diff --git a/libtransmission/announcer.c b/libtransmission/announcer.c
index 0fbd380c3..841a4a104 100644
--- a/libtransmission/announcer.c
+++ b/libtransmission/announcer.c
@@ -77,8 +77,8 @@ enum
 ***/
 
 static int
-compareTransfer( int a_uploaded, int a_downloaded,
-                 int b_uploaded, int b_downloaded )
+compareTransfer( uint32_t a_uploaded, uint32_t a_downloaded,
+                 uint32_t b_uploaded, uint32_t b_downloaded )
 {
     /* higher upload count goes first */
     if( a_uploaded != b_uploaded )
@@ -136,7 +136,7 @@ getHostName( const char * url )
     int port = 0;
     char * host = NULL;
     char * ret;
-    tr_urlParse( url, strlen( url ), NULL, &host, &port, NULL );
+    tr_urlParse( url, -1, NULL, &host, &port, NULL );
     ret = tr_strdup_printf( "%s:%d", ( host ? host : "invalid" ), port );
     tr_free( host );
     return ret;
@@ -172,8 +172,8 @@ struct stop_message
 {
     tr_host * host;
     char * url;
-    int up;
-    int down;
+    uint32_t up;
+    uint32_t down;
 };
 
 static void
@@ -338,7 +338,7 @@ generateKeyParam( char * msg, size_t msglen )
 {
     size_t i;
     const char * pool = "abcdefghijklmnopqrstuvwxyz0123456789";
-    const int poolSize = strlen( pool );
+    const int poolSize = 36;
 
     for( i=0; i<msglen; ++i )
         *msg++ = pool[tr_cryptoRandInt( poolSize )];
@@ -385,7 +385,7 @@ typedef struct
 {
     /* number of up/down/corrupt bytes since the last time we sent an
      * "event=stopped" message that was acknowledged by the tracker */
-    uint64_t byteCounts[3];
+    uint32_t byteCounts[3];
 
     tr_ptrArray trackers; /* tr_tracker_item */
     tr_tracker_item * currentTracker;
@@ -617,14 +617,14 @@ publishWarning( tr_tier * tier, const char * msg )
     publishMessage( tier, msg, TR_TRACKER_WARNING );
 }
 
-static int
+static int8_t
 getSeedProbability( int seeds, int leechers )
 {
     if( !seeds )
         return 0;
 
     if( seeds>=0 && leechers>=0 )
-        return (int)((100.0*seeds)/(seeds+leechers));
+        return (int8_t)((100.0*seeds)/(seeds+leechers));
 
     return -1; /* unknown */
 }
@@ -734,8 +734,8 @@ createAnnounceURL( const tr_announcer     * announcer,
                               "info_hash=%s"
                               "&peer_id=%s"
                               "&port=%d"
-                              "&uploaded=%" PRIu64
-                              "&downloaded=%" PRIu64
+                              "&uploaded=%" PRIu32
+                              "&downloaded=%" PRIu32
                               "&left=%" PRIu64
                               "&numwant=%d"
                               "&key=%s"
@@ -756,7 +756,7 @@ createAnnounceURL( const tr_announcer     * announcer,
         evbuffer_add_printf( buf, "&requirecrypto=1" );
 
     if( tier->byteCounts[TR_ANN_CORRUPT] )
-        evbuffer_add_printf( buf, "&corrupt=%" PRIu64, tier->byteCounts[TR_ANN_CORRUPT] );
+        evbuffer_add_printf( buf, "&corrupt=%" PRIu32, tier->byteCounts[TR_ANN_CORRUPT] );
 
     str = eventName;
     if( str && *str )
@@ -780,7 +780,7 @@ createAnnounceURL( const tr_announcer     * announcer,
         char ipv6_readable[INET6_ADDRSTRLEN];
         inet_ntop( AF_INET6, ipv6, ipv6_readable, INET6_ADDRSTRLEN );
         evbuffer_add_printf( buf, "&ipv6=");
-        tr_http_escape( buf, ipv6_readable, strlen(ipv6_readable), TRUE );
+        tr_http_escape( buf, ipv6_readable, -1, TRUE );
     }
 
     ret = tr_strndup( EVBUFFER_DATA( buf ), EVBUFFER_LENGTH( buf ) );
@@ -1169,7 +1169,7 @@ compareTiers( const void * va, const void * vb )
 }
 
 static uint8_t *
-parseOldPeers( tr_benc * bePeers, size_t *  byteCount )
+parseOldPeers( tr_benc * bePeers, size_t * byteCount )
 {
     int       i;
     uint8_t * array, *walk;
@@ -1197,7 +1197,7 @@ parseOldPeers( tr_benc * bePeers, size_t *  byteCount )
             continue;
 
