From 2777a04ed2ba4fd36138b991d66a32a283361f7e Mon Sep 17 00:00:00 2001
From: John Mark Bell <jmb@netsurf-browser.org>
Date: Thu, 1 May 2008 16:34:46 +0000
Subject: Import parser construction utility library

svn path=/trunk/libparserutils/; revision=4111
---
 src/utils/buffer.c | 156 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)
 create mode 100644 src/utils/buffer.c

(limited to 'src/utils/buffer.c')

diff --git a/src/utils/buffer.c b/src/utils/buffer.c
new file mode 100644
index 0000000..21c47fc
--- /dev/null
+++ b/src/utils/buffer.c
@@ -0,0 +1,156 @@
+/*
+ * This file is part of LibParserUtils.
+ * Licensed under the MIT License,
+ *                http://www.opensource.org/licenses/mit-license.php
+ * Copyright 2008 John-Mark Bell <jmb@netsurf-browser.org>
+ */
+
+#include <string.h>
+
+#include <parserutils/utils/buffer.h>
+
+#define DEFAULT_SIZE (4096)
+
+/**
+ * Create a memory buffer
+ *
+ * \param alloc  Memory (de)allocation function
+ * \param pw     Pointer to client-specific private data
+ * \return Pointer to memory buffer, or NULL on memory exhaustion
+ */
+parserutils_buffer *parserutils_buffer_create(parserutils_alloc alloc, void *pw)
+{
+	parserutils_buffer *buffer = 
+			alloc(NULL, sizeof(parserutils_buffer), pw);
+
+	if (buffer == NULL)
+		return NULL;
+
+	buffer->data = alloc(NULL, DEFAULT_SIZE, pw);
+	if (buffer->data == NULL) {
+		alloc(buffer, 0, pw);
+		return NULL;
+	}
+
+	buffer->length = 0;
+	buffer->allocated = DEFAULT_SIZE;
+
+	buffer->alloc = alloc;
+	buffer->pw = pw;
+
+	return buffer;
+}
+
+/**
+ * Destroy a memory buffer
+ *
+ * \param buffer  The buffer to destroy
+ */
+void parserutils_buffer_destroy(parserutils_buffer *buffer)
+{
+	if (buffer == NULL)
+		return;
+
+	buffer->alloc(buffer->data, 0, buffer->pw);
+	buffer->alloc(buffer, 0, buffer->pw);
+}
+
+/**
+ * Append data to a memory buffer
+ *
+ * \param buffer  The buffer to append to
+ * \param data    The data to append
+ * \param len     The length, in bytes, of the data to append
+ * \return PARSERUTILS_OK on success, appropriate error otherwise.
+ */
+parserutils_error parserutils_buffer_append(parserutils_buffer *buffer, 
+		const uint8_t *data, size_t len)
+{
+	while (len >= buffer->allocated - buffer->length) {
+		parserutils_error error = parserutils_buffer_grow(buffer);
+		if (error != PARSERUTILS_OK)
+			return error;
+	}
+
+	memcpy(buffer->data + buffer->length, data, len);
+
+	buffer->length += len;
+
+	return PARSERUTILS_OK;
+}
+
+/**
+ * Insert data into a memory buffer
+ *
+ * \param buffer  The buffer to insert into
+ * \param offset  The offset into the buffer to insert at
+ * \param data    The data to insert
+ * \param len     The length, in bytes, of the data to insert
+ * \return PARSERUTILS_OK on success, appropriate error otherwise
+ */
+parserutils_error parserutils_buffer_insert(parserutils_buffer *buffer, 
+		size_t offset, const uint8_t *data, size_t len)
+{
+	if (offset > buffer->length)
+		return PARSERUTILS_BADPARM;
+
+	if (offset == buffer->length)
+		return parserutils_buffer_append(buffer, data, len);
+
+	while (len >= buffer->allocated - buffer->length) {
+		parserutils_error error = parserutils_buffer_grow(buffer);
+		if (error != PARSERUTILS_OK)
+			return error;
+	}
+
+	memmove(buffer->data + buffer->length + len, 
+			buffer->data + offset, buffer->length - offset);
+
+	memcpy(buffer->data + offset, data, len);
+
+	buffer->length += len;
+
+	return PARSERUTILS_OK;
+}
+
+/**
+ * Discard a section of a memory buffer
+ *
+ * \param buffer  The buffer to discard data from
+ * \param offset  The offset into the buffer of the start of the section
+ * \param len     The number of bytes to discard
+ * \return PARSERUTILS_OK on success, appropriate error otherwise.
+ */
+parserutils_error parserutils_buffer_discard(parserutils_buffer *buffer, 
+		size_t offset, size_t len)
+{
+	if (offset >= buffer->length || offset + len > buffer->length)
+		return PARSERUTILS_BADPARM;
+
+	memmove(buffer->data + offset, buffer->data + offset + len, 
+			buffer->length - len);
+
+	buffer->length -= len;
+
+	return PARSERUTILS_OK;
+}
+
+/**
+ * Extend the amount of space allocated for a memory buffer
+ *
+ * \param buffer  The buffer to extend
+ * \return PARSERUTILS_OK on success, appropriate error otherwise.
+ */
+parserutils_error parserutils_buffer_grow(parserutils_buffer *buffer)
+{
+	uint8_t *temp = buffer->alloc(buffer->data, 
+			buffer->allocated * 2, buffer->pw);
+	if (temp == NULL)
+		return PARSERUTILS_NOMEM;
+
+	buffer->data = temp;
+	buffer->allocated *= 2;
+
+	return PARSERUTILS_OK;
+}
+
-- 
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