On 01/13/2014 08:27 PM, Paul Berry wrote:
On 2 January 2014 03:58, Tapani Pälli <tapani.pa...@intel.com
<mailto:tapani.pa...@intel.com>> wrote:
Class will be used by the shader binary cache implementation.
Signed-off-by: Tapani Pälli <tapani.pa...@intel.com
<mailto:tapani.pa...@intel.com>>
---
src/glsl/memory_writer.h | 147
+++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 147 insertions(+)
create mode 100644 src/glsl/memory_writer.h
diff --git a/src/glsl/memory_writer.h b/src/glsl/memory_writer.h
new file mode 100644
index 0000000..a6c6b55
--- /dev/null
+++ b/src/glsl/memory_writer.h
@@ -0,0 +1,147 @@
+/* -*- c++ -*- */
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person
obtaining a
+ * copy of this software and associated documentation files (the
"Software"),
+ * to deal in the Software without restriction, including without
limitation
+ * the rights to use, copy, modify, merge, publish, distribute,
sublicense,
+ * and/or sell copies of the Software, and to permit persons to
whom the
+ * Software is furnished to do so, subject to the following
conditions:
+ *
+ * The above copyright notice and this permission notice
(including the next
+ * paragraph) shall be included in all copies or substantial
portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO
EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#pragma once
+#ifndef MEMORY_WRITER_H
+#define MEMORY_WRITER_H
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#ifdef __cplusplus
+/**
+ * Helper class for writing data to memory
+ *
+ * This class maintains a dynamically-sized memory buffer and allows
+ * for data to be efficiently appended to it with automatic resizing.
+ */
+class memory_writer
+{
+public:
+ memory_writer() :
+ memory(NULL),
+ curr_size(0),
+ pos(0) {}
+
+ ~memory_writer()
+ {
+ free(memory);
+ }
+
+ /* user wants to claim the memory */
+ char *release_memory(size_t *size)
+ {
+ /* final realloc to free allocated but unused memory */
+ char *result = (char *) realloc(memory, pos);
+ *size = pos;
+ memory = NULL;
+ curr_size = 0;
+ pos = 0;
+ return result;
+ }
+
+/**
+ * write functions per type
+ */
+#define DECL_WRITER(type) int write_ ##type (const type data) {\
+ return write(&data, sizeof(type));\
+}
+
+ DECL_WRITER(int32_t);
+ DECL_WRITER(int64_t);
+ DECL_WRITER(uint8_t);
+ DECL_WRITER(uint32_t);
+
+ int write_bool(bool data)
+ {
+ uint8_t val = data;
+ return write_uint8_t(val);
+ }
+
+ /* write function that reallocates more memory if required */
+ int write(const void *data, int32_t size)
+ {
+ if (!memory || pos > (int32_t)(curr_size - size))
+ if (grow(size))
+ return -1;
+
+ memcpy(memory + pos, data, size);
+
+ pos += size;
+ return 0;
+ }
+
+ int overwrite(const void *data, int32_t size, int32_t offset)
+ {
+ if (offset < 0 || offset + size > pos)
+ return -1;
+ memcpy(memory + offset, data, size);
+ return 0;
+ }
+
+ int write_string(const char *str)
+ {
+ if (!str)
+ return -1;
+ char terminator = '\0';
+ write(str, strlen(str));
+ write(&terminator, 1);
C strings include a terminator, so there's no reason to write out the
string contents and the terminator separtely. You can just do:
write(str, strlen(str) + 1);
Also, don't forget to propagate the return code to the caller:
return write(str, strlen(str) + 1);
Ah right, will do. It could be that this needs to be modified back to
how it was though (to write to length of the string too). I think it is
otherwise impossible for the reader side to know if terminator really
exists and it might continue to read forever (or call strlen for
unterminated string).
+ return 0;
+ }
+
+ inline int32_t position() { return pos; }
+
+
+private:
+
+ /* reallocate more memory */
+ int grow(int32_t size)
+ {
+ int32_t new_size = 2 * (curr_size + size);
+ char *more_mem = (char *) realloc(memory, new_size);
+ if (more_mem == NULL) {
+ free(memory);
+ memory = NULL;
+ return -1;
+ } else {
+ memory = more_mem;
+ curr_size = new_size;
+ return 0;
+ }
+ }
+
+ /* allocated memory */
+ char *memory;
+
+ /* current size of the whole allocation */
+ int32_t curr_size;
+
+ /* write position / size of the data written */
+ int32_t pos;
+};
+
+#endif /* ifdef __cplusplus */
+
+#endif /* MEMORY_WRITER_H */
--
1.8.3.1
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