         memcpy( walk, &addr, sizeof( tr_address ) );
-        port = htons( itmp );
+        port = htons( (uint16_t)itmp );
         memcpy( walk + sizeof( tr_address ), &port, 2 );
         walk += sizeof( tr_address ) + 2;
     }
diff --git a/libtransmission/clients.c b/libtransmission/clients.c
index 55dabfbb5..4c3c861cd 100644
--- a/libtransmission/clients.c
+++ b/libtransmission/clients.c
@@ -22,7 +22,7 @@
 #include "utils.h" /* tr_snprintf(), tr_strlcpy() */
 
 static int
-charint( char ch )
+charint( uint8_t ch )
 {
     if( '0' <= ch && ch <= '9' ) return      ch - '0';
     if( 'A' <= ch && ch <= 'Z' ) return 10 + ch - 'A';
@@ -31,7 +31,7 @@ charint( char ch )
 }
 
 static int
-getShadowInt( char ch, int * setme )
+getShadowInt( uint8_t ch, int * setme )
 {
     const char * str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz.-";
     const char * pch = strchr( str, ch );
@@ -51,7 +51,7 @@ strint( const void * pch, int span )
 }
 
 static const char*
-getMnemonicEnd( char ch )
+getMnemonicEnd( uint8_t ch )
 {
     switch( ch )
     {
diff --git a/libtransmission/completion.h b/libtransmission/completion.h
index 265798abe..1816ce613 100644
--- a/libtransmission/completion.h
+++ b/libtransmission/completion.h
@@ -92,7 +92,7 @@ static inline uint64_t tr_cpLeftUntilDone( const tr_completion * cp )
     return tr_cpSizeWhenDone( cp ) - cp->sizeNow;
 }
 
-static inline float tr_cpPercentComplete( const tr_completion * cp )
+static inline double tr_cpPercentComplete( const tr_completion * cp )
 {
     const double ratio = tr_getRatio( cp->sizeNow, tr_torrentInfo(cp->tor)->totalSize );
     if( (int)ratio == TR_RATIO_NA )
@@ -103,7 +103,7 @@ static inline float tr_cpPercentComplete( const tr_completion * cp )
         return ratio;
 }
 
-static inline float tr_cpPercentDone( const tr_completion * cp )
+static inline double tr_cpPercentDone( const tr_completion * cp )
 {
     const double ratio = tr_getRatio( cp->sizeNow, tr_cpSizeWhenDone( cp ) );
     const int iratio = (int)ratio;
diff --git a/libtransmission/torrent-magnet.c b/libtransmission/torrent-magnet.c
index 72ebebc86..d64167114 100644
--- a/libtransmission/torrent-magnet.c
+++ b/libtransmission/torrent-magnet.c
@@ -348,10 +348,10 @@ tr_torrentGetNextMetadataRequest( tr_torrent * tor, time_t now, int * setme_piec
     return have_request;
 }
 
-float
+double
 tr_torrentGetMetadataPercent( const tr_torrent * tor )
 {
-    float ret;
+    double ret;
 
     if( tr_torrentHasMetadata( tor ) )
         ret = 1.0;
@@ -360,7 +360,7 @@ tr_torrentGetMetadataPercent( const tr_torrent * tor )
         if( m == NULL )
             ret = 0.0;
         else
-            ret = (m->pieceCount - m->piecesNeededCount) / (float)m->pieceCount;
+            ret = (m->pieceCount - m->piecesNeededCount) / (double)m->pieceCount;
     }
 
     return ret;
diff --git a/libtransmission/torrent-magnet.h b/libtransmission/torrent-magnet.h
index 52c4b016a..8de71c4fe 100644
--- a/libtransmission/torrent-magnet.h
+++ b/libtransmission/torrent-magnet.h
@@ -33,6 +33,6 @@ tr_bool tr_torrentGetNextMetadataRequest( tr_torrent * tor, time_t now, int * se
 
 void tr_torrentSetMetadataSizeHint( tr_torrent * tor, int metadata_size );
 
-float tr_torrentGetMetadataPercent( const tr_torrent * tor );
+double tr_torrentGetMetadataPercent( const tr_torrent * tor );
 
