♻️ check for truncation

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-06-30 19:03:23 +02:00
parent 250787cb54
commit 526c8c5079
2 changed files with 38 additions and 28 deletions
+19 -14
View File
@@ -125,8 +125,7 @@ class serializer
o->write_characters("{\n", 2); o->write_characters("{\n", 2);
// variable to hold indentation for recursive calls // variable to hold indentation for recursive calls
const auto new_indent = current_indent + indent_step; const auto new_indent = reserve_indent(current_indent, indent_step);
reserve_indent(new_indent);
// first n-1 elements // first n-1 elements
auto i = val.m_data.m_value.object->cbegin(); auto i = val.m_data.m_value.object->cbegin();
@@ -195,8 +194,7 @@ class serializer
o->write_characters("[\n", 2); o->write_characters("[\n", 2);
// variable to hold indentation for recursive calls // variable to hold indentation for recursive calls
const auto new_indent = current_indent + indent_step; const auto new_indent = reserve_indent(current_indent, indent_step);
reserve_indent(new_indent);
// first n-1 elements // first n-1 elements
for (auto i = val.m_data.m_value.array->cbegin(); for (auto i = val.m_data.m_value.array->cbegin();
@@ -253,8 +251,7 @@ class serializer
o->write_characters("{\n", 2); o->write_characters("{\n", 2);
// variable to hold indentation for recursive calls // variable to hold indentation for recursive calls
const auto new_indent = current_indent + indent_step; const auto new_indent = reserve_indent(current_indent, indent_step);
reserve_indent(new_indent);
o->write_characters(indent_string.c_str(), new_indent); o->write_characters(indent_string.c_str(), new_indent);
@@ -365,22 +362,30 @@ class serializer
} }
/*! /*!
@brief grow the indentation string so it can hold at least @a new_indent characters @brief compute the next indentation level and grow the indentation string
The indentation string is grown by doubling its size, but at least to Computes the new indentation level @a current_indent + @a indent_step and
@a new_indent characters, so that it can be used as a source for writing grows the indentation string (by doubling its size, but at least to the new
@a new_indent indentation characters. The newly added characters use the level) so that it can be used as a source for writing that many indentation
configured @ref indent_char. characters. The newly added characters use the configured @ref indent_char.
@param[in] new_indent the required number of indentation characters @param[in] current_indent the current indentation level
@param[in] indent_step the number of characters to indent per level
@return the new indentation level @a current_indent + @a indent_step
*/ */
void reserve_indent(const std::size_t new_indent) unsigned int reserve_indent(const unsigned int current_indent, const unsigned int indent_step)
{ {
const unsigned int new_indent = current_indent + indent_step;
// a very large indent_step can wrap the unsigned accumulation on deep
// nesting, which would silently truncate the indentation
JSON_ASSERT(new_indent >= current_indent);
if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent)) if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
{ {
indent_string.resize((std::max)(indent_string.size() * 2, new_indent), indent_char); indent_string.resize((std::max)(indent_string.size() * 2, static_cast<std::size_t>(new_indent)), indent_char);
} }
JSON_ASSERT(indent_string.size() >= new_indent); JSON_ASSERT(indent_string.size() >= new_indent);
return new_indent;
} }
JSON_PRIVATE_UNLESS_TESTED: JSON_PRIVATE_UNLESS_TESTED:
+19 -14
View File
@@ -19299,8 +19299,7 @@ class serializer
o->write_characters("{\n", 2); o->write_characters("{\n", 2);
// variable to hold indentation for recursive calls // variable to hold indentation for recursive calls
const auto new_indent = current_indent + indent_step; const auto new_indent = reserve_indent(current_indent, indent_step);
reserve_indent(new_indent);
// first n-1 elements // first n-1 elements
auto i = val.m_data.m_value.object->cbegin(); auto i = val.m_data.m_value.object->cbegin();
@@ -19369,8 +19368,7 @@ class serializer
o->write_characters("[\n", 2); o->write_characters("[\n", 2);
// variable to hold indentation for recursive calls // variable to hold indentation for recursive calls
const auto new_indent = current_indent + indent_step; const auto new_indent = reserve_indent(current_indent, indent_step);
reserve_indent(new_indent);
// first n-1 elements // first n-1 elements
for (auto i = val.m_data.m_value.array->cbegin(); for (auto i = val.m_data.m_value.array->cbegin();
@@ -19427,8 +19425,7 @@ class serializer
o->write_characters("{\n", 2); o->write_characters("{\n", 2);
// variable to hold indentation for recursive calls // variable to hold indentation for recursive calls
const auto new_indent = current_indent + indent_step; const auto new_indent = reserve_indent(current_indent, indent_step);
reserve_indent(new_indent);
o->write_characters(indent_string.c_str(), new_indent); o->write_characters(indent_string.c_str(), new_indent);
@@ -19539,22 +19536,30 @@ class serializer
} }
/*! /*!
@brief grow the indentation string so it can hold at least @a new_indent characters @brief compute the next indentation level and grow the indentation string
The indentation string is grown by doubling its size, but at least to Computes the new indentation level @a current_indent + @a indent_step and
@a new_indent characters, so that it can be used as a source for writing grows the indentation string (by doubling its size, but at least to the new
@a new_indent indentation characters. The newly added characters use the level) so that it can be used as a source for writing that many indentation
configured @ref indent_char. characters. The newly added characters use the configured @ref indent_char.
@param[in] new_indent the required number of indentation characters @param[in] current_indent the current indentation level
@param[in] indent_step the number of characters to indent per level
@return the new indentation level @a current_indent + @a indent_step
*/ */
void reserve_indent(const std::size_t new_indent) unsigned int reserve_indent(const unsigned int current_indent, const unsigned int indent_step)
{ {
const unsigned int new_indent = current_indent + indent_step;
// a very large indent_step can wrap the unsigned accumulation on deep
// nesting, which would silently truncate the indentation
JSON_ASSERT(new_indent >= current_indent);
if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent)) if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
{ {
indent_string.resize((std::max)(indent_string.size() * 2, new_indent), indent_char); indent_string.resize((std::max)(indent_string.size() * 2, static_cast<std::size_t>(new_indent)), indent_char);
} }
JSON_ASSERT(indent_string.size() >= new_indent); JSON_ASSERT(indent_string.size() >= new_indent);
return new_indent;
} }
JSON_PRIVATE_UNLESS_TESTED: JSON_PRIVATE_UNLESS_TESTED: