CH_Channel.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        Channel Library (C++)
 *
 * COMMENTS:    Definition of a channel
 *
 */

#ifndef __CH_Channel_h__
#define __CH_Channel_h__

#include "CH_API.h"
#include "CH_Collection.h"
#include "CH_ExprLanguage.h"
#include "CH_EventManager.h"
#include "CH_Manager.h"
#include "CH_Segment.h"
#include "CH_Types.h"

#include <UT/UT_Array.h>
#include <UT/UT_Assert.h>
#include <UT/UT_Debug.h>
#include <UT/UT_DeepString.h>
#include <UT/UT_Interval.h>
#include <UT/UT_NonCopyable.h>
#include <UT/UT_RLEBitArray.h>
#include <UT/UT_String.h>
#include <UT/UT_StringHolder.h>
#include <UT/UT_SuperInterval.h>
#include <UT/UT_Swap.h>
#include <UT/UT_VectorTypes.h>

#include <SYS/SYS_Inline.h>
#include <SYS/SYS_Math.h>
#include <SYS/SYS_StaticAssert.h>
#include <SYS/SYS_Types.h>
#include <iosfwd>
#include <stddef.h>


class UT_IStream;
class CH_BatchModifyScope;
class CL_SimpleChannel;

class CH_API CH_HalfKey
{
public:
    fpreal      myV[ CH_NUM_VALUES ];
    bool        myVValid[ CH_NUM_VALUES ];
    bool        myVTied[ CH_NUM_VALUES ];
    bool        myVAuto[ CH_NUM_VALUES ];
};

class CH_API CH_Key
{
public:
    fpreal      myTimeValue;
    bool        myEvaluatedSlopes;
    CH_HalfKey  k[2];

    CH_Key() { clear(); }

    void        display() const;

    void        clear();

    // direction is one of -1, 0, 1
    // -1 = tie using left value
    // 0 = tie averaging both
    // 1 = tie using right value
    void        tie( int direction, CH_ValueTypes t );

    void        tie( int direction );

    void        setAuto( CH_ValueTypes t );

    void        set( CH_ValueTypes t, fpreal value );
    bool        isSet( CH_ValueTypes t ) const;

    void        complete();

    void        get( CH_Segment *left_seg, CH_Segment *right_seg,
                     bool accel_ratio = true );

    void        put( CH_Segment *left_seg, CH_Segment *right_seg,
                     bool accel_ratio = true, bool update_fake_slope_accel_handles = true ) const;

    void        stretch( fpreal xscale, fpreal yscale, bool accel_ratio );

    void        changeAccelsToRatios( fpreal left_seg_len, fpreal right_seg_len );

    void        reverse();

    void        opscript( std::ostream &os, bool use_time,
                            bool only_valid=true ) const;

    bool        verify( bool check_tied_slopes=true ) const;
};

class CH_API CH_FullKey: public CH_Key
{
public:
    bool        myUseExpression;
    UT_String   myExpression;
    CH_ExprLanguage myExprLanguage;

    CH_FullKey()
    {
        myUseExpression = false;
        myExprLanguage = CH_OLD_EXPR_LANGUAGE;
    }

    CH_FullKey( CH_FullKey const& other );
    CH_FullKey &operator=( CH_FullKey const& other );

    void        display() const;
};

class CH_API CH_ReversibleKey: public CH_FullKey
{
public:
    bool        myUseRevExpression;
    UT_String   myRevExpression;
    CH_ExprLanguage myRevExprLanguage;

    CH_ReversibleKey()
    {
        myUseRevExpression = false;
        myRevExprLanguage = CH_OLD_EXPR_LANGUAGE;
    }

    CH_ReversibleKey( CH_ReversibleKey const& other );
    CH_ReversibleKey &operator=( CH_ReversibleKey const& other );

    void        display() const;

    void        stretch( fpreal xscale, fpreal yscale, bool accel_ratio );

    void        reverse();
};

//
// Iterator for going through .chn and .bchn files, 
// channel by channel, until the end of channels for current collection is
// reached. The iterator can be restarted by calling begin() again.
//
class CH_API CH_ChannelIterator
{
// After using begin or nextChannel, the position in the stream
// will be proper for using CH_Channel::load or CH_Collection::loadChannelRange
public:
    CH_ChannelIterator(UT_IStream &is, int binary);
    bool begin(UT_StringHolder &name, const UT_StringHolder *path=nullptr);
    bool end() { return myNoMoreChannels; }
    bool nextChannel(UT_StringHolder &name);
    int getLastError() { return myLastError; }

private:
    UT_IStream *myCurrIs;
    UT_StringRef myCurrColl;
    int myIsBinary;
    int myLastError;
    bool myNoMoreChannels;
};


class CH_API CH_Channel
{
public:
    typedef enum
    {
        SNAP_SNAP,
        SNAP_SNAP_AND_DELETE,
        SNAP_REPLACE,
        SNAP_REPLACE_DOUBLE
    } SnapType;

    CH_Channel(CH_Collection *dad, const UT_StringHolder &name,
               fpreal default_value = 0,
               const char *default_string = nullptr, bool temporary=false);
    CH_Channel(CH_Collection *dad, const CH_Channel &from);
    CH_Channel(CH_Collection *dad, const CH_Channel &from, bool temporary);
   ~CH_Channel();

   UT_NON_COPYABLE(CH_Channel)

    void                 initializeFirstSegment(const char *expr,
                                                CH_ExprLanguage language);
    
    // Initialize parents of mySegments and myDisableSegments to this
    void                 initializeSegmentParents();
    
    // UTILITIES

    /// Clear everything, even the defaults.
    void                 clear();
    void                 swap( CH_Channel &other );

    const UT_StringHolder &getName() const { return myName; }
    const UT_StringHolder &getAlias() const
                            {
                                if (myAlias.isstring())
                                    return myAlias;
                                else
                                    return myName;
                            }

    void                 getFullPath(UT_String &path) const
                         {
                            getCollection()->getFullPath(this, path);
                         }
    void                 getFullPath(UT_StringHolder &path) const
                         {
                            getCollection()->getFullPath(this, path);
                         }

