/* Copyright (c) 2004-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"

#include "unichar.h"

#include "str.h"

#include "str-sanitize.h"

#include <ctype.h>

static size_t str_sanitize_skip_start(const char *src, size_t max_bytes)

{

  unichar_t chr;

  size_t i;

  for (i = 0; i < max_bytes && src[i] != '\0'; ) {

    int len = uni_utf8_get_char_n(src+i, max_bytes-i, &chr);

    if (len <= 0)

      break;

    if (i_iscntrl(src[i]))

      break;

    i += len;

  }

  i_assert(i <= max_bytes);

  return i;

}

static size_t

str_sanitize_skip_start_utf8(const char *src, uintmax_t max_chars)

{

  unichar_t chr;

  uintmax_t c;

  size_t i;

  for (i = 0, c = 0; c < max_chars && src[i] != '\0'; ) {

    int len = uni_utf8_get_char(src+i, &chr);

    if (len <= 0)

      break;

    if (i_iscntrl(src[i]))

      break;

    c++;

    i += len;

  }

  i_assert(c <= max_chars);

  return i;

}

static void str_sanitize_truncate_char(string_t *dest, unsigned int initial_pos)

{

  const unsigned char *data = str_data(dest);

  size_t len = str_len(dest);

  i_assert(len >= initial_pos);

  if (len == initial_pos)

    return;

  data += initial_pos;

  len -= initial_pos;

  str_truncate(dest, initial_pos +

    uni_utf8_data_truncate(data, len, len-1));

}

void str_sanitize_append(string_t *dest, const char *src, size_t max_bytes)

{

  size_t initial_pos = str_len(dest);

  unichar_t chr;

  size_t i;

  for (i = 0; i < max_bytes && src[i] != '\0'; ) {

    int len = uni_utf8_get_char_n(src+i, max_bytes-i, &chr);

    if (len == 0)

      break; /* input ended too early */

    if (len < 0) {

      /* invalid UTF-8 */

      str_append_c(dest, '?');

      i++;

      continue;

    }

    if (i_iscntrl(src[i]))

      str_append_c(dest, '?');

    else

      str_append_data(dest, src+i, len);

    i += len;

  }

  if (src[i] != '\0') {

    if (max_bytes < 3)

      str_truncate(dest, initial_pos);

    else {

      while (str_len(dest) - initial_pos > max_bytes-3)

        str_sanitize_truncate_char(dest, initial_pos);

    }

    str_append(dest, "...");

  }

}

void str_sanitize_append_utf8(string_t *dest, const char *src,

            uintmax_t max_cps)

{

  size_t last_pos = 0;

  unichar_t chr;

  uintmax_t c;

  size_t i;

  i_assert(max_cps > 0);

  for (i = 0, c = 0; c < max_cps && src[i] != '\0'; ) {

    int len = uni_utf8_get_char(src+i, &chr);

    if (len == 0)

      break; /* input ended too early */

    last_pos = str_len(dest);

    if (len < 0) {

      /* invalid UTF-8 */

      str_append(dest, UNICODE_REPLACEMENT_CHAR_UTF8);

      i++;

      continue;

    }

    if (i_iscntrl(src[i]))

      str_append(dest, UNICODE_REPLACEMENT_CHAR_UTF8);

    else

      str_append_data(dest, src+i, len);

    i += len;

    c++;

  }

  if (src[i] != '\0') {

    str_truncate(dest, last_pos);

    str_append(dest, UNICODE_HORIZONTAL_ELLIPSIS_CHAR_UTF8);

  }

}

const char *str_sanitize(const char *src, size_t max_bytes)

{

  string_t *str;

  size_t i;

  if (src == NULL)

    return NULL;

  i = str_sanitize_skip_start(src, max_bytes);

  if (src[i] == '\0')

    return src;

  str = t_str_new(I_MIN(max_bytes, 256));

  str_sanitize_append(str, src, max_bytes);

  return str_c(str);

}

const char *str_sanitize_utf8(const char *src, uintmax_t max_cps)

{

  string_t *str;

  size_t i;

  if (src == NULL)

    return NULL;

  i = str_sanitize_skip_start_utf8(src, max_cps);

  if (src[i] == '\0')

    return src;

  str = t_str_new(I_MIN(max_cps, 256));

  str_sanitize_append_utf8(str, src, max_cps);

  return str_c(str);

}