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mirror of https://github.com/wader/fq.git synced 2024-08-18 00:10:29 +03:00
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Mattias Wadman 2024-05-21 15:46:49 +02:00 committed by GitHub
commit cff09c5d6c
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3 changed files with 420 additions and 0 deletions

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@ -46,6 +46,7 @@ import (
_ "github.com/wader/fq/format/opentimestamps"
_ "github.com/wader/fq/format/opus"
_ "github.com/wader/fq/format/pcap"
_ "github.com/wader/fq/format/pdf"
_ "github.com/wader/fq/format/png"
_ "github.com/wader/fq/format/postgres"
_ "github.com/wader/fq/format/prores"

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@ -154,6 +154,7 @@ var (
Opus_Packet = &decode.Group{Name: "opus_packet"}
PCAP = &decode.Group{Name: "pcap"}
PCAPNG = &decode.Group{Name: "pcapng"}
PDF = &decode.Group{Name: "pdf"}
Pg_BTree = &decode.Group{Name: "pg_btree"}
Pg_Control = &decode.Group{Name: "pg_control"}
Pg_Heap = &decode.Group{Name: "pg_heap"}

418
format/pdf/pdf.go Normal file
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@ -0,0 +1,418 @@
package pdf
// https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf
// https://feliam.wordpress.com/2010/08/14/pdf-a-broken-spec/
// https://github.com/modesty/pdf2json
// TODO: parse-from-end if possible?
// TODO: more unescape?
// TODO: streams filters
// TODO: refs
// TODO: EOL between object number generation "obj"?
// Ex:
// 202 0
// obj
// endobj
import (
"bytes"
"encoding/hex"
"errors"
"io"
"log"
"regexp"
"strconv"
"strings"
"github.com/wader/fq/format"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/interp"
"github.com/wader/fq/pkg/scalar"
"golang.org/x/text/encoding/charmap"
"golang.org/x/text/encoding/unicode"
)
var imageFormat decode.Group
func init() {
interp.RegisterFormat(
format.PDF,
&decode.Format{
Description: "Portable Document Format",
Groups: []*decode.Group{format.Probe},
DecodeFn: pdfDecode,
Dependencies: []decode.Dependency{
{Groups: []*decode.Group{format.Image}, Out: &imageFormat},
},
})
}
var eofLine = `%%EOF`
var whitespaceChars = []byte(" \n\r")
var delimiterChars = []byte(" \n\r()<>[]{}/%")
func isWhitespace(b byte) bool { return bytes.IndexByte(whitespaceChars, b) != -1 }
// \r, \n or \r\n
// TODO: figure someting nicer
func findLineEnd(d *decode.D) int64 {
p := d.Pos()
ei, v, err := d.TryPeekFind(8, 8, -1, func(v uint64) bool {
return v == '\n' || v == '\r'
})
if errors.Is(err, io.EOF) {
// to support %%EOF not having a line ending
eofLineLen := int64(len(eofLine))
if d.BitsLeft()*8 >= eofLineLen {
return eofLineLen
}
return -1
}
if ei == -1 {
return ei
}
ei += 8
d.SeekRel(ei)
if v == '\r' && d.PeekUintBits(8) == '\n' {
ei += 8
}
d.SeekAbs(p)
return ei / 8
}
var strToNumber = scalar.StrFn(func(s scalar.Str) (scalar.Str, error) {
if strings.Contains(s.Actual, ".") {
// real
n, err := strconv.ParseFloat(s.Actual, 64)
if err != nil {
return s, err
}
s.Sym = n
} else {
// integer
n, err := strconv.ParseInt(s.Actual, 10, 64)
if err != nil {
return s, err
}
s.Sym = n
}
return s, nil
})
func decodeLineStr(d *decode.D) string {
ei := findLineEnd(d)
if ei == -1 {
d.Errorf("could not find line ending")
}
return strings.TrimRight(d.UTF8(int(ei)), "\r\n")
}
func decodeStrWhitespace(d *decode.D) string {
ei, _ := d.PeekFind(8, 8, -1, func(v uint64) bool {
return !isWhitespace(byte(v))
})
if ei == -1 {
d.Errorf("could not find line ending")
}
return d.UTF8(int(ei / 8))
}
func decodeStrUntil(b []byte) func(d *decode.D) string {
return func(d *decode.D) string {
ei, _ := d.PeekFind(8, 8, -1, func(v uint64) bool {
return bytes.IndexByte(b, byte(v)) != -1
})
if ei == -1 {
d.Errorf("could not find ending %d", b)
}
return d.UTF8(int(ei / 8))
}
}
var utf16BEExpect = unicode.UTF16(unicode.BigEndian, unicode.ExpectBOM)
var pdfDocEncoding = charmap.ISO8859_1 // TODO: correc?