    //  Used only by CH_Collection
    void                 setName(const UT_StringHolder &s) { myName = s; }
    void                 setAlias(const UT_StringHolder &s) { myAlias = s; }

    CH_Manager          *getManager()   const { return myParent->getManager(); }

    fpreal               getTolerance() const
                                    { return getManager()->getTolerance(); }

    // This returns if the channel is time dependent without evaluating
    // the channel.
    bool                 isTimeDependent() const;

    // These return if the channel is time dependent and will catch more cases
    // than isTimeDependent() by evaluating the channel.
    bool                 isTimeDependentSlow(int thread) const;
    bool                 isStringTimeDependentSlow(int thread) const;

    bool                 hasNonIntegerKeys() const;
    bool                 isDataDependent(fpreal gtime) const;

    // are we using a zero-length segment to represent one key?
    bool                 hasOnlyOneSegment() const;

    bool                 isRotationChannel() const;

    // KEYS
    bool                 getSurroundingSegs( fpreal gtime,
                            CH_Segment *&left, CH_Segment *&right ) const;

    CH_Segment          *getSegmentAfterKey( fpreal gtime ) const;

    //  isAtKey returns true if the channel is considered modifiable at
    //  the given time. This means there's either no segment there or the
    //  segment is constant or there's a timemark there (segment start|end).
    bool                 isAtKey(fpreal gtime) const;

    //  isAtHardKey returns true only if there's a timemark (segment start
    //  or end) at the given time.
    bool                 isAtHardKey(fpreal gtime) const;
    bool                 isAtHardKeyframe(int frame) const;

    fpreal               findKey(fpreal gtime, fpreal direction) const;
    int                  findKeyframe(int frame, int direction) const;

    class CH_API    ConstIntervalIter;
    class CH_API    IntervalIter;

    /// Return an iterator for keys within the given interval. If ascending is
    /// false, then the iterator is initialized at the end of the range
    /// instead of at the beginning of the range.
    /// @{
    IntervalIter         intervalIter(
                            const UT_SuperIntervalR & range,
                            const bool ascending=true) const;
    ConstIntervalIter    constIntervalIter(
                            const UT_SuperIntervalR & range,
                            const bool ascending=true) const;
    /// @}

    // sample functions evaluate the channel to find values
    // getKey functions only evaluate if the time is not already at a hard key
    void                 sampleValueSlope( CH_Segment *seg, fpreal gtime,       
                                           int thread, fpreal &v, fpreal &s );
    bool                 sampleVSA( CH_Segment *seg, fpreal gtime, int thread,
                                            fpreal &v, fpreal &s, fpreal a[2] );
    void                 sampleKey( CH_Segment *seg, fpreal gtime, int thread,
                                    CH_Key &key );
    bool                 getKey( fpreal gtime, CH_Key &key,
                                 bool accel_ratios = true,
                                 CH_GetKeyExtend extend = CH_GETKEY_EXTEND_NONE );
    bool                 getFullKey( fpreal gtime, CH_FullKey &key,
                                     bool reverse = false,
                                     bool accel_ratios = true,
                                     CH_GetKeyExtend extend = CH_GETKEY_EXTEND_NONE );
    bool                 getReversibleKey( fpreal gtime, CH_ReversibleKey &key );

    void                 putKey( fpreal gtime, CH_Key const& key,
                                 bool accel_ratios, bool apply_auto_slope,
                                 bool update_fake_slope_accel_handles);
    void                 putFullKey( fpreal gtime, CH_FullKey const& key,
                                     bool accel_ratios, bool apply_auto_slope,
                                     bool update_fake_slope_accel_handles);

    void                 putKey( fpreal gtime, CH_Key const& key,
                                 bool accel_ratios = true, bool apply_auto_slope = true )
                                 {
                                     putKey(gtime, key, accel_ratios, apply_auto_slope, true);
                                 }
    void                 putFullKey( fpreal gtime, CH_FullKey const& key,
                                     bool accel_ratios = true, bool apply_auto_slope = true )
                                 {
                                    putFullKey(gtime, key, accel_ratios, apply_auto_slope, true);
                                 }

    void                 transferKey(fpreal to_time,
                            CH_Channel *from_chp, fpreal from_time);

    void                 applyPendingToKey( CH_Key &key, fpreal gtime );
    void                 applyDefaultSlopeToKey( CH_Key &key );

    /// Insert key at given time
    void                 insertKeyFrame(fpreal global_t, bool use_auto_slope_pref=true);

    /// Delete key at given time
    void                 destroyKeyFrame(fpreal global_t);

    /// Move key from old time to new time. Requires that a key exists at
    /// old_gtime and that there is no key at new_gtime.
    void                 moveKeyFrame( fpreal old_gtime, fpreal new_gtime );

    void                 saveKeyFrameForUndo( fpreal global_t );
    void                 saveForUndo();

    // this function is a bit confusing
    // Sets the in/out values for a segment to the val at a time specified
    //The method returns 0 if it was successfull,
    //                     -1 if there was no key at the time specified
    // set_pending = if true,the pending value is set to val, unless commit_keys
    //               is true, and gtime falls on a key frame.
    // commit_keys = if true and gtime falls on a key frame, the keyed value
    //               for that frame is set to val, pending is cleared if 
    //               set_pending is true
    int                  setKeyValue(fpreal val, fpreal gtime,
                                     bool set_pending = false,
                                     bool commit_keys = true,
                                     bool propagate = true);
    int                  setKeyString(const UT_String &str, fpreal gtime,
                                      bool set_pending = false,
                                      bool commit_keys = true,
                                      bool propagate = true);
    int                  setKeyString(const UT_String &str, fpreal gtime,
                                      CH_ExprLanguage language,
                                      bool set_pending = false,
                                      bool commit_keys = true,
                                      bool propagate = true);
    void                 holdValue( fpreal gtime, int thread );

