/*
 * Copyright (C) 2002 Nikos Mavroyanopoulos
 * Copyright (C) 2004 Free Software Foundation
 *
 * This file is part of GNUTLS.
 *
 *  The GNUTLS library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public   
 *  License as published by the Free Software Foundation; either 
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of 
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
 *
 */

#include <gnutls_int.h>
#include <gnutls_errors.h>
#include <gnutls_num.h>
#include <gnutls_str.h>

/* These function are like strcat, strcpy. They only
 * do bound checking (they shouldn't cause buffer overruns),
 * and they always produce null terminated strings.
 *
 * They should be used only with null terminated strings.
 */
void _gnutls_str_cat(char *dest, size_t dest_tot_size, const char *src)
{
    size_t str_size = strlen(src);
    size_t dest_size = strlen(dest);

    if (dest_tot_size - dest_size > str_size) {
	strcat(dest, src);
    } else {
	if (dest_tot_size - dest_size > 0) {
	    strncat(dest, src, (dest_tot_size - dest_size) - 1);
	    dest[dest_tot_size - 1] = 0;
	}
    }
}

void _gnutls_str_cpy(char *dest, size_t dest_tot_size, const char *src)
{
    size_t str_size = strlen(src);

    if (dest_tot_size > str_size) {
	strcpy(dest, src);
    } else {
	if (dest_tot_size > 0) {
	    strncpy(dest, src, (dest_tot_size) - 1);
	    dest[dest_tot_size - 1] = 0;
	}
    }
}

void _gnutls_mem_cpy(char *dest, size_t dest_tot_size, const char *src,
		     size_t src_size)
{

    if (dest_tot_size >= src_size) {
	memcpy(dest, src, src_size);
    } else {
	if (dest_tot_size > 0) {
	    memcpy(dest, src, dest_tot_size);
	}
    }
}

void _gnutls_string_init(gnutls_string * str,
			 gnutls_alloc_function alloc_func,
			 gnutls_realloc_function realloc_func,
			 gnutls_free_function free_func)
{
    str->data = NULL;
    str->max_length = 0;
    str->length = 0;

    str->alloc_func = alloc_func;
    str->free_func = free_func;
    str->realloc_func = realloc_func;
}

void _gnutls_string_clear(gnutls_string * str)
{
    if (str == NULL || str->data == NULL)
	return;
    str->free_func(str->data);

    str->data = NULL;
    str->max_length = 0;
    str->length = 0;
}

/* This one does not copy the string.
 */
gnutls_datum_t _gnutls_string2datum(gnutls_string * str)
{
    gnutls_datum_t ret;

    ret.data = str->data;
    ret.size = str->length;

    return ret;
}

#define MIN_CHUNK 256

int _gnutls_string_copy_str(gnutls_string * dest, const char *src)
{
    size_t src_len = strlen(src);

    if (dest->max_length >= src_len) {
	memcpy(dest->data, src, src_len);
	dest->length = src_len;

	return src_len;
    } else {
	dest->data =
	    dest->realloc_func(dest->data, MAX(src_len, MIN_CHUNK));
	if (dest->data == NULL) {
	    gnutls_assert();
	    return GNUTLS_E_MEMORY_ERROR;
	}
	dest->max_length = MAX(MIN_CHUNK, src_len);

	memcpy(dest->data, src, src_len);
	dest->length = src_len;

	return src_len;
    }
}

int _gnutls_string_append_str(gnutls_string * dest, const char *src)
{
    size_t src_len = strlen(src);
    size_t tot_len = src_len + dest->length;

    if (dest->max_length >= tot_len) {
	memcpy(&dest->data[dest->length], src, src_len);
	dest->length = tot_len;

	return tot_len;
    } else {
	size_t new_len =
	    MAX(src_len, MIN_CHUNK) + MAX(dest->max_length, MIN_CHUNK);

	dest->data = dest->realloc_func(dest->data, new_len);
	if (dest->data == NULL) {
	    gnutls_assert();
	    return GNUTLS_E_MEMORY_ERROR;
	}
	dest->max_length = new_len;

	memcpy(&dest->data[dest->length], src, src_len);
	dest->length = tot_len;

	return tot_len;
    }
}

int _gnutls_string_append_data(gnutls_string * dest, const void *data,
			       size_t data_size)
{
    size_t tot_len = data_size + dest->length;

    if (dest->max_length >= tot_len) {
	memcpy(&dest->data[dest->length], data, data_size);
	dest->length = tot_len;

	return tot_len;
    } else {
	size_t new_len =
	    MAX(data_size, MIN_CHUNK) + MAX(dest->max_length, MIN_CHUNK);

	dest->data = dest->realloc_func(dest->data, new_len);
	if (dest->data == NULL) {
	    gnutls_assert();
	    return GNUTLS_E_MEMORY_ERROR;
	}
	dest->max_length = new_len;

	memcpy(&dest->data[dest->length], data, data_size);
	dest->length = tot_len;

	return tot_len;
    }
}

/* Converts the given string (old) to hex. A buffer must be provided
 * to hold the new hex string. The new string will be null terminated.
 * If the buffer does not have enough space to hold the string retuns
 * NULL.
 */
char *_gnutls_bin2hex(const void *_old, size_t oldlen,
		      char *buffer, size_t buffer_size)
{
    unsigned int i, j;
    const opaque *old = _old;

    if ((oldlen * 2) + 1 > buffer_size)
	return NULL;

    for (i = j = 0; i < oldlen; j += 2) {
	sprintf(&buffer[j], "%.2x", old[i]);
	i++;
    }
    buffer[j] = '\0';

    return buffer;
}