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/*
* Copyright 2017 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef FLATBUFFERS_MINIREFLECT_H_
#define FLATBUFFERS_MINIREFLECT_H_
#include "flatbuffers/flatbuffers.h"
#include "flatbuffers/util.h"
namespace flatbuffers {
// Utilities that can be used with the "mini reflection" tables present
// in generated code with --reflect-types (only types) or --reflect-names
// (also names).
// This allows basic reflection functionality such as pretty-printing
// that does not require the use of the schema parser or loading of binary
// schema files at runtime (reflection.h).
// For any of the functions below that take `const TypeTable *`, you pass
// `FooTypeTable()` if the type of the root is `Foo`.
// First, a generic iterator that can be used by multiple algorithms.
struct IterationVisitor {
// These mark the scope of a table or struct.
virtual void StartSequence() {}
virtual void EndSequence() {}
// Called for each field regardless of whether it is present or not.
// If not present, val == nullptr. set_idx is the index of all set fields.
virtual void Field(size_t /*field_idx*/, size_t /*set_idx*/,
ElementaryType /*type*/, bool /*is_vector*/,
const TypeTable * /*type_table*/, const char * /*name*/,
const uint8_t * /*val*/) {}
// Called for a value that is actually present, after a field, or as part
// of a vector.
virtual void UType(uint8_t, const char *) {}
virtual void Bool(bool) {}
virtual void Char(int8_t, const char *) {}
virtual void UChar(uint8_t, const char *) {}
virtual void Short(int16_t, const char *) {}
virtual void UShort(uint16_t, const char *) {}
virtual void Int(int32_t, const char *) {}
virtual void UInt(uint32_t, const char *) {}
virtual void Long(int64_t) {}
virtual void ULong(uint64_t) {}
virtual void Float(float) {}
virtual void Double(double) {}
virtual void String(const String *) {}
virtual void Unknown(const uint8_t *) {} // From a future version.
// These mark the scope of a vector.
virtual void StartVector() {}
virtual void EndVector() {}
virtual void Element(size_t /*i*/, ElementaryType /*type*/,
const TypeTable * /*type_table*/,
const uint8_t * /*val*/) {}
virtual ~IterationVisitor() {}
};
inline size_t InlineSize(ElementaryType type, const TypeTable *type_table) {
switch (type) {
case ET_UTYPE:
case ET_BOOL:
case ET_CHAR:
case ET_UCHAR: return 1;
case ET_SHORT:
case ET_USHORT: return 2;
case ET_INT:
case ET_UINT:
case ET_FLOAT:
case ET_STRING: return 4;
case ET_LONG:
case ET_ULONG:
case ET_DOUBLE: return 8;
case ET_SEQUENCE:
switch (type_table->st) {
case ST_TABLE:
case ST_UNION: return 4;
case ST_STRUCT:
return static_cast<size_t>(type_table->values[type_table->num_elems]);
default: FLATBUFFERS_ASSERT(false); return 1;
}
default: FLATBUFFERS_ASSERT(false); return 1;
}
}
inline int64_t LookupEnum(int64_t enum_val, const int64_t *values,
size_t num_values) {
if (!values) return enum_val;
for (size_t i = 0; i < num_values; i++) {
if (enum_val == values[i]) return static_cast<int64_t>(i);
}
return -1; // Unknown enum value.