    // utility functions for getting keyframe numbers:
    // they return array of keyframes in the channel 
    // the frames are unique and sorted in a ascending order.
    void                 getKeyFrames(const UT_SuperIntervalR &range,
                                      UT_Array<int> &frames,
                                      bool error_frames_only);

    /// Similar to the above, but gets times of all keys in the channel
    /// in the specified range.
    void                 getKeyTimes(const UT_SuperIntervalR &range,
                                     UT_Array<fpreal> &times,
                                     bool error_frames_only);

    // the frames are unique and sorted in a descending order.
    void                 getDisabledFrames(UT_Array<int> &frames,
                                           int minframe, int maxframe);

    // EXPRESSIONS
    CH_Segment          *getExpressionSegment( fpreal gtime ) const;
    const char          *getExpression( fpreal gtime ) const;
    bool                 changeExpression( fpreal gtime,
                                            const char *expr,
                                            CH_ExprLanguage language,
                                            bool convert_accels );
    CH_ExprLanguage      getCollectionExprLanguage() const;
    CH_ExprLanguage      getExprLanguageAtTime(fpreal time) const;
    void                 setExprLanguage(CH_ExprLanguage language);
    void                 setExprLanguageAtTime(CH_ExprLanguage language,
                                               fpreal time);

    // If we were to ask for the value of the channel as a string at a
    // particular time, this function returns what the meaning of that string
    // would be (either a literal or expression in some language).
    CH_StringMeaning     getStringMeaning(fpreal time) const;

    // MULTI-SEGMENT MANIPULATION
    void         clearSegments();

    /// Delete keys in given range
    void         deleteKeys( UT_SuperIntervalR const& range );

    /// Delete keys at the given key indices.
    /// @note Must be sorted in ascending order!
    void         deleteKeys(const UT_Array<int> &ascending_sorted_key_indices);

    void         moveFrames(const UT_Array<int> &frames, int amount);

    bool         copyRangeOverwritesKeys(const CH_Channel &src,
                                    UT_SuperIntervalR const& range,
                                    UT_IntervalR const& to_range);
    bool         copyRangeOverwritesFrames(const CH_Channel &src,
                                    UT_SuperIntervalR const& range,
                                    UT_IntervalR const& to_range);
    bool         copyRangeOverwrites(const CH_Channel &src,
                                    UT_SuperIntervalR const& range,
                                    UT_IntervalR const& to_range);

    void         copyRange(const CH_Channel &src,
                                    UT_SuperIntervalR const& range,
                                    UT_IntervalR const& to_range,
                                    bool apply_auto_slope = true);

    void         copyRangeFrames(const CH_Channel &src,
                                 const UT_SuperIntervalR &range,
                                 const UT_IntervalR &to_range,
                                 const UT_Array<int> *frames = nullptr);

    void         deleteRangeFrames(UT_SuperIntervalR const& range,
                                   const UT_Array<int> *frames = nullptr);

    // copyContents copies everything except name and parent
    void         copyContents(const CH_Channel &from);
    void         swapContents( CH_Channel &other );
    // TODO remove this function:
    // copy a range of keys. Assumes that we already have keys in the src
    // channel at those times
    // another way to do this is: (once we pass UT_SuperIntervalR by value)
    // ch.clear();
    // ch.copyRange( src, UT_SuperIntervalR( start, end ), 0.0f );
    void         copyRange(const CH_Channel &src,
                                   fpreal global_start, fpreal global_end);

    // if os is provided, a verbose description of what's happening is printed
    void         snapKeysInRange( const UT_SuperIntervalR &range,
                                    SnapType type=SNAP_SNAP,
                                    std::ostream *os=nullptr );

    // ENTIRE CHANNEL MANIPULATION
    void        scroll (fpreal new_start, bool update = true);
    void        stretch(fpreal new_start, fpreal new_end);
    void        reverse(fpreal gstart=0, fpreal gend=0, bool whole_chan = true);
    // scroll on the y axis (returns success)
    bool        increaseKeyValues( fpreal delta );

    // DISABLING
    bool        isAllDisabled() const;
    bool        isAllEnabled() const;
    bool        isDisabled(fpreal gtime) const;
    void        disableAll(fpreal gtime);
    void        enableAll();
    void        disable(fpreal gstart, fpreal gend);
    void        enable(fpreal gstart, fpreal gend);

    // PENDING METHODS
    SYS_FORCE_INLINE
    bool                 isPending() const
                            { return myPending; }
    bool                 isPending(fpreal gtime) const;
    bool                 isPendingLocal(fpreal ltime) const;
    void                 clearPending();
    void                 updatePending( fpreal gtime );
    fpreal               getPendingEvalTime() const
                            { return globalTime(myPendingEvalTime); }
    SYS_FORCE_INLINE
    bool                 isPendingHold() const
                         { return myPendingHold; }
    void                 setPendingHold( bool state );

    // SAVE and LOAD
    void                 save(std::ostream &os, bool binary, bool compiled,
                              bool pending_state) const;
    template <typename FPREAL_TYPE>
    bool                 load(UT_IStream &is);
    void                 display() const;
    void                 displayAsKeys() const;

    void                 setDefaultValue(fpreal dv) { myDefValue = dv; }
    fpreal               getDefaultValue() const   { return myDefValue; }

    void                 setDefaultString(const UT_StringHolder &dv)
                         { myDefString = dv; }
    const UT_StringHolder &
                         getDefaultString() const   { return myDefString; }

    void                 setChannelLeftType(CH_ChannelBehavior t);
    void                 setChannelRightType(CH_ChannelBehavior t);
    CH_ChannelBehavior   getChannelLeftType() const  { return myLeftType; }
    CH_ChannelBehavior   getChannelRightType() const { return myRightType; }

    static const char   *getChannelTypeName(CH_ChannelBehavior type);

    void                 setCollection(CH_Collection *chp){ myParent = chp; }
    const CH_Collection *getCollection() const { return myParent; }
    CH_Collection       *getCollection()       { return myParent; }

    void                 setIsTemporary( bool temp ) { myIsTemporary = temp; }
    bool                 isTemporary() const { return myIsTemporary; }

