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Merge pull request #237 from jonsimantov/master

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Add optional root table to SetString and ResizeVector, when your Flatbuffer isn't the schema's root type.
This commit is contained in:
Wouter van Oortmerssen
2015-07-22 12:03:39 -07:00
parent 07e77ad0ff b56020ad3b
commit 62af533820
1 changed files with 17 additions and 9 deletions
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26
include/flatbuffers/reflection.h
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@@ -271,10 +271,13 @@ inline const reflection::Object &GetUnionType(
// "delta" may be negative (shrinking). // "delta" may be negative (shrinking).
// Unless "delta" is a multiple of the largest alignment, you'll create a small // Unless "delta" is a multiple of the largest alignment, you'll create a small
// amount of garbage space in the buffer (usually 0..7 bytes). // amount of garbage space in the buffer (usually 0..7 bytes).
// If your FlatBuffer's root table is not the schema's root table, you should
// pass in your root_table type as well.
class ResizeContext { class ResizeContext {
public: public:
ResizeContext(const reflection::Schema &schema, uoffset_t start, int delta, ResizeContext(const reflection::Schema &schema, uoffset_t start, int delta,
std::vector<uint8_t> *flatbuf) std::vector<uint8_t> *flatbuf,
const reflection::Object *root_table = nullptr)
: schema_(schema), startptr_(flatbuf->data() + start), : schema_(schema), startptr_(flatbuf->data() + start),
delta_(delta), buf_(*flatbuf), delta_(delta), buf_(*flatbuf),
dag_check_(flatbuf->size() / sizeof(uoffset_t), false) { dag_check_(flatbuf->size() / sizeof(uoffset_t), false) {
@@ -284,7 +287,7 @@ class ResizeContext {
// Now change all the offsets by delta_. // Now change all the offsets by delta_.
auto root = GetAnyRoot(buf_.data()); auto root = GetAnyRoot(buf_.data());
Straddle<uoffset_t, 1>(buf_.data(), root, buf_.data()); Straddle<uoffset_t, 1>(buf_.data(), root, buf_.data());
ResizeTable(*schema.root_table(), root); ResizeTable(root_table ? *root_table : *schema.root_table(), root);
// We can now add or remove bytes at start. // We can now add or remove bytes at start.
if (delta_ > 0) buf_.insert(buf_.begin() + start, delta_, 0); if (delta_ > 0) buf_.insert(buf_.begin() + start, delta_, 0);
else buf_.erase(buf_.begin() + start, buf_.begin() + start - delta_); else buf_.erase(buf_.begin() + start, buf_.begin() + start - delta_);
@@ -399,15 +402,18 @@ class ResizeContext {
// Changes the contents of a string inside a FlatBuffer. FlatBuffer must // Changes the contents of a string inside a FlatBuffer. FlatBuffer must
// live inside a std::vector so we can resize the buffer if needed. // live inside a std::vector so we can resize the buffer if needed.
// "str" must live inside "flatbuf" and may be invalidated after this call. // "str" must live inside "flatbuf" and may be invalidated after this call.
// If your FlatBuffer's root table is not the schema's root table, you should
// pass in your root_table type as well.
inline void SetString(const reflection::Schema &schema, const std::string &val, inline void SetString(const reflection::Schema &schema, const std::string &val,
const String *str, std::vector<uint8_t> *flatbuf) { const String *str, std::vector<uint8_t> *flatbuf,
const reflection::Object *root_table = nullptr) {
auto delta = static_cast<int>(val.size()) - static_cast<int>(str->Length()); auto delta = static_cast<int>(val.size()) - static_cast<int>(str->Length());
auto start = static_cast<uoffset_t>(reinterpret_cast<const uint8_t *>(str) - auto start = static_cast<uoffset_t>(reinterpret_cast<const uint8_t *>(str) -
flatbuf->data() + flatbuf->data() +
sizeof(uoffset_t)); sizeof(uoffset_t));
if (delta) { if (delta) {
// Different size, we must expand (or contract). // Different size, we must expand (or contract).
ResizeContext(schema, start, delta, flatbuf); ResizeContext(schema, start, delta, flatbuf, root_table);
if (delta < 0) { if (delta < 0) {
// Clear the old string, since we don't want parts of it remaining. // Clear the old string, since we don't want parts of it remaining.
memset(flatbuf->data() + start, 0, str->Length()); memset(flatbuf->data() + start, 0, str->Length());
@@ -420,17 +426,19 @@ inline void SetString(const reflection::Schema &schema, const std::string &val,
// Resizes a flatbuffers::Vector inside a FlatBuffer. FlatBuffer must // Resizes a flatbuffers::Vector inside a FlatBuffer. FlatBuffer must
// live inside a std::vector so we can resize the buffer if needed. // live inside a std::vector so we can resize the buffer if needed.
// "vec" must live inside "flatbuf" and may be invalidated after this call. // "vec" must live inside "flatbuf" and may be invalidated after this call.
template<typename T> void ResizeVector(const reflection::Schema &schema, // If your FlatBuffer's root table is not the schema's root table, you should
uoffset_t newsize, T val, // pass in your root_table type as well.
const Vector<T> *vec, template <typename T>
std::vector<uint8_t> *flatbuf) { void ResizeVector(const reflection::Schema &schema, uoffset_t newsize, T val,
const Vector<T> *vec, std::vector<uint8_t> *flatbuf,
const reflection::Object *root_table = nullptr) {
auto delta_elem = static_cast<int>(newsize) - static_cast<int>(vec->size()); auto delta_elem = static_cast<int>(newsize) - static_cast<int>(vec->size());
auto delta_bytes = delta_elem * static_cast<int>(sizeof(T)); auto delta_bytes = delta_elem * static_cast<int>(sizeof(T));
auto vec_start = reinterpret_cast<const uint8_t *>(vec) - flatbuf->data(); auto vec_start = reinterpret_cast<const uint8_t *>(vec) - flatbuf->data();
auto start = static_cast<uoffset_t>(vec_start + sizeof(uoffset_t) + auto start = static_cast<uoffset_t>(vec_start + sizeof(uoffset_t) +
sizeof(T) * vec->size()); sizeof(T) * vec->size());
if (delta_bytes) { if (delta_bytes) {
ResizeContext(schema, start, delta_bytes, flatbuf); ResizeContext(schema, start, delta_bytes, flatbuf, root_table);
WriteScalar(flatbuf->data() + vec_start, newsize); // Length field. WriteScalar(flatbuf->data() + vec_start, newsize); // Length field.
// Set new elements to "val". // Set new elements to "val".
for (int i = 0; i < delta_elem; i++) { for (int i = 0; i < delta_elem; i++) {