// TODO: unescape \N \NN \NNN?
func decodeText(bs []byte) string {
if s, err := utf16BEExpect.NewDecoder().String(string(bs)); err == nil {
return s
}
if s, err := pdfDocEncoding.NewDecoder().String(string(bs)); err == nil {
return s
}
return string(bs)
}
// "\" + "\n" or "\r" or "\r\n"
var eolEscapeRe = regexp.MustCompile("\\\\(?:\n|\r|\r\n)")
func decodeStrLiteralString(d *decode.D) string {
ei, _ := d.PeekFind(16, 8, -1, func(v uint64) bool {
c1 := v >> 8
c0 := v & 0xff
// find non-escaped ")"
return c0 != '\\' && c1 == ')'
})
if ei == -1 {
d.Errorf("could not find literal string ending")
}
bs := d.BytesLen(int(ei / 8))
bs = eolEscapeRe.ReplaceAll(bs, []byte{})
return decodeText(bs)
}
var whitespaceRE = regexp.MustCompile(`\s`)
func decodeStrHexString(d *decode.D) string {
ei, _ := d.PeekFind(8, 8, -1, func(v uint64) bool {
return v == '>'
})
if ei == -1 {
d.Errorf("could not find literal string ending")
}
s := d.UTF8(int(ei / 8))
// whitespace should be ignored inside hex string
hexStr := whitespaceRE.ReplaceAllString(s, "")
buf, err := hex.DecodeString(hexStr)
if err != nil {
d.IOPanic(err, "hex.DecodeString")
}
return decodeText(buf)
}
func decodeValue(d *decode.D) any {
var r any
if isWhitespace(byte(d.PeekUintBits(8))) {
d.FieldStrFn("heading_whitespace", decodeStrWhitespace)
}
// currently only returns value for types whose values we are interested in, atm
// only dictionary, name, string and number so we can get stream length and filter
s := string(d.PeekBytes(2))
switch {
case (s[0] >= '0' && s[0] <= '9') || s[0] == '+' || s[0] == '-':
num := d.FieldStrFn("value", decodeStrUntil(delimiterChars), strToNumber)
r = num
case s == "<<":
d.FieldUTF8("start", 2)
d.FieldArray("pairs", func(d *decode.D) {
pairs := map[string]any{}
for string(d.PeekBytes(2)) != ">>" {
d.FieldStruct("pair", func(d *decode.D) {
var keyV any
var valueV any
d.FieldStruct("key", func(d *decode.D) { keyV = decodeValue(d) })
d.FieldStruct("value", func(d *decode.D) { valueV = decodeValue(d) })
if s, ok := keyV.(string); ok {
pairs[s] = valueV
}
})
}
r = pairs
})
d.FieldUTF8("end", 2)
case s[0] == '[':
d.FieldUTF8("start", 1)
d.FieldArray("objects", func(d *decode.D) {
var objectsV []any
for d.PeekUintBits(8) != ']' {
var valueV any
d.FieldStruct("object", func(d *decode.D) { valueV = decodeValue(d) })
objectsV = append(objectsV, valueV)
}
r = objectsV
})
d.FieldUTF8("end", 1)
case s[0] == '/':
d.FieldUTF8("start", 1)
name := d.FieldStrFn("value", decodeStrUntil(delimiterChars))
r = name
case s[0] == '<':
d.FieldUTF8("start", 1)
s := d.FieldStrFn("value", decodeStrHexString)
d.FieldUTF8("end", 1)
r = s
case s[0] == '(':
d.FieldUTF8("start", 1)
s := d.FieldStrFn("value", decodeStrLiteralString)
d.FieldUTF8("end", 1)
r = s
case s[0] == 'R':
// TODO: should handle references differently?