    // FLAGS
    void                 setChangeActive(int state)
                         {
                            if( state ) myFlags |=  CH_CHANNEL_ACTIVE;
                            else        myFlags &= ~CH_CHANNEL_ACTIVE;
                         }
    bool                 isChangeActive() const
                         { return (myFlags & CH_CHANNEL_ACTIVE) ? 1 : 0; }
    

    bool                 getLocked() const
                         { return ((myFlags & CH_CHANNEL_LOCKED) != 0); }
    void                 setLocked(bool f);

    int                  getChanged() const
                         { return (myFlags & CH_CHANNEL_MODIFIED) ? 1 : 0; }
    void                 setChanged(bool on,
                                    CH_CHANGE_TYPE type = CH_CHANNEL_CHANGED);
    void                 dirtyExprCache();

    int                  canAccess(uint mask) const
                         {
                            if( myParent )
                                return myParent->canAccessChannel(mask, this);
                            else
                                return 1;
                         }

    // map collection time to channel time...
    inline fpreal        localTime(fpreal t)   const { return (t-myStart); }

    // map channel time to global time...
    inline fpreal        globalTime(fpreal t)  const { return t + myStart; }

    // Returns collection global time...
    fpreal      getStart()           const { return myStart; }
    fpreal      getEnd()             const { return myStart + myLength;}
    fpreal      getLength()          const { return myLength; }

    // Used to reset the local variables:
    void                 unresolveLocalVars(int thread);

    // Op dependencies
    void                 buildOpDependencies(void *ref_id, int thread);
    void                 changeOpRef(const char *new_fullpath,
                                     const char *old_fullpath,
                                     const char *old_cwd,
                                     const char *chan_name,
                                     const char *old_chan_name,
                                     int thread);

    // Enable or disable value caching in expression segments...
    void         cook(int state);

    // Load values as keys. Returns the number of samples actually loaded.
    int          setRawValues(fpreal from, fpreal to, fpreal *vals, int nsamples);
    int          setRawValues(fpreal *times, fpreal *vals, int n);

    // Channel Scope Flag
    void         setScope(bool on_off);
    bool         isScoped() const;

    // Does this channel have any segments with editable components (eg. value,
    // slope, acceleration, etc.)?
    bool         isEditable();

    // Query methods. Used only by CH_Collection
    fpreal       evaluate(fpreal t, bool no_disabling, int thread);
    void         evaluate(fpreal from, fpreal to, fpreal *vals, int nsamples,
                          bool no_disabling, bool use_cache, int thread);
    fpreal       evaluateSegment(CH_Segment *eval, fpreal localtime,
                                 bool extend, int thread);
    void         evaluateString(UT_String &result, fpreal t, int thread);
    void         evaluateStringSegment(UT_String &result, CH_Segment *eval,
                                       fpreal localtime, bool extend,
                                       int thread);

    int          findString(const char *str, bool fullword,
                            bool usewildcards) const;
    int          changeString(const char *from, const char *to,
                              bool fullword, bool update /*= true*/,
                              int thread);

    //
    //  Methods used only in the channel library glue
    //
    static inline fpreal    getGlueIV(int thread);
    static inline void      getGlueTime(
                                fpreal &t, fpreal &t0, fpreal &t1,
                                fpreal &v0, fpreal &v1, int thread);
    static inline void      getGlueSlope(
                                fpreal *m0, fpreal *m1,
                                fpreal *a0, fpreal *a1, int thread);

//  Used only by CH_Collection
    inline const CH_Segment *getEvaluationSegment(int thread) const
                        {
                            return getManager()->evalContext(thread).segment();
                        }
    inline CH_Segment *getEvaluationSegment(int thread)
                        {
                            return getManager()->evalContext(thread).segment();
                        }
    const CH_Segment    *getPrevEvaluationSegment(int thread) const;
    CH_Segment          *getPrevEvaluationSegment(int thread);
    const CH_Segment    *getNextEvaluationSegment(int thread) const;
    CH_Segment          *getNextEvaluationSegment(int thread);

    fpreal       getInTime(int thread) const;
    fpreal       getOutTime(int thread) const;
    fpreal       getPrevInTime(int thread) const;
    fpreal       getNextOutTime(int thread) const;

    // This method will attempt to match the channel name with the pattern,
    // searching as many parents as necessary regardless of the cwd
    // eg. tx will match true with tx xform1/tx geo1/xform1/tx

    int         match(const char *pattern) const;


    // sets all keys to be 'value', and zeros all slopes & accels.
    void         setConstantValue(fpreal value);
   
    // sets the data and keys so that the channel approximates the
    // raw data of samples within given error using cubic interpolation
    // INPUTS:
    //   data      - an array of pairs (time, value) to be fitted. 
    //   n_pts     - number of elements in data array
    //   error2    - the error to which the channel should approximate data
    //   delete_old_segments - if true, all old segments are cleared before
    //               new ones are generated from data. If false, the segments
    //               that fit the data replace old segments (thus, some
    //               old segments that are outside of the data range will 
    //               remain unchanged)
    // OUTPUTS:
    //             The clip will approximate the curve sampled by data.
    //             The clip will have its start time equal to
    //             the time component of the first pair in the data array,
    //             and the end time equal to the time of the last pair.
    // RETURNS:    
    //             True on success, false if failed. 
    bool         fitToPointData( UT_Vector2R *data, int n_pts, 
                                 bool preserve_extrema,
                                 fpreal error2 = 0.01f,
                                 bool delete_old_segments = false);

