encoding/cbor: initial package implementation

core/encoding/base64/base64.odin

@@ -1,5 +1,9 @@
 package base64
 
+import "core:io"
+import "core:mem"
+import "core:strings"
+
 // @note(zh): Encoding utility for Base64
 // A secondary param can be used to supply a custom alphabet to
 // @link(encode) and a matching decoding table to @link(decode).
@@ -39,59 +43,85 @@ DEC_TABLE := [128]int {
     49, 50, 51, -1, -1, -1, -1, -1,
 }
 
-encode :: proc(data: []byte, ENC_TBL := ENC_TABLE, allocator := context.allocator) -> string #no_bounds_check {
-    length := len(data)
-    if length == 0 {
-        return ""
-    }
+encode :: proc(data: []byte, ENC_TBL := ENC_TABLE, allocator := context.allocator) -> (encoded: string, err: mem.Allocator_Error) #optional_allocator_error {
+	out_length := encoded_length(data)
+	if out_length == 0 {
+		return
+	}
 
-    out_length := ((4 * length / 3) + 3) &~ 3
-    out := make([]byte, out_length, allocator)
+	out: strings.Builder
+	strings.builder_init(&out, 0, out_length, allocator) or_return
 
-    c0, c1, c2, block: int
+	ioerr := encode_into(strings.to_stream(&out), data, ENC_TBL)
+	assert(ioerr == nil)
 
-    for i, d := 0, 0; i < length; i, d = i + 3, d + 4 {
-        c0, c1, c2 = int(data[i]), -1, -1
-
-        if i + 1 < length { c1 = int(data[i + 1]) }
-        if i + 2 < length { c2 = int(data[i + 2]) }
-
-        block = (c0 << 16) | (max(c1, 0) << 8) | max(c2, 0)
-
-        out[d]     = ENC_TBL[block >> 18 & 63]
-        out[d + 1] = ENC_TBL[block >> 12 & 63]
-        out[d + 2] = c1 == -1 ? PADDING : ENC_TBL[block >> 6 & 63]
-        out[d + 3] = c2 == -1 ? PADDING : ENC_TBL[block & 63]
-    }
-    return string(out)
+	return strings.to_string(out), nil
 }
 
-decode :: proc(data: string, DEC_TBL := DEC_TABLE, allocator := context.allocator) -> []byte #no_bounds_check {
-    length := len(data)
-    if length == 0 {
-        return nil
-    }
+encoded_length :: #force_inline proc(data: []byte) -> int {
+	length := len(data)
+	if length == 0 {
+		return 0
+	}
 
-    pad_count := data[length - 1] == PADDING ? (data[length - 2] == PADDING ? 2 : 1) : 0
-    out_length := ((length * 6) >> 3) - pad_count
-    out := make([]byte, out_length, allocator)
-
-    c0, c1, c2, c3: int
-    b0, b1, b2: int
-
-    for i, j := 0, 0; i < length; i, j = i + 4, j + 3 {
-        c0 = DEC_TBL[data[i]]
-        c1 = DEC_TBL[data[i + 1]]
-        c2 = DEC_TBL[data[i + 2]]
-        c3 = DEC_TBL[data[i + 3]]
-
-        b0 = (c0 << 2) | (c1 >> 4)
-        b1 = (c1 << 4) | (c2 >> 2)
-        b2 = (c2 << 6) | c3
-
-        out[j]     = byte(b0)
-        out[j + 1] = byte(b1)
-        out[j + 2] = byte(b2)
-    }
-    return out
+	return ((4 * length / 3) + 3) &~ 3
+}
+
+encode_into :: proc(w: io.Writer, data: []byte, ENC_TBL := ENC_TABLE) -> (err: io.Error) #no_bounds_check {
+	length := len(data)
+	if length == 0 {
+		return
+	}
+
+	c0, c1, c2, block: int
+
+	for i, d := 0, 0; i < length; i, d = i + 3, d + 4 {
+		c0, c1, c2 = int(data[i]), -1, -1
+
+		if i + 1 < length { c1 = int(data[i + 1]) }
+		if i + 2 < length { c2 = int(data[i + 2]) }
+
+		block = (c0 << 16) | (max(c1, 0) << 8) | max(c2, 0)
+		
+		out: [4]byte
+		out[0] = ENC_TBL[block >> 18 & 63]
+		out[1] = ENC_TBL[block >> 12 & 63]
+		out[2] = c1 == -1 ? PADDING : ENC_TBL[block >> 6 & 63]
+		out[3] = c2 == -1 ? PADDING : ENC_TBL[block & 63]
+
+		#bounds_check { io.write_full(w, out[:]) or_return }
+	}
+	return
+}
+
+decode :: proc(data: string, DEC_TBL := DEC_TABLE, allocator := context.allocator) -> (out: []byte, err: mem.Allocator_Error) #optional_allocator_error {
+	#no_bounds_check {
+		length := len(data)
+		if length == 0 {
+			return
+		}
+
+		pad_count := data[length - 1] == PADDING ? (data[length - 2] == PADDING ? 2 : 1) : 0
+		out_length := ((length * 6) >> 3) - pad_count
+		out = make([]byte, out_length, allocator) or_return
+
+		c0, c1, c2, c3: int
+		b0, b1, b2: int
+
+		for i, j := 0, 0; i < length; i, j = i + 4, j + 3 {
+			c0 = DEC_TBL[data[i]]
+			c1 = DEC_TBL[data[i + 1]]
+			c2 = DEC_TBL[data[i + 2]]
+			c3 = DEC_TBL[data[i + 3]]
+
+			b0 = (c0 << 2) | (c1 >> 4)
+			b1 = (c1 << 4) | (c2 >> 2)
+			b2 = (c2 << 6) | c3
+
+			out[j]     = byte(b0)
+			out[j + 1] = byte(b1)
+			out[j + 2] = byte(b2)
+		}
+		return 
+	}
 }