}
template<typename T> const char *EnumName(T tval, const TypeTable *type_table) {
if (!type_table || !type_table->names) return nullptr;
auto i = LookupEnum(static_cast<int64_t>(tval), type_table->values,
type_table->num_elems);
if (i >= 0 && i < static_cast<int64_t>(type_table->num_elems)) {
return type_table->names[i];
}
return nullptr;
}
void IterateObject(const uint8_t *obj, const TypeTable *type_table,
IterationVisitor *visitor);
inline void IterateValue(ElementaryType type, const uint8_t *val,
const TypeTable *type_table, const uint8_t *prev_val,
soffset_t vector_index, IterationVisitor *visitor) {
switch (type) {
case ET_UTYPE: {
auto tval = ReadScalar<uint8_t>(val);
visitor->UType(tval, EnumName(tval, type_table));
break;
}
case ET_BOOL: {
visitor->Bool(ReadScalar<uint8_t>(val) != 0);
break;
}
case ET_CHAR: {
auto tval = ReadScalar<int8_t>(val);
visitor->Char(tval, EnumName(tval, type_table));
break;
}
case ET_UCHAR: {
auto tval = ReadScalar<uint8_t>(val);
visitor->UChar(tval, EnumName(tval, type_table));
break;
}
case ET_SHORT: {
auto tval = ReadScalar<int16_t>(val);
visitor->Short(tval, EnumName(tval, type_table));
break;
}
case ET_USHORT: {
auto tval = ReadScalar<uint16_t>(val);
visitor->UShort(tval, EnumName(tval, type_table));
break;
}
case ET_INT: {
auto tval = ReadScalar<int32_t>(val);
visitor->Int(tval, EnumName(tval, type_table));
break;
}
case ET_UINT: {
auto tval = ReadScalar<uint32_t>(val);
visitor->UInt(tval, EnumName(tval, type_table));
break;
}
case ET_LONG: {
visitor->Long(ReadScalar<int64_t>(val));
break;
}
case ET_ULONG: {
visitor->ULong(ReadScalar<uint64_t>(val));
break;
}
case ET_FLOAT: {
visitor->Float(ReadScalar<float>(val));
break;
}
case ET_DOUBLE: {
visitor->Double(ReadScalar<double>(val));
break;
}
case ET_STRING: {
val += ReadScalar<uoffset_t>(val);
visitor->String(reinterpret_cast<const String *>(val));
break;
}
case ET_SEQUENCE: {
switch (type_table->st) {
case ST_TABLE:
val += ReadScalar<uoffset_t>(val);
IterateObject(val, type_table, visitor);
break;
case ST_STRUCT: IterateObject(val, type_table, visitor); break;
case ST_UNION: {
val += ReadScalar<uoffset_t>(val);
FLATBUFFERS_ASSERT(prev_val);
auto union_type = *prev_val; // Always a uint8_t.
if (vector_index >= 0) {
auto type_vec = reinterpret_cast<const Vector<uint8_t> *>(prev_val);
union_type = type_vec->Get(static_cast<uoffset_t>(vector_index));
}
auto type_code_idx =
LookupEnum(union_type, type_table->values, type_table->num_elems);
if (type_code_idx >= 0 &&
type_code_idx < static_cast<int32_t>(type_table->num_elems)) {
auto type_code = type_table->type_codes[type_code_idx];
switch (type_code.base_type) {
case ET_SEQUENCE: {
auto ref = type_table->type_refs[type_code.sequence_ref]();
IterateObject(val, ref, visitor);
break;
}
case ET_STRING:
visitor->String(reinterpret_cast<const String *>(val));
break;
default: visitor->Unknown(val);
}
} else {
visitor->Unknown(val);
}
break;
}
case ST_ENUM: FLATBUFFERS_ASSERT(false); break;
}
break;
}
default: {
visitor->Unknown(val);
break;
}
}
}
inline void IterateObject(const uint8_t *obj, const TypeTable *type_table,
IterationVisitor *visitor) {
visitor->StartSequence();
const uint8_t *prev_val = nullptr;
size_t set_idx = 0;
size_t array_idx = 0;
for (size_t i = 0; i < type_table->num_elems; i++) {
auto type_code = type_table->type_codes[i];
auto type = static_cast<ElementaryType>(type_code.base_type);
auto is_repeating = type_code.is_repeating != 0;
auto ref_idx = type_code.sequence_ref;
const TypeTable *ref = nullptr;
if (ref_idx >= 0) { ref = type_table->type_refs[ref_idx](); }
auto name = type_table->names ? type_table->names[i] : nullptr;
const uint8_t *val = nullptr;
if (type_table->st == ST_TABLE) {
val = reinterpret_cast<const Table *>(obj)->GetAddressOf(
FieldIndexToOffset(static_cast<voffset_t>(i)));
} else {
val = obj + type_table->values[i];
}
visitor->Field(i, set_idx, type, is_repeating, ref, name, val);
if (val) {
set_idx++;
if (is_repeating) {
auto elem_ptr = val;
size_t size = 0;
if (type_table->st == ST_TABLE) {
// variable length vector
val += ReadScalar<uoffset_t>(val);
auto vec = reinterpret_cast<const Vector<uint8_t> *>(val);
elem_ptr = vec->Data();
size = vec->size();
} else {
// otherwise fixed size array
size = type_table->array_sizes[array_idx];
++array_idx;
}
visitor->StartVector();
for (size_t j = 0; j < size; j++) {
visitor->Element(j, type, ref, elem_ptr);
IterateValue(type, elem_ptr, ref, prev_val, static_cast<soffset_t>(j),
visitor);
elem_ptr += InlineSize(type, ref);
}
visitor->EndVector();
} else {
IterateValue(type, val, ref, prev_val, -1, visitor);
}
}
prev_val = val;
}
visitor->EndSequence();
}
inline void IterateFlatBuffer(const uint8_t *buffer,
const TypeTable *type_table,
IterationVisitor *callback) {
IterateObject(GetRoot<uint8_t>(buffer), type_table, callback);
}
// Outputting a Flatbuffer to a string. Tries to conform as close to JSON /
// the output generated by idl_gen_text.cpp.