    // refits the channel data (or portion of it) with cubic interpolation 
    // within given error tolerance. Inserts new keys, etc.
    // delete_old_segments - if true, all segments are deleted before
    //     refitted range is inserted. Otherwise, old segments outside of the
    //     refitted range are not affected.
    void         refit( fpreal tolerance, bool preserve_extrema );
    void         refit( fpreal tolerance, bool preserve_extrema,
                        fpreal from_gtime, fpreal to_gtime,
                        bool delete_old_segments);

    /// Overwrites segments and keys in the range
    /// [start, start + time_delta * (num_keys - 1)]
    /// @param new_key_values - Array of size num_keys containing the values for
    /// the new keys
    /// @param num_keys - Number of keys to set in the new range
    /// @param global_start - Global start (in time) of the range to replace
    /// keys in. Must be at or after the global start of this channel
    /// @param time_delta - Spacing between keys in time
    /// @param smooth_slopes - Smooth the slopes of the new keys
    /// @param clear - If true, will first clear all keys and segments
    /// keys in a partial region
    /// @param notify - If true, emit a CH_CHANNELS_MAJOR_CHANGE event
    /// @returns true on success, false if failed
    bool         setKeys(fpreal *new_key_values, int num_keys, 
                         fpreal global_start, fpreal time_delta,
                         bool smooth_slopes = true,
                         bool clear = false, bool notify = true);

    // SEGMENT MANAGEMENT
    bool         isEmpty() const;
    int          getNSegments() const;
    int          getNKeys() const;
    int          getNKeysBefore( fpreal gtime ) const;
    int          getNKeysBeforeOrAt( fpreal gtime ) const;

    fpreal       getKeyTime( unsigned idx ) const;

    unsigned     getSegmentIdx(fpreal local_time) const;
    CH_Segment  *getSegment(unsigned idx) const;
    CH_Segment  *getSegment(fpreal local_time) const;

    CH_Segment  *getNextSegment(unsigned idx) const; // Depends on behavior
    CH_Segment  *getPrevSegment(unsigned idx) const; // Depends on behavior

    CH_Segment  *getFirstSegment()  const
                 { 
                     // empty means no keys in the channel if user delete them
                     // all
                     UT_ASSERT_P( isEmpty() || myEndSegment );
                     return isEmpty()
                        ? nullptr : getSegment( (unsigned)0 );
                 }
    CH_Segment  *getLastSegment()  const
                 { 
                     // empty means no keys in the channel if user delete them
                     // all
                     UT_ASSERT_P( isEmpty() || myEndSegment );

                     // old behaviour maintained (ie. don't use end segment)
                     return isEmpty()
                        ? nullptr : getSegment( (unsigned)mySegments.entries()-1 );
                 }

    int64        getMemoryUsage(bool inclusive) const;

    //  The first method takes global time, the second, segment local time.
    void         changeSegLength     (CH_Segment *seg, fpreal gtime,
                                        CH_SegmentScale how = CH_SCALE_ANY,
                                        bool adjust_and_update = true);

    bool         getHaveCompiledExpressions() const;

    bool         verify();
    bool         verify(bool verify_tied_values);

    // Snapshots or buffer curves.
    // Create a deep copy of the channel data for fast modifications and revert workflow.
    // It's more intuitive than to have to do multiple undo to get back to the previous 
    // keyframes.
    void saveSnapshot();
    void undoSnapshot(CH_Channel *previous, bool previous_snapshot_cleared);
    bool loadSnapshot();
    bool swapSnapshot();
    bool clearSnapshot();
    CH_Channel* getSnapshotChannel();

    /// Smooth the specified auto slopes
    /// @param slope_flags - bit array indicating which slopes are to be
    /// smoothed. Each slope (in and out) has a bit and they are arranged
    /// in left-right order. 0th bit is the in slope of the first seg, so
    /// for the ith seg, its in slope is at bit 2i and out slope at 2i+1
    /// @param force - If true, smooths all selected slopes, even if not auto
    /// @param max_step - If > 0, the maximum amount a slope may
    /// change from its existing value during this smoothing pass.
    void smoothAutoSlopesForSegments(
            UT_RLEBitArray &slope_flags,
            bool force=false,
            fpreal max_delta=-1);

    void smoothAutoSlopes();
    /// Smooths slopes of key at time
    /// Can set up a max step based on delta if > 0
    /// @param value_changed - true if delta refers to a value change, false
    /// if delta refers to a time change
    void smoothAutoSlopes( fpreal global_time, fpreal delta = -1, bool value_changed = true );
    /// Smooths slopes of keys at both ends of a segment
    void smoothAutoSlopes( CH_Segment *seg );

    // Layer Scope Flag
    void         setLayerScope(bool on_off);
    bool         isLayerScoped() const;

    // Set an array pointer to capture the copyRange actions
    void setCaptureCopiedKeys(UT_Array<fpreal> *capture_array);

    // chkey version of putFullKey() doesn't do the same validations as putFullKey()
    void putChFullKey( fpreal gtime, CH_FullKey const& key, bool accel_ratios = true );

    fpreal       evaluateSegment(CH_Segment &eval, fpreal localtime,
                                 bool extend, int thread);

    fpreal       evaluateSegment(CH_Segment &eval, fpreal localtime, int thread);
    fpreal       evaluateSegment(CH_Segment *eval, fpreal localtime, int thread);

    fpreal       evaluateSegmentExtend(CH_Segment *eval, fpreal localtime, int thread);
    fpreal       evaluateSegmentExtend(CH_Segment &eval, fpreal localtime, int thread);

    fpreal       evaluateSegmentSlope(CH_Segment *eval, fpreal localtime, int thread);
    fpreal       evaluateSegmentSlopeApprox(CH_Segment *eval, fpreal localtime, int thread);

