Pillow/libImaging/XbmEncode.c

/*
 * The Python Imaging Library.
 * $Id$
 *
 * encoder for Xbm data
 *
 * history:
 *	96-11-01 fl	created
 *
 * Copyright (c) Fredrik Lundh 1996.
 * Copyright (c) Secret Labs AB 1997.
 *
 * See the README file for information on usage and redistribution.
 */


#include "Imaging.h"


int
ImagingXbmEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
{
    const char *hex = "0123456789abcdef";

    UINT8* ptr = buf;
    int i, n;

    if (!state->state) {

	/* 8 pixels are stored in no more than 6 bytes */
	state->bytes = 6*(state->xsize+7)/8;

	state->state = 1;

    }

    if (bytes < state->bytes) {
	state->errcode = IMAGING_CODEC_MEMORY;
	return 0;
    }

    ptr = buf;

    while (bytes >= state->bytes) {

	state->shuffle(state->buffer,
		       (UINT8*) im->image[state->y + state->yoff] +
		       state->xoff * im->pixelsize, state->xsize);

	if (state->y < state->ysize-1) {

	    /* any line but the last */
	    for (n = 0; n < state->xsize; n += 8) {

		i = state->buffer[n/8];

		*ptr++ = '0';
		*ptr++ = 'x';
		*ptr++ = hex[(i>>4)&15];
		*ptr++ = hex[i&15];
		*ptr++ = ',';
		bytes -= 5;

		if (++state->count >= 79/5) {
		    *ptr++ = '\n';
		    bytes--;
		    state->count = 0;
		}

	    }

	    state->y++;

	} else {

	    /* last line */
	    for (n = 0; n < state->xsize; n += 8) {

		i = state->buffer[n/8];

		*ptr++ = '0';
		*ptr++ = 'x';
		*ptr++ = hex[(i>>4)&15];
		*ptr++ = hex[i&15];

		if (n < state->xsize-8) {
		    *ptr++ = ',';
		    if (++state->count >= 79/5) {
			*ptr++ = '\n';
			bytes--;
			state->count = 0;
		    }
		} else
		    *ptr++ = '\n';

		bytes -= 5;

	    }

	    state->errcode = IMAGING_CODEC_END;
	    break;
	}
    }

    return ptr - buf;
}