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xiaoqidun committed
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commit
201082daa0
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@@ -198,6 +198,9 @@ func ParseType1Program(data []byte) (Type1Program, error) {
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return Type1Program{}, fmt.Errorf("Type1 font has no glyphs")
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}
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for index := range program.subrs {
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if program.subrs[index] == nil {
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continue
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}
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program.subrs[index], err = type1CharString(program.subrs[index], program.lenIV)
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if err != nil {
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return Type1Program{}, err
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@@ -212,6 +215,61 @@ func ParseType1Program(data []byte) (Type1Program, error) {
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return program, nil
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}
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// NormalizePDFType1 修复完整加密分段之后的PFB明文尾部，不补齐加密或字形数据
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// 入参: data 原始PFB程序
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// 返回: []byte 原程序或独立修复容器, bool 是否修复, error 容器或程序错误
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func NormalizePDFType1(data []byte) ([]byte, bool, error) {
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if len(data) < 6 || data[0] != 0x80 {
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return data, false, nil
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}
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binarySeen := false
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for offset := 0; offset+2 <= len(data) && data[offset] == 0x80; {
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kind := data[offset+1]
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if kind == 3 {
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return data, false, nil
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}
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if offset+6 > len(data) || kind != 1 && kind != 2 {
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return data, false, fmt.Errorf("incomplete PFB segment header")
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}
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length := uint64(binary.LittleEndian.Uint32(data[offset+2:]))
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remaining := len(data) - offset - 6
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if binarySeen && kind == 1 && remaining == 0 {
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result := append(bytes.Clone(data[:offset]), 0x80, 3)
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if _, err := ParseType1Program(result); err != nil {
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return nil, false, err
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}
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return result, true, nil
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}
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if length > uint64(remaining) {
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return nil, false, fmt.Errorf("incomplete PFB encrypted or text segment")
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}
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if binarySeen && kind == 1 && length == 0 {
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tail := data[offset+6:]
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if len(tail) < 2 || !bytes.Equal(tail[len(tail)-2:], []byte{0x80, 3}) {
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return data, false, fmt.Errorf("unbounded PFB text trailer")
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}
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text := bytes.TrimSpace(tail[:len(tail)-2])
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if !bytes.HasSuffix(text, []byte("cleartomark")) {
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return data, false, fmt.Errorf("PFB trailer lacks cleartomark")
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}
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for _, b := range bytes.TrimSuffix(text, []byte("cleartomark")) {
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if b != '0' && !type1Space(b) {
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return data, false, fmt.Errorf("unexpected PFB text trailer")
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}
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}
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result := bytes.Clone(data)
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binary.LittleEndian.PutUint32(result[offset+2:], uint32(len(tail)-2))
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if _, err := ParseType1Program(result); err != nil {
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return nil, false, err
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}
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return result, true, nil
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}
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binarySeen = binarySeen || kind == 2
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offset += 6 + int(length)
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}
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return data, false, nil
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}
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// readType1Header 读取明文字体矩阵及加密数据起点
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// 入参: data Type1程序
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// 返回: []float64 字体矩阵, int 加密起点, error 头部错误
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@@ -87,6 +87,108 @@ func FileTables(data []byte, index int) (map[string][]byte, error) {
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return tables, nil
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}
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// NormalizePDFProgram 修复可确定的PDF内嵌SFNT封装，不补造TrueType轮廓或字形编号
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// 入参: data 原始字体程序
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// 返回: []byte 原程序或独立修复程序, bool 是否修复, error 无法确认的目录或度量错误
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func NormalizePDFProgram(data []byte) ([]byte, bool, error) {
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if len(data) < 12 || string(data[:4]) != "OTTO" && string(data[:4]) != "\x00\x01\x00\x00" && string(data[:4]) != "true" {
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return data, false, nil
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}
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count := int(binary.BigEndian.Uint16(data[4:6]))
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if count == 0 || count > (len(data)-12)/16 {
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return nil, false, fmt.Errorf("unrecoverable PDF font directory size")
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}
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first := len(data)
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for n := 0; n < count; n++ {
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record := data[12+n*16:]
