rewrote field data structure for simplicity

pkg/field/field.go

@@ -1,7 +1,6 @@
 package field
 
 import (
-	"bytes"
 	"io"
 )
 
@@ -16,15 +15,17 @@ import (
 //                  y|2,147,483,647
 
 type Field struct {
-	firstLineIndex int
+	x     int
-	length         int
+	y     int
+	lx    int
+	ly    int
 	lines []Line
 }
 
 type Line struct {
-	firstColumnIndex int
+	x       int
-	length           int
+	l       int
-	columns          []byte
+	columns []int
 }
 
 func LoadFile(fd io.Reader) (*Field, error) {
@@ -35,11 +36,14 @@ func LoadFile(fd io.Reader) (*Field, error) {
 		data := make([]byte, 4096)
 		if n, errRead := fd.Read(data); errRead != nil {
 			if errRead == io.EOF {
-				if f.length == 0 && l.length == 0 {
+				if f.ly == 0 && l.l == 0 {
 					return nil, newDecodeError("No instruction on the first line of the file produces an unusable program in Befunge98")
 				}
-				if l.length > 0 {
+				if l.l > 0 {
-					f.length++
+					f.ly++
+					if f.lx < l.l {
+						f.lx = l.l
+					}
 					f.lines = append(f.lines, *l)
 				}
 				break
@@ -49,10 +53,13 @@ func LoadFile(fd io.Reader) (*Field, error) {
 		} else {
 			for i := 0; i < n; i++ {
 				if data[i] == '\n' || data[i] == '\r' {
-					if f.length == 0 && l.length == 0 {
+					if f.ly == 0 && l.l == 0 {
 						return nil, newDecodeError("No instruction on the first line of the file produces an unusable program in Befunge98")
 					}
-					f.length++
+					f.ly++
+					if f.lx < l.l {
+						f.lx = l.l
+					}
 					f.lines = append(f.lines, *l)
 					l = new(Line)
 					trailingSpaces = 0
@@ -60,17 +67,18 @@ func LoadFile(fd io.Reader) (*Field, error) {
 						i++
 					}
 				} else {
-					if l.length == 0 && data[i] == ' ' {
+					if l.l == 0 && data[i] == ' ' {
-						l.firstColumnIndex++ // trim leading spaces
+						l.x++ // trim leading spaces
 					} else {
 						if data[i] == ' ' {
 							trailingSpaces++
 						} else {
-							l.columns = append(l.columns, bytes.Repeat([]byte{' '}, trailingSpaces)...)
+							for j := 0; j < trailingSpaces; j++ {
-							l.length += trailingSpaces
+								l.columns = append(l.columns, ' ')
+							}
+							l.l += trailingSpaces + 1
 							trailingSpaces = 0
-							l.length++
+							l.columns = append(l.columns, int(data[i]))
-							l.columns = append(l.columns, data[i])
 						}
 					}
 				}

pkg/field/field_test.go

@@ -6,108 +6,117 @@ import (
 	"testing"
 	"testing/iotest"
 
