feat(ufmt): enhance printf functionnalities by adding flags

examples/gno.land/p/demo/ufmt/ufmt.gno

@@ -8,8 +8,10 @@ package ufmt
 import (
 	"errors"
 	"io"
+	"math"
 	"strconv"
 	"strings"
+	"unicode"
 	"unicode/utf8"
 )
 
@@ -32,13 +34,134 @@ func (b *buffer) writeRune(r rune) {
 	*b = utf8.AppendRune(*b, r)
 }
 
+// the different flags
+const (
+	flagHashtag uint8 = 1
+	flagZero    uint8 = 1 << 1
+	flagMinus   uint8 = 1 << 2
+	flagSpace   uint8 = 1 << 3
+	flagPlus    uint8 = 1 << 4
+)
+
+// the different len modifiers
+const (
+	lenNo uint8 = iota
+	lenHH
+	lenH
+	lenL
+	lenLL
+	lenZ
+)
+
+type printerMeta struct {
+	flags     uint8
+	padding   uint
+	length    uint8
+	width     uint
+	precision int
+}
+
 // printer holds state for formatting operations.
 type printer struct {
-	buf buffer
+	buf  buffer
+	meta printerMeta
+}
+
+func strtoi(s string) (int, string) {
+	i := 0
+	for i < len(s) && unicode.IsDigit(rune(s[i])) {
+		i++
+	}
+	if i == 0 {
+		return 0, s
+	}
+	num, err := strconv.Atoi(s[:i])
+	if err != nil {
+		return 0, s
+	}
+	return num, s[i:]
+}
+
+func ptrForward(ptr *int, runes []rune, inc int) {
+	if inc <= 0 {
+		return
+	}
+	if *ptr + inc > len(runes) {
+		return
+	}
+	*ptr += inc
+}
+
+var c2f = map[rune]uint8{
+	'-': flagMinus,
+	'+': flagPlus,
+	' ': flagSpace,
+	'0': flagZero,
+}
+
+var lenMap = map[string]uint8{
+	"ll": lenLL,
+	"l":  lenL,
+	"h":  lenH,
+	"hh": lenHH,
+	"z":  lenZ,
+}
+
+// parse the flags
+func (p *printer) parse(runes []rune, index *int) {
+	ptrForward(index, runes, 1)
+	if runes[*index] == '#' {
+		p.meta.flags |= flagHashtag
+		ptrForward(index, runes, 1)
+	}
+	stop := false
+	for {
+		x, ok := c2f[runes[*index]]
+		switch {
+		case ok:
+			p.meta.flags |= x
+			ptrForward(index, runes, 1)
+		case unicode.IsNumber(runes[*index]):
+			strRunes := string(runes[*index:])
+			n, rest := strtoi(strRunes)
+			if rest == strRunes {
+				continue
+			}
+			p.meta.padding = uint(n)
+			ptrForward(index, runes, len(strRunes) - len(rest))
+		case runes[*index] == '.':
+			ptrForward(index, runes, 1)
+			strRunes := string(runes[*index:])
+			n, rest := strtoi(strRunes)
+			p.meta.precision = n // 0 by default, not an error
+			if rest == strRunes {
+				continue
+			}
+			ptrForward(index, runes, len(strRunes) - len(rest))
+		default:
+			stop = true
+		}
+		if stop {
+			break
+		}
+	}
+	for k, v := range lenMap {
+		if string(runes[*index:*index+len(k)-1]) == k {
+			p.meta.length = v
+			ptrForward(index, runes, len(k))
+			break
+		}
+	}
+	*index--
 }
 
 func newPrinter() *printer {
-	return &printer{}
+	return &printer{
+		buf: buffer{},
+		meta: printerMeta{
+			precision: 6,
+		},
+	}
 }
 
 // Sprint formats using the default formats for its operands and returns the resulting string.
@@ -110,7 +233,7 @@ func (p *printer) doPrintln(a []any) {
 //	%G: Formats a float value with %G for large exponents, and %F with full precision for smaller numbers
 //	%t: Formats a boolean value to "true" or "false".
 //	%x: Formats an integer value as a hexadecimal string.
-//	    Currently supports only uint8, []uint8, [32]uint8.
+//	    Currently supports only int, uint, uint8, 16, 32, 64 and []uint8.
 //	%c: Formats a rune value as a string.
 //	    Currently supports only rune, int.
 //	%q: Formats a string value as a quoted string.
@@ -150,6 +273,8 @@ func (p *printer) doPrintf(format string, args []any) {
 			continue
 		}
 
+		p.parse(sTor, &i)
+
 		verb := sTor[i+1]
 		if verb == '%' {
 			p.buf.writeRune('%')
@@ -170,14 +295,14 @@ func (p *printer) doPrintf(format string, args []any) {
 			writeString(p, verb, arg)
 		case 'c':
 			writeChar(p, verb, arg)
-		case 'd':
+		case 'd', 'i':
 			writeInt(p, verb, arg)
 		case 'e', 'E', 'f', 'F', 'g', 'G':
 			writeFloat(p, verb, arg)
 		case 't':
 			writeBool(p, verb, arg)
-		case 'x':
-			writeHex(p, verb, arg)
+		case 'x', 'X':
+			writeHex(p, verb, arg, verb == 'X')
 		case 'q':
 			writeQuotedString(p, verb, arg)
 		case 'T':
@@ -276,53 +401,69 @@ func writeChar(p *printer, verb rune, arg any) {
 	}
 }
 