struct ToStringVisitor : public IterationVisitor {
std::string s;
std::string d;
bool q;
std::string in;
size_t indent_level;
bool vector_delimited;
ToStringVisitor(std::string delimiter, bool quotes, std::string indent,
bool vdelimited = true)
: d(delimiter),
q(quotes),
in(indent),
indent_level(0),
vector_delimited(vdelimited) {}
ToStringVisitor(std::string delimiter)
: d(delimiter),
q(false),
in(""),
indent_level(0),
vector_delimited(true) {}
void append_indent() {
for (size_t i = 0; i < indent_level; i++) { s += in; }
}
void StartSequence() {
s += "{";
s += d;
indent_level++;
}
void EndSequence() {
s += d;
indent_level--;
append_indent();
s += "}";
}
void Field(size_t /*field_idx*/, size_t set_idx, ElementaryType /*type*/,
bool /*is_vector*/, const TypeTable * /*type_table*/,
const char *name, const uint8_t *val) {
if (!val) return;
if (set_idx) {
s += ",";
s += d;
}
append_indent();
if (name) {
if (q) s += "\"";
s += name;
if (q) s += "\"";
s += ": ";
}
}
template<typename T> void Named(T x, const char *name) {
if (name) {
if (q) s += "\"";
s += name;
if (q) s += "\"";
} else {
s += NumToString(x);
}
}
void UType(uint8_t x, const char *name) { Named(x, name); }
void Bool(bool x) { s += x ? "true" : "false"; }
void Char(int8_t x, const char *name) { Named(x, name); }
void UChar(uint8_t x, const char *name) { Named(x, name); }
void Short(int16_t x, const char *name) { Named(x, name); }
void UShort(uint16_t x, const char *name) { Named(x, name); }
void Int(int32_t x, const char *name) { Named(x, name); }
void UInt(uint32_t x, const char *name) { Named(x, name); }
void Long(int64_t x) { s += NumToString(x); }
void ULong(uint64_t x) { s += NumToString(x); }
void Float(float x) { s += NumToString(x); }
void Double(double x) { s += NumToString(x); }
void String(const struct String *str) {
EscapeString(str->c_str(), str->size(), &s, true, false);
}
void Unknown(const uint8_t *) { s += "(?)"; }
void StartVector() {
s += "[";
if (vector_delimited) {
s += d;
indent_level++;
append_indent();
} else {
s += " ";
}
}
void EndVector() {
if (vector_delimited) {
s += d;
indent_level--;
append_indent();
} else {
s += " ";
}
s += "]";
}
void Element(size_t i, ElementaryType /*type*/,
const TypeTable * /*type_table*/, const uint8_t * /*val*/) {
if (i) {
s += ",";
if (vector_delimited) {
s += d;
append_indent();
} else {
s += " ";
}
}
}
};
inline std::string FlatBufferToString(const uint8_t *buffer,
const TypeTable *type_table,
bool multi_line = false,
bool vector_delimited = true,
const std::string &indent = "",
bool quotes = false) {
ToStringVisitor tostring_visitor(multi_line ? "\n" : " ", quotes, indent,
vector_delimited);
IterateFlatBuffer(buffer, type_table, &tostring_visitor);
return tostring_visitor.s;
}
} // namespace flatbuffers
#endif // FLATBUFFERS_MINIREFLECT_H_