-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
 func TestLoadFile(t *testing.T) {
 	// minimal b98 file
 	minimalField := Field{
-		firstLineIndex: 0,
+		x:  0,
-		length:         1,
+		y:  0,
+		lx: 1,
+		ly: 1,
 		lines: []Line{
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           1,
+				l:       1,
-				columns:          []byte{'@'},
+				columns: []int{'@'},
 			},
 		},
 	}
 	// hello b98 file
 	helloField := Field{
-		firstLineIndex: 0,
+		x:  0,
-		length:         1,
+		y:  0,
+		lx: 24,
+		ly: 1,
 		lines: []Line{
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           24,
+				l:       24,
-				columns:          []byte{'6', '4', '+', '"', '!', 'd', 'l', 'r', 'o', 'W', ' ', ',', 'o', 'l', 'l', 'e', 'H', '"', '>', ':', '#', ',', '_', '@'},
+				columns: []int{'6', '4', '+', '"', '!', 'd', 'l', 'r', 'o', 'W', ' ', ',', 'o', 'l', 'l', 'e', 'H', '"', '>', ':', '#', ',', '_', '@'},
 			},
 		},
 	}
 	// factorial b98 file
 	factorialField := Field{
-		firstLineIndex: 0,
+		x:  0,
-		length:         2,
+		y:  0,
+		lx: 15,
+		ly: 2,
 		lines: []Line{
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           15,
+				l:       15,
-				columns:          []byte{'&', '>', ':', '1', '-', ':', 'v', ' ', 'v', ' ', '*', '_', '$', '.', '@'},
+				columns: []int{'&', '>', ':', '1', '-', ':', 'v', ' ', 'v', ' ', '*', '_', '$', '.', '@'},
 			},
 			Line{
-				firstColumnIndex: 1,
+				x:       1,
-				length:           11,
+				l:       11,
-				columns:          []byte{'^', ' ', ' ', ' ', ' ', '_', '$', '>', '\\', ':', '^'},
+				columns: []int{'^', ' ', ' ', ' ', ' ', '_', '$', '>', '\\', ':', '^'},
 			},
 		},
 	}
 	// dna b98 file
 	dnaField := Field{
-		firstLineIndex: 0,
+		x:  0,
-		length:         8,
+		y:  0,
+		lx: 7,
+		ly: 8,
 		lines: []Line{
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           7,
+				l:       7,
-				columns:          []byte{'7', '^', 'D', 'N', '>', 'v', 'A'},
+				columns: []int{'7', '^', 'D', 'N', '>', 'v', 'A'},
 			},
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           7,
+				l:       7,
-				columns:          []byte{'v', '_', '#', 'v', '?', ' ', 'v'},
+				columns: []int{'v', '_', '#', 'v', '?', ' ', 'v'},
 			},
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           7,
+				l:       7,
-				columns:          []byte{'7', '^', '<', '"', '"', '"', '"'},
+				columns: []int{'7', '^', '<', '"', '"', '"', '"'},
 			},
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           7,
+				l:       7,
-				columns:          []byte{'3', ' ', ' ', 'A', 'C', 'G', 'T'},
+				columns: []int{'3', ' ', ' ', 'A', 'C', 'G', 'T'},
 			},
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           7,
+				l:       7,
-				columns:          []byte{'9', '0', '!', '"', '"', '"', '"'},
+				columns: []int{'9', '0', '!', '"', '"', '"', '"'},
 			},
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           7,
+				l:       7,
-				columns:          []byte{'4', '*', ':', '>', '>', '>', 'v'},
+				columns: []int{'4', '*', ':', '>', '>', '>', 'v'},
 			},
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           7,
+				l:       7,
-				columns:          []byte{'+', '8', '^', '-', '1', ',', '<'},
+				columns: []int{'+', '8', '^', '-', '1', ',', '<'},
 			},
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           7,
+				l:       7,
-				columns:          []byte{'>', ' ', ',', '+', ',', '@', ')'},
+				columns: []int{'>', ' ', ',', '+', ',', '@', ')'},
 			},
 		},
 	}
 	// \r\n file b98 file
 	rnField := Field{
-		firstLineIndex: 0,
+		x:  0,
-		length:         1,
+		y:  0,
+		lx: 24,
+		ly: 1,
 		lines: []Line{
 			Line{
-				firstColumnIndex: 0,
+				x:       0,
-				length:           24,
+				l:       24,
-				columns:          []byte{'6', '4', '+', '"', '!', 'd', 'l', 'r', 'o', 'W', ' ', ',', 'o', 'l', 'l', 'e', 'H', '"', '>', ':', '#', ',', '_', '@'},
+				columns: []int{'6', '4', '+', '"', '!', 'd', 'l', 'r', 'o', 'W', ' ', ',', 'o', 'l', 'l', 'e', 'H', '"', '>', ':', '#', ',', '_', '@'},
 			},
 		},
 	}
@@ -148,7 +157,7 @@ func TestLoadFile(t *testing.T) {
 			} else {
 				require.NoError(t, err)
 			}
-			assert.Equal(t, tc.expected, valid, "Invalid value")
+			require.Equal(t, tc.expected, valid, "Invalid value")
 		})
 	}
 }