 #endif
diff --git a/libtransmission/torrent.c b/libtransmission/torrent.c
index b253424df..ea9cb448b 100644
--- a/libtransmission/torrent.c
+++ b/libtransmission/torrent.c
@@ -1841,7 +1841,7 @@ static void
 setFileDND( tr_torrent * tor, tr_file_index_t fileIndex, int doDownload )
 {
     tr_file *        file;
-    const uint8_t    dnd = !doDownload;
+    const int8_t     dnd = !doDownload;
     tr_piece_index_t firstPiece, firstPieceDND;
     tr_piece_index_t lastPiece, lastPieceDND;
     tr_file_index_t  i;
diff --git a/libtransmission/torrent.h b/libtransmission/torrent.h
index 0c221dfaf..04b90ae07 100644
--- a/libtransmission/torrent.h
+++ b/libtransmission/torrent.h
@@ -276,8 +276,10 @@ tr_torBlockPiece( const tr_torrent * tor, const tr_block_index_t block )
 static inline uint16_t
 tr_torPieceCountBlocks( const tr_torrent * tor, const tr_piece_index_t piece )
 {
-    return piece == tor->info.pieceCount - 1 ? tor->blockCountInLastPiece
-                                             : tor->blockCountInPiece;
+    if( piece + 1 == tor->info.pieceCount )
+        return tor->blockCountInLastPiece;
+    else
+        return tor->blockCountInPiece;
 }
 
 /* how many bytes are in this piece? */
diff --git a/libtransmission/transmission.h b/libtransmission/transmission.h
index 52a832b29..4c6a48a3a 100644
--- a/libtransmission/transmission.h
+++ b/libtransmission/transmission.h
@@ -63,7 +63,9 @@ extern "C" {
 
 typedef uint32_t tr_file_index_t;
 typedef uint32_t tr_piece_index_t;
-typedef uint64_t tr_block_index_t;
+/* assuming a 16 KiB block, a 32-bit block index gives us a maximum torrent size of 63 TiB.
+ * if we ever need to grow past that, change this to uint64_t ;) */
+typedef uint32_t tr_block_index_t;
 typedef uint16_t tr_port;
 typedef uint8_t tr_bool;
 
@@ -1721,28 +1723,28 @@ typedef struct tr_stat
         verified.  When it gets to 1, the verify process is done.
         Range is [0..1]
         @see tr_stat.status */
-    float    recheckProgress;
+    double recheckProgress;
 
     /** How much has been downloaded of the entire torrent.
         Range is [0..1] */
-    float    percentComplete;
+    double percentComplete;
 
     /** How much of the metadata the torrent has.
         For torrents added from a .torrent this will always be 1.
         For magnet links, this number will from from 0 to 1 as the metadata is downloaded.
         Range is [0..1] */
-    float    metadataPercentComplete;
+    double metadataPercentComplete;
 
     /** How much has been downloaded of the files the user wants.  This differs
         from percentComplete if the user wants only some of the torrent's files.
         Range is [0..1]
         @see tr_stat.leftUntilDone */
-    float    percentDone;
+    double percentDone;
 
     /** How much has been uploaded to satisfy the seed ratio.
         This is 1 if the ratio is reached or the torrent is set to seed forever.
         Range is [0..1] */
-    float    seedRatioPercentDone;
+    double seedRatioPercentDone;
 
     /** Speed all data being sent for this torrent. (KiB/s)
         This includes piece data, protocol messages, and TCP overhead */
diff --git a/libtransmission/utils.c b/libtransmission/utils.c
index 2af98c52f..54d45d4a8 100644
--- a/libtransmission/utils.c
+++ b/libtransmission/utils.c
@@ -866,13 +866,13 @@ tr_strlcpy( char *       dst,
 ***/
 
 double
-tr_getRatio( double numerator, double denominator )
+tr_getRatio( uint64_t numerator, uint64_t denominator )
 {
     double ratio;
 
-    if( fabs(denominator) > 0.01 )
-        ratio = numerator / denominator;
-    else if( fabs(numerator) > 0.01 )
+    if( denominator > 0 )
+        ratio = numerator / (double)denominator;
+    else if( numerator > 0 )
         ratio = TR_RATIO_INF;
     else
         ratio = TR_RATIO_NA;
diff --git a/libtransmission/utils.h b/libtransmission/utils.h
index bd605dd7a..5b223dc2a 100644
--- a/libtransmission/utils.h
+++ b/libtransmission/utils.h
@@ -464,7 +464,7 @@ int  tr_urlParse( const char * url,
 
 /** @brief return TR_RATIO_NA, TR_RATIO_INF, or a number in [0..1]
     @return TR_RATIO_NA, TR_RATIO_INF, or a number in [0..1] */
-double tr_getRatio( double numerator, double denominator );
+double tr_getRatio( uint64_t numerator, uint64_t denominator );
 
 /**
  * @brief Given a string like "1-4" or "1-4,6,9,14-51", this returns a