Implement portable LA sample packing and unpacking.

diff --git a/pv/data/logicsnapshot.cpp b/pv/data/logicsnapshot.cpp
index 754a456cc8f2e6c078cfd5a46e8b1c756571f79a..a1beafb9c4e4e3e3c50a111077e62fd3c2d261d5 100644 (file)
--- a/pv/data/logicsnapshot.cpp
+++ b/pv/data/logicsnapshot.cpp
@@ -62,6 +62,72 @@ LogicSnapshot::~LogicSnapshot()
                free(l.data);
 }
 
+uint64_t LogicSnapshot::unpack_sample(const uint8_t *ptr) const
+{
+       uint64_t value = 0;
+       switch(_unit_size) {
+       default:
+               value |= ((uint64_t)ptr[7]) << 56;
+               /* FALLTHRU */
+       case 7:
+               value |= ((uint64_t)ptr[6]) << 48;
+               /* FALLTHRU */
+       case 6:
+               value |= ((uint64_t)ptr[5]) << 40;
+               /* FALLTHRU */
+       case 5:
+               value |= ((uint64_t)ptr[4]) << 32;
+               /* FALLTHRU */
+       case 4:
+               value |= ((uint32_t)ptr[3]) << 24;
+               /* FALLTHRU */
+       case 3:
+               value |= ((uint32_t)ptr[2]) << 16;
+               /* FALLTHRU */
+       case 2:
+               value |= ptr[1] << 8;
+               /* FALLTHRU */
+       case 1:
+               value |= ptr[0];
+               /* FALLTHRU */
+       case 0:
+               break;
+       }
+       return value;
+}
+
+void LogicSnapshot::pack_sample(uint8_t *ptr, uint64_t value)
+{
+       switch(_unit_size) {
+       default:
+               ptr[7] = value >> 56;
+               /* FALLTHRU */
+       case 7:
+               ptr[6] = value >> 48;
+               /* FALLTHRU */
+       case 6:
+               ptr[5] = value >> 40;
+               /* FALLTHRU */
+       case 5:
+               ptr[4] = value >> 32;
+               /* FALLTHRU */
+       case 4:
+               ptr[3] = value >> 24;
+               /* FALLTHRU */
+       case 3:
+               ptr[2] = value >> 16;
+               /* FALLTHRU */
+       case 2:
+               ptr[1] = value >> 8;
+               /* FALLTHRU */
+       case 1:
+               ptr[0] = value;
+               /* FALLTHRU */
+       case 0:
+               break;
+       }
+}
+
 void LogicSnapshot::append_payload(
        const sr_datafeed_logic &logic)
 {
@@ -139,13 +205,13 @@ void LogicSnapshot::append_payload_to_mipmap()
                diff_counter = MipMapScaleFactor;
                while (diff_counter-- > 0)
                {
-                       const uint64_t sample = *(uint64_t*)src_ptr;
+                       const uint64_t sample = unpack_sample(src_ptr);
                        accumulator |= _last_append_sample ^ sample;
                        _last_append_sample = sample;
                        src_ptr += _unit_size;
                }
 
-               *(uint64_t*)dest_ptr = accumulator;
+               pack_sample(dest_ptr, accumulator);
                dest_ptr += _unit_size;
        }
 
@@ -179,11 +245,11 @@ void LogicSnapshot::append_payload_to_mipmap()
                        diff_counter = MipMapScaleFactor;
                        while (diff_counter-- > 0)
                        {
-                               accumulator |= *(uint64_t*)src_ptr;
+                               accumulator |= unpack_sample(src_ptr);
                                src_ptr += _unit_size;
                        }
 
-                       *(uint64_t*)dest_ptr = accumulator;
+                       pack_sample(dest_ptr, accumulator);
                }
        }
 }
@@ -193,7 +259,7 @@ uint64_t LogicSnapshot::get_sample(uint64_t index) const
        assert(_data);
        assert(index < _sample_count);
 
-       return *(uint64_t*)((uint8_t*)_data + index * _unit_size);
+       return unpack_sample((uint8_t*)_data + index * _unit_size);
 }
 
 void LogicSnapshot::get_subsampled_edges(
@@ -379,7 +445,7 @@ uint64_t LogicSnapshot::get_subsample(int level, uint64_t offset) const
 {
        assert(level >= 0);
        assert(_mip_map[level].data);
-       return *(uint64_t*)((uint8_t*)_mip_map[level].data +
+       return unpack_sample((uint8_t*)_mip_map[level].data +
                _unit_size * offset);
 }
 

diff --git a/pv/data/logicsnapshot.h b/pv/data/logicsnapshot.h
index 50fb6f8335b97e883007f45bfa9e26207dc30a47..0f6f410c962487dd8828bda493e86fe33670e050 100644 (file)
--- a/pv/data/logicsnapshot.h
+++ b/pv/data/logicsnapshot.h
@@ -69,6 +69,9 @@ public:
                int64_t start_sample, int64_t end_sample) const;
 
 private:
+       uint64_t unpack_sample(const uint8_t *ptr) const;
+       void pack_sample(uint8_t *ptr, uint64_t value);
+       
        void reallocate_mipmap_level(MipMapLevel &m);
 
        void append_payload_to_mipmap();