263 lines
9.0 KiB
Rust
263 lines
9.0 KiB
Rust
//! Function for reading TIFF tags
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use std::collections::HashMap;
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use std::convert::TryFrom;
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use std::io::{self, Read, Seek};
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use std::mem;
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use super::stream::{ByteOrder, EndianReader, SmartReader};
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use tags::{Tag, Type};
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use {TiffError, TiffFormatError, TiffResult, TiffUnsupportedError};
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use self::Value::{Ascii, List, Rational, Unsigned, Signed, SRational};
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#[allow(unused_qualifications)]
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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pub enum Value {
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Signed(i32),
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Unsigned(u32),
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List(Vec<Value>),
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Rational(u32, u32),
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SRational(i32, i32),
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Ascii(String),
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#[doc(hidden)] // Do not match against this.
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__NonExhaustive,
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}
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impl Value {
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pub fn into_u32(self) -> TiffResult<u32> {
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match self {
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Unsigned(val) => Ok(val),
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val => Err(TiffError::FormatError(
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TiffFormatError::UnsignedIntegerExpected(val),
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)),
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}
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}
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pub fn into_i32(self) -> TiffResult<i32> {
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match self {
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Signed(val) => Ok(val),
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val => Err(TiffError::FormatError(
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TiffFormatError::SignedIntegerExpected(val),
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)),
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}
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}
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pub fn into_u32_vec(self) -> TiffResult<Vec<u32>> {
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match self {
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List(vec) => {
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let mut new_vec = Vec::with_capacity(vec.len());
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for v in vec {
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new_vec.push(v.into_u32()?)
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}
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Ok(new_vec)
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}
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Unsigned(val) => Ok(vec![val]),
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Rational(numerator, denominator) => Ok(vec![numerator, denominator]),
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Ascii(val) => Ok(val.chars().map(u32::from).collect()),
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val => Err(TiffError::FormatError(
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TiffFormatError::UnsignedIntegerExpected(val),
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)),
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}
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}
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pub fn into_i32_vec(self) -> TiffResult<Vec<i32>> {
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match self {
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List(vec) => {
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let mut new_vec = Vec::with_capacity(vec.len());
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for v in vec {
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match v {
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SRational(numerator, denominator) => {
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new_vec.push(numerator);
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new_vec.push(denominator);
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}
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_ => new_vec.push(v.into_i32()?)
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}
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}
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Ok(new_vec)
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}
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Signed(val) => Ok(vec![val]),
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SRational(numerator, denominator) => Ok(vec![numerator, denominator]),
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val => Err(TiffError::FormatError(
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TiffFormatError::SignedIntegerExpected(val),
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)),
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}
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}
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}
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#[derive(Clone)]
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pub struct Entry {
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type_: Type,
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count: u32,
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offset: [u8; 4],
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}
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impl ::std::fmt::Debug for Entry {
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fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> Result<(), ::std::fmt::Error> {
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fmt.write_str(&format!(
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"Entry {{ type_: {:?}, count: {:?}, offset: {:?} }}",
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self.type_, self.count, &self.offset
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))
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}
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}
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impl Entry {
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pub fn new(type_: Type, count: u32, offset: [u8; 4]) -> Entry {
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Entry {
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type_,
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count,
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offset,
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}
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}
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/// Returns a mem_reader for the offset/value field
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fn r(&self, byte_order: ByteOrder) -> SmartReader<io::Cursor<Vec<u8>>> {
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SmartReader::wrap(io::Cursor::new(self.offset.to_vec()), byte_order)
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}
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pub fn val<R: Read + Seek>(
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&self,
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limits: &super::Limits,
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decoder: &mut super::Decoder<R>,
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) -> TiffResult<Value> {
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let bo = decoder.byte_order();
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match (self.type_, self.count) {
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// TODO check if this could give wrong results
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// at a different endianess of file/computer.
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(Type::BYTE, 1) => Ok(Unsigned(u32::from(self.offset[0]))),
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(Type::BYTE, 2) => offset_to_bytes(2, self),
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(Type::BYTE, 3) => offset_to_bytes(3, self),
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(Type::BYTE, 4) => offset_to_bytes(4, self),
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(Type::BYTE, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
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Ok(Unsigned(u32::from(decoder.read_byte()?)))