-// writeInt handles %d formatting
+// writeInt handles %d & %i formatting
 func writeInt(p *printer, verb rune, arg any) {
+	var subBuf string
 	switch v := arg.(type) {
 	case int:
-		p.buf.writeString(strconv.Itoa(v))
+		subBuf = strconv.Itoa(v)
 	case int8:
-		p.buf.writeString(strconv.Itoa(int(v)))
+		subBuf = strconv.Itoa(int(v))
 	case int16:
-		p.buf.writeString(strconv.Itoa(int(v)))
+		subBuf = strconv.Itoa(int(v))
 	case int32:
-		p.buf.writeString(strconv.Itoa(int(v)))
+		subBuf = strconv.Itoa(int(v))
 	case int64:
-		p.buf.writeString(strconv.Itoa(int(v)))
+		subBuf = strconv.Itoa(int(v))
 	case uint:
-		p.buf.writeString(strconv.FormatUint(uint64(v), 10))
+		subBuf = strconv.FormatUint(uint64(v), 10)
 	case uint8:
-		p.buf.writeString(strconv.FormatUint(uint64(v), 10))
+		subBuf = strconv.FormatUint(uint64(v), 10)
 	case uint16:
-		p.buf.writeString(strconv.FormatUint(uint64(v), 10))
+		subBuf = strconv.FormatUint(uint64(v), 10)
 	case uint32:
-		p.buf.writeString(strconv.FormatUint(uint64(v), 10))
+		subBuf = strconv.FormatUint(uint64(v), 10)
 	case uint64:
-		p.buf.writeString(strconv.FormatUint(v, 10))
+		subBuf = strconv.FormatUint(v, 10)
 	default:
-		p.buf.writeString(fallback(verb, v))
+		subBuf = fallback(verb, v)
+	}
+	paddingCount := int(p.meta.padding) - len(subBuf)
+	if paddingCount < 0 {
+		paddingCount = 0
+	}
+	if p.meta.flags&flagSpace != 0 {
+		subBuf = strings.Repeat(" ", paddingCount) + subBuf
+	} else if p.meta.flags&flagZero != 0 {
+		subBuf = strings.Repeat("0", paddingCount) + subBuf
 	}
+	p.buf.writeString(subBuf)
 }
 
 // writeFloat handles floating-point formatting verbs
 func writeFloat(p *printer, verb rune, arg any) {
+	var subBuf string
+	bits := 64
+	n := 0.
 	switch v := arg.(type) {
 	case float64:
-		switch verb {
-		case 'e':
-			p.buf.writeString(strconv.FormatFloat(v, 'e', -1, 64))
-		case 'E':
-			p.buf.writeString(strconv.FormatFloat(v, 'E', -1, 64))
-		case 'f', 'F':
-			p.buf.writeString(strconv.FormatFloat(v, 'f', 6, 64))
-		case 'g':
-			p.buf.writeString(strconv.FormatFloat(v, 'g', -1, 64))
-		case 'G':
-			p.buf.writeString(strconv.FormatFloat(v, 'G', -1, 64))
-		}
+		bits = 64
+		n = v
+	case float32:
+		bits = 32
+		n = float64(v)
 	default:
 		p.buf.writeString(fallback(verb, v))
+		return
+	}
+	prec := -1
+	verbChar := byte(verb)
+	if verbChar == 'f' || verbChar == 'F' {
+		prec = p.meta.precision
+		verbChar = 'f'
 	}
+	subBuf = strconv.FormatFloat(n, verbChar, prec, bits)
+	p.buf.writeString(subBuf)
 }
 
 // writeBool handles %t formatting
@@ -339,14 +480,46 @@ func writeBool(p *printer, verb rune, arg any) {
 	}
 }
 
