Rework ZramMeter and remove MeterClass.comprisedValues

The 'comprisedValues' boolean property unnecessarily complicates the
drawing algorithms of Bar meters and Graph meters. Since the only user
of 'comprisedValues' is ZramMeter, it is better to rework the meter so
that it no longer needs 'comprisedValues'.

The 'values[ZRAM_METER_UNCOMPRESSED]' now stores the difference between
uncompressed and compressed data size.

Signed-off-by: Kang-Che Sung <explorer09@gmail.com>

Meter.c

@@ -219,7 +219,6 @@ static void BarMeterMode_draw(Meter* this, int x, int y, int w) {
    assert(startPos + w <= RichString_sizeVal(bar));
 
    int blockSizes[10];
-   int blockSizeSum = 0;
 
    // First draw in the bar[] buffer...
    int offset = 0;
@@ -231,12 +230,6 @@ static void BarMeterMode_draw(Meter* this, int x, int y, int w) {
       } else {
          blockSizes[i] = 0;
       }
-
-      if (Meter_comprisedValues(this)) {
-         blockSizes[i] = MAXIMUM(blockSizes[i] - blockSizeSum, 0);
-         blockSizeSum += blockSizes[i];
-      }
-
       int nextOffset = offset + blockSizes[i];
       // (Control against invalid values)
       nextOffset = CLAMP(nextOffset, 0, w);
@@ -330,11 +323,7 @@ static void GraphMeterMode_draw(Meter* this, int x, int y, int w) {
       for (int i = 0; i < nValues - 1; i++)
          data->values[i] = data->values[i + 1];
 
-      if (Meter_comprisedValues(this)) {
-         data->values[nValues - 1] = (this->curItems > 0) ? this->values[this->curItems - 1] : 0.0;
-      } else {
-         data->values[nValues - 1] = sumPositiveValues(this->values, this->curItems);
-      }
+      data->values[nValues - 1] = sumPositiveValues(this->values, this->curItems);
    }
 
    int i = nValues - (w * 2), k = 0;

Meter.h

@@ -74,7 +74,6 @@ typedef struct MeterClass_ {
    const char* const description;          /* optional meter description in header setup menu */
    const uint8_t maxItems;
    const bool isMultiColumn;               /* whether the meter draws multiple sub-columns (defaults to false) */
-   const bool comprisedValues;             /* whether latter values comprise previous ones (defaults to false) */
 } MeterClass;
 
 #define As_Meter(this_)                ((const MeterClass*)((this_)->super.klass))
@@ -95,7 +94,6 @@ typedef struct MeterClass_ {
 #define Meter_name(this_)              As_Meter(this_)->name
 #define Meter_uiName(this_)            As_Meter(this_)->uiName
 #define Meter_isMultiColumn(this_)     As_Meter(this_)->isMultiColumn
-#define Meter_comprisedValues(this_)   As_Meter(this_)->comprisedValues
 
 typedef struct GraphData_ {
    struct timeval time;

linux/LinuxMachine.c

@@ -337,6 +337,9 @@ static void LinuxMachine_scanZramInfo(LinuxMachine* this) {
    this->zram.totalZram = totalZram / 1024;
    this->zram.usedZramComp = usedZramComp / 1024;
    this->zram.usedZramOrig = usedZramOrig / 1024;
+   if (this->zram.usedZramComp > this->zram.usedZramOrig) {
+      this->zram.usedZramComp = this->zram.usedZramOrig;
+   }
 }
 
 static void LinuxMachine_scanZfsArcstats(LinuxMachine* this) {

linux/Platform.c

@@ -418,7 +418,7 @@ void Platform_setZramValues(Meter* this) {
 
    this->total = lhost->zram.totalZram;
    this->values[ZRAM_METER_COMPRESSED] = lhost->zram.usedZramComp;
-   this->values[ZRAM_METER_UNCOMPRESSED] = lhost->zram.usedZramOrig;
+   this->values[ZRAM_METER_UNCOMPRESSED] = lhost->zram.usedZramOrig - lhost->zram.usedZramComp;
 }
 
 void Platform_setZfsArcValues(Meter* this) {

linux/ZramMeter.c

@@ -27,7 +27,8 @@ static void ZramMeter_updateValues(Meter* this) {
 
    METER_BUFFER_APPEND_CHR(buffer, size, '(');
 
-   written = Meter_humanUnit(buffer, this->values[ZRAM_METER_UNCOMPRESSED], size);
+   double uncompressed = this->values[ZRAM_METER_COMPRESSED] + this->values[ZRAM_METER_UNCOMPRESSED];
+   written = Meter_humanUnit(buffer, uncompressed, size);
    METER_BUFFER_CHECK(buffer, size, written);
 
    METER_BUFFER_APPEND_CHR(buffer, size, ')');
@@ -50,7 +51,8 @@ static void ZramMeter_display(const Object* cast, RichString* out) {
    RichString_appendAscii(out, CRT_colors[METER_TEXT], " used:");
    RichString_appendAscii(out, CRT_colors[METER_VALUE], buffer);
 
-   Meter_humanUnit(buffer, this->values[ZRAM_METER_UNCOMPRESSED], sizeof(buffer));
+   double uncompressed = this->values[ZRAM_METER_COMPRESSED] + this->values[ZRAM_METER_UNCOMPRESSED];
+   Meter_humanUnit(buffer, uncompressed, sizeof(buffer));
    RichString_appendAscii(out, CRT_colors[METER_TEXT], " uncompressed:");
    RichString_appendAscii(out, CRT_colors[METER_VALUE], buffer);
 }
@@ -64,7 +66,6 @@ const MeterClass ZramMeter_class = {
    .updateValues = ZramMeter_updateValues,
    .defaultMode = BAR_METERMODE,
    .maxItems = ZRAM_METER_ITEMCOUNT,
-   .comprisedValues = true,
    .total = 100.0,
    .attributes = ZramMeter_attributes,
    .name = "Zram",

pcp/Platform.c

@@ -593,9 +593,13 @@ void Platform_setZramValues(Meter* this) {
 
    free(values);
 
+   if (stats.usedZramComp > stats.usedZramOrig) {
+      stats.usedZramComp = stats.usedZramOrig;
+   }
+
    this->total = stats.totalZram;
    this->values[0] = stats.usedZramComp;
-   this->values[1] = stats.usedZramOrig;
+   this->values[1] = stats.usedZramOrig - stats.usedZramComp;
 }
 
 void Platform_setZfsArcValues(Meter* this) {