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}),
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(Type::SBYTE, 1) => Ok(Signed(i32::from(self.offset[0] as i8))),
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(Type::SBYTE, 2) => offset_to_sbytes(2, self),
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(Type::SBYTE, 3) => offset_to_sbytes(3, self),
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(Type::SBYTE, 4) => offset_to_sbytes(4, self),
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(Type::SBYTE, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
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Ok(Signed(i32::from(decoder.read_byte()? as i8)))
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}),
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(Type::SHORT, 1) => Ok(Unsigned(u32::from(self.r(bo).read_u16()?))),
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(Type::SSHORT, 1) => Ok(Signed(i32::from(self.r(bo).read_i16()?))),
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(Type::SHORT, 2) => {
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let mut r = self.r(bo);
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Ok(List(vec![
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Unsigned(u32::from(r.read_u16()?)),
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Unsigned(u32::from(r.read_u16()?)),
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]))
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}
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(Type::SSHORT, 2) => {
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let mut r = self.r(bo);
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Ok(List(vec![
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Signed(i32::from(r.read_i16()?)),
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Signed(i32::from(r.read_i16()?)),
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]))
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}
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(Type::SHORT, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
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Ok(Unsigned(u32::from(decoder.read_short()?)))
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}),
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(Type::SSHORT, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
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Ok(Signed(i32::from(decoder.read_sshort()?)))
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}),
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(Type::LONG, 1) => Ok(Unsigned(self.r(bo).read_u32()?)),
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(Type::SLONG, 1) => Ok(Signed(self.r(bo).read_i32()?)),
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(Type::LONG, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
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Ok(Unsigned(decoder.read_long()?))
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}),
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(Type::SLONG, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
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Ok(Signed(decoder.read_slong()?))
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}),
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(Type::RATIONAL, 1) => {
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decoder.goto_offset(self.r(bo).read_u32()?)?;
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let numerator = decoder.read_long()?;
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let denominator = decoder.read_long()?;
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Ok(Rational(numerator, denominator))
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}
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(Type::SRATIONAL, 1) => {
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decoder.goto_offset(self.r(bo).read_u32()?)?;
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let numerator = decoder.read_slong()?;
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let denominator = decoder.read_slong()?;
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Ok(SRational(numerator, denominator))
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}
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(Type::RATIONAL, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
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Ok(Rational(
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decoder.read_long()?,
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decoder.read_long()?,
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))
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}),
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(Type::SRATIONAL, n) => self.decode_offset(n, bo, limits, decoder, |decoder| {
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Ok(SRational(
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decoder.read_slong()?,
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decoder.read_slong()?,
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))
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}),
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(Type::ASCII, n) => {
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let n = usize::try_from(n)?;
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if n > limits.decoding_buffer_size {
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return Err(TiffError::LimitsExceeded);
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}
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if n <= 4 {
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let mut buf = vec![0; n];
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self.r(bo).read_exact(&mut buf )?;
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let v = String::from_utf8(buf)?;
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let v = v.trim_matches(char::from(0));
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Ok(Ascii(v.into()))
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} else {
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decoder.goto_offset(self.r(bo).read_u32()?)?;
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let string = decoder.read_string(n)?;
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Ok(Ascii(string))
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}
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}
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_ => Err(TiffError::UnsupportedError(
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TiffUnsupportedError::UnsupportedDataType,
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)),
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}
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}
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#[inline]
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fn decode_offset<R, F>(&self, value_count: u32, bo: ByteOrder, limits: &super::Limits, decoder: &mut super::Decoder<R>, decode_fn: F) -> TiffResult<Value>
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where
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R: Read + Seek,
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F: Fn(&mut super::Decoder<R>) -> TiffResult<Value>,
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{
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let value_count = usize::try_from(value_count)?;
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if value_count > limits.decoding_buffer_size / mem::size_of::<Value>() {
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return Err(TiffError::LimitsExceeded);
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}
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let mut v = Vec::with_capacity(value_count);
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decoder.goto_offset(self.r(bo).read_u32()?)?;
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for _ in 0..value_count {
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v.push(decode_fn(decoder)?)
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}
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Ok(List(v))
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}
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}
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/// Extracts a list of BYTE tags stored in an offset
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#[inline]
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fn offset_to_bytes(n: usize, entry: &Entry) -> TiffResult<Value> {
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Ok(List(
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entry.offset[0..n]
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.iter()
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.map(|&e| Unsigned(u32::from(e)))
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.collect()
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))
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}
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/// Extracts a list of SBYTE tags stored in an offset
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#[inline]
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fn offset_to_sbytes(n: usize, entry: &Entry) -> TiffResult<Value> {
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Ok(List(
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entry.offset[0..n]
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.iter()
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.map(|&e| Signed(i32::from(e as i8)))
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.collect()
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))
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}
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/// Type representing an Image File Directory
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pub type Directory = HashMap<Tag, Entry>;
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