-/* pb_decode.c -- decode a protobuf using callback functions
+/* pb_decode.c -- decode a protobuf using minimal resources
*
* 2011 Petteri Aimonen <jpa@kapsi.fi>
*/
+
+#ifdef __GNUC__
+/* Verify that we remember to check all return values for proper error propagation */
+#define checkreturn __attribute__((warn_unused_result))
+#else
+#define checkreturn
+#endif
+
+#include "pb.h"
#include "pb_decode.h"
+#include <string.h>
+
+typedef bool (*pb_decoder_t)(pb_istream_t *stream, const pb_field_t *field, void *dest) checkreturn;
-const pb_decoder_t PB_DECODERS[PB_LAST_ACT] = {
- NULL,
- &pb_dec_uint32,
- &pb_dec_sint32,
- &pb_dec_uint32, // Cast to int32
+/* --- Function pointers to field decoders ---
+ * Order in the array must match pb_action_t LTYPE numbering.
+ */
+static const pb_decoder_t PB_DECODERS[PB_LTYPES_COUNT] = {
+ &pb_dec_varint,
+ &pb_dec_svarint,
&pb_dec_fixed32,
- &pb_dec_fixed32, // Cast to int32
- &pb_dec_uint64,
- &pb_dec_sint64,
- &pb_dec_uint64, // Cast to int64
&pb_dec_fixed64,
- &pb_dec_fixed64, // Cast to int64
- &pb_dec_bool,
- &pb_dec_float,
- &pb_dec_double,
+
&pb_dec_bytes,
&pb_dec_string,
&pb_dec_submessage
};
-enum wire_type {
- WT_VARINT = 0,
- WT_64BIT = 1,
- WT_STRING = 2,
- WT_32BIT = 5
-};
+/**************
+ * pb_istream *
+ **************/
-// Note: pb_decode_varint32 is a bit un-orthodox:
-// it will refuse to decode values that exceed uint32 range.
-// The Google implementation would simply cast to 32 bits.
-bool pb_decode_varint32(pb_istream_t *stream, uint32_t *dest)
+bool checkreturn pb_read(pb_istream_t *stream, uint8_t *buf, size_t count)
{
- char byte;
- int bitpos = 0;
- *dest = 0;
+ if (stream->bytes_left < count)
+ return false;
- while (bitpos < 32 && pb_read(stream, &byte, 1))
- {
- *dest |= (byte & 0x7F) << bitpos;
- bitpos += 7;
-
- if (!(byte & 0x80))
- return true;
- }
+ if (!stream->callback(stream, buf, count))
+ return false;
- return false;
+ stream->bytes_left -= count;
+ return true;
}
-bool pb_decode_varint64(pb_istream_t *stream, uint64_t *dest)
+static bool checkreturn buf_read(pb_istream_t *stream, uint8_t *buf, size_t count)
{
- char byte;
- int bitpos = 0;
+ uint8_t *source = (uint8_t*)stream->state;
+
+ if (buf != NULL)
+ memcpy(buf, source, count);
+
+ stream->state = source + count;
+ return true;
+}
+
+pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize)
+{
+ pb_istream_t stream;
+ stream.callback = &buf_read;
+ stream.state = buf;
+ stream.bytes_left = bufsize;
+ return stream;
+}
+
+/********************
+ * Helper functions *
+ ********************/
+
+static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest)
+{
+ uint64_t temp;
+ bool status = pb_decode_varint(stream, &temp);
+ *dest = temp;
+ return status;
+}
+
+bool checkreturn pb_decode_varint(pb_istream_t *stream, uint64_t *dest)
+{
+ uint8_t byte;
+ uint8_t bitpos = 0;
*dest = 0;
while (bitpos < 64 && pb_read(stream, &byte, 1))
{
- *dest |= (byte & 0x7F) << bitpos;
+ *dest |= (uint64_t)(byte & 0x7F) << bitpos;
bitpos += 7;
if (!(byte & 0x80))
return false;
}
-bool pb_skip_varint(pb_istream_t *stream)
+bool checkreturn pb_skip_varint(pb_istream_t *stream)
{
- char byte;
+ uint8_t byte;
do
{
if (!pb_read(stream, &byte, 1))
return true;
}
-bool pb_skip_string(pb_istream_t *stream)
+bool checkreturn pb_skip_string(pb_istream_t *stream)
{
uint32_t length;
if (!pb_decode_varint32(stream, &length))
return pb_read(stream, NULL, length);
}
-bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest)
+/* Currently the wire type related stuff is kept hidden from
+ * callbacks. They shouldn't need it. It's better for performance
+ * to just assume the correct type and fail safely on corrupt message.
