Method _writeString

Fleece/Core/Encoder.cc:349–386

Writes a string, or a pointer to an already-written copy of the same string. This is the main body of writeString() and writeKey(). Returns the address where s got written to, if possible, just like writeData above.

    // This is the main body of writeString() and writeKey().
    // Returns the address where s got written to, if possible, just like writeData above.
    const void* Encoder::_writeString(slice s) {
        if (!_usuallyTrue(_uniqueStrings && s.size >= kNarrow && s.size <= kMaxSharedStringSize)) {
            // Not uniquing this string, so just write it:
            return writeData(kStringTag, s);
        }

        // Check whether this string's already been written:
        StringTable::entry_t *entry;
        bool isNew;
        std::tie(entry, isNew) = _strings.insert(s, 0);
        if (!isNew) {
            // String exists: Write pointer to it, as long as the offset's not too large:
            ssize_t offset = entry->second - _base.size;
            if (_items->wide || nextWritePos() - offset <= Pointer::kMaxNarrowOffset - 32) {
                writePointer(offset);
                if (offset < 0) {
                    const void *stringVal = &_base[_base.size + offset];
                    if (stringVal < _baseMinUsed)
                        _baseMinUsed = stringVal;
                }
#ifndef NDEBUG
                _numSavedStrings++;
#endif
                return entry->first.buf; // done!
            }
        }

        // Write the string to the output:
        auto offset = _base.size + nextWritePos();
        throwIf(offset > 1u<<31, MemoryError, "encoded data too large");
        writeData(kStringTag, s);

        // Store a copy of the string, since _out won't necessarily keep it around (if it's
        // writing to a file, or if the caller calls snip()), and the offset:
        const void* writtenStr = _stringStorage.write(s);
        *entry = {{writtenStr, s.size}, (uint32_t)offset};
        return writtenStr;
    }

    // Adds a preexisting string to the cache
    void Encoder::cacheString(slice s, size_t offsetInBase) {