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