Add BlockStorageDevice class.

devices/CMakeLists.txt

@@ -15,6 +15,7 @@ file(GLOB SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/*.cpp"
                   "${CMAKE_CURRENT_SOURCE_DIR}/memctrl/*.cpp"
                   "${CMAKE_CURRENT_SOURCE_DIR}/serial/*.cpp"
                   "${CMAKE_CURRENT_SOURCE_DIR}/sound/*.cpp"
+                  "${CMAKE_CURRENT_SOURCE_DIR}/storage/*.cpp"
                   "${CMAKE_CURRENT_SOURCE_DIR}/video/*.cpp"
     )
 

devices/storage/blockstoragedevice.cpp

@@ -0,0 +1,111 @@
+/*
+DingusPPC - The Experimental PowerPC Macintosh emulator
+Copyright (C) 2018-23 divingkatae and maximum
+                      (theweirdo)     spatium
+
+(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/** @file Block storage device implementation. */
+
+#include <devices/storage/blockstoragedevice.h>
+#include <loguru.hpp>
+
+#include <stdio.h>
+#include <sys/stat.h>
+
+using namespace std;
+
+BlockStorageDevice::BlockStorageDevice(const uint32_t cache_blocks, const uint32_t block_size) {
+    this->block_size = block_size;
+    this->cache_size = cache_blocks * this->block_size;
+
+    // allocate device cache and fill it with zeroes
+    this->data_cache = std::unique_ptr<char[]>(new char[this->cache_size] ());
+}
+
+BlockStorageDevice::~BlockStorageDevice() {
+    if (this->img_file)
+        this->img_file.close();
+}
+
+int BlockStorageDevice::set_host_file(std::string file_path) {
+    this->is_ready = false;
+
+    this->img_file.open(file_path, ios::out | ios::in | ios::binary);
+
+    struct stat stat_buf;
+    int rc = stat(file_path.c_str(), &stat_buf);
+    if (rc)
+        return -1;
+
+    this->size_bytes  = stat_buf.st_size;
+    this->size_blocks = this->size_bytes / this->block_size;
+    this->set_fpos(0);
+
+    this->is_ready = true;
+
+    return 0;
+}
+
+int BlockStorageDevice::set_fpos(const uint32_t lba) {
+    this->cur_fpos = lba * this->block_size;
+    this->img_file.seekg(this->cur_fpos, this->img_file.beg);
+    return 0;
+}
+
+int BlockStorageDevice::read_begin(int nblocks, uint32_t max_len) {
+    uint32_t xfer_len = std::min(this->cache_size, max_len);
+    uint32_t read_size = nblocks * this->block_size;
+    if (read_size > xfer_len) {
+        this->remain_size = read_size - xfer_len;
+        read_size = xfer_len;
+    } else {
+        this->remain_size = 0;
+    }
+
+    this->img_file.read(this->data_cache.get(), read_size);
+    this->cur_fpos += read_size;
+
+    return read_size;
+}
+
+int BlockStorageDevice::read_more() {
+    uint32_t read_size;
+
+    if (!this->remain_size)
+        return 0;
+
+    if (this->remain_size > this->cache_size) {
+        this->remain_size -= this->cache_size;
+        read_size = this->cache_size;
+    } else {
+        read_size = this->remain_size;
+        this->remain_size = 0;
+    }
+
+    this->img_file.read(this->data_cache.get(), read_size);
+    this->cur_fpos += read_size;
+
+    return read_size;
+}
+
+int BlockStorageDevice::write_begin(char *buf, int nblocks) {
+    if (!this->is_writeable)
+        return -1;
+
+    return 0;
+}

devices/storage/blockstoragedevice.h

@@ -0,0 +1,61 @@
+/*
+DingusPPC - The Experimental PowerPC Macintosh emulator
+Copyright (C) 2018-23 divingkatae and maximum
+                      (theweirdo)     spatium
+
+(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/** @file Block storage device definitions. */
+
+#ifndef BLOCK_STORAGE_DEVICE_H
+#define BLOCK_STORAGE_DEVICE_H
+
+#include <cinttypes>
+#include <fstream>
+#include <memory>
+#include <string>
+
+class BlockStorageDevice {
+public:
+    BlockStorageDevice(const uint32_t cache_blocks, const uint32_t block_size=512);
+    ~BlockStorageDevice();
+
+    void set_block_size(const int blk_size) { this->block_size = blk_size; };
+
+    int set_host_file(std::string file_path);
+
+    int set_fpos(const uint32_t lba);
+    int read_begin(int nblocks, uint32_t max_len);
+    int data_left() { return this->remain_size; };
+    int read_more();
+    int write_begin(char *buf, int nblocks);
+
+protected:
+    std::fstream    img_file     = {};
+    uint64_t        size_bytes   = 0;   // image file size in bytes
+    uint64_t        size_blocks  = 0;   // image file size in blocks
+    uint64_t        cur_fpos     = 0;   // current image file pointer position
+    uint32_t        block_size   = 512; // physical block size
+    uint32_t        cache_size   = 0;   // cache size
+    uint32_t        remain_size  = 0;
+    bool            is_writeable = false;
+    bool            is_ready     = false; // ready for operation
+
+    std::unique_ptr<char[]>  data_cache;
+};
+
+#endif // BLOCK_STORAGE_DEVICE_H