Fix compile error of sign-conversion in gcc-9

Author: r08ertliu

smbios.c

@@ -156,10 +156,13 @@ static uint16_t read_uint16(struct ParserContext *context)
     }
 
     #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-        uint16_t value = context->ptr[0] | ((uint16_t)context->ptr[1] << 8);
+        uint16_t low = (uint16_t)context->ptr[0];
+        uint16_t high = (uint16_t)(context->ptr[1] << 8);
     #else
-        uint16_t value = ((uint16_t)context->ptr[0] << 8) | context->ptr[1];
+        uint16_t low = (uint16_t)context->ptr[1];
+        uint16_t high = (uint16_t)(context->ptr[0] << 8);
     #endif
+    uint16_t value = high | low;
 
     context->ptr += 2;
     return value;
@@ -177,10 +180,11 @@ static uint32_t read_uint32(struct ParserContext *context)
     for (int i = 0; i < 4; ++i)
     {
         #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-        value |= context->ptr[i] << (i * 8);
+        uint32_t v = (uint32_t)(context->ptr[i] << (i * 8));
         #else
-        value |= context->ptr[i] << ((3 - i) * 8);
+        uint32_t v = (uint32_t)(context->ptr[i] << ((3 - i) * 8));
         #endif
+        value |= v;
     }
     context->ptr += 4;
     return value;
@@ -198,10 +202,11 @@ static uint64_t read_uint64(struct ParserContext *context)
     for (int i = 0; i < 8; ++i)
     {
         #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-        value |= context->ptr[i] << (i * 8);
+        uint64_t v = (uint64_t)(context->ptr[i] << (i * 8));
         #else
-        value |= context->ptr[i] << ((7 - i) * 8);
+        uint64_t v = (uint64_t)(context->ptr[i] << ((7 - i) * 8));
         #endif
+        value |= v;
     }
 
     context->ptr += 8;