    /// Check if all segment expressions are simple expressions such as
    /// linear(), bezier(), constant().
    /// Note that you can still convert to a simple channel even if this returns false,
    /// but any custom segment expressions will be evaluated as beziers instead.
    bool isSimpleChannel() const;

    /// Constructs and returns a simple channel from this channel
    /// Converts all the segments to CL_SimpleSegments
    CL_SimpleChannel asSimpleChannel() const;
    /// Clears this channel and sets it from the given simple channel
    void fromSimpleChannel(const CL_SimpleChannel &sc);


    /// clear method that can keep the default values.
    /// @param clear_defaults - true to clear myDefValue and myDefString.
    void clear(bool clear_defaults);

private:

    void         ensureEndSegmentCreated();
    void         updateEndSegment();
    void         destroyEndSegment();

    bool         isTwoSegChannelTimeDep() const;

    template <typename T>
    bool         isTimeDependentSlowImpl(int thread) const;

    // TODO: Remove this. It's abysmally slow, doing a binary search each time
    bool         nextTimeInRange(UT_SuperIntervalR const& range,
                                 fpreal &t, bool first) const;
                                            
    friend class CH_BatchModifyScope;

    void         moveKeyInternal(fpreal old_gtime, fpreal new_gtime,
                                 CH_BatchModifyScope &scope);
    void         splitSegment(fpreal gtime, bool accel_ratio = true);
    void         destroyKeyInternal(unsigned seg_i, CH_BatchModifyScope &scope);

    // cuts out a portion of a channel. Returns an index at which the cut began
    int          cutOut( fpreal from_gtime, fpreal to_gtime );

    CH_Segment  *appendSegment(CH_Segment *seg);

    // remove and delete the segment
    void         deleteSegment(unsigned idx);

    int          getNDisableSegments() const
                 { return myDisableSegments.entries(); }
    CH_Segment  *getDisableSegment(unsigned idx) const
                 {
                    return (idx < myDisableSegments.entries()) ?
                            myDisableSegments(idx) : 0;
                 }

    CH_Segment  *getDisableSegmentForLocalTime(fpreal local_time) const;
    CH_Segment  *getPrevDisableSegment(CH_Segment *) const;
    CH_Segment  *getNextDisableSegment(CH_Segment *) const;

    int          getDisableSegmentIndex(fpreal ltime, bool closest_prev) const;

    CH_Segment  *getFirstDisableSegment()  const
                 { 
                    return (myDisableSegments.entries() > 0) ?
                        myDisableSegments(0) : 0;
                 }
    CH_Segment  *getLastDisableSegment()  const
                 { 
                    return (myDisableSegments.entries() > 0)
                          ? myDisableSegments(myDisableSegments.entries()-1)
                          : 0;
                 }
    CH_Segment  *appendDisableSegment(CH_Segment *seg);

    CH_Segment  *insertDisableSegment(CH_Segment *seg);
    CH_Segment  *insertDisableSegment(CH_Segment *seg, int idx);
    CH_Segment  *insertDisableSegment(CH_Segment *seg, CH_Segment *before);

    // Remove but don't delete
    void         removeDisableSegment(CH_Segment *seg);
    void         removeDisableSegment(int idx);

    void         deleteDisableSegment(CH_Segment *);
    void         deleteDisableSegment(int idx);

    void         setPending( bool on_off, fpreal ltime );
    void         updatePendingStateToManager();

    void         deNormalize(fpreal scale);

    int          isCooking() const
                 {
                    return (myFlags & CH_CHANNEL_COOKING) != 0;
                 }
    void         setCooking(bool on_off)
                 {
                    if (on_off) myFlags |=  CH_CHANNEL_COOKING;
                    else        myFlags &= ~CH_CHANNEL_COOKING;
                 }

    void         adjustSegments(int begin_i, int end_i,
                                CH_CHANGE_TYPE event_type);

    // Get Segment methods that can return disabled segments.
    CH_Segment  *getFirstSegment(bool no_disabling )  const;
    CH_Segment  *getLastSegment(bool no_disabling )  const;
    CH_Segment  *getEndSegment(bool no_disabling )  const;
    CH_Segment  *getSegment(bool no_disabling, fpreal ltime ) const;

    enum chGetOrSampleReturn
    {
        Sampled, Get, FirstLast
    };
    chGetOrSampleReturn getOrSampleKey( fpreal ltime, CH_Key &key, bool accel_ratio, int thread );

    /// Overwrite all segments and keys for this channel, placing new keys at evenly
    /// spaced intervals
    /// This is called by setKeys when the clear parameter is true
    /// @param new_key_values - Array of size num_keys containing the values for
    /// the new keys
    /// @param num_keys - Number of keys to set on the modified curve
    /// @param new_start - New starting time for the first segment/key
    /// @param time_delta - Spacing between keys in time
    /// @returns true on success, false if failed
    bool         setAllKeys(fpreal *new_key_values, int num_keys,
                            fpreal new_start, fpreal time_delta,
                            bool smooth_slopes, bool notify);

    fpreal transitionSlope(fpreal target, fpreal val, fpreal max_delta);

    /// Checks if the key at the start of segment seg_idx has one neighbour
    /// slope which is fixed, and one which is free. If so, applies
    /// appropriate SDDE smoothing method and returns the number of keys
    /// affected (0, 1 or 2)
    int smoothSlopeHalfFixed(int seg_idx, UT_RLEBitArray &flags, fpreal max_delta, bool force);

private: // data

    CH_Collection               *myParent;      // Who I belong to
    UT_StringHolder              myName;
    UT_StringHolder              myAlias;

