Add get_bit() method for Ints and Bytes

5 files changed, 39 insertions, 2 deletions

diff --git a/src/environment.c b/src/environment.c
index 5fb6714a..eb2d28be 100644
--- a/src/environment.c
+++ b/src/environment.c
@@ -90,10 +90,11 @@ env_t *global_env(bool source_mapping)
         )},
         {"Byte", Type(ByteType), "Byte_t", "Byte$info", TypedList(ns_entry_t,
             {"max", "Byte$max", "Byte"},
+            {"get_bit", "Byte$get_bit", "func(x:Byte, bit_index:Int -> Bool)"},
             {"hex", "Byte$hex", "func(byte:Byte, uppercase=yes, prefix=no -> Text)"},
-            {"is_between", "Byte$is_between", "func(x:Byte,low:Byte,high:Byte -> Bool)"},
+            {"is_between", "Byte$is_between", "func(x:Byte, low:Byte, high:Byte -> Bool)"},
             {"min", "Byte$min", "Byte"},
-            {"to", "Byte$to", "func(first:Byte,last:Byte,step:Int8?=none -> func(->Byte?))"},
+            {"to", "Byte$to", "func(first:Byte, last:Byte, step:Int8?=none -> func(->Byte?))"},
         )},
         {"Int", Type(BigIntType), "Int_t", "Int$info", TypedList(ns_entry_t,
             {"abs", "Int$abs", "func(x:Int -> Int)"},
@@ -105,6 +106,7 @@ env_t *global_env(bool source_mapping)
             {"divided_by", "Int$divided_by", "func(x,y:Int -> Int)"},
             {"factorial", "Int$factorial", "func(x:Int -> Int)"},
             {"gcd", "Int$gcd", "func(x,y:Int -> Int)"},
+            {"get_bit", "Int$get_bit", "func(x,bit_index:Int -> Bool)"},
             {"hex", "Int$hex", "func(i:Int, digits=0, uppercase=yes, prefix=yes -> Text)"},
             {"is_between", "Int$is_between", "func(x:Int,low:Int,high:Int -> Bool)"},
             {"is_prime", "Int$is_prime", "func(x:Int,reps=50 -> Bool)"},
@@ -137,6 +139,7 @@ env_t *global_env(bool source_mapping)
             {"divided_by", "Int64$divided_by", "func(x,y:Int64 -> Int64)"},
             {"gcd", "Int64$gcd", "func(x,y:Int64 -> Int64)"},
             {"parse", "Int64$parse", "func(text:Text -> Int64?)"},
+            {"get_bit", "Int64$get_bit", "func(x:Int64, bit_index:Int -> Bool)"},
             {"hex", "Int64$hex", "func(i:Int64, digits=0, uppercase=yes, prefix=yes -> Text)"},
             {"is_between", "Int64$is_between", "func(x:Int64,low:Int64,high:Int64 -> Bool)"},
             {"max", "Int64$max", "Int64"},
@@ -158,6 +161,7 @@ env_t *global_env(bool source_mapping)
             {"divided_by", "Int32$divided_by", "func(x,y:Int32 -> Int32)"},
             {"gcd", "Int32$gcd", "func(x,y:Int32 -> Int32)"},
             {"parse", "Int32$parse", "func(text:Text -> Int32?)"},
+            {"get_bit", "Int32$get_bit", "func(x:Int32, bit_index:Int -> Bool)"},
             {"hex", "Int32$hex", "func(i:Int32, digits=0, uppercase=yes, prefix=yes -> Text)"},
             {"is_between", "Int32$is_between", "func(x:Int32,low:Int32,high:Int32 -> Bool)"},
             {"max", "Int32$max", "Int32"},
@@ -179,6 +183,7 @@ env_t *global_env(bool source_mapping)
             {"divided_by", "Int16$divided_by", "func(x,y:Int16 -> Int16)"},
             {"gcd", "Int16$gcd", "func(x,y:Int16 -> Int16)"},
             {"parse", "Int16$parse", "func(text:Text -> Int16?)"},
+            {"get_bit", "Int16$get_bit", "func(x:Int16, bit_index:Int -> Bool)"},
             {"hex", "Int16$hex", "func(i:Int16, digits=0, uppercase=yes, prefix=yes -> Text)"},
             {"is_between", "Int16$is_between", "func(x:Int16,low:Int16,high:Int16 -> Bool)"},
             {"max", "Int16$max", "Int16"},
@@ -200,6 +205,7 @@ env_t *global_env(bool source_mapping)
             {"divided_by", "Int8$divided_by", "func(x,y:Int8 -> Int8)"},
             {"gcd", "Int8$gcd", "func(x,y:Int8 -> Int8)"},
             {"parse", "Int8$parse", "func(text:Text -> Int8?)"},
+            {"get_bit", "Int8$get_bit", "func(x:Int8, bit_index:Int -> Bool)"},
             {"hex", "Int8$hex", "func(i:Int8, digits=0, uppercase=yes, prefix=yes -> Text)"},
             {"is_between", "Int8$is_between", "func(x:Int8,low:Int8,high:Int8 -> Bool)"},
             {"max", "Int8$max", "Int8"},
diff --git a/src/stdlib/bytes.c b/src/stdlib/bytes.c
index b5c10aa2..48c8b93b 100644
--- a/src/stdlib/bytes.c
+++ b/src/stdlib/bytes.c
@@ -49,6 +49,14 @@ public Text_t Byte$hex(Byte_t byte, bool uppercase, bool prefix) {
     return text;
 }
 
