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find * -type f "-(" -name "*.bdf" -o -name "*.c" -o -name "*.h" -o -name "*.py" -o -name "*.rst" -o -name "*.txt" "-)" -exec sed -e "s/[[:space:]]*$//" -i {} \;
139 lines
3.8 KiB
C
139 lines
3.8 KiB
C
/*
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* The Python Imaging Library.
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* $Id$
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*
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* decoder for packed bitfields (converts to floating point)
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*
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* history:
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* 97-05-31 fl created (much more than originally intended)
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*
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* Copyright (c) Fredrik Lundh 1997.
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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 "Bit.h"
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int
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ImagingBitDecode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
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{
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BITSTATE* bitstate = 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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/* this decoder only works for float32 image buffers */
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if (im->type != IMAGING_TYPE_FLOAT32) {
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state->errcode = IMAGING_CODEC_CONFIG;
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return -1;
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}
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/* sanity check */
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if (bitstate->bits < 1 || bitstate->bits >= 32) {
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state->errcode = IMAGING_CODEC_CONFIG;
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return -1;
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}
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bitstate->mask = (1<<bitstate->bits)-1;
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if (bitstate->sign)
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bitstate->signmask = (1<<(bitstate->bits-1));
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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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state->state = 1;
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}
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ptr = buf;
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while (bytes > 0) {
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UINT8 byte = *ptr;
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ptr++;
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bytes--;
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/* get a byte from the input stream and insert in the bit buffer */
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if (bitstate->fill&1)
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/* fill MSB first */
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bitstate->bitbuffer |= (unsigned long) byte << bitstate->bitcount;
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else
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/* fill LSB first */
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bitstate->bitbuffer = (bitstate->bitbuffer << 8) | byte;
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bitstate->bitcount += 8;
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while (bitstate->bitcount >= bitstate->bits) {
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/* get a pixel from the bit buffer */
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unsigned long data;
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FLOAT32 pixel;
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if (bitstate->fill&2) {
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/* store LSB first */
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data = bitstate->bitbuffer & bitstate->mask;
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if (bitstate->bitcount > 32)
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/* bitbuffer overflow; restore it from last input byte */
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bitstate->bitbuffer = byte >> (8 - (bitstate->bitcount -
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bitstate->bits));
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else
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bitstate->bitbuffer >>= bitstate->bits;
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} else
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/* store MSB first */
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data = (bitstate->bitbuffer >> (bitstate->bitcount -
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bitstate->bits))
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& bitstate->mask;
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bitstate->bitcount -= bitstate->bits;
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if (bitstate->lutsize > 0) {
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/* map through lookup table */
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if (data <= 0)
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pixel = bitstate->lut[0];
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else if (data >= bitstate->lutsize)
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pixel = bitstate->lut[bitstate->lutsize-1];
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else
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pixel = bitstate->lut[data];
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} else {
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/* convert */
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if (data & bitstate->signmask)
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/* image memory contains signed data */
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pixel = (FLOAT32) (INT32) (data | ~bitstate->mask);
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else
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pixel = (FLOAT32) data;
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}
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*(FLOAT32*)(&im->image32[state->y][state->x]) = pixel;
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/* step forward */
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if (++state->x >= state->xsize) {
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/* new line */
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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->x = 0;
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/* reset bit buffer */
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if (bitstate->pad > 0)
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bitstate->bitcount = 0;
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}
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}
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}
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return ptr - buf;
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}
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