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/*
* This file is part of LibParserUtils.
* Licensed under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
* Copyright 2008 John-Mark Bell <jmb@netsurf-browser.org>
*/
#include <string.h>
#include <stdarg.h>
#include <parserutils/utils/buffer.h>
#define DEFAULT_SIZE (4096)
/**
* Create a memory buffer
*
* \param buffer Pointer to location to receive memory buffer
* \return PARSERUTILS_OK on success,
* PARSERUTILS_BADPARM on bad parameters,
* PARSERUTILS_NOMEM on memory exhausion
*/
parserutils_error parserutils_buffer_create(parserutils_buffer **buffer)
{
parserutils_buffer *b;
if (buffer == NULL)
return PARSERUTILS_BADPARM;
b = malloc(sizeof(parserutils_buffer));
if (b == NULL)
return PARSERUTILS_NOMEM;
b->alloc = malloc(DEFAULT_SIZE);
if (b->alloc == NULL) {
free(b);
return PARSERUTILS_NOMEM;
}
b->data = b->alloc;
b->length = 0;
b->allocated = DEFAULT_SIZE;
*buffer = b;
return PARSERUTILS_OK;
}
/**
* Destroy a memory buffer
*
* \param buffer The buffer to destroy
* \return PARSERUTILS_OK on success, appropriate error otherwise
*/
parserutils_error parserutils_buffer_destroy(parserutils_buffer *buffer)
{
if (buffer == NULL)
return PARSERUTILS_BADPARM;
free(buffer->alloc);
free(buffer);
return PARSERUTILS_OK;
}
/**
* Get current data offset within buffer's allocation.
*
* \param[in] buffer The buffer object.
* \return data offset in bytes.
*/
static inline size_t get_offset(parserutils_buffer *buffer)
{
return buffer->data - buffer->alloc;
}
/**
* Try moving the data to the start of the allocation.
*
* \param[in] buffer The buffer object.
*/
static inline void try_rebase(parserutils_buffer *buffer)
{
if (get_offset(buffer) >= buffer->length) {
memcpy(buffer->alloc, buffer->data, buffer->length);
buffer->data = buffer->alloc;
}
}
/**
* Ensure that the buffer has enough space at the end to add len bytes.
*
* \param[in] buffer The buffer object.
* \param[in] len Number of bytes to ensure there is space for.
* \return PARSERUTILS_OK on success, appropriate error otherwise.
*/
static inline parserutils_error ensure_space(
parserutils_buffer *buffer,
size_t len)
{
try_rebase(buffer);
while (len >= buffer->allocated - buffer->length - get_offset(buffer)) {
parserutils_error error = parserutils_buffer_grow(buffer);
if (error != PARSERUTILS_OK)
return error;
}
return PARSERUTILS_OK;
}
/**
* Append data to a memory buffer
*
* \param buffer The buffer to append to
* \param data The data to append
* \param len The length, in bytes, of the data to append
* \return PARSERUTILS_OK on success, appropriate error otherwise.
*/
parserutils_error parserutils_buffer_append(parserutils_buffer *buffer,
const uint8_t *data, size_t len)
{
parserutils_error error = ensure_space(buffer, len);
if (error != PARSERUTILS_OK)
return error;
memcpy(buffer->data + buffer->length, data, len);
buffer->length += len;
return PARSERUTILS_OK;
}
/**
* Append multiple data blocks to a memory buffer.
*
* Each data block must be passed as a pair of const uint8_t* and size_t
*
* \param buffer The buffer to append to
* \param count The number of data blocks to append
* \param ... The pairs of pointer and size
* \return PARSERUTILS_OK on success, appropriate error otherwise.
*/
parserutils_error parserutils_buffer_appendv(parserutils_buffer *buffer,
size_t count, ...)
{
va_list ap;
parserutils_error error;
const uint8_t *data;
size_t len;
va_start(ap, count);
while (count > 0) {
data = va_arg(ap, const uint8_t *);
len = va_arg(ap, size_t);
error = parserutils_buffer_append(buffer, data, len);
if (error != PARSERUTILS_OK)
break;
count--;
}
va_end(ap);
return error;
}
/**
* Insert data into a memory buffer
*
* \param buffer The buffer to insert into
* \param offset The offset into the buffer to insert at
* \param data The data to insert
* \param len The length, in bytes, of the data to insert
* \return PARSERUTILS_OK on success, appropriate error otherwise
*/
parserutils_error parserutils_buffer_insert(parserutils_buffer *buffer,
size_t offset, const uint8_t *data, size_t len)
{
parserutils_error error;
if (offset > buffer->length)
return PARSERUTILS_BADPARM;
if (offset == buffer->length)
return parserutils_buffer_append(buffer, data, len);
error = ensure_space(buffer, len);
if (error != PARSERUTILS_OK)
return error;
memmove(buffer->data + offset + len,
buffer->data + offset, buffer->length - offset);
memcpy(buffer->data + offset, data, len);
buffer->length += len;
return PARSERUTILS_OK;
}
/**
* Discard a section of a memory buffer
*
* \param buffer The buffer to discard data from
* \param offset The offset into the buffer of the start of the section
* \param len The number of bytes to discard
* \return PARSERUTILS_OK on success, appropriate error otherwise.
*/
parserutils_error parserutils_buffer_discard(parserutils_buffer *buffer,
size_t offset, size_t len)
{
if (offset >= buffer->length || offset + len > buffer->length)
return PARSERUTILS_BADPARM;
if (offset == 0) {
buffer->data += len;
buffer->length -= len;
try_rebase(buffer);
return PARSERUTILS_OK;
}
memmove(buffer->data + offset, buffer->data + offset + len,
buffer->length - (len + offset));
buffer->length -= len;
return PARSERUTILS_OK;
}
/**
* Extend the amount of space allocated for a memory buffer
*
* \param buffer The buffer to extend
* \return PARSERUTILS_OK on success, appropriate error otherwise.
*/
parserutils_error parserutils_buffer_grow(parserutils_buffer *buffer)
{
size_t offset = get_offset(buffer);
uint8_t *temp = realloc(buffer->alloc, buffer->allocated * 2);
if (temp == NULL)
return PARSERUTILS_NOMEM;
buffer->alloc = temp;
buffer->data = buffer->alloc + offset;
buffer->allocated *= 2;
return PARSERUTILS_OK;
}
parserutils_error parserutils_buffer_randomise(parserutils_buffer *buffer)
{
#ifndef NDEBUG
uint8_t *temp;
#endif
if (buffer == NULL)
return PARSERUTILS_BADPARM;
#ifndef NDEBUG
temp = malloc(buffer->allocated);
if (temp == NULL)
return PARSERUTILS_NOMEM;
memcpy(temp, buffer->data, buffer->length);
memset(buffer->data, 0xff, buffer->length);
/* Leak the buffer's current data, so we don't reuse it */
/* buffer->alloc(buffer->data, 0, buffer->pw); */
buffer->alloc = buffer->data = temp;
#endif
return PARSERUTILS_OK;
}
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