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#pragma once
#include <base/types.h>
#include <Common/Exception.h>
#include <Common/PODArray.h>
#include <Common/StringUtils/StringUtils.h>
namespace DB
{
namespace ErrorCodes
{
extern const int BAD_ARGUMENTS;
}
namespace Format
{
using IndexPositions = PODArrayWithStackMemory<UInt64, 64>;
static inline UInt64 parseNumber(const String & description, UInt64 l, UInt64 r, UInt64 argument_number)
{
UInt64 res = 0;
for (UInt64 pos = l; pos < r; ++pos)
{
if (!isNumericASCII(description[pos]))
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Not a number in curly braces at position {}", pos);
res = res * 10 + description[pos] - '0';
if (res >= argument_number)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Too big number for arguments, must be at most {}", argument_number - 1);
}
return res;
}
static inline void init(
const String & pattern,
size_t argument_number,
const std::vector<std::optional<String>> & constant_strings,
IndexPositions & index_positions,
std::vector<String> & substrings)
{
/// Is current position after open curly brace.
bool is_open_curly = false;
/// The position of last open token.
size_t last_open = -1;
/// Is formatting in a plain {} token.
std::optional<bool> is_plain_numbering;
UInt64 index_if_plain = 0;
/// Left position of adding substrings, just to the closed brace position or the start of the string.
/// Invariant --- the start of substring is in this position.
size_t start_pos = 0;
/// A flag to decide whether we should glue the constant strings.
bool glue_to_next = false;
/// Handling double braces (escaping).
auto double_brace_removal = [](String & str)
{
size_t i = 0;
bool should_delete = true;
std::erase_if(
str,
[&i, &should_delete, &str](char)
{
bool is_double_brace = (str[i] == '{' && str[i + 1] == '{') || (str[i] == '}' && str[i + 1] == '}');
++i;
if (is_double_brace && should_delete)
{
should_delete = false;
return true;
}
should_delete = true;
return false;
});
};
index_positions.emplace_back();
for (size_t i = 0; i < pattern.size(); ++i)
{
if (pattern[i] == '{')
{
/// Escaping handling
/// It is safe to access because of null termination
if (pattern[i + 1] == '{')
{
++i;
continue;
}
if (is_open_curly)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Two open curly braces without close one at position {}", i);
String to_add = String(pattern.data() + start_pos, i - start_pos);
double_brace_removal(to_add);
if (!glue_to_next)
substrings.emplace_back(to_add);
else
substrings.back() += to_add;
glue_to_next = false;
is_open_curly = true;
last_open = i + 1;
}
else if (pattern[i] == '}')
{
if (pattern[i + 1] == '}')
{
++i;
continue;
}
if (!is_open_curly)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Closed curly brace without open one at position {}", i);
is_open_curly = false;
if (last_open == i)
{
if (is_plain_numbering && !*is_plain_numbering)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Cannot switch from automatic field numbering to manual field specification");
is_plain_numbering = true;
if (index_if_plain >= argument_number)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Argument is too big for formatting");
index_positions.back() = index_if_plain++;
}
else
{
if (is_plain_numbering && *is_plain_numbering)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Cannot switch from automatic field numbering to manual field specification");
is_plain_numbering = false;
UInt64 arg = parseNumber(pattern, last_open, i, argument_number);
if (arg >= argument_number)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Argument is too big for formatting. Note that indexing starts from zero");
index_positions.back() = arg;
}
if (!constant_strings.empty() && constant_strings[index_positions.back()])
{
/// The next string should be glued to last `A {} C`.format('B') -> `A B C`.
glue_to_next = true;
substrings.back() += *constant_strings[index_positions.back()];
}
else
index_positions.emplace_back(); /// Otherwise we commit arg number and proceed.
start_pos = i + 1;
}
}
if (is_open_curly)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Last open curly brace is not closed");
String to_add = String(pattern.data() + start_pos, pattern.size() - start_pos);
double_brace_removal(to_add);
if (!glue_to_next)
substrings.emplace_back(to_add);
else
substrings.back() += to_add;
index_positions.pop_back();
}
}
}
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