+ */
+
+static bool checkreturn skip(pb_istream_t *stream, pb_wire_type_t wire_type)
{
- while (stream->bytes_left)
+ switch (wire_type)
{
- uint32_t temp;
- if (!pb_decode_varint32(stream, &temp))
- return false;
+ case PB_WT_VARINT: return pb_skip_varint(stream);
+ case PB_WT_64BIT: return pb_read(stream, NULL, 8);
+ case PB_WT_STRING: return pb_skip_string(stream);
+ case PB_WT_32BIT: return pb_read(stream, NULL, 4);
+ default: return false;
+ }
+}
+
+/* Read a raw value to buffer, for the purpose of passing it to callback as
+ * a substream. Size is maximum size on call, and actual size on return.
+ */
+static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size)
+{
+ size_t max_size = *size;
+ switch (wire_type)
+ {
+ case PB_WT_VARINT:
+ *size = 0;
+ do
+ {
+ (*size)++;
+ if (*size > max_size) return false;
+ if (!pb_read(stream, buf, 1)) return false;
+ } while (*buf++ & 0x80);
+ return true;
+
+ case PB_WT_64BIT:
+ *size = 8;
+ return pb_read(stream, buf, 8);
- int field_number = temp >> 3;
- int wire_type = temp & 7;
+ case PB_WT_32BIT:
+ *size = 4;
+ return pb_read(stream, buf, 4);
- const pb_field_t *field = fields;
- while (field->field_number != 0)
- {
- if (field->field_number != field_number)
+ default: return false;
+ }
+}
+
+/* Decode string length from stream and return a substream with limited length.
+ * Before disposing the substream, remember to copy the substream->state back
+ * to stream->state.
+ */
+static bool checkreturn make_string_substream(pb_istream_t *stream, pb_istream_t *substream)
+{
+ uint32_t size;
+ if (!pb_decode_varint32(stream, &size))
+ return false;
+
+ *substream = *stream;
+ if (substream->bytes_left < size)
+ return false;
+
+ substream->bytes_left = size;
+ stream->bytes_left -= size;
+ return true;
+}
+
+/* Iterator for pb_field_t list */
+typedef struct {
+ const pb_field_t *start;
+ const pb_field_t *current;
+ int field_index;
+ void *dest_struct;
+ void *pData;
+ void *pSize;
+} pb_field_iterator_t;
+
+static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct)
+{
+ iter->start = iter->current = fields;
+ iter->field_index = 0;
+ iter->pData = (char*)dest_struct + iter->current->data_offset;
+ iter->pSize = (char*)iter->pData + iter->current->size_offset;
+ iter->dest_struct = dest_struct;
+}
+
+static bool pb_field_next(pb_field_iterator_t *iter)
+{
+ bool notwrapped = true;
+ size_t prev_size = iter->current->data_size;
+
+ if (PB_HTYPE(iter->current->type) == PB_HTYPE_ARRAY)
+ prev_size *= iter->current->array_size;
+
+ iter->current++;
+ iter->field_index++;
+ if (iter->current->tag == 0)
+ {
+ iter->current = iter->start;
+ iter->field_index = 0;
+ iter->pData = iter->dest_struct;
+ prev_size = 0;
+ notwrapped = false;
+ }
+
+ iter->pData = (char*)iter->pData + prev_size + iter->current->data_offset;
+ iter->pSize = (char*)iter->pData + iter->current->size_offset;
+ return notwrapped;
+}
+
+static bool checkreturn pb_field_find(pb_field_iterator_t *iter, int tag)
+{
+ int start = iter->field_index;
+
+ do {
+ if (iter->current->tag == tag)
+ return true;
+ pb_field_next(iter);
+ } while (iter->field_index != start);
+
