/*
 * Copyright (c) 2012-2013 Apple Computer, Inc.  All Rights Reserved.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#define __STDC_LIMIT_MACROS     // what are the C++ equivalents?
#include <stdint.h>

#include <IOKit/IOKernelReportStructs.h>
#include <IOKit/IOKernelReporters.h>
#include "IOReporterDefs.h"


#define super IOReporter
OSDefineMetaClassAndStructors(IOHistogramReporter, IOReporter);

/* static */
IOHistogramReporter*
IOHistogramReporter::with(IOService *reportingService,
                          IOReportCategories categories,
                          uint64_t channelID,
                          const char *channelName,
                          IOReportUnits unit,
                          int nSegments,
                          IOHistogramSegmentConfig *config)
{
    IOHistogramReporter *reporter = new IOHistogramReporter;
    
    const OSSymbol *tmpChannelName = NULL;
    
    if (reporter) {
        
        if (channelName)
            tmpChannelName = OSSymbol::withCString(channelName);
                
        if(reporter->initWith(reportingService, categories,
                              channelID, tmpChannelName,
                              unit, nSegments, config)) {
            return reporter;
        }
    }
    
    return 0;
}


bool
IOHistogramReporter::initWith(IOService *reportingService,
                              IOReportCategories categories,
                              uint64_t channelID,
                              const OSSymbol *channelName,
                              IOReportUnits unit,
                              int nSegments,
                              IOHistogramSegmentConfig *config)
{
    bool            result = false;
    IOReturn        res;        // for PREFL_MEMOP
    size_t          configSize, elementsSize, eCountsSize, boundsSize;
    int             cnt, cnt2, cnt3 = 0;
    int64_t        bucketBound = 0, previousBucketBound = 0;
    
    // analyzer appeasement
    configSize = elementsSize = eCountsSize = boundsSize = 0;
    
    IORLOG("IOHistogramReporter::initWith");

    // For now, this reporter is currently limited to a single channel
    _nChannels = 1;

    IOReportChannelType channelType = {
        .categories = categories,
        .report_format = kIOReportFormatHistogram,
        .nelements = 0,  // Initialized when Config is unpacked
        .element_idx = 0
    };
    
    if (super::init(reportingService, channelType, unit) != true) {
        IORLOG("%s - ERROR: super::init failed", __func__);
        result = false;
        goto finish;
    }
    
    // Make sure to call this after the commit init phase
    if (channelName) _channelNames->setObject(channelName);
    
    _segmentCount = nSegments;
    if (_segmentCount == 0) {
        IORLOG("IOReportHistogram init ERROR. No configuration provided!");
        result = false;
        goto finish;
    }
    
    IORLOG("%s - %u segment(s)", __func__, _segmentCount);
    
    PREFL_MEMOP_FAIL(_segmentCount, IOHistogramSegmentConfig);
    configSize = (size_t)_segmentCount * sizeof(IOHistogramSegmentConfig);
    _histogramSegmentsConfig = (IOHistogramSegmentConfig*)IOMalloc(configSize);
    if (!_histogramSegmentsConfig)      goto finish;
    memcpy(_histogramSegmentsConfig, config, configSize);
    
    // Find out how many elements are need to store the histogram
    for (cnt = 0; cnt < _segmentCount; cnt++) {
        
        _nElements += _histogramSegmentsConfig[cnt].segment_bucket_count;
        _channelDimension += _histogramSegmentsConfig[cnt].segment_bucket_count;
        
        IORLOG("\t\t bucket_base_width: %u | log_scale: %u | buckets: %u",
                _histogramSegmentsConfig[cnt].base_bucket_width,
                _histogramSegmentsConfig[cnt].scale_flag,
                _histogramSegmentsConfig[cnt].segment_bucket_count);
        
        if (_histogramSegmentsConfig[cnt].scale_flag > 1
            || _histogramSegmentsConfig[cnt].base_bucket_width == 0) {
            result = false;
            goto finish;
        }

    }
    
    // Update the channel type with discovered dimension
    _channelType.nelements = _channelDimension;

    IORLOG("%s - %u channel(s) of dimension %u",
           __func__, _nChannels, _channelDimension);

    IORLOG("%s %d segments for a total dimension of %d elements",
           __func__, _nChannels, _nElements);
    
    // Allocate memory for the array of report elements
    PREFL_MEMOP_FAIL(_nElements, IOReportElement);
    elementsSize = (size_t)_nElements * sizeof(IOReportElement);
    _elements = (IOReportElement *)IOMalloc(elementsSize);
    if (!_elements)             goto finish;
    memset(_elements, 0, elementsSize);
    
    // Allocate memory for the array of element watch count
    PREFL_MEMOP_FAIL(_nElements, int);
    eCountsSize = (size_t)_nChannels * sizeof(int);
    _enableCounts = (int *)IOMalloc(eCountsSize);
    if (!_enableCounts)         goto finish;
    memset(_enableCounts, 0, eCountsSize);
    
    lockReporter();
    for (cnt2 = 0; cnt2 < _channelDimension; cnt2++) {
        IOHistogramReportValues hist_values;
        if (copyElementValues(cnt2, (IOReportElementValues*)&hist_values)){
            goto finish;
        }
        hist_values.bucket_min = kIOReportInvalidIntValue;
        hist_values.bucket_max = kIOReportInvalidIntValue;
        hist_values.bucket_sum = kIOReportInvalidIntValue;
        if (setElementValues(cnt2, (IOReportElementValues*)&hist_values)){
            goto finish;
        }

        // Setup IOReporter's channel IDs
        _elements[cnt2].channel_id = channelID;
        
