From d869320da1a689b9af9298ce39d50174dfee2ef0 Mon Sep 17 00:00:00 2001
From: wenxuanjun <wenxuanjun@yahoo.com>
Date: Sun, 3 Nov 2024 08:28:17 +0800
Subject: [PATCH] Add example code

---
 README.md  | 44 ++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs | 20 +++++++-------------
 2 files changed, 51 insertions(+), 13 deletions(-)

diff --git a/README.md b/README.md
index 1f8dff6..3fcd613 100644
--- a/README.md
+++ b/README.md
@@ -24,3 +24,47 @@ And use `cbindgen` to generate the header file:
 cargo install cbindgen
 cbindgen --output elf_parse.h
 ```
+
+## Example
+
+```c
+#include <stdint.h>
+#include "elf_parser.h"
+
+extern void *page_table;
+
+void segment_callback(struct Segment segment) {
+    printk("Segment address: 0x%lx\n", segment.address);
+    printk("Segment size: %lu bytes\n", segment.size);
+    alloc_and_map(page_table, segment.address, segment.size);
+    write_to_mapped_address(page_table, segment.data, segment.size, segment.address);
+}
+
+void elf_load_example() {
+    const uint8_t elf_data[] = {};
+    size_t elf_size = sizeof(elf_data);
+
+    struct ElfParseResult result = parse_elf(elf_data, elf_size, segment_callback);
+
+    switch (result.tag) {
+        case EntryPoint:
+            printk("ELF Entry Point: 0x%lx\n", result.entry_point);
+            break;
+        case InvalidElfData:
+            printk("Invalid ELF data.\n");
+            break;
+        case ElfContainsNoSegments:
+            printk("ELF contains no segments.\n");
+            break;
+        case FailedToGetSegmentData:
+            printk("Failed to get segment data.\n");
+            break;
+        case AllocFunctionNotProvided:
+            printk("Allocation function not provided.\n");
+            break;
+        default:
+            printk("Unknown error.\n");
+            break;
+    }
+}
+```
diff --git a/src/lib.rs b/src/lib.rs
index 52fbff4..3ecae9d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -15,21 +15,11 @@ unsafe fn panic(_info: &PanicInfo) -> ! {
 
 #[repr(C)]
 pub struct Segment {
-    address: u64,
-    size: u64,
+    address: usize,
+    size: usize,
     data: *const u8,
 }
 
-impl Segment {
-    pub fn new(address: u64, size: u64, data: *const u8) -> Self {
-        Self {
-            address,
-            size,
-            data,
-        }
-    }
-}
-
 #[repr(C)]
 pub enum ElfParseResult {
     EntryPoint(usize),
@@ -64,7 +54,11 @@ pub unsafe extern "C" fn parse_elf(
                 Err(_) => return ElfParseResult::FailedToGetSegmentData,
             };
 
-            let segment = Segment::new(header.p_vaddr, header.p_memsz, data.as_ptr());
+            let segment = Segment {
+                address: header.p_vaddr as usize,
+                size: header.p_memsz as usize,
+                data: data.as_ptr(),
+            };
             mapping_callback(segment);
         }
     }