+ return false;
+}
+
+/*************************
+ * Decode a single field *
+ *************************/
+
+static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+{
+ pb_decoder_t func = PB_DECODERS[PB_LTYPE(iter->current->type)];
+
+ switch (PB_HTYPE(iter->current->type))
+ {
+ case PB_HTYPE_REQUIRED:
+ return func(stream, iter->current, iter->pData);
+
+ case PB_HTYPE_OPTIONAL:
+ *(bool*)iter->pSize = true;
+ return func(stream, iter->current, iter->pData);
+
+ case PB_HTYPE_ARRAY:
+ if (wire_type == PB_WT_STRING
+ && PB_LTYPE(iter->current->type) <= PB_LTYPE_LAST_PACKABLE)
{
- field++;
- continue;
+ /* Packed array */
+ size_t *size = (size_t*)iter->pSize;
+ pb_istream_t substream;
+ if (!make_string_substream(stream, &substream))
+ return false;
+
+ while (substream.bytes_left && *size < iter->current->array_size)
+ {
+ void *pItem = (uint8_t*)iter->pData + iter->current->data_size * (*size);
+ if (!func(&substream, iter->current, pItem))
+ return false;
+ (*size)++;
+ }
+ return (substream.bytes_left == 0);
}
-
- void *destfield = dest + field->offset;
-
- if (field->action == PB_ACT_HAS)
+ else
{
- *(bool*)destfield = true;
- field++;
- continue;
+ /* Repeated field */
+ size_t *size = (size_t*)iter->pSize;
+ void *pItem = (uint8_t*)iter->pData + iter->current->data_size * (*size);
+ if (*size >= iter->current->array_size)
+ return false;
+
+ (*size)++;
+ return func(stream, iter->current, pItem);
}
-
- pb_decoder_t func = PB_DECODERS[field->action];
- if (!func(stream, field, destfield))
- return false;
-
- break;
- }
- if (field->field_number == 0) // No match found, skip data
+ case PB_HTYPE_CALLBACK:
{
- bool status = false;
- switch (wire_type)
+ pb_callback_t *pCallback = (pb_callback_t*)iter->pData;
+
+ if (pCallback->funcs.decode == NULL)
+ return skip(stream, wire_type);
+
+ if (wire_type == PB_WT_STRING)
{
- case WT_VARINT:
- status = pb_skip_varint(stream);
- break;
+ pb_istream_t substream;
- case WT_64BIT:
- status = pb_read(stream, NULL, 8);
- break;
+ if (!make_string_substream(stream, &substream))
+ return false;
- case WT_STRING:
- status = pb_skip_string(stream);
- break;
+ while (substream.bytes_left)
+ {
+ if (!pCallback->funcs.decode(&substream, iter->current, pCallback->arg))
+ return false;
+ }
- case WT_32BIT:
- status = pb_read(stream, NULL, 4);
- break;
+ stream->state = substream.state;
+ return true;
+ }
+ else
+ {
+ /* Copy the single scalar value to stack.
+ * This is required so that we can limit the stream length,
+ * which in turn allows to use same callback for packed and
+ * not-packed fields. */
+ pb_istream_t substream;
+ uint8_t buffer[10];
+ size_t size = sizeof(buffer);
+
+ if (!read_raw_value(stream, wire_type, buffer, &size))
+ return false;
+ substream = pb_istream_from_buffer(buffer, size);
+
+ return pCallback->funcs.decode(&substream, iter->current, pCallback->arg);
}
-
- if (!status)
- return false;
}
+
+ default:
+ return false;
}
-
- return true;
}
-bool pb_dec_uint32(pb_istream_t *stream, const pb_field_t *field, void *dest)
+/* Initialize message fields to default values, recursively */
+static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct)
