb.h
index 2cae75c..99e4bf7 100644
--- a/pb.h
+++ b/pb.h
@@ -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 {