feat(文件拆分): 拆分PDF格式适配模块

ofdgo_pdf_media.go

@@ -15,17 +15,15 @@
 package ofdgo
 
 import (
-	"bytes"
 	"context"
-	"encoding/binary"
 	"errors"
 	"fmt"
 	"math"
-	"net/url"
 	"path"
 	"reflect"
 	"strings"
 
+	codecpdf "github.com/xiaoqidun/ofdgo/internal/codec/pdf"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -134,9 +132,9 @@ func (p *pdfImporter) soundResource(ctx context.Context, sound pdfgo.Sound) (str
 		if err != nil || !available {
 			return "", err
 		}
-		format = pdfMediaFormat(*sound.File)
+		format = codecpdf.MediaFormat(*sound.File)
 	} else {
-		data, err = pdfSoundWAV(ctx, sound)
+		data, err = codecpdf.SoundWAV(ctx, sound)
 	}
 	if err != nil {
 		return "", err
@@ -220,7 +218,7 @@ func (p *pdfImporter) interactiveAnnotation(ctx context.Context, page *pdfgo.Pag
 					if config.Subtype == "Sound" {
 						kind = "Audio"
 					}
-					id, err := p.editor.AddMedia(kind, pdfMediaFormat(file), data)
+					id, err := p.editor.AddMedia(kind, codecpdf.MediaFormat(file), data)
 					if err != nil {
 						return err
 					}
@@ -315,137 +313,3 @@ func (p *pdfImporter) mediaData(ctx context.Context, file pdfgo.FileSpecificatio
 	}
 	return data, true, nil
 }
-
-// pdfMediaFormat 获取媒体文件扩展名，URL参数和片段不参与格式判断
-// 入参: file PDF文件说明
-// 返回: string 媒体格式，未声明扩展名时为空
-func pdfMediaFormat(file pdfgo.FileSpecification) string {
-	name := strings.ReplaceAll(file.Name, "\\", "/")
-	if file.FileSystem == "URL" {
-		if location, err := url.Parse(name); err == nil {
-			name = location.Path
-		}
-	}
-	return strings.TrimPrefix(path.Ext(name), ".")
-}
-
-// pdfSoundWAV 封装PDF采样音频，保持采样率、声道及数值，超过RIFF容量时使用RF64
-// 入参: ctx 取消上下文, sound 音频流及参数
-// 返回: []byte WAVE文件, error 不可表示的参数或损坏的采样数据
-func pdfSoundWAV(ctx context.Context, sound pdfgo.Sound) ([]byte, error) {
-	if err := ctx.Err(); err != nil {
-		return nil, err
-	}
-	if sound.File != nil || sound.Compression != "" {
-		return nil, &pdfgo.UnsupportedError{Feature: "external or compressed sound samples"}
-	}
-	if sound.Stream == nil || sound.Channels <= 0 || math.IsNaN(sound.Rate) || math.IsInf(sound.Rate, 0) || sound.Rate <= 0 {
-		return nil, fmt.Errorf("invalid sound sample parameters")
-	}
-	if sound.Rate != math.Trunc(sound.Rate) || sound.Rate > math.MaxUint32 || sound.Channels > math.MaxUint16 || sound.Bits != 8 && sound.Bits != 16 && sound.Bits != 24 && sound.Bits != 32 {
-		return nil, &pdfgo.UnsupportedError{Feature: "sound parameters in WAVE"}
-	}
-	format := uint16(1)
-	if sound.Encoding == "muLaw" {
-		format = 7
-	} else if sound.Encoding == "ALaw" {
-		format = 6
-	}
-	if format != 1 && sound.Bits != 8 {
-		return nil, fmt.Errorf("invalid companded sound depth")
-	}
-	width := sound.Bits / 8
-	align := uint64(sound.Channels) * uint64(width)
-	rate := uint64(sound.Rate)
-	if align > math.MaxUint16 || rate*align > math.MaxUint32 {
-		return nil, &pdfgo.UnsupportedError{Feature: "sound block alignment in WAVE"}
-	}
-	data, err := sound.Stream.DecodeContext(ctx)
-	if err != nil {
-		return nil, err
-	}
-	if uint64(len(data))%align != 0 {
-		return nil, fmt.Errorf("incomplete sound sample frame")
-	}
-	if format == 1 {
-		for offset := 0; offset < len(data); offset += width {
-			if offset%(1<<16) == 0 {
-				if err := ctx.Err(); err != nil {
-					return nil, err
-				}
-			}
-			if sound.Encoding == "Raw" && width > 1 || sound.Encoding == "Signed" && width == 1 {
-				data[offset] ^= 0x80
-			}
-			for left, right := offset, offset+width-1; left < right; left, right = left+1, right-1 {
-				data[left], data[right] = data[right], data[left]
-			}
-		}
-	}
-	formatSize := uint32(16)
-	extra := uint64(0)
-	if format == 1 && (sound.Bits > 16 || sound.Channels > 2) {
-		format = 0xfffe
-		formatSize = 40
-		extra = 36
-	} else if format != 1 {
-		formatSize = 18
-		extra = 14
-	}
-	size := uint64(36) + extra + uint64(len(data)) + uint64(len(data)%2)
-	large := size > math.MaxUint32
-	var out bytes.Buffer
-	put16 := func(v uint16) { _ = binary.Write(&out, binary.LittleEndian, v) }
-	put32 := func(v uint32) { _ = binary.Write(&out, binary.LittleEndian, v) }
-	put64 := func(v uint64) { _ = binary.Write(&out, binary.LittleEndian, v) }
-	if large {
-		out.WriteString("RF64")
-		put32(math.MaxUint32)
-		out.WriteString("WAVEds64")
-		put32(28)
-		put64(size + 36)
-		put64(uint64(len(data)))
-		put64(uint64(len(data)) / align)
-		put32(0)
-	} else {
-		out.WriteString("RIFF")
-		put32(uint32(size))
-		out.WriteString("WAVE")
-	}
-	out.WriteString("fmt ")
-	put32(formatSize)
-	put16(format)
-	put16(uint16(sound.Channels))
-	put32(uint32(rate))
-	put32(uint32(rate * align))
-	put16(uint16(align))
-	put16(uint16(sound.Bits))
-	if format != 1 {
-		if format == 0xfffe {
-			put16(22)
-			put16(uint16(sound.Bits))
-			put32(0)
-			out.Write([]byte{1, 0, 0, 0, 0, 0, 0x10, 0, 0x80, 0, 0, 0xaa, 0, 0x38, 0x9b, 0x71})
-		} else {
-			put16(0)
-		}
-		out.WriteString("fact")
-		put32(4)
-		if large {
-			put32(math.MaxUint32)
-		} else {
-			put32(uint32(uint64(len(data)) / align))
-		}
-	}
-	out.WriteString("data")
-	if large {
-		put32(math.MaxUint32)
-	} else {
-		put32(uint32(len(data)))
-	}
-	out.Write(data)
-	if len(data)%2 != 0 {
-		out.WriteByte(0)
-	}
-	return out.Bytes(), ctx.Err()
-}