From 44c7d3b5896b070089ba4b3782b4a1f352727b87 Mon Sep 17 00:00:00 2001
From: lifegpc <g1710431395@gmail.com>
Date: Fri, 7 Jan 2022 21:59:30 +0800
Subject: [PATCH] file reader support custom IO

---
 file_reader.c | 54 +++++++++++++++++++++++++++++++++++++++------------
 file_reader.h | 14 +++++++++++++
 2 files changed, 56 insertions(+), 12 deletions(-)

diff --git a/file_reader.c b/file_reader.c
index 4691f80..8580ef6 100644
--- a/file_reader.c
+++ b/file_reader.c
@@ -6,16 +6,46 @@
 #include "cstr_util.h"
 
 typedef struct file_reader_file {
-    FILE* f;
+    void* f;
+    file_reader_file_read read;
+    file_reader_file_seek seek;
+    file_reader_file_tell tell;
     /// 0 if little endian otherwise big endian
     unsigned char endian;
 } file_reader_file;
 
+size_t file_reader_default_read(void* f, size_t buf_len, char* buf) {
+    return fread(buf, 1, buf_len, (FILE*)f);
+}
+
+int file_reader_default_seek(void* f, int64_t offset, int origin) {
+    return fileop_fseek((FILE*)f, offset, origin);
+}
+
+int64_t file_reader_default_tell(void* f) {
+    return fileop_ftell((FILE*)f);
+}
+
 file_reader_file* create_file_reader(FILE* f, unsigned char endian) {
     if (!f) return NULL;
     file_reader_file* r = malloc(sizeof(file_reader_file));
     if (!r) return NULL;
+    r->f = (void*)f;
+    r->read = &file_reader_default_read;
+    r->seek = &file_reader_default_seek;
+    r->tell = &file_reader_default_tell;
+    r->endian = endian;
+    return r;
+}
+
+file_reader_file* create_file_reader2(void* f, file_reader_file_read read, file_reader_file_seek seek, file_reader_file_tell tell, unsigned char endian) {
+    if (!f || !read || !seek | !tell) return NULL;
+    file_reader_file* r = malloc(sizeof(file_reader_file));
+    if (!r) return NULL;
     r->f = f;
+    r->read = read;
+    r->seek = seek;
+    r->tell = tell;
     r->endian = endian;
     return r;
 }
@@ -32,7 +62,7 @@ void set_file_reader_endian(file_reader_file* f, unsigned char endian) {
 
 int file_reader_read_int32(file_reader_file* f, int32_t* re) {
     if (!f) return 1;
-    int64_t offset = fileop_ftell(f->f);
+    int64_t offset = f->tell(f->f);
     int32_t r = 0;
     int origin = SEEK_SET;
     if (offset == -1) {
@@ -40,9 +70,9 @@ int file_reader_read_int32(file_reader_file* f, int32_t* re) {
     }
     size_t c;
     uint8_t buf[4];
-    if ((c = fread(buf, 1, 4, f->f)) < 4) {
+    if ((c = f->read(f->f, 4, buf)) < 4) {
         if (origin == SEEK_CUR) offset = -c;
-        fileop_fseek(f->f, offset, origin);
+        f->seek(f->f, offset, origin);
         return 1;
     }
     r = cstr_read_int32(buf, f->endian);
@@ -56,16 +86,16 @@ int file_reader_read_uint32(file_reader_file* f, uint32_t* re) {
 
 int file_reader_read_int64(file_reader_file* f, int64_t* re) {
     if (!f) return 1;
-    int64_t offset = fileop_ftell(f->f), r = 0;
+    int64_t offset = f->tell(f->f), r = 0;
     int origin = SEEK_SET;
     if (offset == -1) {
         origin = SEEK_CUR;
     }
     size_t c;
     uint8_t buf[8];
-    if ((c = fread(buf, 1, 8, f->f)) < 8) {
+    if ((c = f->read(f->f, 8, buf)) < 8) {
         if (origin == SEEK_CUR) offset = -c;
-        fileop_fseek(f->f, offset, origin);
+        f->seek(f->f, offset, origin);
         return 1;
     }
     r = cstr_read_int64(buf, f->endian);
@@ -82,19 +112,19 @@ int file_reader_read_str(file_reader_file* f, char** buf) {
         b = malloc(blen);
         if (!b) return 1;
     }
-    int64_t offset = fileop_ftell(f->f);
+    int64_t offset = f->tell(f->f);
     int origin = SEEK_SET;
     if (offset == -1) {
         origin = SEEK_CUR;
     }
     while (1) {
         if (n >= c) {
-            if (!(tc = fread(bu, 1, 128, f->f))) {
+            if (!(tc = f->read(f->f, 128, bu))) {
                 if (b) free(b);
                 if (origin == SEEK_CUR) {
                     offset = -c;
                 }
-                fileop_fseek(f->f, offset, origin);
+                f->seek(f->f, offset, origin);
                 return 1;
             }
             c += tc;
@@ -107,7 +137,7 @@ int file_reader_read_str(file_reader_file* f, char** buf) {
                 if (origin == SEEK_CUR) {
                     offset = -c;
                 }
-                fileop_fseek(f->f, offset, origin);
+                f->seek(f->f, offset, origin);
                 return 1;
             }
             b = nb;
@@ -131,6 +161,6 @@ int file_reader_read_str(file_reader_file* f, char** buf) {
     } else {
         offset = -(c - n - 1);
     }
-    fileop_fseek(f->f, offset, origin);
+    f->seek(f->f, offset, origin);
     return 0;
 }
diff --git a/file_reader.h b/file_reader.h
index 9c06019..6046ad4 100644
--- a/file_reader.h
+++ b/file_reader.h
@@ -1,11 +1,15 @@
 #ifndef _UTILS_FILE_READER_H
 #define _UTILS_FILE_READER_H
+#include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
 #if __cplusplus
 extern "C" {
 #endif
 typedef struct file_reader_file file_reader_file;
+typedef size_t(*file_reader_file_read)(void* f, size_t buf_len, char* buf);
+typedef int(*file_reader_file_seek)(void* f, int64_t offset, int origin);
+typedef int64_t(*file_reader_file_tell)(void* f);
 /**
  * @brief Create a reader from a stream
  * @param f File stream
@@ -13,6 +17,16 @@ typedef struct file_reader_file file_reader_file;
  * @return the reader, NULL if OOM or stream is NULL.
 */
 file_reader_file* create_file_reader(FILE* f, unsigned char endian);
+/**
+ * @brief Create a reader from a custom IO stream
+ * @param f The data to pass to function
+ * @param read The read function. Must not be NULL.
+ * @param seek The seek function. Must not be NULL.
+ * @param tell The tell function. Must not be NULL.
+ * @param endian 0 if little endian otherwise big endian
+ * @return the reader, NULL if OOM or any parameters is NULL.
+*/
+file_reader_file* create_file_reader2(void* f, file_reader_file_read read, file_reader_file_seek seek, file_reader_file_tell tell, unsigned char endian);
 /**
  * @brief Free a reader. This will not close stream.
  * @param f the pointer to reader struct