Simplify page CRC calculation (speeduino#1416)

* Simplify page CRC calculation.

* Optimize calculatePageCRC32() for size - it's not performance sensitive, since it's only called during I/O

Author: adbancroft

speeduino/page_crc.cpp

@@ -2,104 +2,18 @@
 #include "page_crc.h"
 #include "pages.h"
 
-// Abstract the FastCrC32 functions 
-// - they have have very slight differences in signatures, which causes the Arduino
-// compiler to fail for some boards (the Platform IO compiler works fine though)
-static inline uint32_t initializeCrc(FastCRC32 &crc, const uint8_t *buffer, uint16_t len) {
-  return crc.crc32(buffer, len);
-}
-static inline uint32_t updateCrc(FastCRC32 &crc, const uint8_t *buffer, uint16_t len) {
-  return crc.crc32_upd(buffer, len);
-}
-
-using pCrcCalc = uint32_t (*)(FastCRC32 &, const uint8_t *, uint16_t);
-
-static inline uint32_t compute_raw_crc(const page_iterator_t &entity, pCrcCalc calcFunc, FastCRC32 &crcCalc)
-{
-    return calcFunc(crcCalc, (uint8_t*)entity.pData, entity.address.size);
-}
-
-static inline uint32_t compute_row_crc(const table_row_iterator &row, pCrcCalc calcFunc, FastCRC32 &crcCalc)
+uint32_t __attribute__((optimize("Os"))) calculatePageCRC32(byte pageNum)
 {
-    return calcFunc(crcCalc, &*row, row.size());
-}
+    FastCRC32 crcCalc;
+    
+    byte buffer = getPageValue(pageNum, 0);
+    uint32_t crc = crcCalc.crc32(&buffer, 1U);
 
-static inline uint32_t compute_tablevalues_crc(table_value_iterator it, pCrcCalc calcFunc, FastCRC32 &crcCalc)
-{
-    uint32_t crc = compute_row_crc(*it, calcFunc, crcCalc);
-    ++it;
-
-    while (!it.at_end())
+    for (uint16_t offset=1; offset<getPageSize(pageNum); ++offset)
     {
-        crc = compute_row_crc(*it, &updateCrc, crcCalc);
-        ++it;
+        buffer = getPageValue(pageNum, offset);
+        crc = crcCalc.crc32_upd(&buffer, 1U);
     }
-    return crc;
-}
-
-static inline uint32_t compute_tableaxis_crc(table_axis_iterator it, uint32_t crc, FastCRC32 &crcCalc)
-{
-    byte values[32]; // Fingers crossed we don't have a table bigger than 32x32
-    byte *pValue = values;
-    while (!it.at_end())
-    {
-        *pValue++ = (byte)*it;
-        ++it;
-    }
-    return pValue-values==0 ? crc : crcCalc.crc32_upd(values, pValue-values);
-}
-
-static inline uint32_t compute_table_crc(const page_iterator_t &entity, pCrcCalc calcFunc, FastCRC32 &crcCalc)
-{
-    return compute_tableaxis_crc(y_begin(entity), 
-                compute_tableaxis_crc(x_begin(entity),
-                    compute_tablevalues_crc(rows_begin(entity), calcFunc, crcCalc),
-                    crcCalc),
-                crcCalc);
-}
 
-static inline uint32_t pad_crc(uint16_t padding, uint32_t crc, FastCRC32 &crcCalc)
-{
-    const uint8_t raw_value = 0u;
-    while (padding>0)
-    {
-        crc = crcCalc.crc32_upd(&raw_value, 1);
-        --padding;
-    }
     return crc;
-}
-
-static inline uint32_t compute_crc(const page_iterator_t &entity, pCrcCalc calcFunc, FastCRC32 &crcCalc)
-{
-    switch (entity.type)
-    {
-    case Raw:
-        return compute_raw_crc(entity, calcFunc, crcCalc);
-        break;
-
-    case Table:
-        return compute_table_crc(entity, calcFunc, crcCalc);
-        break;
-
-    default:
-    case NoEntity:
-        return pad_crc(entity.address.size, 0U, crcCalc);
-        break;
-    }
-}
-
-uint32_t calculatePageCRC32(byte pageNum)
-{
-  FastCRC32 crcCalc;
-  page_iterator_t entity = page_begin(pageNum);
-  // Initial CRC calc
-  uint32_t crc = compute_crc(entity, &initializeCrc, crcCalc);
-
-  entity = advance(entity);
-  while (entity.type!=End)
-  {
-    crc = compute_crc(entity, &updateCrc /* Note that we are *updating* */, crcCalc);
-    entity = advance(entity);
-  }
-  return pad_crc(getPageSize(pageNum) - (entity.address.start+entity.address.size), crc, crcCalc);
 }

test/test_pages/test_page_crc.cpp

@@ -10,13 +10,6 @@ static void setPageValues_Incremental(uint8_t pageNum, char seedValue)
         setPageValue(boostvvtPage2, offset, seedValue+(uint8_t)offset);
     }
 }
-static void setPageValues_Same(uint8_t pageNum, char seedValue)
-{
-    for (uint16_t offset=0; offset<getPageSize(pageNum); ++offset)
-    {
-        setPageValue(boostvvtPage2, offset, seedValue);
-    }
-}
 
 static void test_calculatePageCRC32(void)
 {