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/* Copyright (C) 2001-2007 Peter Selinger.
* This file is part of Potrace. It is free software and it is covered
* by the GNU General Public License. See the file COPYING for details. */
/* operations on potrace_progress_t objects, which are defined in
* potracelib.h. Note: the code attempts to minimize runtime overhead
* when no progress monitoring was requested. It also tries to
* minimize excessive progress calculations beneath the "epsilon"
* threshold. */
#ifndef PROGRESS_H
#define PROGRESS_H
/* structure to hold progress bar callback data */
struct progress_s
{
void (* callback)( double progress, void* privdata ); /* callback fn */
void* data; /* callback function's private data */
double min, max; /* desired range of progress, e.g. 0.0 to 1.0 */
double epsilon; /* granularity: can skip smaller increments */
double b; /* upper limit of subrange in superrange units */
double d_prev; /* previous value of d */
};
typedef struct progress_s progress_t;
/* notify given progress object of current progress. Note that d is
* given in the 0.0-1.0 range, which will be scaled and translated to
* the progress object's range. */
static inline void progress_update( double d, progress_t* prog )
{
double d_scaled;
if( prog->callback != NULL )
{
d_scaled = prog->min * (1 - d) + prog->max * d;
if( d == 1.0 || d_scaled >= prog->d_prev + prog->epsilon )
{
prog->callback( prog->min * (1 - d) + prog->max * d, prog->data );
prog->d_prev = d_scaled;
}
}
}
/* start a subrange of the given progress object. The range is
* narrowed to [a..b], relative to 0.0-1.0 coordinates. If new range
* is below granularity threshold, disable further subdivisions. */
static inline void progress_subrange_start( double a,
double b,
const progress_t* prog,
progress_t* sub )
{
double min, max;
if( prog->callback == NULL )
{
sub->callback = NULL;
return;
}
min = prog->min * (1 - a) + prog->max * a;
max = prog->min * (1 - b) + prog->max * b;
if( max - min < prog->epsilon )
{
sub->callback = NULL; /* no further progress info in subrange */
sub->b = b;
return;
}
sub->callback = prog->callback;
sub->data = prog->data;
sub->epsilon = prog->epsilon;
sub->min = min;
sub->max = max;
sub->d_prev = prog->d_prev;
return;
}
static inline void progress_subrange_end( progress_t* prog, progress_t* sub )
{
if( prog->callback != NULL )
{
if( sub->callback == NULL )
{
progress_update( sub->b, prog );
}
else
{
prog->d_prev = sub->d_prev;
}
}
}
#endif /* PROGRESS_H */
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