Pillow

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/*
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 * The Python Imaging Library.
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 * $Id$
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 *
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 * decoder for raw (uncompressed) image data
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 *
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 * history:
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 * 96-03-07 fl rewritten
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 *
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 * Copyright (c) Fredrik Lundh 1996.
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 * Copyright (c) Secret Labs AB 1997.
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 *
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 * See the README file for information on usage and redistribution.
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 */
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#include "Imaging.h"
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#include "Raw.h"
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int
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ImagingRawDecode(Imaging im, ImagingCodecState state, UINT8 *buf, Py_ssize_t bytes) {
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    enum { LINE = 1, SKIP };
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    RAWSTATE *rawstate = state->context;
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    UINT8 *ptr;
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    if (state->state == 0) {
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        /* Initialize context variables */
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        /* get size of image data and padding */
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        state->bytes = (state->xsize * state->bits + 7) / 8;
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        if (rawstate->stride) {
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            rawstate->skip = rawstate->stride - state->bytes;
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            if (rawstate->skip < 0) {
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                state->errcode = IMAGING_CODEC_CONFIG;
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                return -1;
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            }
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        } else {
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            rawstate->skip = 0;
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        }
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        /* check image orientation */
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        if (state->ystep < 0) {
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            state->y = state->ysize - 1;
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            state->ystep = -1;
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        } else {
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            state->ystep = 1;
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        }
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        state->state = LINE;
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    }
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    ptr = buf;
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    for (;;) {
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        if (state->state == SKIP) {
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            /* Skip padding between lines */
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            if (bytes < rawstate->skip) {
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                return ptr - buf;
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            }
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            ptr += rawstate->skip;
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            bytes -= rawstate->skip;
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            state->state = LINE;
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        }
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        if (bytes < state->bytes) {
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            return ptr - buf;
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        }
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        /* Unpack data */
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        state->shuffle(
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            (UINT8 *)im->image[state->y + state->yoff] + state->xoff * im->pixelsize,
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            ptr,
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            state->xsize
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        );
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        ptr += state->bytes;
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        bytes -= state->bytes;
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        state->y += state->ystep;
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        if (state->y < 0 || state->y >= state->ysize) {
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            /* End of file (errcode = 0) */
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            return -1;
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        }
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        state->state = SKIP;
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    }
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}
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