horrible-harry/utils.cpp

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include "utils.h"

// http://c-faq.com/lib/randrange.html
int randint(int N) { return rand() / (RAND_MAX / N + 1); }

// http://c-faq.com/lib/randrange.html
// numbers in the range [M, N] could be generated with something like

int randrange(int M, int N) {
  return M + rand() / (RAND_MAX / (N - M + 1) + 1);
}

/**
 * Display a repr of the given string.
 *
 * This converts most \n\r\v\f\t codes,
 * defaults to \xHH (hex value).
 */
char *repr(const char *data) {
  static char buffer[40960];
  char *cp;

  strcpy(buffer, data);
  cp = buffer;
  while (*cp != 0) {
    char c = *cp;

    if (c == ' ') {
      cp++;
      continue;
    };
    /* Ok, it's form-feed ('\f'), newline ('\n'), carriage return ('\r'),
     * horizontal tab ('\t'), and vertical tab ('\v') */
    if (strchr("\f\n\r\t\v\?", c) != NULL) {
      memmove(cp + 1, cp, strlen(cp) + 1);
      *cp = '\\';
      cp++;
      switch (c) {
      case '\f':
        *cp = 'f';
        cp++;
        break;
      case '\n':
        *cp = 'n';
        cp++;
        break;
      case '\r':
        *cp = 'r';
        cp++;
        break;
      case '\t':
        *cp = 't';
        cp++;
        break;
      case '\v':
        *cp = 'v';
        cp++;
        break;
      default:
        *cp = '?';
        cp++;
        break;
      }
      continue;
    }

    if (c == '\\') {
      memmove(cp + 1, cp, strlen(cp) + 1);
      *cp = '\\';
      cp += 2;
      continue;
    }
    if (c == '"') {
      memmove(cp + 1, cp, strlen(cp) + 1);
      *cp = '\\';
      cp += 2;
      continue;
    }
    if (strchr("[()]{}:;,.<>?!@#$%^&*", c) != NULL) {
      cp++;
      continue;
    }
    if (strchr("0123456789", c) != NULL) {
      cp++;
      continue;
    }
    if (strchr("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ", c) !=
        NULL) {
      cp++;
      continue;
    }

    // Ok, default to \xHH output.
    memmove(cp + 3, cp, strlen(cp) + 1);
    char buffer[10];
    sprintf(buffer, "\\x%02x", (int)c & 0xff);
    strncpy(cp, buffer, 4);
    cp += 4;
    continue;
  }

  return buffer;
}

/*
 * strnstr()
 *
 * buffer safe version that looks for a string.
 */
const char *strnstr(const char *source, int len, const char *needle) {
  int pos;

  for (pos = 0; pos < len; pos++) {
    if (source[pos] == needle[0]) {
      if (strncmp(source + pos, needle, strlen(needle)) == 0) {
        return source + pos;
      }
    }
  }
  return NULL;
}

/*
 * rstrnstr() Reverse string find in a string
 *
 * This obeys the len, and handles nulls in buffer.
 * find is a c-string (null terminated)
 */
int rstrnstr(const char *buffer, int len, const char *find) {
  int flen = strlen(find);

  if (len < flen) {
    // I can't find a string in a buffer smaller then it is!
    return -1;
  }
  int pos = len - flen;
  while (pos > 0) {
    if (buffer[pos] == find[0]) {
      // First chars match, check them all.
      if (strncmp(buffer + pos, find, flen) == 0) {
        return pos;
      }
    }
    pos--;
  }
  return -1;
}