/*
 * Copyright (C) 2002 Nikos Mavroyanopoulos
 *
 * 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);
	memset( str, 0, sizeof( gnutls_string));
}

/* This one does not copy the string.
 */
gnutls_datum _gnutls_string2datum( gnutls_string* str)
{
	gnutls_datum 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, GMAX(src_len, MIN_CHUNK));
		if (dest->data == NULL) {
			gnutls_assert();
			return GNUTLS_E_MEMORY_ERROR;
		}
		dest->max_length = GMAX( 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 = GMAX( src_len, MIN_CHUNK) + GMAX( 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 = GMAX( data_size, MIN_CHUNK) + GMAX(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;
}