-// writeHex handles %x formatting
-func writeHex(p *printer, verb rune, arg any) {
+// writeHex handles %x & %X formatting
+func writeHex(p *printer, verb rune, arg any, big bool) {
+	var subBuf string
 	switch v := arg.(type) {
+	case int:
+		subBuf += strconv.FormatUint(uint64(v), 16)
+	case uint:
+		subBuf += strconv.FormatUint(uint64(v), 16)
 	case uint8:
-		p.buf.writeString(strconv.FormatUint(uint64(v), 16))
+		subBuf += strconv.FormatUint(uint64(v), 16)
+	case uint16:
+		subBuf += strconv.FormatUint(uint64(v), 16)
+	case uint32:
+		subBuf += strconv.FormatUint(uint64(v), 16)
+	case uint64:
+		subBuf += strconv.FormatUint(v, 16)
+	case []uint8:
+		for _, v := range v {
+			x := strconv.FormatUint(uint64(v), 16)
+			if len(x) == 1 {
+				x = "0" + x
+			}
+			subBuf += x
+		}
 	default:
 		p.buf.writeString("(unhandled)")
+		return
+	}
+	if p.meta.flags&flagSpace != 0 {
+		subBuf = strings.Repeat(" ", int(math.Max(0, float64(int(p.meta.padding)-len(subBuf))))) + subBuf
+	} else if p.meta.flags&flagZero != 0 {
+		subBuf = strings.Repeat("0", int(math.Max(0, float64(int(p.meta.padding)-len(subBuf))))) + subBuf
+	}
+	if p.meta.flags&flagHashtag != 0 {
+		subBuf = "0x" + subBuf
+	}
+	if big {
+		subBuf = strings.ToUpper(subBuf)
 	}
+	p.buf.writeString(subBuf)
 }
 
 // writeQuotedString handles %q formatting

examples/gno.land/p/demo/ufmt/ufmt_test.gno

@@ -20,12 +20,28 @@ func TestSprintf(t *testing.T) {
 		values         []any
 		expectedOutput string
 	}{
+		// normal usage
 		{"hello %s!", []any{"planet"}, "hello planet!"},
 		{"hello %v!", []any{"planet"}, "hello planet!"},
 		{"hi %%%s!", []any{"worl%d"}, "hi %worl%d!"},
 		{"%s %c %d %t", []any{"foo", 'α', 421, true}, "foo α 421 true"},
 		{"string [%s]", []any{"foo"}, "string [foo]"},
+
+		// ints
 		{"int [%d]", []any{int(42)}, "int [42]"},
+		{"int [%03d]", []any{int(42)}, "int [042]"},
+		{"int [%010d]", []any{int(42)}, "int [0000000042]"},
+		{"int [% 10d]", []any{int(42)}, "int [        42]"},
+		{"hex [%x]", []any{int(42)}, "hex [2a]"},
+		{"hex [%X]", []any{int(42)}, "hex [2A]"},
+		{"hex [%02x]", []any{int(42)}, "hex [2a]"},
+		{"hex [%03x]", []any{int(42)}, "hex [02a]"},
+		{"hex [%#03x]", []any{int(42)}, "hex [0x02a]"},
+		{"hex [%#03X]", []any{int(42)}, "hex [0X02A]"},
+		{"hex [%#X]", []any{[]uint8{1, 2, 42}}, "hex [0X01022A]"},
+		{"hex [%x]", []any{[]uint8("hello")}, "hex [68656c6c6f]"},
+		{"hex [%x]", []any{[]uint8{0, 0}}, "hex [0000]"},
+		{"hex [%x]", []any{uint8(0)}, "hex [0]"},
 		{"int [%v]", []any{int(42)}, "int [42]"},
 		{"int8 [%d]", []any{int8(8)}, "int8 [8]"},
 		{"int8 [%v]", []any{int8(8)}, "int8 [8]"},
@@ -45,16 +61,28 @@ func TestSprintf(t *testing.T) {
 		{"uint32 [%v]", []any{uint32(32)}, "uint32 [32]"},
 		{"uint64 [%d]", []any{uint64(64)}, "uint64 [64]"},
 		{"uint64 [%v]", []any{uint64(64)}, "uint64 [64]"},
+
+		// floats
 		{"float64 [%e]", []any{float64(64.1)}, "float64 [6.41e+01]"},
 		{"float64 [%E]", []any{float64(64.1)}, "float64 [6.41E+01]"},
 		{"float64 [%f]", []any{float64(64.1)}, "float64 [64.100000]"},
+		{"float64 [%.2f]", []any{float64(64.1)}, "float64 [64.10]"},
+		{"float32 [%.1f]", []any{float32(64.1)}, "float32 [64.1]"},
+		{"float64 [%.f]", []any{float64(64.1)}, "float64 [64]"},
+		{"float64 [%.0f]", []any{float64(64.1)}, "float64 [64]"},
+		{"float64 [%.1f]", []any{float64(64.1)}, "float64 [64.1]"},
 		{"float64 [%F]", []any{float64(64.1)}, "float64 [64.100000]"},
 		{"float64 [%g]", []any{float64(64.1)}, "float64 [64.1]"},
 		{"float64 [%G]", []any{float64(64.1)}, "float64 [64.1]"},
+		{"float64 [%.000001f]", []any{float64(64.1)}, "float64 [64.1]"},
+
+		// bool
 		{"bool [%t]", []any{true}, "bool [true]"},
 		{"bool [%v]", []any{true}, "bool [true]"},
 		{"bool [%t]", []any{false}, "bool [false]"},
 		{"bool [%v]", []any{false}, "bool [false]"},
+
+		// errros/special cases
 		{"no args", nil, "no args"},
 		{"finish with %", nil, "finish with %"},
 		{"stringer [%s]", []any{stringer{}}, "stringer [I'm a stringer]"},