Replace other .position() patterns with memchr

This makes `memchr` a non-optional dependency, due to its use in
`read_string` method of `pod::Bytes`.

Cargo.toml

@@ -17,7 +17,7 @@ crc32fast = { version = "1.2", optional = true }
 flate2 = { version = "1", optional = true }
 indexmap = { version = "1.1", optional = true }
 wasmparser = { version = "0.57", optional = true }
-memchr = { version = "2.4", optional = true, default-features = false }
+memchr = { version = "2.4", default-features = false }
 
 # Internal feature, only used when building as part of libstd, not part of the
 # stable interface of this crate.
@@ -59,7 +59,7 @@ unaligned = []
 
 #=======================================
 # File format features.
-archive = ["memchr"]
+archive = []
 coff = []
 elf = []
 macho = []

src/pod.rs

@@ -284,7 +284,7 @@ impl<'data> Bytes<'data> {
     /// Reads past the null byte, but doesn't return it.
     #[inline]
     pub fn read_string(&mut self) -> Result<&'data [u8]> {
-        match self.0.iter().position(|&x| x == 0) {
+        match memchr::memchr(b'\0', self.0) {
             Some(null) => {
                 // These will never fail.
                 let bytes = self.read_bytes(null)?;

src/read/coff/section.rs

@@ -347,7 +347,7 @@ impl pe::ImageSectionHeader {
     /// Return the raw section name.
     pub fn raw_name(&self) -> &[u8] {
         let bytes = &self.name;
-        match bytes.iter().position(|&x| x == 0) {
+        match memchr::memchr(b'\0', bytes) {
             Some(end) => &bytes[..end],
             None => &bytes[..],
         }

src/read/coff/symbol.rs

@@ -114,7 +114,7 @@ impl<'data> SymbolTable<'data> {
             .read_error("Invalid COFF symbol index")?;
         let bytes = bytes_of_slice(entries);
         // The name is padded with nulls.
-        Ok(match bytes.iter().position(|&x| x == 0) {
+        Ok(match memchr::memchr(b'\0', bytes) {
             Some(end) => &bytes[..end],
             None => &bytes[..],
         })
@@ -182,7 +182,7 @@ impl pe::ImageSymbol {
                 .read_error("Invalid COFF symbol name offset")
         } else {
             // The name is inline and padded with nulls.
-            Ok(match self.name.iter().position(|&x| x == 0) {
+            Ok(match memchr::memchr(b'\0', &self.name) {
                 Some(end) => &self.name[..end],
                 None => &self.name[..],
             })

src/read/macho/section.rs

@@ -245,7 +245,7 @@ pub trait Section: Debug + Pod {
     /// Return the `sectname` bytes up until the null terminator.
     fn name(&self) -> &[u8] {
         let sectname = &self.sectname()[..];
-        match sectname.iter().position(|&x| x == 0) {
+        match memchr::memchr(b'\0', sectname) {
             Some(end) => &sectname[..end],
             None => sectname,
         }
@@ -254,7 +254,7 @@ pub trait Section: Debug + Pod {
     /// Return the `segname` bytes up until the null terminator.
     fn segment_name(&self) -> &[u8] {
         let segname = &self.segname()[..];
-        match segname.iter().position(|&x| x == 0) {
+        match memchr::memchr(b'\0', segname) {
             Some(end) => &segname[..end],
             None => segname,
         }

src/read/macho/segment.rs

@@ -158,7 +158,7 @@ pub trait Segment: Debug + Pod {
     /// Return the `segname` bytes up until the null terminator.
     fn name(&self) -> &[u8] {
         let segname = &self.segname()[..];
-        match segname.iter().position(|&x| x == 0) {
+        match memchr::memchr(b'\0', segname) {
             Some(end) => &segname[..end],
             None => segname,
         }