diff options
| -rw-r--r-- | docs/reference.rst | 17 | ||||
| -rw-r--r-- | generator/nanopb_generator.py | 63 | ||||
| -rw-r--r-- | pb.h | 19 |
3 files changed, 65 insertions, 34 deletions
diff --git a/docs/reference.rst b/docs/reference.rst index aefc25f7..3331c6d3 100644 --- a/docs/reference.rst +++ b/docs/reference.rst @@ -10,14 +10,21 @@ Compilation options =================== The following options can be specified using -D switch given to the C compiler: -============================ ============================================================================================== +============================ ================================================================================================ __BIG_ENDIAN__ Set this if your platform stores integers and floats in big-endian format. Mixed-endian systems (different layout for ints and floats) are currently not supported. NANOPB_INTERNALS Set this to expose the field encoder functions that are hidden since nanopb-0.1.3. -PB_MAX_REQUIRED_FIELDS Maximum number of required fields to check for presence. Default value is 64. -PB_MANY_FIELDS Add support for tag numbers > 255 and fields larger than 255 bytes or 255 array entries. +PB_MAX_REQUIRED_FIELDS Maximum number of required fields to check for presence. Default value is 64. Increases stack + usage 1 byte per every 8 fields. Compiler warning will tell if you need this. +PB_FIELD_16BIT Add support for tag numbers > 255 and fields larger than 255 bytes or 255 array entries. + Increases code size 3 bytes per each field. Compiler error will tell if you need this. +PB_FIELD_32BIT Add support for tag numbers > 65535 and fields larger than 65535 bytes or 65535 array entries. Increases code size 9 bytes per each field. Compiler error will tell if you need this. -============================ ============================================================================================== +============================ ================================================================================================ + +The PB_MAX_REQUIRED_FIELDS, PB_FIELD_16BIT and PB_FIELD_32BIT settings allow raising some datatype limits to suit larger messages. +Their need is recognized automatically by C-preprocessor #if-directives in the generated .pb.h files. The default setting is to use +the smallest datatypes (least resources used). pb.h ==== @@ -79,7 +86,7 @@ Describes a single structure field with memory position in relation to others. T :array_size: Maximum number of entries in an array, if it is an array type. :ptr: Pointer to default value for optional fields, or to submessage description for PB_LTYPE_SUBMESSAGE. -The *uint8_t* datatypes limit the maximum size of a single item to 255 bytes and arrays to 255 items. Compiler will give error if the values are too large. The types can be changed to larger ones by defining *PB_MANY_FIELDS*. +The *uint8_t* datatypes limit the maximum size of a single item to 255 bytes and arrays to 255 items. Compiler will give error if the values are too large. The types can be changed to larger ones by defining *PB_FIELD_16BIT*. pb_bytes_array_t ---------------- diff --git a/generator/nanopb_generator.py b/generator/nanopb_generator.py index 405fedaf..9e2a30ed 100644 --- a/generator/nanopb_generator.py +++ b/generator/nanopb_generator.py @@ -252,19 +252,17 @@ class Field: return result - def needs_32bit_pb_field_t(self): - '''Determine if this field needs 32bit pb_field_t structure to compile properly. - Returns True, False or a C-expression for assert.''' - if self.tag > 255 or self.max_size > 255: - return True - + def largest_field_value(self): + '''Determine if this field needs 16bit or 32bit pb_field_t structure to compile properly. + Returns numeric value or a C-expression for assert.''' if self.ltype == 'PB_LTYPE_SUBMESSAGE': if self.htype == 'PB_HTYPE_ARRAY': - return 'pb_membersize(%s, %s[0]) > 255' % (self.struct_name, self.name) + return 'pb_membersize(%s, %s[0])' % (self.struct_name, self.name) else: - return 'pb_membersize(%s, %s) > 255' % (self.struct_name, self.name) - - return False + return 'pb_membersize(%s, %s)' % (self.struct_name, self.name) + + return max(self.tag, self.max_size, self.max_count) + class Message: def __init__(self, names, desc): @@ -426,28 +424,41 @@ def generate_header(dependencies, headername, enums, messages): yield ' setting PB_MAX_REQUIRED_FIELDS to %d or more.\n' % largest_count yield '#endif\n' - worst = False + worst = 0 worst_field = '' + checks = [] for msg in messages: for field in msg.fields: - status = field.needs_32bit_pb_field_t() - if status == True: - worst = True + status = field.largest_field_value() + if isinstance(status, (str, unicode)): + checks.append(status) + elif status > worst: + worst = status worst_field = str(field.struct_name) + '.' + str(field.name) - elif status != False: - if worst == False: - worst = status - elif worst != True: - worst += ' || ' + status - if worst != False: + if worst > 255 or checks: yield '\n/* Check that field information fits in pb_field_t */\n' - yield '#ifndef PB_MANY_FIELDS\n' - if worst == True: - yield '#error Field descriptor for %s is too large. Define PB_MANY_FIELDS to fix this.\n' % worst_field - else: - yield 'STATIC_ASSERT(!(%s), YOU_MUST_DEFINE_PB_MANY_FIELDS)\n' % worst - yield '#endif\n' + yield '/* (Largest message has %d fields' % worst + if checks: yield ' and submessages have to be checked at compile-time.' + yield ') */\n' + + if worst < 65536: + yield '#if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)\n' + if worst > 255: + yield '#error Field descriptor for %s is too large. Define PB_FIELD_16BIT to fix this.\n' % worst_field + else: + assertion = ' && '.join(str(c) + ' < 256' for c in checks) + yield 'STATIC_ASSERT((%s), YOU_MUST_DEFINE_PB_FIELD_16BIT)\n' % assertion + yield '#endif\n\n' + + if worst > 65535 or checks: + yield '#if !defined(PB_FIELD_32BIT)\n' + if worst > 65535: + yield '#error Field descriptor for %s is too large. Define PB_FIELD_32BIT to fix this.\n' % worst_field + else: + assertion = ' && '.join(str(c) + ' < 65536' for c in checks) + yield 'STATIC_ASSERT((%s), YOU_MUST_DEFINE_PB_FIELD_32BIT)\n' % assertion + yield '#endif\n' # End of header yield '\n#endif\n' @@ -33,6 +33,11 @@ #define PB_MAX_REQUIRED_FIELDS 64 #endif +#if PB_MAX_REQUIRED_FIELDS < 64 +#warning You should not lower PB_MAX_REQUIRED_FIELDS from the default value (64). \ + The automatic checks against too low value will not be active. +#endif + /* List of possible field types. These are used in the autogenerated code. * Least-significant 4 bits tell the scalar type * Most-significant 4 bits specify repeated/required/packed etc. @@ -99,21 +104,29 @@ typedef enum { /* This structure is used in auto-generated constants * to specify struct fields. - * You can change field sizes here if you need structures + * You can change field sizes 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"). + * structures. Fix that by defining PB_FIELD_16BIT or + * PB_FIELD_32BIT. */ typedef struct _pb_field_t pb_field_t; struct _pb_field_t { -#ifndef PB_MANY_FIELDS +#if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT) uint8_t tag; pb_type_t type; uint8_t data_offset; /* Offset of field data, relative to previous field. */ int8_t size_offset; /* Offset of array size or has-boolean, relative to data */ uint8_t data_size; /* Data size in bytes for a single item */ uint8_t array_size; /* Maximum number of entries in array */ +#elif defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT) + uint16_t tag; + pb_type_t type; + uint8_t data_offset; + int8_t size_offset; + uint16_t data_size; + uint16_t array_size; #else uint32_t tag; pb_type_t type; |