text: /*
   * Copyright (c) 2014 Kaprica Security, Inc.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   *
   */
  #include <libcgc.h>
  
  #include <ctype.h>
  #include <stdlib.h>
  
  int read_balanced_expression(int fd, char *buf, size_t max)
  {
    size_t rx = 0;
    size_t depth = 0;
    char nl;
  
    while (receive(fd, buf, 1, &rx) == 0) {
      if (rx ==  0)
        break;
  
      // Ensure first character is a open paren
      if (depth == 0 && *buf != '(')
          return -1;
  
      if (*buf == '(') {
        if (depth == SIZE_MAX)
          return -1;
        else
          depth += 1;
      } else if (*buf == ')') {
        if (depth == 0)
          return -1;
        else
          depth -= 1;
      }
  
      max -= rx;
      if (max == 0)
        break;
      buf += rx;
  
      if (depth == 0)
        break;
    }
  
    // chomp
    while (receive(fd, &nl, 1, &rx) == 0) {
      if (rx == 0 || nl == '\n')
        break;
      if (!isspace(nl))
        return -1;
    }
  
    *buf = '\0';
    return depth;
  }
  