b210c570fc
instead the length of the string can be passed in. This is first step in process to allow Value to work without null terminator.
102 lines
2.2 KiB
C++
102 lines
2.2 KiB
C++
#include "ArrayParser.h"
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#include <stdexcept>
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using namespace Pgsql;
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namespace {
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constexpr char ArrayStart = '{';
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constexpr char ArrayEnd = '}';
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constexpr char Quote = '"';
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constexpr char Seperator = ',';
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}
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ArrayParser::ArrayParser(const char *array_string, int length)
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: data(array_string)
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, end(length >= 0 ? array_string + length : array_string + strlen(array_string))
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, pos(array_string)
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{
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initializeParse();
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}
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ArrayParser::NextElemResult ArrayParser::GetNextElem()
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{
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// We should be at the start of an element or at the end of the array
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NextElemResult result = { false, std::nullopt };
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if (pos < end && *pos != ArrayEnd) {
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if (*pos == Quote) {
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// parse quoted value, slow path removing escapes
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parseQuotedValue();
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result.ok = true;
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result.value = std::string_view(temp);
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}
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else {
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// parse unquoted value, fast path no escapes
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const char *start = pos;
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while (pos < end && *pos != Seperator && *pos != ArrayEnd) ++pos;
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if (pos == end) // reached end of data shouldn't happen
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throw std::runtime_error("Invalid input");
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result.ok = true;
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if ((pos - start) != 4 || std::strncmp(start, "NULL", 4) != 0)
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result.value = std::string_view(start, pos-start);
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}
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// move to start of next element
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++pos; // skip seperator
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skipWhitespace();
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}
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return result;
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}
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void ArrayParser::parseQuotedValue()
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{
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std::string s;
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// internal function thus we can safely assumed the caller already verified
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// the opening quote
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++pos;
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if (pos == end)
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throw std::runtime_error("Invalid input");
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while (pos < end) {
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if (*pos == Quote) {
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++pos;
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break;
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}
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if (*pos == '\\') {
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++pos;
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if (pos == end)
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throw std::runtime_error("Invalid input");
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}
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s += *pos;
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++pos;
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}
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temp = std::move(s);
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}
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void ArrayParser::initializeParse()
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{
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// Test if non empty string (empty string is an empty array)
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//
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skipWhitespace();
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if (pos < end) {
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// first character should be opening brace
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if (*pos != ArrayStart) {
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throw std::runtime_error("Unexpected input");
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}
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++pos;
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skipWhitespace();
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// Position is now first element or end of array when the array is empty
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// GetNextElem can take it from here
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}
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}
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inline void ArrayParser::skipWhitespace()
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{
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while (pos < end && (*pos == ' ' || *pos == '\t')) ++pos;
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}
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