Initial commit into public repository0.0

Signed-off-by: Michael Krelin <hacker@klever.net>

1 files changed, 121 insertions, 0 deletions

diff --git a/lib/st-decode.cc b/lib/st-decode.cc
new file mode 100644
index 0000000..f8459ac
--- a/dev/null
+++ b/lib/st-decode.cc
@@ -0,0 +1,121 @@
+#include <stdexcept>
+#include <numeric>
+#include <napkin/exception.h>
+#include <napkin/st/decode.h>
+
+namespace napkin {
+    namespace sleeptracker {
+        using std::invalid_argument;
+        using std::runtime_error;
+
+        struct st_time_t {
+            uint8_t hour;
+            uint8_t min;
+        };
+        struct st_date_t {
+            uint8_t month;
+            uint8_t day;
+        };
+        struct st_fulltime_t {
+            uint8_t hour;
+            uint8_t min;
+            uint8_t sec;
+        };
+        struct st_data_header_t {
+            char magic;
+            st_date_t today;
+            uint8_t unknown;
+            uint8_t window;
+            st_time_t to_bed;
+            st_time_t alarm;
+            uint8_t nawakes;
+        };
+        struct st_data_footer_t {
+            uint16_t data_a;
+            uint8_t checksum;
+            uint8_t eof_mark;
+        };
+
+        static void back_a_day(struct tm& t) {
+            time_t ts = mktime(&t);
+            if(ts==(time_t)-1)
+                throw exception_st_data("failed to make up time to step back a day");
+            ts -= 60*60*24;
+            if(!localtime_r(&ts,&t))
+                throw exception_st_data("failed to localtime_r() while stepping back a day");
+        }
+
+        hypnodata_t& decode(hypnodata_t& rv,const void *data,size_t data_length) {
+            if(data_length < (sizeof(st_data_header_t)+sizeof(st_data_footer_t)))
+                throw exception_st_data_envelope("not enough sleeptracker data to decode");
+            st_data_header_t *h = (st_data_header_t*)data;
+            if(h->magic != 'V')
+                throw exception_st_data_envelope("invalid magic in the data");
+            st_data_footer_t *f = (st_data_footer_t*)(static_cast<const char *>(data)+data_length-sizeof(st_data_footer_t));
+            if( (std::accumulate((uint8_t*)&h->today,(uint8_t*)&f->checksum,0)&0xFF) != f->checksum )
+                throw exception_st_data_integrity("checksum mismatch");
+            st_fulltime_t *aawake = (st_fulltime_t*)&h[1];
+            if((void*)&aawake[h->nawakes] != (void*)f)
+                throw exception_st_data_envelope("unbelievably screwed up data");
+            rv.clear();
+            time_t now = time(0);
+            struct tm t;
+            if(!localtime_r(&now,&t))
+                throw exception_st_data("failed to localtime_r()");
+            t.tm_mon = h->today.month-1;
+            t.tm_mday = h->today.day;
+            time_t mkt = mktime(&t);
+            if(mkt == (time_t)-1)
+                throw exception_st_data("failed to mktime() for a timestamp");
+            if(mkt > now) {
+                --t.tm_year;
+            }
+            struct tm ta;
+            memmove(&ta,&t,sizeof(ta));
+            ta.tm_sec = 0;
+            ta.tm_hour = h->alarm.hour; ta.tm_min = h->alarm.min;
+            rv.alarm = mktime(&ta);
+            if(rv.alarm == (time_t)-1)
+                throw exception_st_data("failed to mktime() for alarm");
+            struct tm tb;
+            memmove(&tb,&ta,sizeof(tb));
+            tb.tm_hour = h->to_bed.hour; tb.tm_min = h->to_bed.min;
+            rv.to_bed = mktime(&tb);
+            if(rv.to_bed == (time_t)-1)
+                throw exception_st_data("failed to mktime() for 'to bed'");
+            if(rv.to_bed > rv.alarm) {
+                back_a_day(tb);
+                rv.to_bed -= 24*60*60;
+            }
+            struct tm taaw;
+            memmove(&taaw,&tb,sizeof(taaw));
+            for(int rest=h->nawakes;rest;--rest,++aawake) {
+                if(
+                        taaw.tm_mday!=ta.tm_mday
+                        && (
+                            aawake->hour < tb.tm_hour
+                            || (
+                                aawake->hour==tb.tm_hour
+                                && aawake->min < tb.tm_min )
+                           ) )
+                    memmove(&taaw,&ta,sizeof(taaw));
+                taaw.tm_hour = aawake->hour;
+                taaw.tm_min = aawake->min;
+                taaw.tm_sec = aawake->sec;
+                rv.almost_awakes.push_back( mktime(&taaw) );
+                if(rv.almost_awakes.back() == (time_t)-1)
+                    throw exception_st_data("failed to mktime() for almost awake moment");
+            }
+            rv.window = h->window;
+            rv.data_a = f->data_a;
+            return rv;
+        }
+
+        hypnodata_ptr_t decode(const void *data,size_t data_length) {
+            hypnodata_ptr_t rv( new hypnodata_t );
+            decode(*rv,data,data_length);
+            return rv;
+        }
+
+    }
+}