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start, size := uint64(binary.BigEndian.Uint32(record[8:])), uint64(binary.BigEndian.Uint32(record[12:]))
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if size != 0 && start >= 12 && start+size <= uint64(len(data)) {
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first = min(first, int(start))
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}
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}
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changed := false
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if first < 12+count*16 {
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if (first-12)%16 != 0 {
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return nil, false, fmt.Errorf("ambiguous PDF font directory overlap")
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}
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actual := (first - 12) / 16
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for n := 0; n < count; n++ {
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record := data[12+n*16:]
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printable := true
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for _, b := range record[:4] {
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printable = printable && b >= 32 && b <= 126
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}
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if printable != (n < actual) {
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return nil, false, fmt.Errorf("ambiguous PDF font table count")
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}
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if n < actual {
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start, size := uint64(binary.BigEndian.Uint32(record[8:])), uint64(binary.BigEndian.Uint32(record[12:]))
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if size != 0 && (start < uint64(first) || start+size > uint64(len(data))) {
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return nil, false, fmt.Errorf("incomplete PDF font table")
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}
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}
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}
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data = bytes.Clone(data)
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binary.BigEndian.PutUint16(data[4:6], uint16(actual))
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changed = true
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}
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tables, err := FileTables(data, 0)
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if err != nil {
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return nil, false, err
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}
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if head := tables["head"]; len(head) > 54 && len(head) <= 57 {
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tables["head"] = head[:54]
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changed = true
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}
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if hhea := tables["hhea"]; len(hhea) > 36 && len(hhea) <= 39 && binary.BigEndian.Uint32(hhea) == 0x00010000 {
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tables["hhea"] = hhea[:36]
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changed = true
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}
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if maxp := tables["maxp"]; tables["glyf"] != nil && len(maxp) > 32 && len(maxp) <= 35 && binary.BigEndian.Uint32(maxp) == 0x00010000 {
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tables["maxp"] = maxp[:32]
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changed = true
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}
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if post := tables["post"]; len(post) > 32 && binary.BigEndian.Uint32(post) == 0x00030000 {
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tables["post"] = post[:32]
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changed = true
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}
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if cvt := tables["cvt "]; len(cvt)%2 != 0 && cvt[len(cvt)-1] == 0 {
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tables["cvt "] = cvt[:len(cvt)-1]
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changed = true
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}
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if len(tables["CFF "]) != 0 && len(tables["head"]) == 0 && len(tables["maxp"]) == 0 && len(tables["hhea"]) == 0 && len(tables["hmtx"]) == 0 {
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program, _, err := WrapCFFToOTF(tables["CFF "])
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return program, true, err
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}
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if maxp := tables["maxp"]; len(tables["CFF "]) != 0 && tables["glyf"] == nil && len(maxp) >= 6 && (binary.BigEndian.Uint32(maxp) == 0x00010000 || binary.BigEndian.Uint32(maxp) == 0x00005000 && len(maxp) != 6) {
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count, err := parseCFFAndCountGlyphs(tables["CFF "])
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if err != nil {
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return nil, false, err
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}
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if count != int(binary.BigEndian.Uint16(maxp[4:6])) {
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program, _, err := WrapCFFToOTF(tables["CFF "])
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if err != nil {
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return nil, false, err
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}
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rebuilt, err := FileTables(program, 0)
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if err != nil {
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return nil, false, err
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}
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if len(tables["head"]) < 20 || !bytes.Equal(tables["head"][18:20], rebuilt["head"][18:20]) {
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return nil, false, fmt.Errorf("CFF and SFNT design units differ")
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}
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return program, true, nil
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}
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tables["maxp"] = buildCFFMaxpTable(uint16(count))
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changed = true
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}
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if !changed {
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return data, false, nil
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}
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program, err := SerializeOTF(tables)
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return program, true, err
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}
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// calcTableChecksum 计算字体表校验和
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// 入参: data 表数据
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// 返回: uint32 校验和
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