/**

 * vim: set ts=4 :

 * =============================================================================

 * SourceMod

 * Copyright (C) 2004-2007 AlliedModders LLC.  All rights reserved.

 * =============================================================================

 *

 * This program is free software; you can redistribute it and/or modify it under

 * the terms of the GNU General Public License, version 3.0, as published by the

 * Free Software Foundation.

 * 

 * This program is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more

 * details.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 * As a special exception, AlliedModders LLC gives you permission to link the

 * code of this program (as well as its derivative works) to "Half-Life 2," the

 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

 * by the Valve Corporation.  You must obey the GNU General Public License in

 * all respects for all other code used.  Additionally, AlliedModders LLC grants

 * this exception to all derivative works.  AlliedModders LLC defines further

 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

 * or <http://www.sourcemod.net/license.php>.

 *

 * Version: $Id$

 */

#include <stdio.h>

#include <ctype.h>

#include <wctype.h>

#include <string.h>

#include <stdlib.h>

#include <assert.h>

#include "TextParsers.h"

#include "ShareSys.h"

#include "sm_stringutil.h"

#include "LibrarySys.h"

TextParsers g_TextParser;

ITextParsers *textparsers = &g_TextParser;

static int g_ini_chartable1[255] = {0};

static int g_ws_chartable[255] = {0};

bool TextParsers::IsWhitespace(const char *stream)

{

	return g_ws_chartable[(unsigned)*stream] == 1;

}

TextParsers::TextParsers()

{

	g_ini_chartable1[(unsigned)'_'] = 1;

	g_ini_chartable1[(unsigned)'-'] = 1;

	g_ini_chartable1[(unsigned)','] = 1;

	g_ini_chartable1[(unsigned)'+'] = 1;

	g_ini_chartable1[(unsigned)'.'] = 1;

	g_ini_chartable1[(unsigned)'$'] = 1;

	g_ini_chartable1[(unsigned)'?'] = 1;

	g_ini_chartable1[(unsigned)'/'] = 1;

	g_ws_chartable[(unsigned)'\n'] = 1;

	g_ws_chartable[(unsigned)'\v'] = 1;

	g_ws_chartable[(unsigned)'\r'] = 1;

	g_ws_chartable[(unsigned)'\t'] = 1;

	g_ws_chartable[(unsigned)'\f'] = 1;

	g_ws_chartable[(unsigned)' '] = 1;

}

void TextParsers::OnSourceModAllInitialized()

{

	g_ShareSys.AddInterface(NULL, this);

}

unsigned int TextParsers::GetUTF8CharBytes(const char *stream)

{

	return _GetUTF8CharBytes(stream);

}

/**

 * Character streams

 */

struct CharStream

{

	const char *curpos;

};

bool CharStreamReader(void *stream, char *buffer, size_t maxlength, unsigned int *read)

{

	CharStream *srdr = (CharStream *)stream;

	const char *ptr = srdr->curpos;

	for (size_t i=0; i<maxlength; i++)

	{

		if (*ptr == '\0')

		{

			break;

		}

		*buffer++ = *ptr++;

	}

	*read = ptr - srdr->curpos;

	srdr->curpos = ptr;

	return true;

}

SMCError TextParsers::ParseString_SMC(const char *stream, 

					 ITextListener_SMC *smc,

					 SMCStates *states)

{

	CharStream srdr = { stream };

	return ParseStream_SMC(&srdr, CharStreamReader, smc, states);

}

/**

 * File streams

 */

bool FileStreamReader(void *stream, char *buffer, size_t maxlength, unsigned int *read)

{

	size_t num = fread(buffer, 1, maxlength, (FILE *)stream);

	*read = static_cast<unsigned int>(num);

	if (num == 0 && feof((FILE *)stream))

	{

		return true;

	}

	return (ferror((FILE *)stream) == 0);

}

SMCError TextParsers::ParseFile_SMC(const char *file, ITextListener_SMC *smc, SMCStates *states)

{

	FILE *fp = fopen(file, "rt");

	if (!fp)

	{

		if (states != NULL)

		{

			states->line = 0;

			states->col = 0;

		}

		return SMCError_StreamOpen;

	}

	SMCError result = ParseStream_SMC(fp, FileStreamReader, smc, states);

	fclose(fp);

	return result;

}

SMCError TextParsers::ParseSMCFile(const char *file,

								   ITextListener_SMC *smc_listener,

								   SMCStates *states,

								   char *buffer,

								   size_t maxsize)

{

	const char *errstr;

	FILE *fp = fopen(file, "rt");

	if (fp == NULL)

	{

		char error[256] = "unknown";

		if (states != NULL)

		{

			states->line = 0;

			states->col = 0;

		}

		g_LibSys.GetPlatformError(error, sizeof(error));

		UTIL_Format(buffer, maxsize, "File could not be opened: %s", error);

		return SMCError_StreamOpen;

	}

	SMCError result = ParseStream_SMC(fp, FileStreamReader, smc_listener, states);

	fclose(fp);

	errstr = GetSMCErrorString(result);

	UTIL_Format(buffer, maxsize, "%s", errstr != NULL ? errstr : "Unknown error");

	return result;

}

/** 

 * Raw parsing of streams with helper functions

 */

struct StringInfo

{

	StringInfo() : quoted(false), ptr(NULL), end(NULL), special(false) { }

	bool quoted;

	char *ptr;

	char *end;

	bool special;

};

const char *FixupString(StringInfo &data)

{

	if (!data.ptr)

	{

		return NULL;

	}

	if (data.quoted)

	{

		data.ptr++;

	}

#if defined _DEBUG

	else {

		/* A string will never have beginning whitespace because we ignore it in the stream.

