nmap/string_pool.cc

/***************************************************************************
 * string_pool.cc -- String interning for memory optimization              *
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#include "string_pool.h"
#include <nbase.h>

#include <set>
#include <string>
#include <utility>
#include <stdarg.h>
#include <ctype.h>

/* Keep assert() defined for security reasons */
#undef NDEBUG
#include <assert.h>

const char *string_pool_insert(const char *s)
{
  static std::set<std::string> pool;
  static std::pair<std::set<std::string>::iterator, bool> pair;

  pair = pool.insert(s);

  return pair.first->c_str();
}

const char *string_pool_substr(const char *s, const char *t)
{
  return string_pool_insert(std::string(s, t).c_str());
}

const char *string_pool_substr_strip(const char *s, const char *t) {
  while (isspace((int) (unsigned char) *s))
    s++;
  while (t > s && isspace((int) (unsigned char) *(t - 1)))
    t--;

  return string_pool_substr(s, t);
}

const char *string_pool_strip_word(const char *s) {
  const char *t;

  while (isspace((int) (unsigned char) *s))
    s++;
  t = s;
  while (*t != '\0' && !isspace((int) (unsigned char) *t))
    t++;

  if (s == t)
    return NULL;

  return string_pool_substr(s, t);
}

/* Format a string with sprintf and insert it with string_pool_insert. */
const char *string_pool_sprintf(const char *fmt, ...)
{
  const char *s;
  char *buf;
  int size, n;
  va_list ap;

  buf = NULL;
  size = 32;
  /* Loop until we allocate a string big enough for the sprintf. */
  for (;;) {
    buf = (char *) realloc(buf, size);
    assert(buf != NULL);
    va_start(ap, fmt);
    n = Vsnprintf(buf, size, fmt, ap);
    va_end(ap);
    if (n < 0)
      size = size * 2;
    else if (n >= size)
      size = n + 1;
    else
      break;
  }

  s = string_pool_insert(buf);
  free(buf);

  return s;
}