fygue: support read() primitive

CMakeLists.txt

@@ -271,6 +271,7 @@ set(SOURCES
   src/fs/fygue/fygue_file_lseek.c
   src/fs/fygue/fygue_file_write.c
   src/fs/fygue/fygue_file_close.c
+  src/fs/fygue/fygue_file_read.c
   src/fs/fygue/fat/cluster.c
   src/fs/fygue/fat/initialize.c
   src/fs/fygue/fat/fat_dir_read.c
@@ -278,6 +279,8 @@ set(SOURCES
   src/fs/fygue/fat/fat_dir_stat.c
   src/fs/fygue/fat/fat_file_stat.c
   src/fs/fygue/fat/fat_file_close.c
+  src/fs/fygue/fat/fat_file_read.c
+  src/fs/fygue/fat/fat_file_seek.c
   src/fs/fygue/fat/resolve.c
   src/fs/fygue/fat/sector.c
   src/fs/fygue/flash/cluster.c

src/fs/fygue/fat/fat.h

@@ -89,6 +89,8 @@ struct fygue_fat_file
         int cluster_count;
     } *chunk;
     int chunk_count;
+    int chunk_rd_index;
+    int chunk_rd_offset;
 };
 
 /* fygue_fat_resolve: internal resolve information */
@@ -145,14 +147,29 @@ extern int fygue_fat_dir_stat(
 // File interface
 //---
 
-/* fygue_fat_file_stat(): directory stat primitive */
+/* fygue_fat_file_read(): read primitive */
+extern int fygue_fat_file_read(
+    struct fygue_fat *fat,
+    struct fygue_fat_file *file,
+    void *buffer,
+    size_t size
+);
+
+/* fygue_fat_file_stat(): stat primitive */
 extern int fygue_fat_file_stat(
     struct fygue_fat *fat,
     struct fygue_fat_file *file,
     struct stat *statbuf
 );
 
-/* fygue_fat_file_close(): closedir primitive */
+/* fygue_fat_file_seek(): lseek primitive */
+extern int fygue_fat_file_seek(
+    struct fygue_fat *fat,
+    struct fygue_fat_file *file,
+    off_t offset
+);
+
+/* fygue_fat_file_close(): close primitive */
 extern int fygue_fat_file_close(
     struct fygue_fat *fat,
     struct fygue_fat_file *dir

src/fs/fygue/fat/fat_file_read.c

@@ -0,0 +1,47 @@
+#include <errno.h>
+#include <string.h>
+#include "fat.h"
+
+/* fygue_fat_file_read(): read primitive */
+int fygue_fat_file_read(
+    struct fygue_fat *fat,
+    struct fygue_fat_file *file,
+    void *buffer,
+    size_t size
+) {
+    void *chunk_data_addr;
+    size_t chunk_data_available;
+    size_t chunk_data_offset;
+    size_t read;
+
+    if (fat == NULL || file == NULL || buffer == NULL) {
+        errno = EIO;
+        return -1;
+    }
+    if (file->chunk == NULL) {
+        errno = EIO;
+        return -1;
+    }
+    read = 0;
+    chunk_data_offset = file->chunk_rd_offset;
+    while (read < size)
+    {
+        if (file->chunk_rd_index >= file->chunk_count)
+            break;
+        chunk_data_addr = (void*)file->chunk[file->chunk_rd_index].addr;
+        chunk_data_available  = file->chunk[file->chunk_rd_index].size;
+        chunk_data_available -= chunk_data_offset;
+        if (read + chunk_data_available > size)
+        {
+            chunk_data_offset = size - read;
+            memcpy(buffer, chunk_data_addr, chunk_data_offset);
+            break;
+        }
+        memcpy(buffer, chunk_data_addr, chunk_data_available);
+        read += chunk_data_available;
+        file->chunk_rd_index += 1;
+        chunk_data_offset = 0;
+    }
+    file->chunk_rd_offset = chunk_data_offset;
+    return read;
+}

