src/lib/str-sanitize.c

	str-sanitize.c revision 2e37d45867d081db150ab78dad303b9077aea24f
/* Copyright (c) 2004-2011 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "unichar.h"
#include "str.h"
#include "str-sanitize.h"

static size_t str_sanitize_skip_start(const char *src, size_t max_len)
{
    unsigned int len;
    unichar_t chr;
    size_t i;

    for (i = 0; i < max_len; ) {
        len = uni_utf8_char_bytes(src[i]);
        if (uni_utf8_get_char(src+i, &chr) <= 0)
            break;
        if ((unsigned char)src[i] < 32)
            break;
        i += len;
    }
    return i;
}

void str_sanitize_append(string_t *dest, const char *src, size_t max_len)
{
    unsigned int len;
    unichar_t chr;
    size_t i;
    int ret;

    for (i = 0; i < max_len && src[i] != '\0'; ) {
        len = uni_utf8_char_bytes(src[i]);
        ret = uni_utf8_get_char(src+i, &chr);
        if (ret <= 0) {
            /* invalid UTF-8 */
            str_append_c(dest, '?');
            if (ret == 0) {
                /* input ended too early */
                return;
            }
            i++;
            continue;
        }
        if ((unsigned char)src[i] < 32)
            str_append_c(dest, '?');
        else
            str_append_c(dest, src[i]);
        i += len;
    }

    if (src[i] != '\0') {
        str_truncate(dest, str_len(dest) <= 3 ? 0 : str_len(dest)-3);
        str_append(dest, "...");
    }
}

const char *str_sanitize(const char *src, size_t max_len)
{
    string_t *str;
    size_t i;

    if (src == NULL)
        return NULL;

    i = str_sanitize_skip_start(src, max_len);
    if (src[i] == '\0')
        return src;

    str = t_str_new(I_MIN(max_len, 256));
    str_append_n(str, src, i);
    str_sanitize_append(str, src + i, max_len - i);
    return str_c(str);
}