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-rw-r--r--fuzz/fuzz_targets/display_does_not_panic.rs18
-rw-r--r--src/protected_mode/display.rs104
-rw-r--r--src/protected_mode/mod.rs2
-rw-r--r--src/real_mode/display.rs104
-rw-r--r--src/real_mode/mod.rs2
5 files changed, 227 insertions, 3 deletions
diff --git a/fuzz/fuzz_targets/display_does_not_panic.rs b/fuzz/fuzz_targets/display_does_not_panic.rs
index 97a14b8..39f5753 100644
--- a/fuzz/fuzz_targets/display_does_not_panic.rs
+++ b/fuzz/fuzz_targets/display_does_not_panic.rs
@@ -8,14 +8,26 @@ fuzz_target!(|data: &[u8]| {
let x86_16_decoder = yaxpeax_x86::real_mode::InstDecoder::default();
if let Ok(inst) = x86_64_decoder.decode_slice(data) {
- inst.write_to(&mut String::new()).expect("format does not panic");
+ let mut out = String::new();
+ inst.write_to(&mut out).expect("format does not panic");
+ let mut text_buf = yaxpeax_x86::long_mode::InstructionTextBuffer::new();
+ text_buf.format_inst(&inst.display_with(yaxpeax_x86::long_mode::DisplayStyle::Intel)).expect("can format");
+ assert_eq!(text_buf.text_str(), out);
};
if let Ok(inst) = x86_32_decoder.decode_slice(data) {
- inst.write_to(&mut String::new()).expect("format does not panic");
+ let mut out = String::new();
+ inst.write_to(&mut out).expect("format does not panic");
+ let mut text_buf = yaxpeax_x86::protected_mode::InstructionTextBuffer::new();
+ text_buf.format_inst(&inst.display_with(yaxpeax_x86::protected_mode::DisplayStyle::Intel)).expect("can format");
+ assert_eq!(text_buf.text_str(), out);
};
if let Ok(inst) = x86_16_decoder.decode_slice(data) {
- inst.write_to(&mut String::new()).expect("format does not panic");
+ let mut out = String::new();
+ inst.write_to(&mut out).expect("format does not panic");
+ let mut text_buf = yaxpeax_x86::real_mode::InstructionTextBuffer::new();
+ text_buf.format_inst(&inst.display_with(yaxpeax_x86::real_mode::DisplayStyle::Intel)).expect("can format");
+ assert_eq!(text_buf.text_str(), out);
};
});
diff --git a/src/protected_mode/display.rs b/src/protected_mode/display.rs
index 1db34cb..0291246 100644
--- a/src/protected_mode/display.rs
+++ b/src/protected_mode/display.rs
@@ -2942,3 +2942,107 @@ impl<'a, F: DisplaySink> super::OperandVisitor for RelativeBranchPrinter<'a, F>
Ok(false)
}
}
+
+#[cfg(feature="alloc")]
+mod buffer_sink {
+ use core::fmt;
+ use super::super::{DisplayStyle, InstructionDisplayer};
+ use super::{contextualize_c, contextualize_intel};
+
+ /// helper to format `amd64` instructions with highest throughput and least configuration. this is
+ /// functionally a buffer for one x86 instruction's text.
+ ///
+ /// ### when to use this over `fmt::Display`?
+ ///
+ /// `fmt::Display` is a fair choice in most cases. in some cases, `InstructionTextBuffer` may
+ /// support formatting options that may be difficult to configure for a `Display` impl.
+ /// additionally, `InstructionTextBuffer` may be able to specialize more effectively where
+ /// `fmt::Display`, writing to a generic `fmt::Write`, may not.
+ ///
+ /// if your use case for `yaxpeax-x86` involves being bounded on the speed of disassembling and
+ /// formatting instructions, [`InstructionTextBuffer::format_inst`] has been measured as up to 11%
+ /// faster than an equivalent `write!(buf, "{}", inst)`.
+ ///
+ /// `InstructionTextBuffer` involves internal allocations; if your use case for `yaxpeax-x86`
+ /// requires allocations never occurring, it is not an appropriate tool.
