/*
* Copyright (c) 2008-2023 Jonathan Schleifer <js@nil.im>
*
* All rights reserved.
*
* This file is part of ObjFW. It may be distributed under the terms of the
* Q Public License 1.0, which can be found in the file LICENSE.QPL included in
* the packaging of this file.
*
* Alternatively, it may be distributed under the terms of the GNU General
* Public License, either version 2 or 3, which can be found in the file
* LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
* file.
*/
#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);
extern OFHuffmanTree _Nonnull OFHuffmanTreeNewSingle(uint16_t value);
extern void OFHuffmanTreeFree(OFHuffmanTree _Nonnull tree);
#ifdef __cplusplus
}
#endif
OF_ASSUME_NONNULL_END