{
- return pb_decode_varint32(stream, (uint32_t*)dest);
+ pb_field_iterator_t iter;
+ pb_field_init(&iter, fields, dest_struct);
+
+ /* Initialize size/has fields and apply default values */
+ do
+ {
+ if (iter.current->tag == 0)
+ continue;
+
+ /* Initialize the size field for optional/repeated fields to 0. */
+ if (PB_HTYPE(iter.current->type) == PB_HTYPE_OPTIONAL)
+ {
+ *(bool*)iter.pSize = false;
+ }
+ else if (PB_HTYPE(iter.current->type) == PB_HTYPE_ARRAY)
+ {
+ *(size_t*)iter.pSize = 0;
+ continue; /* Array is empty, no need to initialize contents */
+ }
+
+ /* Initialize field contents to default value */
+ if (PB_HTYPE(iter.current->type) == PB_HTYPE_CALLBACK)
+ {
+ continue; /* Don't overwrite callback */
+ }
+ else if (PB_LTYPE(iter.current->type) == PB_LTYPE_SUBMESSAGE)
+ {
+ pb_message_set_to_defaults(iter.current->ptr, iter.pData);
+ }
+ else if (iter.current->ptr != NULL)
+ {
+ memcpy(iter.pData, iter.current->ptr, iter.current->data_size);
+ }
+ else
+ {
+ memset(iter.pData, 0, iter.current->data_size);
+ }
+ } while (pb_field_next(&iter));
}
-bool pb_dec_sint32(pb_istream_t *stream, const pb_field_t *field, void *dest)
-{
- uint32_t *x = (uint32_t*)dest;
- bool status = pb_decode_varint32(stream, x);
- *x = (*x >> 1) ^ -(int32_t)(*x & 1);
- return status;
-}
+/*********************
+ * Decode all fields *
+ *********************/
-bool pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest)
+bool checkreturn pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
{
- char bytes[4] = {0};
- bool status = pb_read(stream, bytes, 4);
- *(uint32_t*)dest =
- bytes[0] | ((uint32_t)bytes[1] << 8) |
- ((uint32_t)bytes[2] << 16) | ((uint32_t)bytes[3] << 24);
- return status;
+ uint32_t fields_seen = 0; /* Used to check for required fields */
+ pb_field_iterator_t iter;
+ int i;
+
+ pb_message_set_to_defaults(fields, dest_struct);
+
+ pb_field_init(&iter, fields, dest_struct);
+
+ while (stream->bytes_left)
+ {
+ uint32_t temp;
+ int tag;
+ pb_wire_type_t wire_type;
+ if (!pb_decode_varint32(stream, &temp))
+ {
+ if (stream->bytes_left == 0)
+ break; /* It was EOF */
+ else
+ return false; /* It was error */
+ }
+
+ if (temp == 0)
+ break; /* Special feature: allow 0-terminated messages. */
+
+ tag = temp >> 3;
+ wire_type = (pb_wire_type_t)(temp & 7);
+
+ if (!pb_field_find(&iter, tag))
+ {
+ /* No match found, skip data */
+ if (!skip(stream, wire_type))
+ return false;
+ continue;
+ }
+
+ fields_seen |= 1 << (iter.field_index & 31);
+
+ if (!decode_field(stream, wire_type, &iter))
+ return false;
+ }
+
+ /* Check that all required fields (mod 31) were present. */
+ for (i = 0; fields[i].tag != 0; i++)
+ {
+ if (PB_HTYPE(fields[i].type) == PB_HTYPE_REQUIRED &&
+ !(fields_seen & (1 << (i & 31))))
+ {
+ return false;
+ }
+ }
+
+ return true;
}
-bool pb_dec_uint64(pb_istream_t *stream, const pb_field_t *field, void *dest)
-{
- return pb_decode_varint64(stream, (uint64_t*)dest);
-}
+/* Field decoders */
-bool pb_dec_sint64(pb_istream_t *stream, const pb_field_t *field, void *dest)
+/* Copy destsize bytes from src so that values are casted properly.