    CH_ChannelBehavior           myLeftType;    // Type of channel
    CH_ChannelBehavior           myRightType;   // Type of channel
    CH_Segment                  *myEndSegment;

    fpreal                       myDefValue;    // Default/Pending value
    fpreal                       myStart;       // Start time of channel
    fpreal                       myLength;      // Kept for efficiency (local)

    UT_StringHolder              myDefString;   // Default/Pending string value

    UT_Array<CH_Segment *>       mySegments;    // Array of segments
    UT_Array<CH_Segment *>       myDisableSegments;

    fpreal                       myPendingEvalTime;
    CH_Channel                  *mySnapshot;
    UT_Array<fpreal>            *myCaptureCopiedKeys;

    unsigned char                myFlags;
    bool                         myPending;
    bool                         myPendingHold;
    bool                         myScope;
    bool                         myLayerScope;
    bool                         myIsTemporary;
    bool                         myDoingChKey;
    bool                         mySnapshotCleared;

};

UT_SWAPPER_CLASS(CH_Channel)

inline CH_Segment *
CH_Channel::getSegment(unsigned idx) const
{
    if( idx<mySegments.entries() )
        return mySegments(idx);
    if( idx==(unsigned)-1 || idx==mySegments.entries() )
    {
        UT_ASSERT(myEndSegment || mySegments.entries() == 0);
        return myEndSegment;
    }
    UT_ASSERT( false );
    return nullptr;
}

inline int
CH_Channel::getNSegments() const
{
    return myEndSegment ? 1 + mySegments.entries() : 0;
}

inline bool
CH_Channel::isEmpty() const
{
    return mySegments.isEmpty() && !myEndSegment;
}

inline int
CH_Channel::getNKeys() const
{
    return getNSegments();
}

inline fpreal
CH_Channel::getKeyTime( unsigned idx ) const
{
    CH_Segment  *segp;
    if( idx == mySegments.entries() )
    {
        segp = myEndSegment;
        UT_ASSERT( segp );
        return globalTime( segp->getStart() );
    }
    segp = getSegment( idx );
    UT_ASSERT( segp );
    return globalTime( segp->getStart() );
}

inline bool
CH_Channel::hasOnlyOneSegment() const
{
    return getNSegments() == 1;
}

inline bool
CH_Channel::isRotationChannel() const
{
    // NB: This is actually slightly weaker than PRM_Float::isRotationParm()
    return myName == "rx" || myName == "ry" || myName == "rz";
}


/// Const iterator over an interval
class CH_Channel::ConstIntervalIter
{
public:
    ConstIntervalIter()
        : myChannel(nullptr)
        , myI(-1)
        , myTol(0.0)
    {
    }

    ConstIntervalIter &operator++()
    {
        ++myI;
        return *this;
    }
    ConstIntervalIter &operator--()
    {
        --myI;
        return *this;
    }

    bool atEnd() const
    {
        if (myI >= myChannel->getNSegments())
            return true;
        fpreal lt = localTime();
        return !(myRange.myMaxInclusive ?
                      SYSisLessOrEqual(lt, myRange.max, myTol)
                    : SYSisLess(lt, myRange.max, myTol));
    }
    bool atPre() const
    {
        if (myI < 0)
            return true;
        fpreal lt = localTime();
        return !(myRange.myMinInclusive ?
                      SYSisGreaterOrEqual(lt, myRange.min, myTol)
                    : SYSisGreater(lt, myRange.min, myTol));
    }

    unsigned index() const
    {
        return (unsigned)myI;
    }

    const CH_Segment &segment() const
    {
        return *(myChannel->getSegment((unsigned)myI));
    }

    // Local time at start of segment
    fpreal localTime() const
    {
        return myChannel->getSegment((unsigned)myI)->getStart();
    }

    fpreal operator*() const { return myChannel->globalTime(localTime()); }

protected:
    ConstIntervalIter(
            const CH_Channel &ch, const UT_SuperIntervalR &range,
            const bool ascending)
        : myChannel(&ch)
        , myRange(range)
        , myTol(ch.getTolerance())
    {
        myRange.min = ch.localTime(myRange.min);
        myRange.max = ch.localTime(myRange.max);
        UT_ASSERT(myRange.min <= myRange.max);
        if (ascending)
        {
            // If myRange.min is less than the first segment's start time, then
            // the first segment is returned by getSegmentIdx().
            myI = ch.getSegmentIdx(myRange.min);
            CH_Segment *seg = ch.getSegment((unsigned)myI);
            if (seg)
            {
                fpreal lt = seg->getStart();
                if (range.myMinInclusive)
                {
                    if (SYSisLess(lt, myRange.min, myTol))
                        ++myI;
                }
                else
                {
                    if (SYSisLessOrEqual(lt, myRange.min, myTol))
                        ++myI;
                }
            }
            else
            {
                myI = ch.getNSegments();
            }
            UT_ASSERT(atEnd() || myRange.contains(localTime(), myTol));
        }
        else // descending
        {
            myI = ch.getSegmentIdx(myRange.max);
            CH_Segment *seg = ch.getSegment((unsigned)myI);
            if (seg)
            {
                fpreal lt = seg->getStart();
                if (range.myMaxInclusive)
                {
                    if (SYSisGreater(lt, myRange.max, myTol))
                        --myI;
                }
                else
                {
                    if (SYSisGreaterOrEqual(lt, myRange.max, myTol))
                        --myI;
                }
            }
            else
            {
                myI = -1;
            }
            UT_ASSERT(atPre() || myRange.contains(localTime(), myTol));
        }
    }

private:
    const CH_Channel *  myChannel;
    UT_SuperIntervalR   myRange;
    int                 myI;
    fpreal              myTol;

    friend class CH_Channel;
};

/// Iterator over an interval
class CH_Channel::IntervalIter : public CH_Channel::ConstIntervalIter
{
public:
    IntervalIter()
        : ConstIntervalIter()
    {
    }
    
