Diff: SemihostedFileSystem.cpp

Revision:

0:d5e731da01f0

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SemihostedFileSystem.cpp	Wed Oct 11 23:14:14 2017 +0000
@@ -0,0 +1,179 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "SemihostedFileSystem.h"
+#include "mbed_semihost_api_shim.h"
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <cstdarg>
+
+#define STRING_STACK_LIMIT    120
+
+#define OPEN_R          0
+#define OPEN_B          1
+#define OPEN_PLUS       2
+#define OPEN_W          4
+#define OPEN_A          8
+#define OPEN_INVALID   -1
+
+static int posix_to_semihost_open_flags(int flags) {
+    /* POSIX flags -> semihosting open mode */
+    int openmode;
+    if (flags & O_RDWR) {
+        /* a plus mode */
+        openmode = OPEN_PLUS;
+        if (flags & O_APPEND) {
+            openmode |= OPEN_A;
+        } else if (flags & O_TRUNC) {
+            openmode |= OPEN_W;
+        } else {
+            openmode |= OPEN_R;
+        }
+    } else if (flags & O_WRONLY) {
+        /* write or append */
+        if (flags & O_APPEND) {
+            openmode = OPEN_A;
+        } else {
+            openmode = OPEN_W;
+        }
+    } else if (flags == O_RDONLY) {
+        /* read mode */
+        openmode = OPEN_R;
+    } else {
+        /* invalid flags */
+        openmode = OPEN_INVALID;
+    }
+
+    return openmode;
+}
+
+FILEHANDLE semihosted_file_open(const char* name, int flags) {
+    int openmode = posix_to_semihost_open_flags(flags);
+    if (openmode == OPEN_INVALID) {
+        return (FILEHANDLE)NULL;
+    }
+
+    FILEHANDLE fh = semihost_open(name, openmode);
+    if (fh == -1) {
+        return (FILEHANDLE)NULL;
+    }
+
+    return fh;
+}
+
+SemihostedFileHandle::SemihostedFileHandle(FILEHANDLE fh) : _fh(fh), pos(0) {
+    // No lock needed in constructor
+}
+
+SemihostedFileHandle::SemihostedFileHandle(const char* name, int flags)
+    : _fh(semihosted_file_open(name, flags)), pos(0) {
+    // No lock needed in constructor
+}
+
+int SemihostedFileHandle::close() {
+    int retval = semihost_close(_fh);
+    delete this;
+    return retval;
+}
+
+ssize_t SemihostedFileHandle::write(const void *buffer, size_t length) {
+    lock();
+    ssize_t n = semihost_write(_fh, (const unsigned char*)buffer, length, 0); // number of characters not written
+    n = length - n; // number of characters written
+    pos += n;
+    unlock();
+    return n;
+}
+
+ssize_t SemihostedFileHandle::read(void *buffer, size_t length) {
+    lock();
+    ssize_t n = semihost_read(_fh, (unsigned char*)buffer, length, 0); // number of characters not read
+    n = length - n; // number of characters read
+    pos += n;
+    unlock();
+    return n;
+}
+
+int SemihostedFileHandle::isatty() {
+    lock();
+    int ret = semihost_istty(_fh);
+    unlock();
+    return ret;
+}
+
+off_t SemihostedFileHandle::seek(off_t position, int whence) {
+    lock();
+    if (whence == SEEK_CUR) {
+        position += pos;
+    } else if (whence == SEEK_END) {
+        position += semihost_flen(_fh);
+    } /* otherwise SEEK_SET, so position is fine */
+
+    /* Always seems to return -1, so just ignore for now. */
+    semihost_seek(_fh, position);
+    pos = position;
+    unlock();
+    return position;
+}
+
+int SemihostedFileHandle::sync() {
+    lock();
+    int ret = semihost_ensure(_fh);
+    unlock();
+    return ret;
+}
+
+off_t SemihostedFileHandle::size() {
+    lock();
+    off_t off = semihost_flen(_fh);
+    unlock();
+    return off;
+}
+
+void SemihostedFileHandle::lock() {
+    _mutex.lock();
+}
+
+void SemihostedFileHandle::unlock() {
+    _mutex.unlock();
+}
+
+// Experimental support for printf in RawSerial. No Stream inheritance
+// means we can't call printf() directly, so we use sprintf() instead.
+// We only call malloc() for the sprintf() buffer if the buffer
+// length is above a certain threshold, otherwise we use just the stack.
+int SemihostedFileHandle::printf(const char *format, ...) {
+    lock();
+    std::va_list arg;
+    va_start(arg, format);
+    // ARMCC microlib does not properly handle a size of 0.
+    // As a workaround supply a dummy buffer with a size of 1.
+    char dummy_buf[1];
+    int len = vsnprintf(dummy_buf, sizeof(dummy_buf), format, arg);
+    if (len < STRING_STACK_LIMIT) {
+        char temp[STRING_STACK_LIMIT];
+        vsprintf(temp, format, arg);
+        write(temp, len);
+    } else {
+        char *temp = new char[len + 1];
+        vsprintf(temp, format, arg);
+        write(temp, len);
+        delete[] temp;
+    }
+    va_end(arg);
+    unlock();
+    return len;
+}
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