Class string_buffer

libhsclient/string_buffer.hpp:22–113

namespace dena {

struct string_buffer : private noncopyable {
  string_buffer() : buffer(0), begin_offset(0), end_offset(0), alloc_size(0) { }
  ~string_buffer() {
    DENA_FREE(buffer);
  }
  const char *begin() const {
    return buffer + begin_offset;
  }
  const char *end() const {
    return buffer + end_offset;
  }
  char *begin() {
    return buffer + begin_offset;
  }
  char *end() {
    return buffer + end_offset;
  }
  size_t size() const {
    return end_offset - begin_offset;
  }
  void clear() {
    begin_offset = end_offset = 0;
  }
  void resize(size_t len) {
    if (size() < len) {
      reserve(len);
      memset(buffer + end_offset, 0, len - size());
    }
    end_offset = begin_offset + len;
  }
  void reserve(size_t len) {
    if (alloc_size >= begin_offset + len) {
      return;
    }
    size_t asz = alloc_size;
    while (asz < begin_offset + len) {
      if (asz == 0) {
	asz = 16;
      }
      const size_t asz_n = asz << 1;
      if (asz_n < asz) {
	fatal_abort("string_buffer::resize() overflow");
      }
      asz = asz_n;
    }
    void *const p = DENA_REALLOC(buffer, asz);
    if (p == 0) {
      fatal_abort("string_buffer::resize() realloc");
    }
    buffer = static_cast<char *>(p);
    alloc_size = asz;
  }
  void erase_front(size_t len) {
    if (len >= size()) {
      clear();
    } else {
      begin_offset += len;
    }