vgmstream/ext_includes/clHCA.h
2018-10-13 19:50:42 +02:00

94 lines
3.7 KiB
C

#ifndef _clHCA_H
#define _clHCA_H
#ifdef __cplusplus
extern "C" {
#endif
/* Must pass at least 8 bytes of data to this function.
* Returns <0 on non-match, or header size on success. */
int clHCA_isOurFile(const void *data, unsigned int size);
/* The opaque state structure. */
typedef struct clHCA clHCA;
/* In case you wish to allocate and reset the structure on your own. */
int clHCA_sizeof();
void clHCA_clear(clHCA *);
void clHCA_done(clHCA *);
/* Or you could let the library allocate it. */
clHCA * clHCA_new();
void clHCA_delete(clHCA *);
/* Parses the HCA header. Must be called before any decoding may be performed,
* and size must be at least headerSize long. The recommended way is to detect
* the header length with clHCA_isOurFile, then read data and call this.
* May be called multiple times to reset decoder state.
* Returns 0 on success, <0 on failure. */
int clHCA_DecodeHeader(clHCA *, const void *data, unsigned int size);
typedef struct clHCA_stInfo {
unsigned int version;
unsigned int headerSize;
unsigned int samplingRate;
unsigned int channelCount;
unsigned int blockSize;
unsigned int blockCount;
unsigned int encoderDelay; /* samples appended to the beginning */
unsigned int encoderPadding; /* samples appended to the end */
unsigned int loopEnabled;
unsigned int loopStartBlock;
unsigned int loopEndBlock;
unsigned int loopStartDelay; /* samples in block before loop starts */
unsigned int loopEndPadding; /* samples in block after loop ends */
unsigned int samplesPerBlock; /* should be 1024 */
const char *comment;
unsigned int encryptionEnabled; /* requires keycode */
/* Derived sample formulas:
* - sample count: blockCount*samplesPerBlock - encoderDelay - encoderPadding;
* - loop start sample = loopStartBlock*samplesPerBlock - encoderDelay + loopStartDelay
* - loop end sample = loopEndBlock*samplesPerBlock - encoderDelay + (samplesPerBlock - info.loopEndPadding)
*/
} clHCA_stInfo;
/* Retrieves header information for decoding and playback (it's the caller's responsability
* to apply looping, encoder delay/skip samples, etc). May be called after clHCA_DecodeHeader.
* Returns 0 on success, <0 on failure. */
int clHCA_getInfo(clHCA *, clHCA_stInfo *out);
/* Decodes a single frame, from data after headerSize. Should be called after
* clHCA_DecodeHeader and size must be at least blockSize long.
* Data may be modified if encrypted.
* Returns 0 on success, <0 on failure. */
int clHCA_DecodeBlock(clHCA *, void *data, unsigned int size);
/* Extracts signed and clipped 16 bit samples into sample buffer.
* May be called after clHCA_DecodeBlock, and will return the same data until
* next decode. Buffer must be at least (samplesPerBlock*channels) long. */
void clHCA_ReadSamples16(clHCA *, signed short * outSamples);
/* Sets a 64 bit encryption key, to properly decode blocks. This may be called
* multiple times to change the key, before or after clHCA_DecodeHeader.
* Key is ignored if the file is not encrypted. */
void clHCA_SetKey(clHCA *, unsigned long long keycode);
/* Tests a single frame for validity, mainly to test if current key is correct.
* Returns <0 on incorrect block (wrong key), 0 on silent block (not useful to determine)
* and >0 if block is correct (the closer to 1 the more likely).
* Incorrect keys may give a few valid frames, so it's best to test a number of them
* and select the key with scores closer to 1. */
int clHCA_TestBlock(clHCA *hca, void *data, unsigned int size);
/* Resets the internal decode state, used when restarting to decode the file from the beginning.
* Without it there are minor differences, mainly useful when testing a new key. */
void clHCA_DecodeReset(clHCA * hca);
#ifdef __cplusplus
}
#endif
#endif