1 files changed, 134 insertions, 0 deletions

diff --git a/utils/jztool/src/buffer.c b/utils/jztool/src/buffer.c
new file mode 100644
index 0000000000..9e9c9ff5d1
--- /dev/null
+++ b/utils/jztool/src/buffer.c
@@ -0,0 +1,134 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2021 Aidan MacDonald
+ *
+ * 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 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include "jztool.h"
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+/** \brief Allocate a buffer, optionally providing its contents.
+ * \param size  Number of bytes to allocate
+ * \param data  Initial contents of the buffer, must be at least `size` bytes
+ * \return Pointer to buffer or NULL if out of memory.
+ * \note The buffer will not take ownership of the `data` pointer, instead it
+ *       allocates a fresh buffer and copies the contents of `data` into it.
+ */
+jz_buffer* jz_buffer_alloc(size_t size, const void* data)
+{
+    jz_buffer* buf = malloc(sizeof(struct jz_buffer));
+    if(!buf)
+        return NULL;
+
+    buf->data = malloc(size);
+    if(!buf->data) {
+        free(buf);
+        return NULL;
+    }
+
+    if(data)
+        memcpy(buf->data, data, size);
+
+    buf->size = size;
+    return buf;
+}
+
+/** \brief Free a buffer
+ */
+void jz_buffer_free(jz_buffer* buf)
+{
+    if(buf) {
+        free(buf->data);
+        free(buf);
+    }
+}
+
+/** \brief Load a buffer from a file
+ * \param buf       Returns loaded buffer on success, unmodified on error
+ * \param filename  Path to the file
+ * \return either JZ_SUCCESS, or one of the following errors
+ * \retval JZ_ERR_OPEN_FILE     file cannot be opened
+ * \retval JZ_ERR_OUT_OF_MEMORY cannot allocate buffer to hold file contents
+ * \retval JZ_ERR_FILE_IO       problem reading file data
+ */
+int jz_buffer_load(jz_buffer** buf, const char* filename)
+{
+    FILE* f;
+    jz_buffer* b;
+    int rc;
+
+    f = fopen(filename, "rb");
+    if(!f)
+        return JZ_ERR_OPEN_FILE;
+
+    fseek(f, 0, SEEK_END);
+    int size = ftell(f);
+    fseek(f, 0, SEEK_SET);
+
+    b = jz_buffer_alloc(size, NULL);
+    if(!b) {
+        rc = JZ_ERR_OUT_OF_MEMORY;
+        goto err_fclose;
+    }
+
+    if(fread(b->data, size, 1, f) != 1) {
+        rc = JZ_ERR_FILE_IO;
+        goto err_free_buf;
+    }
+
+    rc = JZ_SUCCESS;
+    *buf = b;
+
+  err_fclose:
+    fclose(f);
+    return rc;
+
+  err_free_buf:
+    jz_buffer_free(b);
+    goto err_fclose;
+}
+
+/** \brief Save a buffer to a file
+ * \param buf       Buffer to be written out
+ * \param filename  Path to the file
+ * \return either JZ_SUCCESS, or one of the following errors
+ * \retval JZ_ERR_OPEN_FILE     file cannot be opened
+ * \retval JZ_ERR_FILE_IO       problem writing file data
+ */
+int jz_buffer_save(jz_buffer* buf, const char* filename)
+{
+    int rc;
+    FILE* f;
+
+    f = fopen(filename, "wb");
+    if(!f)
+        return JZ_ERR_OPEN_FILE;
+
+    if(fwrite(buf->data, buf->size, 1, f) != 1) {
+        rc = JZ_ERR_FILE_IO;
+        goto err_fclose;
+    }
+
+    rc = JZ_SUCCESS;
+
+  err_fclose:
+    fclose(f);
+    return rc;
+}