src/fs/fygue/fat/fat_file_seek.c

@@ -0,0 +1,30 @@
+#include <errno.h>
+#include "fat.h"
+
+/* fygue_fat_file_seek(): seek primitive */
+int fygue_fat_file_seek(
+    struct fygue_fat *fat,
+    struct fygue_fat_file *file,
+    off_t offset
+) {
+    off_t offset_test;
+
+    if (fat == NULL || file == NULL) {
+        errno = EIO;
+        return -1;
+    }
+    offset_test = 0;
+    file->chunk_rd_index = 0;
+    file->chunk_rd_offset = 0;
+    for (int i = 0; i < file->chunk_count; i++)
+    {
+        offset_test += file->chunk[i].size;
+        if (offset_test > offset) {
+            file->chunk_rd_offset = offset - offset_test;
+            return 0;
+        }
+        file->chunk_rd_index += 1;
+    }
+    errno = EIO;
+    return -1;
+}

src/fs/fygue/fygue.c

@@ -84,7 +84,7 @@ int fygue_resolve(char const * const path, struct fygue_resolve *resolve)
 //---
 
 const fs_descriptor_type_t fygue_descriptor_type = {
-    .read   = NULL,
+    .read   = (void*)&fygue_file_read,
     .write  = (void*)&fygue_file_write,
     .lseek  = (void*)&fygue_file_lseek,
     .close  = (void*)&fygue_file_close,

src/fs/fygue/fygue.h

@@ -114,7 +114,7 @@ extern off_t fygue_dir_lseek(
 );
 
 /* fygue_dir_write(): write directory (EISDIR) */
-ssize_t fygue_dir_write(
+extern ssize_t fygue_dir_write(
     struct fygue_descriptor *desc,
     void *buffer,
     size_t size
@@ -127,6 +127,13 @@ extern int fygue_dir_close(struct fygue_descriptor *desc);
 // File interface
 //---
 
+/* fygue_file_read(): read primitive */
+extern ssize_t fygue_file_read(
+    struct fygue_descriptor *desc,
+    void *buffer,
+    size_t size
+);
+
 /* fygue_file_lseek(): seek directory */
 extern off_t fygue_file_lseek(
     struct fygue_descriptor *desc,

src/fs/fygue/fygue_dir_read.c

@@ -24,7 +24,7 @@ static int _fygue_dir_fat_read(
 
     rc = fygue_fat_dir_read(
         &(fsinfo->fat),
-        &desc->resolve.dir.fat,
+        &(desc->resolve.dir.fat),
         &fat_dirent
     );
     if (rc <= -3)

src/fs/fygue/fygue_file_lseek.c

@@ -6,6 +6,8 @@ off_t fygue_file_lseek(
     off_t offset,
     int whence
 ) {
+    struct fygue_fsinfo *fsinfo;
+
     ENOTSUP_IF_NOT_FYGUE(-1);
     if (desc == NULL || desc->resolve.type != FYGUE_FILE_TYPE_FILE) {
         errno = EBADF;
@@ -15,6 +17,10 @@ off_t fygue_file_lseek(
         errno = EINVAL;
         return -1;
     }
+    if (fygue_mount(&fsinfo, true) != 0) {
+        errno = EIO;
+        return -1;
+    }
     if(whence == SEEK_CUR)
         offset += desc->resolve.dir.pos;
     if(whence == SEEK_END)
@@ -24,5 +30,10 @@ off_t fygue_file_lseek(
         return -1;
     }
     desc->resolve.file.cursor = offset;
+    fygue_fat_file_seek(
+        &(fsinfo->fat),
+        &(desc->resolve.file.fat),
+        offset
+    );
     return desc->resolve.file.cursor;
 }

src/fs/fygue/fygue_file_read.c

@@ -0,0 +1,32 @@
+#include <stdlib.h>
+#include <string.h>
+#include "fygue.h"
+
+/* fygue_file_read(): write directory (EISDIR) */
+ssize_t fygue_file_read(
+    struct fygue_descriptor *desc,
+    void *buffer,
+    size_t size
+) {
+    struct fygue_fsinfo *fsinfo;
+
+    ENOTSUP_IF_NOT_FYGUE(-1);
+    if (desc == NULL || desc->resolve.type != FYGUE_FILE_TYPE_FILE) {
+        errno = EBADF;
+        return -1;
+    }
+    if (buffer == NULL) {
+        errno = EFAULT;
+        return -1;
+    }
+    if (fygue_mount(&fsinfo, true) != 0) {
+        errno = EIO;
+        return -1;
+    }
+    return fygue_fat_file_read(
+        &(fsinfo->fat),
+        &(desc->resolve.file.fat),
+        buffer,
+        size
+    );
+}