        // Setup IOReporter's reporting provider service
        _elements[cnt2].provider_id = _driver_id;
        
        // Setup IOReporter's channel type
        _elements[cnt2].channel_type = _channelType;
        _elements[cnt2].channel_type.element_idx = cnt2;
        
        //IOREPORTER_DEBUG_ELEMENT(cnt2);
    }
    unlockReporter();
    
    // Allocate memory for the bucket upper bounds
    PREFL_MEMOP_FAIL(_nElements, uint64_t);
    boundsSize = (size_t)_nElements * sizeof(uint64_t);
    _bucketBounds = (int64_t*)IOMalloc(boundsSize);
    if (!_bucketBounds)         goto finish;
    memset(_bucketBounds, 0, boundsSize);
    _bucketCount = _nElements;

    for (cnt = 0; cnt < _segmentCount; cnt++) {
        
        if (_histogramSegmentsConfig[cnt].segment_bucket_count > INT_MAX
            || _histogramSegmentsConfig[cnt].base_bucket_width > INT_MAX) {
            goto finish;
        }
        for (cnt2 = 0; cnt2 < (int)_histogramSegmentsConfig[cnt].segment_bucket_count; cnt2++) {
            
            if (cnt3 >= _nElements) {
                IORLOG("ERROR: _bucketBounds init");
                return false;
            }
            
            if (_histogramSegmentsConfig[cnt].scale_flag) {
                // FIXME: Could use pow() but not sure how to include math.h
                int64_t power = 1;
                int exponent = cnt2 + 1;
                while (exponent) {
                    power *= _histogramSegmentsConfig[cnt].base_bucket_width;
                    exponent--;
                }
                bucketBound = power;
            }
            
            else {
                bucketBound = _histogramSegmentsConfig[cnt].base_bucket_width *
                                                    ((unsigned)cnt2 + 1);
            }
            
            if (previousBucketBound >= bucketBound) {
                IORLOG("Histogram ERROR: bucket bound does not increase linearly (segment %u / bucket # %u)",
                       cnt, cnt2);
                result = false;
                goto finish;
            }
            
            _bucketBounds[cnt3] = bucketBound;
            // IORLOG("_bucketBounds[%u] = %llu", cnt3, bucketBound);
            previousBucketBound = _bucketBounds[cnt3];
            cnt3++;
        }
    }
    
    // success
    result = true;
    
finish:
    if (result != true) {
        
        if (_histogramSegmentsConfig)
            IOFree(_histogramSegmentsConfig, configSize);
        
        if (_elements)
            IOFree(_elements, elementsSize);
        
        if (_enableCounts)
            IOFree(_enableCounts, eCountsSize);
        
        if (_bucketBounds)
            IOFree(_bucketBounds, boundsSize);
    }
    
    return result;
}


void
IOHistogramReporter::free(void)
{
    if (_bucketBounds) {
        PREFL_MEMOP_PANIC(_nElements, int64_t);
        IOFree(_bucketBounds, (size_t)_nElements * sizeof(int64_t));
    }
    if (_histogramSegmentsConfig) {
        PREFL_MEMOP_PANIC(_segmentCount, IOHistogramSegmentConfig);
        IOFree(_histogramSegmentsConfig,
               (size_t)_segmentCount * sizeof(IOHistogramSegmentConfig));
    }
    
    super::free();
}


IOReportLegendEntry*
IOHistogramReporter::handleCreateLegend(void)
{
    OSData                  *tmpConfigData;
    OSDictionary            *tmpDict;
    IOReportLegendEntry     *legendEntry = NULL;
        
    legendEntry = super::handleCreateLegend();
    
    if (legendEntry) {
        
        PREFL_MEMOP_PANIC(_segmentCount, IOHistogramSegmentConfig);
        tmpConfigData = OSData::withBytes(_histogramSegmentsConfig,
                                          (unsigned)_segmentCount *
                                            (unsigned)sizeof(IOHistogramSegmentConfig));
        if (!tmpConfigData) {
            legendEntry->release();
            goto finish;
        }
        
        tmpDict = OSDynamicCast(OSDictionary, legendEntry->getObject(kIOReportLegendInfoKey));
        if (!tmpDict) {
            legendEntry->release();
            goto finish;
        }
        
        tmpDict->setObject(kIOReportLegendConfigKey, tmpConfigData);
    }
    
finish:
    return legendEntry;
}

int
IOHistogramReporter::tallyValue(int64_t value)
{
    int result = -1;
    int cnt = 0, element_index = 0;
    IOHistogramReportValues hist_values;
    
    lockReporter();
    
    // Iterate over _bucketCount minus one to make last bucket of infinite width
    for (cnt = 0; cnt < _bucketCount - 1; cnt++) {
        if (value <= _bucketBounds[cnt]) break;
    }
    
    element_index = cnt;
    
    if (copyElementValues(element_index, (IOReportElementValues *)&hist_values) != kIOReturnSuccess) {
        goto finish;
    }
    
    // init stats on first hit
    if (hist_values.bucket_hits == 0) {
        hist_values.bucket_min = hist_values.bucket_max = value;
        hist_values.bucket_sum = 0;     // += is below
    }

    // update all values
    if (value < hist_values.bucket_min) {
        hist_values.bucket_min = value;
    } else if (value > hist_values.bucket_max) {
        hist_values.bucket_max = value;
    }
    hist_values.bucket_sum += value;
    hist_values.bucket_hits++;
    
    if (setElementValues(element_index, (IOReportElementValues *)&hist_values) == kIOReturnSuccess) {
        goto finish;
    }

    // success!
    result = element_index;
    
finish:
    unlockReporter();
    return result;
}