1 files changed, 155 insertions, 0 deletions
diff --git a/include/orcus/parser_base.hpp b/include/orcus/parser_base.hpp
new file mode 100644
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+++ b/include/orcus/parser_base.hpp
@@ -0,0 +1,155 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef INCLUDED_ORCUS_PARSER_BASE_HPP
+#define INCLUDED_ORCUS_PARSER_BASE_HPP
+
+#include "env.hpp"
+#include "exception.hpp"
+
+#include <string>
+#include <cstdlib>
+#include <cstddef>
+#include <cassert>
+#include <functional>
+
+namespace orcus {
+
+class ORCUS_PSR_DLLPUBLIC parser_base
+{
+protected:
+    using numeric_parser_type = std::function<const char*(const char*, const char*, double&)>;
+
+    const char* const mp_begin;
+    const char* mp_char;
+    const char* mp_end;
+
+private:
+    numeric_parser_type m_func_parse_numeric;
+
+protected:
+    parser_base(const char* p, size_t n);
+
+    void set_numeric_parser(const numeric_parser_type& func)
+    {
+        m_func_parse_numeric = func;
+    }
+
+    bool has_char() const
+    {
+        assert(mp_char <= mp_end);
+        return mp_char != mp_end;
+    }
+
+    bool has_next() const
+    {
+        assert((mp_char+1) <= mp_end);
+        return (mp_char+1) != mp_end;
+    }
+
+    void next(size_t inc=1) { mp_char += inc; }
+
+    void prev(size_t dec=1);
+
+    char cur_char() const { return *mp_char; }
+
+    /**
+     * Peek a character at specified offset from the current position without
+     * advancing the current position.
+     *
+     * @note The caller <strong>must</strong> ensure that the specified offset
+     *       position is a valid position.  This method does not check its
+     *       validity.
+     *
+     * @param offset offset from the current position to peek at.
+     *
+     * @return character at a specified offset position from the current
+     *         position.
+     */
+    char peek_char(std::size_t offset=1) const;
+
+    /**
+     * Peek a segment of contiguous characters of a specified length starting
+     * from the current position.
+     *
+     * @note The caller <strong>must</strong> ensure that the specified
+     *       substring segment is entirely valid.  This method does not check
+     *       its validity.
+     *
+     * @param length length of the segment to peek.
+     *
+     * @return segment of contiguous characters.
+     */
+    std::string_view peek_chars(std::size_t length) const;
+
+    /**
+     * Skip an optional byte order mark at the current position of the stream.
+     *
+     * Currently we only check for UTF-8 BOM.
+     */
+    void skip_bom();
+
+    void skip(std::string_view chars_to_skip);
+
+    /**
+     * Skip all characters that are 0-32 in ASCII range
+     */
+    void skip_space_and_control();
+
+    /**
+     * Parse and check next characters to see if it matches specified
+     * character sequence.
+     *
+     * @param expected sequence of characters to match against.
+     *
+     * @return true if it matches specified character sequence, false
+     *         otherwise.
+     */
+    bool parse_expected(std::string_view expected);
+
+    /**
+     * Try to parse the next characters as double, or return NaN in case of
+     * failure.
+     *
+     * @return double value on success, or NaN on failure.
+     */
+    double parse_double();
+
+    /**
+     * Determine the number of characters remaining <strong>after</strong> the
+     * current character.  For instance, if the current character is on the
+     * last character in the stream, this method will return 0, whereas if
+     * it's on the first character, it will return the total length - 1.
+     *
+     * @return number of characters remaining after the current character.
+     */
+    size_t remaining_size() const;
+
+    /**
+     * Determine the number of characters available from the current character
+     * to the end of the buffer.  The current character is included.
+     *
+     * @return number of characters available including the current character.
+     */
+    size_t available_size() const
+    {
+        return std::distance(mp_char, mp_end);
+    }
+
+    /**
+     * Return the current offset from the beginning of the character stream.
+     *
+     * @return current offset from the beginning of the character stream.
+     */
+    std::ptrdiff_t offset() const;
+};
+
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */