Add Byte.to() method and improved micro optimization of iterating over

fixed-width integer ranges

3 files changed, 35 insertions, 7 deletions

diff --git a/src/stdlib/bytes.c b/src/stdlib/bytes.c
index 09e19c40..1203aa55 100644
--- a/src/stdlib/bytes.c
+++ b/src/stdlib/bytes.c
@@ -30,6 +30,31 @@ public Text_t Byte$hex(Byte_t byte, bool uppercase, bool prefix) {
     return text;
 }
 
+typedef struct {
+    OptionalByte_t current, last;
+    Int8_t step;
+} ByteRange_t;
+
+static OptionalByte_t _next_Byte(ByteRange_t *info) {
+    OptionalByte_t i = info->current;
+    if (!i.is_none) {
+        Byte_t next; bool overflow = __builtin_add_overflow(i.value, info->step, &next);
+        if (overflow || (!info->last.is_none && (info->step >= 0 ? next > info->last.value : next < info->last.value)))
+            info->current = (OptionalByte_t){.is_none=true};
+        else
+            info->current = (OptionalByte_t){.value=next};
+    }
+    return i;
+}
+
+public CONSTFUNC Closure_t Byte$to(Byte_t first, Byte_t last, OptionalInt8_t step) {
+    ByteRange_t *range = GC_MALLOC(sizeof(ByteRange_t));
+    range->current = (OptionalByte_t){.value=first};
+    range->last = (OptionalByte_t){.value=last};
+    range->step = step.is_none ? (last >= first ? 1 : -1) : step.value;
+    return (Closure_t){.fn=_next_Byte, .userdata=range};
+}
+
 public PUREFUNC Byte_t Byte$from_int(Int_t i, bool truncate) {
     if unlikely (truncate && Int$compare_value(i, I_small(0xFF)) > 0)
         fail("This value is too large to convert to a byte without truncation: ", i);
diff --git a/src/stdlib/bytes.h b/src/stdlib/bytes.h
index ac1b61a3..f875e7cb 100644
--- a/src/stdlib/bytes.h
+++ b/src/stdlib/bytes.h
@@ -6,6 +6,7 @@
 #include <stdint.h>
 
 #include "datatypes.h"
+#include "integers.h"
 #include "stdlib.h"
 #include "types.h"
 #include "util.h"
@@ -18,6 +19,7 @@ Byte_t Byte$from_int(Int_t i, bool truncate);
 Byte_t Byte$from_int64(int64_t i, bool truncate);
 Byte_t Byte$from_int32(int32_t i, bool truncate);
 Byte_t Byte$from_int16(int16_t i, bool truncate);
+Closure_t Byte$to(Byte_t first, Byte_t last, OptionalInt8_t step);
 MACROLIKE Byte_t Byte$from_int8(int8_t i) { return (Byte_t)i; }
 MACROLIKE Byte_t Byte$from_bool(bool b) { return (Byte_t)b; }
 
@@ -28,11 +30,4 @@ extern const TypeInfo_t Byte$info;
 
 Text_t Byte$hex(Byte_t byte, bool uppercase, bool prefix);
 
-typedef struct {
-    Byte_t value;
-    bool has_value:1;
-} OptionalByte_t;
-
-#define NONE_BYTE ((OptionalByte_t){.has_value=false})
-
 // vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0
diff --git a/src/stdlib/datatypes.h b/src/stdlib/datatypes.h
index 950c9457..77c09ddb 100644
--- a/src/stdlib/datatypes.h
+++ b/src/stdlib/datatypes.h
@@ -111,4 +111,12 @@ typedef struct {
 #define OptionalText_t Text_t
 #define OptionalClosure_t Closure_t
 
+typedef struct {
+    Byte_t value;
+    bool is_none:1;
+} OptionalByte_t;
+
+#define NONE_BYTE ((OptionalByte_t){.is_none=true})
+
+
 // vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0