		 * Furthermore, if there is trailing whitespace, the end ptr will point to it, so it is valid

		 * to overwrite!  Lastly, the last character must be whitespace or a comment/invalid character.

		 */

 	}

#endif

	/* Do some extra work on strings that have special quoted characters. */

	if (data.special)

	{

		char *outptr = data.ptr;

		size_t len = data.end - data.ptr;

		if (len >= 2)

		{

			for (size_t i=0; i<len; i++)

			{

				if (data.ptr[i] == '\\' && i < len - 1)

				{

					/* Resolve the next character. */

					i++;

					if (data.ptr[i] == 'n')

					{

						data.ptr[i] = '\n';

					} else if (data.ptr[i] == 't') {

						data.ptr[i] = '\t';

					} else if (data.ptr[i] == 'r') {

						data.ptr[i] = '\r';

					} else if (data.ptr[i] != '\\'

						&& data.ptr[i] != '"') {

						/* This character is invalid, so go back one */

						i--;

					}

				}

				*outptr++ = data.ptr[i];

			}

			*outptr = '\0';

		}

	}

	if (data.end)

	{

		*(data.end) = '\0';

	}

	return data.ptr;

}

const char *rotate(StringInfo info[3])

{

	if (info[2].ptr != NULL)

	{

		return info[2].ptr;

	}

	if (info[0].ptr != NULL)

	{

		info[2] = info[1];

		info[1] = info[0];

		info[0] = StringInfo();

	}

	return NULL;

}

void scrap(StringInfo info[3])

{

	info[2] = StringInfo();

	info[1] = StringInfo();

	info[0] = StringInfo();

}

void reloc(StringInfo &data, unsigned int bytes)

{

	if (data.ptr)

	{

		data.ptr -= bytes;

	}

	if (data.end)

	{

		data.end -= bytes;

	}

}

char *lowstring(StringInfo info[3])

{

	for (int i=2; i>=0; i--)

	{

		if (info[i].ptr)

		{

			return info[i].ptr;

		}

	}

	return NULL;

}

SMCError TextParsers::ParseStream_SMC(void *stream, 

								   STREAMREADER srdr, 

								   ITextListener_SMC *smc, 

								   SMCStates *pStates)

{

	char *reparse_point = NULL;

	char in_buf[4096];

	char *parse_point = in_buf;

	char *line_begin = in_buf;

	unsigned int read;

	unsigned int curlevel = 0;

	bool in_quote = false;

	bool ignoring = false;

	bool eol_comment = false;

	bool ml_comment = false;

	unsigned int i;

	SMCError err = SMCError_Okay;

	SMCResult res;

	SMCStates states;

	char c;

	StringInfo strings[3];

	StringInfo emptystring;

	states.line = 1;

	states.col = 0;

	smc->ReadSMC_ParseStart();

	/**

	 * The stream reader reads in as much as it can fill the buffer with.

	 * It then processes the buffer.  If the buffer cannot be fully processed, for example, 

	 * a line is left hanging with no newline, then the contents of the buffer is shifted 

	 * down, and the buffer is filled from the stream reader again.

	 *

	 * What makes this particularly annoying is that we cache pointers everywhere, so when 

	 * the shifting process takes place, all those pointers must be shifted as well.

	 */

	while (srdr(stream, parse_point, sizeof(in_buf) - (parse_point - in_buf) - 1, &read))

	{

		if (!read)

		{

			break;

		}

		/* Check for BOM markings, which is only relevant on the first line.

		 * Not worth it, but it could be moved out of the loop.

		 */

		if (states.line == 1 && 

			in_buf[0] == (char)0xEF && 

			in_buf[1] == (char)0xBB && 

			in_buf[2] == (char)0xBF)

		{

			/* Move EVERYTHING down :\ */

			memmove(in_buf, &in_buf[3], read - 3);

			read -= 3;

		}

		if (reparse_point)

		{

			read += (parse_point - reparse_point);

			parse_point = reparse_point;

			reparse_point = NULL;

		}

		for (i=0; i<read; i++)

		{

			c = parse_point[i];

			if (c == '\n')

			{

				/* If we got a newline, there's a lot of things that could have happened in the interim.

				 * First, let's make sure the staged strings are rotated.

				 */

				if (strings[0].ptr)

				{

					strings[0].end = &parse_point[i];

					if (rotate(strings) != NULL)

					{

						err = SMCError_InvalidTokens;

						goto failed;

					}

				}

				/* Next, let's clear some line-based values that may no longer have meaning */

				eol_comment = false;

				in_quote = false;

				if (ignoring && !ml_comment)

				{

					ignoring = false;

				}

				/* Pass the raw line onto the listener.  We terminate the line so the receiver 

				 * doesn't get tons of useless info.  We restore the newline after.

