mirror of
https://github.com/unidoc/unipdf.git
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24648f4481
* Fixing platform indepenedent integer size * Cleared test logs. * Cleared unnecessary int32 * Defined precise integer size for jbig2 segments.
112 lines
2.3 KiB
Go
112 lines
2.3 KiB
Go
/*
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* This file is subject to the terms and conditions defined in
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* file 'LICENSE.md', which is part of this source code package.
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*/
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package segments
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import (
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"fmt"
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"math"
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"github.com/unidoc/unipdf/v3/internal/jbig2/decoder/huffman"
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"github.com/unidoc/unipdf/v3/internal/jbig2/reader"
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)
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// TableSegment is the model used for user defined Huffman Table Segment - see 7.4.13 and appendix B.
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type TableSegment struct {
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r reader.StreamReader
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// Code Table Flags B.2.1
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htOutOfBand int32
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htPS int32
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htRS int32
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// Code Table lowest value B.2.2
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htLow int32
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// Code Table highest value B.2.3
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htHight int32
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}
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// Compile time check if the TableSegment implements huffman.BasicTabler.
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var _ huffman.BasicTabler = &TableSegment{}
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// Init initializes the table segment.
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// Implements Segmenter interface.
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func (t *TableSegment) Init(h *Header, r reader.StreamReader) error {
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t.r = r
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return t.parseHeader()
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}
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// HtPS implements huffman.BasicTabler interface.
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func (t *TableSegment) HtPS() int32 {
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return t.htPS
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}
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// HtRS implements huffman.BasicTabler interface.
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func (t *TableSegment) HtRS() int32 {
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return t.htRS
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}
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// HtLow implements huffman.BasicTabler interface.
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func (t *TableSegment) HtLow() int32 {
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return t.htLow
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}
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// HtHigh implements huffman.BasicTabler interface.
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func (t *TableSegment) HtHigh() int32 {
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return t.htHight
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}
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// HtOOB implements huffman.BasicTabler interface.
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func (t *TableSegment) HtOOB() int32 {
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return t.htOutOfBand
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}
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// StreamReader implements huffman.BasicTabler interface.
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func (t *TableSegment) StreamReader() reader.StreamReader {
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return t.r
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}
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func (t *TableSegment) parseHeader() error {
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var (
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bit int
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bits uint64
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err error
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)
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bit, err = t.r.ReadBit()
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if err != nil {
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return err
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}
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if bit == 1 {
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return fmt.Errorf("invalid table segment definition. B.2.1 Code Table flags: Bit 7 must be zero. Was: %d", bit)
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}
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// Bit 4-6
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if bits, err = t.r.ReadBits(3); err != nil {
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return err
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}
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t.htRS = (int32(bits) + 1) & 0xf
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// Bit 1-3
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if bits, err = t.r.ReadBits(3); err != nil {
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return err
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}
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t.htPS = (int32(bits) + 1) & 0xf
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// 4 bytes
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if bits, err = t.r.ReadBits(32); err != nil {
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return err
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}
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t.htLow = int32(bits & math.MaxInt32)
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// 4 bytes
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if bits, err = t.r.ReadBits(32); err != nil {
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return err
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}
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t.htHight = int32(bits & math.MaxInt32)
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return nil
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}
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