    CH_Segment &segment() const
    {
        return const_cast<CH_Segment &>(ConstIntervalIter::segment());
    }

    IntervalIter &operator++()
    {
        ConstIntervalIter::operator++();
        return *this;
    }
    IntervalIter &operator--()
    {
        ConstIntervalIter::operator--();
        return *this;
    }

protected:
    IntervalIter(
            const CH_Channel &ch, const UT_SuperIntervalR &range, bool reverse)
        : ConstIntervalIter(ch, range, reverse)
    {
    }

private:

    friend class CH_Channel;
};

inline CH_Channel::IntervalIter
CH_Channel::intervalIter(
        const UT_SuperIntervalR & range, const bool ascending) const
{
    return IntervalIter(*this, range, ascending);
}
inline CH_Channel::ConstIntervalIter
CH_Channel::constIntervalIter(
        const UT_SuperIntervalR & range, const bool ascending) const
{
    return ConstIntervalIter(*this, range, ascending);
}

// this will move attempted_dt towards accepted_dt so that:
// keys[i]+attempted_dt does not land on another key
// attempted_dt stays on the same side of accepted_dt as it started
//      (so that if you're moving one way, they don't snap backwards before
//      where they started)
// if snap_to_frame, attempted_dt+base_time will land on a frame
CH_API extern void
CHfindMoveKeysDelta(const CH_Channel *chp, bool snap_to_frame, fpreal base_time,
                    const UT_Array<fpreal> &sorted_orig_keys,
                    fpreal accepted_dt, fpreal &attempted_dt);

CH_API extern void
CHmoveKeysWithDelta(CH_Channel *chp, const UT_Array<fpreal> &orig_keys,
                    fpreal old_accepted_dt, fpreal new_accepted_dt);

// Move a list of keys using a list of time offset and value offsets.
CH_API extern void
CHmoveKeysWithDeltas(CH_Channel *chp, const UT_Array<fpreal> &orig_keys,
                     const UT_Array<fpreal> &time_offsets,
                     const UT_Array<fpreal> &value_offsets);

///////////////////////////////////////////////////////////////////////////////
//
// Inline Implementations
//

/*static*/ inline fpreal
CH_Channel::getGlueIV(int thread)
{
    const CH_EvalContext &      ctx = CHgetManager()->evalContext(thread);
    const CH_Channel *          eval_channel = ctx.channel();
    const CH_Segment *          segp = ctx.segment();

    if (segp)
    {
        if (eval_channel->isPending(ctx.time()))
            return eval_channel->getDefaultValue();
        else
            return segp->getInValue();
    }

    return 0.0f;
}

/*static*/ inline void
CH_Channel::getGlueTime(fpreal &t, fpreal &t0, fpreal &t1,
                        fpreal &v0, fpreal &v1, int thread)
{
    CH_Manager &        mgr = *CHgetManager();
    CH_EvalContext &    ctx = mgr.evalContext(thread);
    const CH_Channel *  eval_channel = ctx.channel();
    const CH_Segment *  segp = ctx.segment();

    if (eval_channel)
    {
        t = eval_channel->localTime(ctx.time());
        if (segp)
        {
            t0 = segp->getStart();
            t1 = segp->getEnd();
            if( eval_channel->isPendingLocal(t) )
            {
                v0 = v1 = eval_channel->getDefaultValue();
                t0 = t1 = t;
            }
            else
            {
                v0 = segp->getInValue();
                v1 = segp->getOutValue();
                if( segp->isEndSegment() )
                {
                    // Since our segment length is zero, we want fake it so
                    // that it uses either the in or out values because most
                    // existing expression functions will take the average of
                    // them when encountering a zero length segement.
                    // NB: the in/out values are swapped on end segments.
                    if (SYSisGreaterOrEqual(t, t0, mgr.getTolerance()))
                        v1 = v0;
                    else
                        v0 = v1;
                }
            }
        }
        else
        {
            t0 = eval_channel->getStart();
            t1 = eval_channel->getEnd();
            v0 = v1 = 0;
        }
    }
    else
    {
        t = 0.0f;
        t0 = 0.0f;
        t1 = 0.0f;
        v0 = 0.0f;
        v1 = 0.0f;
    }
}

/*static*/ inline void
CH_Channel::getGlueSlope(fpreal *m0, fpreal *m1, fpreal *a0, fpreal *a1,
                         int thread)
{
    CH_EvalContext &    ctx = CHgetManager()->evalContext(thread);
    const CH_Segment *  segp = ctx.segment();

    if (segp)
    {
        if (m0) *m0 = segp->getInSlope();
        if (m1) *m1 = segp->getOutSlope();
        if (a0) *a0 = segp->getInAccel();
        if (a1) *a1 = segp->getOutAccel();
    }
    else
    {
        if (m0) *m0 = 0.0f;
        if (m1) *m1 = 0.0f;
        if (a0) *a0 = 0.0f;
        if (a1) *a1 = 0.0f;
    }
}

// this returns if the channel is time dependent without evaluating
// the channel
inline bool
CH_Channel::isTimeDependent() const
{
    const int nsegs = getNSegments();

    if (nsegs == 0)
        return false;

    if (nsegs == 1)
        return getSegment(0U)->isTimeDependent();

    if (nsegs == 2)
        return isTwoSegChannelTimeDep();

    // Else, assume time dependent when more than 1 segment
    UT_ASSERT_P(nsegs > 1);
    return true;
}


// UTformat support.
static inline size_t
format(char *buffer, size_t buffer_size, const CH_Channel &v)
{
    UT_String s;
    v.getFullPath(s);
    if (!buffer)
        return s.length();
    else
    {
        size_t len = std::min(size_t(s.length()), buffer_size);
        ::memcpy(buffer, s.c_str(), len);
        return len;
    }
}

#endif // __CH_Channel_h__