d.FieldUTF8("reference", 1)
case s[0] == 't':
d.FieldUTF8("value", 4, scalar.StrSym(true))
case s[0] == 'f':
d.FieldUTF8("value", 5, scalar.StrSym(false))
case s[0] == 'n':
d.FieldUTF8("value", 4, scalar.StrSym(nil))
default:
d.Fatalf("unknown type %q", s)
}
if isWhitespace(byte(d.PeekUintBits(8))) {
d.FieldStrFn("tailing_whitespace", decodeStrWhitespace)
}
return r
}
func pdfObjBodyDecode(d *decode.D) {
d.FieldValueStr("type", "body")
d.FieldArray("objects", func(d *decode.D) {
d.FieldStruct("object", func(d *decode.D) {
d.FieldStrFn("start", decodeLineStr)
var dictV any
d.FieldStruct("dictionary", func(d *decode.D) { dictV = decodeValue(d) })
log.Printf("dictV: %#+v\n", dictV)
endObj := false
for !endObj {
e := d.Pos()
line := decodeLineStr(d)
d.SeekAbs(e)
switch line {
case "endobj":
d.FieldStrFn("end", decodeLineStr)
endObj = true
case "stream":
d.FieldStruct("stream", func(d *decode.D) {
d.FieldStrFn("start", decodeLineStr)
// TODO: proper string find
ei, _ := d.PeekFind(64, 8, -1, func(v uint64) bool {
return v == (0 |
'e'<<56 |
'n'<<48 |
'd'<<40 |
's'<<32 |
't'<<24 |
'r'<<16 |
'e'<<8 |
'a')
})
// _ = d.FieldRawLen("data", ei)
if dv, _, _ := d.TryFieldFormatLen("data", ei, &imageFormat, nil); dv == nil {
_ = d.FieldRawLen("data", ei)
}
// d.FieldFormatReaderLen("uncompressed", dataLen, zlib.NewReader, iccProfileFormat)
// var rFn func(r io.Reader) io.Reader
// switch compressionMethod {
// case delfateMethod:
// *bitio.Buffer implements io.ByteReader so hat deflate don't do own
// // buffering and might read more than needed messing up knowing compressed size
// rFn = func(r io.Reader) io.Reader { return flate.NewReader(r) }
// // }
// if rFn != nil {
// readCompressedSize, uncompressedBB, dv, _, err := d.TryFieldReaderRangeFormat("uncompressed", d.Pos(), ei, rFn, imageFormat, nil)
// log.Printf("err: %#+v\n", err)
// if uncompressedBB != nil {
// if dv == nil {
// d.FieldRootBitBuf("uncompressed", uncompressedBB)
// }
// d.FieldRawLen("compressed", readCompressedSize)
// }
// }
d.FieldStrFn("end", decodeLineStr)
})
default:
d.Fatalf("bla")
}
}
})
})
}
func pdfDecode(d *decode.D) any {
d.FieldStruct("header", func(d *decode.D) {
d.FieldUTF8("version", 8, d.StrAssert(
"%PDF-1.0",
"%PDF-1.1",
"%PDF-1.2",
"%PDF-1.3",
"%PDF-1.4",
"%PDF-1.5",
"%PDF-1.6",
"%PDF-1.7",
))
d.SeekAbs(0)
// TODO: has binary comment, byte >= 128
d.FieldArray("comments", func(d *decode.D) {
for d.PeekUintBits(8) == '%' {
d.FieldStrFn("comment", decodeLineStr)
}
})
})
d.FieldArray("parts", func(d *decode.D) {
for !d.End() {
p := d.Pos()
line := decodeLineStr(d)
d.SeekAbs(p)
switch {
case strings.HasPrefix(line, "%"):
d.FieldStruct("comment", func(d *decode.D) {
d.FieldValueStr("type", "comment")
d.FieldStrFn("line", decodeLineStr)
})
case strings.TrimSpace(line) == "":
d.FieldStruct("whitespace", func(d *decode.D) {
d.FieldValueStr("type", "whitespace")
d.FieldStrFn("line", decodeLineStr)
})
case strings.HasSuffix(line, "obj"):
d.FieldStruct("body", pdfObjBodyDecode)
case line == "xref":
d.FieldStruct("xref", func(d *decode.D) {
d.FieldValueStr("type", "xref")
d.FieldStrFn("start", decodeLineStr)
d.FieldArray("lines", func(d *decode.D) {
for {
b := byte(d.PeekUintBits(8))
if !(b >= '0' && b <= '9') {
break
}
d.FieldStrFn("start", decodeLineStr)
}
})
})
case line == "trailer":
d.FieldStruct("trailer", func(d *decode.D) {
d.FieldValueStr("type", "trailer")
d.FieldStrFn("start", decodeLineStr)
d.FieldStruct("dictionary", func(d *decode.D) { decodeValue(d) })
})
case line == "startxref":
d.FieldStruct("startxref", func(d *decode.D) {
d.FieldValueStr("type", "startxref")
d.FieldStrFn("start", decodeLineStr)
d.FieldStrFn("offset", decodeLineStr, strToNumber)
})
default:
d.Fatalf("unknown line %q", line)
}
}
})
return nil
}