Meter: allocate GraphData buffer dynamically

On wide screens the previous value of 256 could end up insufficient to
cover the screen space allocated to the graph, leaving it awkwardly
truncated mid-column.  We now allocate the buffer dynamically instead,
growing it to accommodate whatever width the graph occupies.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>

2 files changed, 17 insertions, 11 deletions

diff --git a/Meter.c b/Meter.c
index 5e7d3b70..b6fe6402 100644
--- a/Meter.c
+++ b/Meter.c
@@ -86,7 +86,7 @@ void Meter_delete(Object* cast) {
    if (Meter_doneFn(this)) {
       Meter_done(this);
    }
-   free(this->drawData);
+   free(this->drawData.values);
    free(this->caption);
    free(this->values);
    free(this);
@@ -121,8 +121,9 @@ void Meter_setMode(Meter* this, int modeIndex) {
       }
    } else {
       assert(modeIndex >= 1);
-      free(this->drawData);
-      this->drawData = NULL;
+      free(this->drawData.values);
+      this->drawData.values = NULL;
+      this->drawData.nValues = 0;
 
       const MeterMode* mode = Meter_modes[modeIndex];
       this->draw = mode->draw;
@@ -289,12 +290,17 @@ static const char* const GraphMeterMode_dotsAscii[] = {
 
 static void GraphMeterMode_draw(Meter* this, int x, int y, int w) {
    const Machine* host = this->host;
-
-   if (!this->drawData) {
-      this->drawData = xCalloc(1, sizeof(GraphData));
+   GraphData* data = &this->drawData;
+
+   assert(w > 0);
+   if ((size_t)w * 2 > data->nValues) {
+      size_t oldNValues = data->nValues;
+      data->nValues = MAXIMUM(oldNValues + (oldNValues / 2), (unsigned int)w * 2);
+      data->values = xReallocArray(data->values, data->nValues, sizeof(*data->values));
+      memmove(data->values + (data->nValues - oldNValues), data->values, oldNValues * sizeof(*data->values));
+      memset(data->values, 0, (data->nValues - oldNValues) * sizeof(*data->values));
    }
-   GraphData* data = this->drawData;
-   const int nValues = METER_GRAPHDATA_SIZE;
+   const int nValues = data->nValues;
 
    const char* const* GraphMeterMode_dots;
    int GraphMeterMode_pixPerRow;
diff --git a/Meter.h b/Meter.h
index 89f0570a..c0a44338 100644
--- a/Meter.h
+++ b/Meter.h
@@ -20,7 +20,6 @@ in the source distribution for its full text.
 
 
 #define METER_TXTBUFFER_LEN 256
-#define METER_GRAPHDATA_SIZE 256
 
 #define METER_BUFFER_CHECK(buffer, size, written)          \
    do {                                                    \
@@ -97,7 +96,8 @@ typedef struct MeterClass_ {
 
 typedef struct GraphData_ {
    struct timeval time;
-   double values[METER_GRAPHDATA_SIZE];
+   size_t nValues;
+   double* values;
 } GraphData;
 
 struct Meter_ {
@@ -108,7 +108,7 @@ struct Meter_ {
    char* caption;
    int mode;
    unsigned int param;
-   GraphData* drawData;
+   GraphData drawData;
    int h;
    int columnWidthCount;      /**< only used internally by the Header */
    uint8_t curItems;