+ * On little endian machine, copy first n bytes of src
+ * On big endian machine, copy last n bytes of src
+ * srcsize must always be larger than destsize
+ */
+static void endian_copy(void *dest, void *src, size_t destsize, size_t srcsize)
{
- uint64_t *x = (uint64_t*)dest;
- bool status = pb_decode_varint64(stream, x);
- *x = (*x >> 1) ^ -(int64_t)(*x & 1);
- return status;
+#ifdef __BIG_ENDIAN__
+ memcpy(dest, (char*)src + (srcsize - destsize), destsize);
+#else
+ memcpy(dest, src, destsize);
+#endif
}
-bool pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest)
+bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest)
{
- char bytes[8] = {0};
- bool status = pb_read(stream, bytes, 8);
- *(uint64_t*)dest =
- (uint64_t)bytes[0] | ((uint64_t)bytes[1] << 8) |
- ((uint64_t)bytes[2] << 16) | ((uint64_t)bytes[3] << 24) |
- ((uint64_t)bytes[4] << 32) | ((uint64_t)bytes[5] << 40) |
- ((uint64_t)bytes[6] << 48) | ((uint64_t)bytes[7] << 56);
+ uint64_t temp;
+ bool status = pb_decode_varint(stream, &temp);
+ endian_copy(dest, &temp, field->data_size, sizeof(temp));
return status;
}
-bool pb_dec_bool(pb_istream_t *stream, const pb_field_t *field, void *dest)
+bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest)
{
- uint32_t temp = 0;
- bool status = pb_decode_varint32(stream, &temp);
- *(bool*)dest = !!temp;
+ uint64_t temp;
+ bool status = pb_decode_varint(stream, &temp);
+ temp = (temp >> 1) ^ -(int64_t)(temp & 1);
+ endian_copy(dest, &temp, field->data_size, sizeof(temp));
return status;
}
-bool pb_dec_float(pb_istream_t *stream, const pb_field_t *field, void *dest)
+bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest)
{
- return pb_read(stream, (char*)dest, sizeof(float));
+#ifdef __BIG_ENDIAN__
+ uint8_t bytes[4] = {0};
+ bool status = pb_read(stream, bytes, 4);
+ if (status) {
+ uint8_t bebytes[4] = {bytes[3], bytes[2], bytes[1], bytes[0]};
+ memcpy(dest, bebytes, 4);
+ }
+ return status;
+#else
+ return pb_read(stream, (uint8_t*)dest, 4);
+#endif
}
-bool pb_dec_double(pb_istream_t *stream, const pb_field_t *field, void *dest)
+bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest)
{
- return pb_read(stream, (char*)dest, sizeof(double));
+#ifdef __BIG_ENDIAN__
+ uint8_t bytes[8] = {0};
+ bool status = pb_read(stream, bytes, 8);
+ if (status) {
+ uint8_t bebytes[8] = {bytes[7], bytes[6], bytes[5], bytes[4],
+ bytes[3], bytes[2], bytes[1], bytes[0]};
+ memcpy(dest, bebytes, 8);
+ }
+ return status;
+#else
+ return pb_read(stream, (uint8_t*)dest, 8);
+#endif
}
-bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest)
+bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest)
{
- pb_bytearray_t *x = (pb_bytearray_t*)dest;
+ pb_bytes_array_t *x = (pb_bytes_array_t*)dest;
+
uint32_t temp;
if (!pb_decode_varint32(stream, &temp))
return false;
x->size = temp;
- if (x->size > field->fieldsize)
+ /* Check length, noting the space taken by the size_t header. */
+ if (x->size > field->data_size - offsetof(pb_bytes_array_t, bytes))
return false;
return pb_read(stream, x->bytes, x->size);
}
-bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest)
+bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest)
{
uint32_t size;
+ bool status;
if (!pb_decode_varint32(stream, &size))
return false;
- if (size > field->fieldsize - 1)
+ /* Check length, noting the null terminator */
+ if (size > field->data_size - 1)
return false;
- bool status = pb_read(stream, (char*)dest, size);
- *((char*)dest + size) = 0;
+ status = pb_read(stream, (uint8_t*)dest, size);
+ *((uint8_t*)dest + size) = 0;
return status;
}
-bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
+bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
{
- pb_callback_t *x = (pb_callback_t*)dest;
-
- if (x->funcs.decode == NULL)
- return pb_skip_string(stream);
+ bool status;
+ pb_istream_t substream;
- uint32_t size;
- if (!pb_decode_varint32(stream, &size))
+ if (!make_string_substream(stream, &substream))
return false;
- if (stream->bytes_left < size)
+ if (field->ptr == NULL)
return false;
- // Make a limited-length istream for decoding submessage
- pb_istream_t shortstream = *stream;
- shortstream.bytes_left = size;
- bool status = x->funcs.decode(&shortstream, field, x->arg);
- stream->bytes_left -= size - shortstream.bytes_left;
+ status = pb_decode(&substream, (pb_field_t*)field->ptr, dest);
+ stream->state = substream.state;
return status;
}
Code Review / apps / agl-service-can-low-level.git / blobdiff