+ ///
+ /// ### example
+ ///
+ /// ```
+ /// use yaxpeax_x86::long_mode::InstDecoder;
+ /// use yaxpeax_x86::long_mode::InstructionTextBuffer;
+ /// use yaxpeax_x86::long_mode::DisplayStyle;
+ ///
+ /// let bytes = &[0x33, 0xc0];
+ /// let inst = InstDecoder::default().decode_slice(bytes).expect("can decode");
+ /// let mut text_buf = InstructionTextBuffer::new();
+ /// assert_eq!(
+ /// text_buf.format_inst(&inst.display_with(DisplayStyle::Intel)).expect("can format"),
+ /// "xor eax, eax"
+ /// );
+ ///
+ /// // or, getting the formatted instruction with `text_str`:
+ /// assert_eq!(
+ /// text_buf.text_str(),
+ /// "xor eax, eax"
+ /// );
+ /// ```
+ pub struct InstructionTextBuffer {
+ content: alloc::string::String,
+ }
+
+ impl InstructionTextBuffer {
+ /// create an `InstructionTextBuffer` with default settings. `InstructionTextBuffer`'s default
+ /// settings format instructions identically to their corresponding `fmt::Display`.
+ pub fn new() -> Self {
+ let mut buf = alloc::string::String::new();
+ // TODO: move 512 out to a MAX_INSTRUCTION_LEN const and appropriate justification (and
+ // fuzzing and ..)
+ buf.reserve(512);
+ Self {
+ content: buf,
+ }
+ }
+
+ /// format `inst` into this buffer. returns a borrow of that same internal buffer for convenience.
+ ///
+ /// this clears and reuses an internal buffer; if an instruction had been previously formatted
+ /// through this buffer, it will be overwritten.
+ pub fn format_inst<'buf, 'instr>(&'buf mut self, display: &InstructionDisplayer<'instr>) -> Result<&'buf str, fmt::Error> {
+ // Safety: this sink is used to format exactly one instruction and then dropped. it can
+ // never escape `format_inst`.
+ let mut handle = unsafe { self.write_handle() };
+
+ match display.style {
+ DisplayStyle::Intel => {
+ contextualize_intel(&display.instr, &mut handle)?;
+ }
+ DisplayStyle::C => {
+ contextualize_c(&display.instr, &mut handle)?;
+ }
+ }
+
+ Ok(self.text_str())
+ }
+
+ /// return a borrow of the internal buffer. if an instruction has been formatted, the
+ /// returned `&str` contains that instruction's buffered text.
+ pub fn text_str(&self) -> &str {
+ self.content.as_str()
+ }
+
+ /// do the necessary bookkeeping and provide an `InstructionTextSink` to write an instruction
+ /// into.
+ ///
+ /// SAFETY: callers must print at most one instruction into this handle.
+ unsafe fn write_handle(&mut self) -> yaxpeax_arch::display::InstructionTextSink {
+ self.content.clear();
+ // Safety: `content` was just cleared, so writing begins at the start of the buffer.
+ // `content`is large enough to hold a fully-formatted instruction (see
+ // `InstructionTextBuffer::new`).
+ yaxpeax_arch::display::InstructionTextSink::new(&mut self.content)
+ }
+ }
+}
+#[cfg(feature="alloc")]
+pub use buffer_sink::InstructionTextBuffer;
diff --git a/src/protected_mode/mod.rs b/src/protected_mode/mod.rs
index 38f8310..6d9031a 100644
--- a/src/protected_mode/mod.rs
+++ b/src/protected_mode/mod.rs
@@ -8,6 +8,8 @@ pub use crate::MemoryAccessSize;
#[cfg(feature = "fmt")]
pub use self::display::{DisplayStyle, InstructionDisplayer};
+#[cfg(all(feature = "fmt", feature = "alloc"))]
+pub use self::display::InstructionTextBuffer;
use core::cmp::PartialEq;
use crate::safer_unchecked::unreachable_kinda_unchecked as unreachable_unchecked;
diff --git a/src/real_mode/display.rs b/src/real_mode/display.rs
index 90b4f0a..fdd51cf 100644
--- a/src/real_mode/display.rs
+++ b/src/real_mode/display.rs
@@ -2942,3 +2942,107 @@ impl<'a, F: DisplaySink> super::OperandVisitor for RelativeBranchPrinter<'a, F>
Ok(false)
}
}
+
+#[cfg(feature="alloc")]
+mod buffer_sink {
+ use core::fmt;
+ use super::super::{DisplayStyle, InstructionDisplayer};
+ use super::{contextualize_c, contextualize_intel};
+
+ /// helper to format `amd64` instructions with highest throughput and least configuration. this is
+ /// functionally a buffer for one x86 instruction's text.
+ ///
+ /// ### when to use this over `fmt::Display`?
+ ///
+ /// `fmt::Display` is a fair choice in most cases. in some cases, `InstructionTextBuffer` may
+ /// support formatting options that may be difficult to configure for a `Display` impl.
+ /// additionally, `InstructionTextBuffer` may be able to specialize more effectively where
+ /// `fmt::Display`, writing to a generic `fmt::Write`, may not.
