Method parse

crates/environ/src/frame_table.rs:67–147

Parse a frame table section from a byte-slice as produced by [`crate::compile::FrameTableBuilder`].

(data: &'a [u8], original_text: &'a [u8])

    /// Parse a frame table section from a byte-slice as produced by
    /// [`crate::compile::FrameTableBuilder`].
    pub fn parse(data: &'a [u8], original_text: &'a [u8]) -> anyhow::Result<FrameTable<'a>> {
        let mut data = Bytes(data);
        let num_frame_descriptors = data
            .read::<U32<LittleEndian>>()
            .map_err(|_| anyhow::anyhow!("Unable to read frame descriptor count prefix"))?;
        let num_frame_descriptors = usize::try_from(num_frame_descriptors.get(LittleEndian))?;
        let num_progpoint_descriptors = data
            .read::<U32<LittleEndian>>()
            .map_err(|_| anyhow::anyhow!("Unable to read progpoint descriptor count prefix"))?;
        let num_progpoint_descriptors =
            usize::try_from(num_progpoint_descriptors.get(LittleEndian))?;
        let num_breakpoints = data
            .read::<U32<LittleEndian>>()
            .map_err(|_| anyhow::anyhow!("Unable to read breakpoint count prefix"))?;
        let num_breakpoints = usize::try_from(num_breakpoints.get(LittleEndian))?;

        let frame_descriptor_pool_length = data
            .read::<U32<LittleEndian>>()
            .map_err(|_| anyhow::anyhow!("Unable to read frame descriptor pool length"))?;
        let frame_descriptor_pool_length =
            usize::try_from(frame_descriptor_pool_length.get(LittleEndian))?;
        let progpoint_descriptor_pool_length = data
            .read::<U32<LittleEndian>>()
            .map_err(|_| anyhow::anyhow!("Unable to read progpoint descriptor pool length"))?;
        let progpoint_descriptor_pool_length =
            usize::try_from(progpoint_descriptor_pool_length.get(LittleEndian))?;
        let breakpoint_patch_pool_length = data
            .read::<U32<LittleEndian>>()
            .map_err(|_| anyhow::anyhow!("Unable to read breakpoint patch pool length"))?;
        let breakpoint_patch_pool_length =
            usize::try_from(breakpoint_patch_pool_length.get(LittleEndian))?;

        let (frame_descriptor_ranges, data) =
            object::slice_from_bytes::<U32<LittleEndian>>(data.0, 2 * num_frame_descriptors)
                .map_err(|_| anyhow::anyhow!("Unable to read frame descriptor ranges slice"))?;
        let (frame_descriptor_fp_offsets, data) =
            object::slice_from_bytes::<U32<LittleEndian>>(data, num_frame_descriptors)
                .map_err(|_| anyhow::anyhow!("Unable to read frame descriptor FP offset slice"))?;

        let (progpoint_pcs, data) =
            object::slice_from_bytes::<U32<LittleEndian>>(data, num_progpoint_descriptors)
                .map_err(|_| anyhow::anyhow!("Unable to read progpoint PC slice"))?;
        let (progpoint_descriptor_offsets, data) =
            object::slice_from_bytes::<U32<LittleEndian>>(data, num_progpoint_descriptors)
                .map_err(|_| anyhow::anyhow!("Unable to read progpoint descriptor offset slice"))?;
        let (breakpoint_pcs, data) =
            object::slice_from_bytes::<U32<LittleEndian>>(data, num_breakpoints)
                .map_err(|_| anyhow::anyhow!("Unable to read breakpoint PC slice"))?;
        let (breakpoint_patch_offsets, data) =
            object::slice_from_bytes::<U32<LittleEndian>>(data, num_breakpoints)
                .map_err(|_| anyhow::anyhow!("Unable to read breakpoint patch offsets slice"))?;
        let (breakpoint_patch_data_ends, data) =
            object::slice_from_bytes::<U32<LittleEndian>>(data, num_breakpoints)
                .map_err(|_| anyhow::anyhow!("Unable to read breakpoint patch data ends slice"))?;

        let (frame_descriptor_data, data) = data
            .split_at_checked(frame_descriptor_pool_length)
            .ok_or_else(|| anyhow::anyhow!("Unable to read frame descriptor pool"))?;