buffer.c

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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 <parserutils/utils/buffer.h>

#define DEFAULT_SIZE (4096)

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->data = malloc(DEFAULT_SIZE);
        if (b->data == NULL) {
                free(b);
                return PARSERUTILS_NOMEM;
        }

        b->length = 0;
        b->allocated = DEFAULT_SIZE;

        *buffer = b;

        return PARSERUTILS_OK;
}

parserutils_error parserutils_buffer_destroy(parserutils_buffer *buffer)
{
        if (buffer == NULL)
                return PARSERUTILS_BADPARM;

        free(buffer->data);
        free(buffer);

        return PARSERUTILS_OK;
}

parserutils_error parserutils_buffer_append(parserutils_buffer *buffer, 
                const uint8_t *data, size_t len)
{
        while (len >= buffer->allocated - buffer->length) {
                parserutils_error error = parserutils_buffer_grow(buffer);
                if (error != PARSERUTILS_OK)
                        return error;
        }

        memcpy(buffer->data + buffer->length, data, len);

        buffer->length += len;

        return PARSERUTILS_OK;
}

parserutils_error parserutils_buffer_insert(parserutils_buffer *buffer, 
                size_t offset, const uint8_t *data, size_t len)
{
        if (offset > buffer->length)
                return PARSERUTILS_BADPARM;

        if (offset == buffer->length)
                return parserutils_buffer_append(buffer, data, len);

        while (len >= buffer->allocated - buffer->length) {
                parserutils_error error = parserutils_buffer_grow(buffer);
                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;
}

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;

        memmove(buffer->data + offset, buffer->data + offset + len, 
                        buffer->length - (len + offset));

        buffer->length -= len;

        return PARSERUTILS_OK;
}

parserutils_error parserutils_buffer_grow(parserutils_buffer *buffer)
{
        uint8_t *temp = realloc(buffer->data, buffer->allocated * 2);
        if (temp == NULL)
                return PARSERUTILS_NOMEM;

        buffer->data = temp;
        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->data = temp;
#endif


        return PARSERUTILS_OK;
}