+ ///
+ /// if your use case for `yaxpeax-x86` involves being bounded on the speed of disassembling and
+ /// formatting instructions, [`InstructionTextBuffer::format_inst`] has been measured as up to 11%
+ /// faster than an equivalent `write!(buf, "{}", inst)`.
+ ///
+ /// `InstructionTextBuffer` involves internal allocations; if your use case for `yaxpeax-x86`
+ /// requires allocations never occurring, it is not an appropriate tool.
+ ///
+ /// ### example
+ ///
+ /// ```
+ /// use yaxpeax_x86::long_mode::InstDecoder;
+ /// use yaxpeax_x86::long_mode::InstructionTextBuffer;
+ /// use yaxpeax_x86::long_mode::DisplayStyle;
+ ///
+ /// let bytes = &[0x33, 0xc0];
+ /// let inst = InstDecoder::default().decode_slice(bytes).expect("can decode");
+ /// let mut text_buf = InstructionTextBuffer::new();
+ /// assert_eq!(
+ /// text_buf.format_inst(&inst.display_with(DisplayStyle::Intel)).expect("can format"),
+ /// "xor eax, eax"
+ /// );
+ ///
+ /// // or, getting the formatted instruction with `text_str`:
+ /// assert_eq!(
+ /// text_buf.text_str(),
+ /// "xor eax, eax"
+ /// );
+ /// ```
+ pub struct InstructionTextBuffer {
+ content: alloc::string::String,
+ }
+
+ impl InstructionTextBuffer {
+ /// create an `InstructionTextBuffer` with default settings. `InstructionTextBuffer`'s default
+ /// settings format instructions identically to their corresponding `fmt::Display`.
+ pub fn new() -> Self {
+ let mut buf = alloc::string::String::new();
+ // TODO: move 512 out to a MAX_INSTRUCTION_LEN const and appropriate justification (and
+ // fuzzing and ..)
+ buf.reserve(512);
+ Self {
+ content: buf,
+ }
+ }
+
+ /// format `inst` into this buffer. returns a borrow of that same internal buffer for convenience.
+ ///
+ /// this clears and reuses an internal buffer; if an instruction had been previously formatted
+ /// through this buffer, it will be overwritten.
+ pub fn format_inst<'buf, 'instr>(&'buf mut self, display: &InstructionDisplayer<'instr>) -> Result<&'buf str, fmt::Error> {
+ // Safety: this sink is used to format exactly one instruction and then dropped. it can
+ // never escape `format_inst`.
+ let mut handle = unsafe { self.write_handle() };
+
+ match display.style {
+ DisplayStyle::Intel => {
+ contextualize_intel(&display.instr, &mut handle)?;
+ }
+ DisplayStyle::C => {
+ contextualize_c(&display.instr, &mut handle)?;
+ }
+ }
+
+ Ok(self.text_str())
+ }
+
+ /// return a borrow of the internal buffer. if an instruction has been formatted, the
+ /// returned `&str` contains that instruction's buffered text.
+ pub fn text_str(&self) -> &str {
+ self.content.as_str()
+ }
+
+ /// do the necessary bookkeeping and provide an `InstructionTextSink` to write an instruction
+ /// into.
+ ///
+ /// SAFETY: callers must print at most one instruction into this handle.
+ unsafe fn write_handle(&mut self) -> yaxpeax_arch::display::InstructionTextSink {
+ self.content.clear();
+ // Safety: `content` was just cleared, so writing begins at the start of the buffer.
+ // `content`is large enough to hold a fully-formatted instruction (see
+ // `InstructionTextBuffer::new`).
+ yaxpeax_arch::display::InstructionTextSink::new(&mut self.content)
+ }
+ }
+}
+#[cfg(feature="alloc")]
+pub use buffer_sink::InstructionTextBuffer;
diff --git a/src/real_mode/mod.rs b/src/real_mode/mod.rs
index b1aaf7d..162b380 100644
--- a/src/real_mode/mod.rs
+++ b/src/real_mode/mod.rs
@@ -8,6 +8,8 @@ pub use crate::MemoryAccessSize;
#[cfg(feature = "fmt")]
pub use self::display::{DisplayStyle, InstructionDisplayer};
+#[cfg(all(feature = "fmt", feature = "alloc"))]
+pub use self::display::InstructionTextBuffer;
use core::cmp::PartialEq;
use crate::safer_unchecked::unreachable_kinda_unchecked as unreachable_unchecked;
generated by cgit v1.1 at 2024-12-27 13:19:52 +0000