inputstream.h

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/*
 * This file is part of LibParserUtils.
 * Licensed under the MIT License,
 *                http://www.opensource.org/licenses/mit-license.php
 * Copyright 2007 John-Mark Bell <jmb@netsurf-browser.org>
 */

#ifndef parserutils_input_inputstream_h_
#define parserutils_input_inputstream_h_

#ifdef __cplusplus
extern "C"
{
#endif

#include <stdbool.h>
#ifndef NDEBUG
#include <stdio.h>
#endif
#include <stdlib.h>
#include <inttypes.h>

#include <parserutils/errors.h>
#include <parserutils/functypes.h>
#include <parserutils/types.h>
#include <parserutils/charset/utf8.h>
#include <parserutils/utils/buffer.h>

typedef parserutils_error (*parserutils_charset_detect_func)(
                const uint8_t *data, size_t len, 
                uint16_t *mibenum, uint32_t *source);

typedef struct parserutils_inputstream 
{
        parserutils_buffer *utf8;       
        uint32_t cursor;                
        bool had_eof;                   
} parserutils_inputstream;

/* Create an input stream */
parserutils_error parserutils_inputstream_create(const char *enc,
                uint32_t encsrc, parserutils_charset_detect_func csdetect,
                parserutils_inputstream **stream);
/* Destroy an input stream */
parserutils_error parserutils_inputstream_destroy(
                parserutils_inputstream *stream);

/* Append data to an input stream */
parserutils_error parserutils_inputstream_append(
                parserutils_inputstream *stream,
                const uint8_t *data, size_t len);
/* Insert data into stream at current location */
parserutils_error parserutils_inputstream_insert(
                parserutils_inputstream *stream,
                const uint8_t *data, size_t len);

/* Slow form of css_inputstream_peek. */
parserutils_error parserutils_inputstream_peek_slow(
                parserutils_inputstream *stream, 
                size_t offset, const uint8_t **ptr, size_t *length);

static inline parserutils_error parserutils_inputstream_peek(
                parserutils_inputstream *stream, size_t offset, 
                const uint8_t **ptr, size_t *length)
{
        parserutils_error error = PARSERUTILS_OK;
        const parserutils_buffer *utf8;
        const uint8_t *utf8_data;
        size_t len, off, utf8_len;

        if (stream == NULL || ptr == NULL || length == NULL)
                return PARSERUTILS_BADPARM;

#ifndef NDEBUG
#ifdef VERBOSE_INPUTSTREAM
        fprintf(stdout, "Peek: len: %zu cur: %u off: %zu\n",
                        stream->utf8->length, stream->cursor, offset);
#endif
#ifdef RANDOMISE_INPUTSTREAM
        parserutils_buffer_randomise(stream->utf8);
#endif
#endif

        utf8 = stream->utf8;
        utf8_data = utf8->data;
        utf8_len = utf8->length;
        off = stream->cursor + offset;

#define IS_ASCII(x) (((x) & 0x80) == 0)

        if (off < utf8_len) {
                if (IS_ASCII(utf8_data[off])) {
                        /* Early exit for ASCII case */
                        (*length) = 1;
                        (*ptr) = (utf8_data + off);
                        return PARSERUTILS_OK;
                } else {
                        error = parserutils_charset_utf8_char_byte_length(
                                utf8_data + off, &len);

                        if (error == PARSERUTILS_OK) {
                                (*length) = len;
                                (*ptr) = (utf8_data + off);
                                return PARSERUTILS_OK;
                        } else if (error != PARSERUTILS_NEEDDATA) {
                                return error;
                        }
                }
        }

#undef IS_ASCII

        return parserutils_inputstream_peek_slow(stream, offset, ptr, length);
}

static inline void parserutils_inputstream_advance(
                parserutils_inputstream *stream, size_t bytes)
{
        if (stream == NULL)
                return;

#if !defined(NDEBUG) && defined(VERBOSE_INPUTSTREAM)
        fprintf(stdout, "Advance: len: %zu cur: %u bytes: %zu\n",
                        stream->utf8->length, stream->cursor, bytes);
#endif

        if (bytes > stream->utf8->length - stream->cursor)
                bytes = stream->utf8->length - stream->cursor;

        if (stream->cursor == stream->utf8->length)
                return;

        stream->cursor += bytes;
}

/* Read the document charset */
const char *parserutils_inputstream_read_charset(
                parserutils_inputstream *stream, uint32_t *source);
/* Change the document charset */
parserutils_error parserutils_inputstream_change_charset(
                parserutils_inputstream *stream, 
                const char *enc, uint32_t source);

#ifdef __cplusplus
}
#endif

#endif