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1547 palkovsky 1
/*
2071 jermar 2
 * Copyright (c) 2006 Ondrej Palkovsky
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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2541 jermar 29
#include <sys/types.h>
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#include <errno.h>
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#include "ppm.h"
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static void skip_whitespace(unsigned char **data)
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{
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retry:
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    while (**data == ' ' || **data == '\t' || **data == '\n' ||
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        **data == '\r')
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        (*data)++;
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    if (**data == '#') {
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        while (1) {
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            if (**data == '\n' || **data == '\r')
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                break;
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            (*data)++;
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        }
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        goto retry;
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    }
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}
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static void read_num(unsigned char **data, unsigned int *num)
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{
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    *num = 0;
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    while (**data >= '0' && **data <= '9') {
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        *num *= 10;
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        *num += **data - '0';
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        (*data)++;
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    }
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}
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2541 jermar 60
int ppm_get_data(unsigned char *data, size_t dtsz, unsigned int *width,
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    unsigned int *height)
1555 palkovsky 62
{
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    /* Read magic */
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    if (data[0] != 'P' || data[1] != '6')
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        return EINVAL;
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    data+=2;
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    skip_whitespace(&data);
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    read_num(&data, width);
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    skip_whitespace(&data);
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    read_num(&data,height);
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    return 0;
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}
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/** Draw PPM pixmap
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 *
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 * @param data Pointer to PPM data
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 * @param datasz Maximum data size
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 * @param sx Coordinate of upper left corner
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 * @param sy Coordinate of upper left corner
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 * @param maxwidth Maximum allowed width for picture
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 * @param maxheight Maximum allowed height for picture
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 * @param putpixel Putpixel function used to print bitmap
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 */
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int ppm_draw(unsigned char *data, size_t datasz, unsigned int sx,
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    unsigned int sy, unsigned int maxwidth, unsigned int maxheight,
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    putpixel_cb_t putpixel, void *vport)
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{
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    unsigned int width, height;
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    unsigned int maxcolor;
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    unsigned int i;
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    unsigned int color;
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    unsigned int coef;
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    /* Read magic */
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    if ((data[0] != 'P') || (data[1] != '6'))
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        return EINVAL;
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    data += 2;
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    skip_whitespace(&data);
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    read_num(&data, &width);
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    skip_whitespace(&data);
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    read_num(&data, &height);
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    skip_whitespace(&data);
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    read_num(&data, &maxcolor);
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    data++;
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    if ((maxcolor == 0) || (maxcolor > 255) || (width * height > datasz))
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        return EINVAL;
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2541 jermar 112
    coef = 255 / maxcolor;
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    if (coef * maxcolor > 255)
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        coef -= 1;
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2541 jermar 116
    for (i = 0; i < width * height; i++) {
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        /* Crop picture if we don't fit into region */
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        if (i % width > maxwidth || i / width > maxheight) {
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            data += 3;
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            continue;
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        }
2541 jermar 122
        color = ((data[0] * coef) << 16) + ((data[1] * coef) << 8) +
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            data[2] * coef;
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2541 jermar 125
        (*putpixel)(vport, sx + (i % width), sy + (i / width), color);
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        data += 3;
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    }
4377 svoboda 128
 
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    return 0;
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}