				 */

				parse_point[i] = '\0';

				if ((res=smc->ReadSMC_RawLine(&states, line_begin)) != SMCResult_Continue)

				{

					err = (res == SMCResult_HaltFail) ? SMCError_Custom : SMCError_Okay;

					goto failed;

				}

				parse_point[i] = '\n';

				/* Now we check the sanity of our staged strings! */

				if (strings[2].ptr)

				{

					if (!curlevel)

					{

						err = SMCError_InvalidProperty1;

						goto failed;

					}

					/* Assume the next string is a property and pass the info on. */

					if ((res=smc->ReadSMC_KeyValue(

						&states,

						FixupString(strings[2]),

						FixupString(strings[1]))) != SMCResult_Continue)

					{

						err = (res == SMCResult_HaltFail) ? SMCError_Custom : SMCError_Okay;

						goto failed;

					}

					scrap(strings);

				}

				/* Change the states for the next line */

				states.col = 0;

				states.line++;

				line_begin = &parse_point[i+1];		//Note: safe because this gets relocated later

			} 

			else if (ignoring) 

			{

				if (in_quote)

				{

					/* If i was 0, we could have reparsed, so make sure there's no buffer underrun */

					if ((&parse_point[i] != in_buf) && c == '"' && parse_point[i-1] != '\\')

					{

						/* If we reached a quote in an ignore phase,

						 * we're staging a string and we must rotate it out.

						 */

						in_quote = false;

						ignoring = false;

						/* Set our info */

						strings[0].end = &parse_point[i];

						strings[0].quoted = true;

						if (rotate(strings) != NULL)

						{

							/* If we rotated too many strings, there was too much crap on one line */

							err = SMCError_InvalidTokens;

							goto failed;

						}

					} 

					else if (c == '\\') 

					{

						strings[0].special = true;

						if (i == (read - 1))

						{

							reparse_point = &parse_point[i];

							break;

						}

					}

				} 

				else if (ml_comment) 

				{

					if (c == '*')

					{

						/* Check if we need to get more input first */

						if (i == read - 1)

						{

							reparse_point = &parse_point[i];

							break;

						}

						if (parse_point[i+1] == '/')

						{

							ml_comment = false;

							ignoring = false;

							/* We should not be staging anything right now. */

							assert(strings[0].ptr == NULL);

							/* Advance the input stream so we don't choke on this token */

							i++;

							states.col++;

						}

					}

				}

			} 

			else 

			{

				/* Check if we're whitespace or not */

				if (!g_ws_chartable[(unsigned)c])

				{

					bool restage = false;

					/* Check various special tokens:

					 * ;

					 * //

					 * / *

					 * {

					 * }

					 */

					if (c == ';' || c == '/')

					{

						/* If it's a line-based comment (that is, ; or //)

						 * we will need to scrap everything until the end of the line.

						 */

						if (c == '/')

						{

							if (i == read - 1)

							{

								/* If we reached the end of the look-ahead, we need to re-check our input.

								 * Breaking out will force this to be the new reparse point!

								 */

								reparse_point = &parse_point[i];

								break;

							}

							if (parse_point[i + 1] == '/')

							{

								/* standard comment */

								ignoring = true;

								eol_comment = true;

								restage = true;

							} 

							else if (parse_point[i+1] == '*') 

							{

								/* inline comment - start ignoring */

								ignoring = true;

								ml_comment = true;

								/* yes, we restage, meaning that:

								 * STR/ *stuff* /ING  (space because ml comments don't nest in C++)

								 * will not generate 'STRING', but rather 'STR' and 'ING'.

								 * This should be a rare occurrence and is done here for convenience.

								 */

								restage = true;

							}

						} 

						else 

						{

							ignoring = true;

							eol_comment = true;

							restage = true;

						}

					} 

					else if (c == '{') 

					{

						/* If we are staging a string, we must rotate here */

						if (strings[0].ptr)

						{

							/* We have unacceptable tokens on this line */

							if (rotate(strings) != NULL)

							{

								err = SMCError_InvalidSection1;

								goto failed;

							}

						}

						/* Sections must always be alone */

						if (strings[2].ptr != NULL)

						{

							err = SMCError_InvalidSection1;

							goto failed;

						} 

						else if (strings[1].ptr == NULL)

						{

							err = SMCError_InvalidSection2;

							goto failed;

						}

						if ((res=smc->ReadSMC_NewSection(&states, FixupString(strings[1])))

							!= SMCResult_Continue)

						{

							err = (res == SMCResult_HaltFail) ? SMCError_Custom : SMCError_Okay;

							goto failed;

						}

						strings[1] = emptystring;

						curlevel++;

					} 

					else if (c == '}') 

					{

						/* Unlike our matching friend, this can be on the same line as something prior */

						if (rotate(strings) != NULL)

						{

							err = SMCError_InvalidSection3;

							goto failed;