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/*
Copyright (C) 2009 Red Hat, Inc.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#define SHORT_PIX_IMAGE_DIST_LEVEL_1 64 //(1 << 6)
#define SHORT_PIX_IMAGE_DIST_LEVEL_2 16384 // (1 << 14)
#define SHORT_PIX_IMAGE_DIST_LEVEL_3 4194304 // (1 << 22)
#define FAR_PIX_IMAGE_DIST_LEVEL_1 256 // (1 << 8)
#define FAR_PIX_IMAGE_DIST_LEVEL_2 65536 // (1 << 16)
#define FAR_PIX_IMAGE_DIST_LEVEL_3 16777216 // (1 << 24)
/* if image_distance = 0, pixel_distance is the distance between the matching pixels.
Otherwise, it is the offset from the beginning of the referred image */
#if defined(GLZ_ENCODE_MATCH) /* actually perfroming the encoding */
static INLINE void encode_match(Encoder *encoder, uint32_t image_distance,
size_t pixel_distance, size_t len)
#elif defined(GLZ_ENCODE_SIZE) /* compute the size of the encoding except for the match length*/
static INLINE int get_encode_ref_size(uint32_t image_distance, size_t pixel_distance)
#endif
{
#if defined(GLZ_ENCODE_SIZE)
int encode_size;
#endif
#if defined(GLZ_ENCODE_MATCH)
/* encoding the match length + Long/Short dist bit + 12 LSB pixels of pixel_distance*/
if (len < 7) {
if (pixel_distance < MAX_PIXEL_SHORT_DISTANCE) {
encode(encoder, (uint8_t)((len << 5) + (pixel_distance & 0x0f)));
} else {
encode(encoder, (uint8_t)((len << 5) + 16 + (pixel_distance & 0x0f)));
}
encode(encoder, (uint8_t)((pixel_distance >> 4) & 255));
} else {
if (pixel_distance < MAX_PIXEL_SHORT_DISTANCE) {
encode(encoder, (uint8_t)((7 << 5) + (pixel_distance & 0x0f)));
} else {
encode(encoder, (uint8_t)((7 << 5) + 16 + (pixel_distance & 0x0f)));
}
for (len -= 7; len >= 255; len -= 255) {
encode(encoder, 255);
}
encode(encoder, (uint8_t)len);
encode(encoder, (uint8_t)((pixel_distance >> 4) & 255));
}
#endif
/* encoding the rest of the pixel ditsance and the image_dist and its 2 control bits */
/* The first 2 MSB bits indicate how many more bytes should be read for image dist */
if (pixel_distance < MAX_PIXEL_SHORT_DISTANCE) {
if (image_distance < SHORT_PIX_IMAGE_DIST_LEVEL_1) {
#if defined(GLZ_ENCODE_MATCH)
encode(encoder, (uint8_t)(image_distance & 0x3f));
#elif defined(GLZ_ENCODE_SIZE)
encode_size = 3;
#endif
} else if (image_distance < SHORT_PIX_IMAGE_DIST_LEVEL_2) {
#if defined(GLZ_ENCODE_MATCH)
encode(encoder, (uint8_t)((1 << 6) + (image_distance & 0x3f)));
encode(encoder, (uint8_t)((image_distance >> 6) & 255));
#elif defined(GLZ_ENCODE_SIZE)
encode_size = 4;
#endif
} else if (image_distance < SHORT_PIX_IMAGE_DIST_LEVEL_3) {
#if defined(GLZ_ENCODE_MATCH)
encode(encoder, (uint8_t)((1 << 7) + (image_distance & 0x3f)));
encode(encoder, (uint8_t)((image_distance >> 6) & 255));
encode(encoder, (uint8_t)((image_distance >> 14) & 255));
#elif defined(GLZ_ENCODE_SIZE)
encode_size = 5;
#endif
} else {
#if defined(GLZ_ENCODE_MATCH)
encode(encoder, (uint8_t)((1 << 7) + (1 << 6) + (image_distance & 0x3f)));
encode(encoder, (uint8_t)((image_distance >> 6) & 255));
encode(encoder, (uint8_t)((image_distance >> 14) & 255));
encode(encoder, (uint8_t)((image_distance >> 22) & 255));
#elif defined(GLZ_ENCODE_SIZE)
encode_size = 6;
#endif
}
} else {
/* the third MSB bit indicates if the pixel_distance is medium/long*/
uint8_t long_dist_control = (pixel_distance < MAX_PIXEL_MEDIUM_DISTANCE) ? 0 : 32;
if (image_distance == 0) {
#if defined(GLZ_ENCODE_MATCH)
encode(encoder, (uint8_t)(long_dist_control + ((pixel_distance >> 12) & 31)));
#elif defined(GLZ_ENCODE_SIZE)
encode_size = 3;
#endif
} else if (image_distance < FAR_PIX_IMAGE_DIST_LEVEL_1) {
#if defined(GLZ_ENCODE_MATCH)
encode(encoder,
(uint8_t)(long_dist_control + (1 << 6) + ((pixel_distance >> 12) & 31)));
encode(encoder, (uint8_t)(image_distance & 255));
#elif defined(GLZ_ENCODE_SIZE)
encode_size = 4;
#endif
} else if (image_distance < FAR_PIX_IMAGE_DIST_LEVEL_2) {
#if defined(GLZ_ENCODE_MATCH)
encode(encoder,
(uint8_t)(long_dist_control + (1 << 7) + ((pixel_distance >> 12) & 31)));
encode(encoder, (uint8_t)(image_distance & 255));
encode(encoder, (uint8_t)((image_distance >> 8) & 255));
#elif defined(GLZ_ENCODE_SIZE)
encode_size = 5;
#endif
} else {
#if defined(GLZ_ENCODE_MATCH)
encode(encoder,
(uint8_t)(long_dist_control + (1 << 7) + (1 << 6) +
((pixel_distance >> 12) & 31)));
encode(encoder, (uint8_t)(image_distance & 255));
encode(encoder, (uint8_t)((image_distance >> 8) & 255));
encode(encoder, (uint8_t)((image_distance >> 16) & 255));
#elif defined(GLZ_ENCODE_SIZE)
encode_size = 6;
#endif
}
if (long_dist_control) {
#if defined(GLZ_ENCODE_MATCH)
encode(encoder, (uint8_t)((pixel_distance >> 17) & 255));
#elif defined(GLZ_ENCODE_SIZE)
encode_size++;
#endif
}
}
#if defined(GLZ_ENCODE_SIZE)
return encode_size;
#endif
}
#undef GLZ_ENCODE_SIZE
#undef GLZ_ENCODE_MATCH
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