+public bool Byte$get_bit(Byte_t x, Int_t bit_index) {
+    if (Int$compare_value(bit_index, I(1)) < 0)
+        fail("Invalid bit index (expected 1 or higher): ", bit_index);
+    if (Int$compare_value(bit_index, I(8)) > 0)
+        fail("Bit index is too large! There are only 8 bits in a byte, but index is: ", bit_index);
+    return ((x & (Byte_t)(1L << (Int64$from_int(bit_index, true)-1L))) != 0);
+}
+
 #ifdef __TINYC__
 #define __builtin_add_overflow(x, y, result) ({ *(result) = (x) + (y); false; })
 #endif
diff --git a/src/stdlib/bytes.h b/src/stdlib/bytes.h
index 5c64687d..e733c274 100644
--- a/src/stdlib/bytes.h
+++ b/src/stdlib/bytes.h
@@ -30,5 +30,6 @@ extern const Byte_t Byte$max;
 extern const TypeInfo_t Byte$info;
 
 Text_t Byte$hex(Byte_t byte, bool uppercase, bool prefix);
+bool Byte$get_bit(Byte_t x, Int_t bit_index);
 
 // vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0
diff --git a/src/stdlib/integers.c b/src/stdlib/integers.c
index 7c623663..018798ec 100644
--- a/src/stdlib/integers.c
+++ b/src/stdlib/integers.c
@@ -359,6 +359,19 @@ public OptionalInt_t Int$sqrt(Int_t i)
     return Int$from_mpz(result);
 }
 
+public bool Int$get_bit(Int_t x, Int_t bit_index)
+{
+    mpz_t i;
+    mpz_init_set_int(i, x);
+    if (Int$compare_value(bit_index, I(1)) < 0)
+        fail("Invalid bit index (expected 1 or higher): ", bit_index);
+    if (Int$compare_value(bit_index, Int$from_int64(INT64_MAX)) > 0)
+        fail("Bit index is too large! ", bit_index);
+
+    int is_bit_set = mpz_tstbit(i, (mp_bitcnt_t)(Int64$from_int(bit_index, true)-1));
+    return (bool)is_bit_set;
+}
+
 typedef struct {
     OptionalInt_t current, last;
     Int_t step;
@@ -620,6 +633,13 @@ public void Int32$deserialize(FILE *in, void *outval, List_t *pointers, const Ty
         } \
         return bit_list; \
     } \
+    public bool KindOfInt ## $get_bit(c_type x, Int_t bit_index) { \
+        if (Int$compare_value(bit_index, I(1)) < 0) \
+            fail("Invalid bit index (expected 1 or higher): ", bit_index); \
+        if (Int$compare_value(bit_index, Int$from_int64(sizeof(c_type)*8)) > 0) \
+            fail("Bit index is too large! There are only ", sizeof(c_type)*8, " bits, but index is: ", bit_index); \
+        return ((x & (c_type)(1L << (Int64$from_int(bit_index, true)-1L))) != 0); \
+    } \
     typedef struct { \
         Optional##KindOfInt##_t current, last; \
         KindOfInt##_t step; \
diff --git a/src/stdlib/integers.h b/src/stdlib/integers.h
index 4eaac916..beb26bd6 100644
--- a/src/stdlib/integers.h
+++ b/src/stdlib/integers.h
@@ -29,6 +29,7 @@
     Text_t type_name ## $hex(c_type i, Int_t digits, bool uppercase, bool prefix); \
     Text_t type_name ## $octal(c_type i, Int_t digits, bool prefix); \
     List_t type_name ## $bits(c_type x); \
+    bool type_name ## $get_bit(c_type x, Int_t bit_index); \
     Closure_t type_name ## $to(c_type first, c_type last, Optional ## type_name ## _t step); \
     Closure_t type_name ## $onward(c_type first, c_type step); \
     PUREFUNC Optional ## type_name ## _t type_name ## $parse(Text_t text); \
@@ -105,6 +106,7 @@ Int_t Int$abs(Int_t x);
 Int_t Int$power(Int_t base, Int_t exponent);
 Int_t Int$gcd(Int_t x, Int_t y);
 OptionalInt_t Int$sqrt(Int_t i);
+bool Int$get_bit(Int_t x, Int_t bit_index);
 
 #define BIGGEST_SMALL_INT 0x3fffffff
 #define SMALLEST_SMALL_INT -0x40000000