/*
* Copyright (c) 2008-2024 Jonathan Schleifer <js@nil.im>
*
* All rights reserved.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License version 3.0 only,
* as published by the Free Software Foundation.
*
* This program 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
* version 3.0 for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* version 3.0 along with this program. If not, see
* <https://www.gnu.org/licenses/>.
*/
#include <stdbool.h>
#include <stdint.h>
#import "macros.h"
#import "OFInvalidFormatException.h"
OF_ASSUME_NONNULL_BEGIN
typedef struct _OFHuffmanTree {
struct _OFHuffmanTree *_Nullable leaves[2];
uint16_t value;
} *OFHuffmanTree;
/* Inlined for performance. */
static OF_INLINE bool
_OFHuffmanTreeWalk(id _Nullable stream,
bool (*bitReader)(id _Nullable, uint16_t *_Nonnull, uint8_t),
OFHuffmanTree _Nonnull *_Nonnull tree, uint16_t *_Nonnull value)
{
OFHuffmanTree iter = *tree;
uint16_t bits;
while (iter->value == 0xFFFF) {
if OF_UNLIKELY (!bitReader(stream, &bits, 1)) {
*tree = iter;
return false;
}
if OF_UNLIKELY (iter->leaves[bits] == NULL)
@throw [OFInvalidFormatException exception];
iter = iter->leaves[bits];
}
*value = iter->value;
return true;
}
#ifdef __cplusplus
extern "C" {
#endif
extern OFHuffmanTree _Nonnull _OFHuffmanTreeNew(uint8_t lengths[_Nonnull],
uint16_t count) OF_VISIBILITY_HIDDEN;
extern OFHuffmanTree _Nonnull _OFHuffmanTreeNewSingle(uint16_t value)
OF_VISIBILITY_HIDDEN;
extern void _OFHuffmanTreeFree(OFHuffmanTree _Nonnull tree)
OF_VISIBILITY_HIDDEN;
#ifdef __cplusplus
}
#endif
OF_ASSUME_NONNULL_END