libupnp/ixml/src/ixmlmembuf.c

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 * Copyright (c) 2000-2003 Intel Corporation 
 * All rights reserved. 
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 * modification, are permitted provided that the following conditions are met: 
 *
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 * this list of conditions and the following disclaimer. 
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 * may be used to endorse or promote products derived from this software 
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/*!
 * \file
 */


#include "ixmlmembuf.h"
#include "ixml.h"


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


/*!
 * \brief Increases or decreases buffer capacity so that at least 'new_length'
 * bytes can be stored.
 *
 * On error, m's fields do not change.
 *
 * \return
 * 	\li UPNP_E_SUCCESS
 * 	\li UPNP_E_OUTOF_MEMORY
 */
static int ixml_membuf_set_size(
	/*! [in,out] The memory buffer. */
	INOUT ixml_membuf *m,
	/*! [in] The new lenght. */
	IN size_t new_length)
{
	size_t diff;
	size_t alloc_len;
	char *temp_buf;

	if (new_length >= m->length) {
		/* increase length */
		/* need more mem? */
		if (new_length <= m->capacity) {
			/* have enough mem; done */
			return 0;
		}

		diff = new_length - m->length;
		alloc_len = MAXVAL(m->size_inc, diff) + m->capacity;
	} else {
		// decrease length
		assert(new_length <= m->length);

		// if diff is 0..m->size_inc, don't free
		if ((m->capacity - new_length) <= m->size_inc) {
			return 0;
		}
		alloc_len = new_length + m->size_inc;
	}

	assert(alloc_len >= new_length);

	temp_buf = realloc(m->buf, alloc_len + 1);
	if (temp_buf == NULL) {
		/* try smaller size */
		alloc_len = new_length;
		temp_buf = realloc(m->buf, alloc_len + 1);
		if (temp_buf == NULL) {
			return IXML_INSUFFICIENT_MEMORY;
		}
	}
	/* save */
	m->buf = temp_buf;
	m->capacity = alloc_len;

	return 0;
}


void ixml_membuf_init(ixml_membuf *m)
{
	assert(m != NULL);

	m->size_inc = MEMBUF_DEF_SIZE_INC;
	m->buf = NULL;
	m->length = 0;
	m->capacity = 0;
}


void ixml_membuf_destroy(ixml_membuf *m)
{
	if (m == NULL) {
		return;
	}

	free(m->buf);
	ixml_membuf_init(m);
}


int ixml_membuf_assign(
	ixml_membuf *m,
	const void *buf,
	size_t buf_len)
{
	int return_code;

	assert(m != NULL);

	// set value to null
	if (buf == NULL) {
		ixml_membuf_destroy(m);
		return IXML_SUCCESS;
	}
	// alloc mem
	return_code = ixml_membuf_set_size(m, buf_len);
	if (return_code != 0) {
		return return_code;
	}

	// copy
	memcpy(m->buf, buf, buf_len);

	// null-terminate
	m->buf[buf_len] = 0;
	m->length = buf_len;

	return IXML_SUCCESS;
}


int ixml_membuf_assign_str(
	ixml_membuf *m,
	const char *c_str)
{
	return ixml_membuf_assign(m, c_str, strlen(c_str));
}


int ixml_membuf_append(
	INOUT ixml_membuf *m,
	IN const void *buf)
{
	assert(m != NULL);

	return ixml_membuf_insert(m, buf, 1, m->length);
}


int ixml_membuf_append_str(
	INOUT ixml_membuf *m,
	IN const char *c_str)
{
	return ixml_membuf_insert(m, c_str, strlen(c_str), m->length);
}


int ixml_membuf_insert(
	INOUT ixml_membuf *m,
	IN const void *buf,
	IN size_t buf_len,
	int index)
{
	int return_code = 0;

	assert(m != NULL);

	if (index < 0 || index > (int)m->length) {
		return IXML_INDEX_SIZE_ERR;
	}

	if (buf == NULL || buf_len == 0) {
		return 0;
	}
	/* alloc mem */
	return_code = ixml_membuf_set_size(m, m->length + buf_len);
	if (return_code != 0) {
		return return_code;
	}
	/* insert data */
	/* move data to right of insertion point */
	memmove(m->buf + index + buf_len, m->buf + index, m->length - index);
	memcpy(m->buf + index, buf, buf_len);
	m->length += buf_len;
	/* Null terminate */
	m->buf[m->length] = 0;

	return 0;
}