%{
/*
**  OSSP cfg - Configuration Parsing
**  Copyright (c) 2002-2004 Ralf S. Engelschall <rse@engelschall.com>
**  Copyright (c) 2002-2004 The OSSP Project (http://www.ossp.org/)
**  Copyright (c) 2002-2004 Cable & Wireless (http://www.cw.com/)
**
**  This file is part of OSSP cfg, a configuration parsing
**  library which can be found at http://www.ossp.org/pkg/lib/cfg/.
**
**  Permission to use, copy, modify, and distribute this software for
**  any purpose with or without fee is hereby granted, provided that
**  the above copyright notice and this permission notice appear in all
**  copies.
**
**  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
**  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
**  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
**  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
**  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
**  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
**  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
**  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
**  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
**  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
**  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
**  SUCH DAMAGE.
**
**  cfg_syn_scan.l: regular grammar specification for GNU Flex
**
**  ATTENTION: This requires GNU Flex 2.5.10 or newer!
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "cfg.h"
#include "cfg_global.h"
#include "cfg_syn.h"
#include "cfg_syn_parse.h"

/* how to find our own context */
#define CTX ((cfg_syn_ctx_t *)yyget_extra(yyscanner))

/* provide own input handling */
#define YY_NO_UNPUT 1
#undef  YY_INPUT
#define YY_INPUT(buf,result,max_size) (result = yyinput(CTX, buf, max_size))
static int yyinput(cfg_syn_ctx_t *ctx, char *buf, int max_size);

/* location tracking */
#define YY_USER_INIT \
    yylloc->first = 0; \
    yylloc->last  = 0;
#define YY_USER_ACTION \
    yylloc->first = yylloc->last; \
    yylloc->last += yyleng;
#define YY_USER_ACTION_ROLLBACK \
    yylloc->last = yylloc->first

static char closing_brace(char open);
static int hex_nibble(const char hex);
static int hex_sequence(char *out_ptr, size_t out_len, const char *in_ptr, size_t in_len);
%}

/* scanner options */
%pointer
%option stack
%option reentrant
%option bison-bridge
%option bison-locations
%option never-interactive
%option noyywrap

/* scanner states */
%x SS_DQ
%x SS_SQ
%x SS_FQ
%x SS_PT
%x SS_CO_C

/* the delimiting character for flexible quoting has to one a
   special character c, i.e., one of !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~ or
   in C code: isprint(c) && !isspace(c) && !iscntrl(c) && !isalpha(i) && !isdigit(i) */
FQDEL   [\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\@\[\\\]\^\_\`\{\|\}\~]
FQDELN [^\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\@\[\\\]\^\_\`\{\|\}\~]

%%

    /* local variables */
    char  caStr[1024];
    char *cpStr = NULL;
    int   nCommentOpen = 0;
    int   nQuoteOpen = 0;
    char  cQuoteOpen = '\0';
    char  cQuoteClose = '\0';

    /* whitespaces */
[ \t\n]+ {
    /* no-op */
}

    /* C-style block comment */
"/*" {
    nCommentOpen = 1;
    BEGIN(SS_CO_C);
}
<SS_CO_C>"/*" {
    nCommentOpen++;
}
<SS_CO_C>"*/" {
    nCommentOpen--;
    if (nCommentOpen == 0)
        BEGIN(INITIAL);
}
<SS_CO_C>(.|\n) {
    /* no-op */
}
<SS_CO_C><<EOF>> {
    cfg_syn_error(CTX, CFG_ERR_SYN, yylloc, "unterminated C-style block comment");
    return 0;
}

    /* C++-style EOL comment */
"//"[^\n]* {
    /* no-op */
}

    /* Shell-style EOL comment */
"#"[^\n]* {
    /* no-op */
}

    /* double-quoted word ("...") */
\" {
    cpStr = caStr;
    BEGIN(SS_DQ);
}
<SS_DQ>\" {
    *cpStr = '\0';
    yylval->cpString = strdup(caStr);
    BEGIN(INITIAL);
    return T_STRING;
}
<SS_DQ>\\\n[ \t]* {
    /* no-op */
}
<SS_DQ>\\[0-7]{1,3} {
    unsigned int result;
    (void)sscanf(yytext+1, "%o", &result);
    if (result > 0xff) {
        cfg_syn_error(CTX, CFG_ERR_SYN, yylloc, "escape sequence out of bound");
        return 0;
    }
    *cpStr++ = result;
}
<SS_DQ>\\x\{[0-9a-fA-F]+\} {
    cpStr += hex_sequence(cpStr, sizeof(caStr)-(cpStr-caStr), yytext+3, yyleng-3-1);
}
<SS_DQ>\\x[0-9a-fA-F]{2} {
    cpStr += hex_sequence(cpStr, sizeof(caStr)-(cpStr-caStr), yytext+2, 2);
}
<SS_DQ>\\n { *cpStr++ = '\n'; }
<SS_DQ>\\r { *cpStr++ = '\r'; }
<SS_DQ>\\t { *cpStr++ = '\t'; }
<SS_DQ>\\b { *cpStr++ = '\b'; }
<SS_DQ>\\f { *cpStr++ = '\f'; }
<SS_DQ>\\a { *cpStr++ = '\007'; }
<SS_DQ>\\e { *cpStr++ = '\033'; }
<SS_DQ>\\(.|\n) {
    *cpStr++ = yytext[1];
}
<SS_DQ>[^\\\"]+ {
    char *cp = yytext;
    while (*cp != '\0')
        *cpStr++ = *cp++;
}
<SS_DQ>(.|\n) {
    *cpStr++ = yytext[1];
}
<SS_DQ><<EOF>> {
    cfg_syn_error(CTX, CFG_ERR_SYN, yylloc, "unterminated double-quoted string");
    return 0;
}

    /* single-quoted word ('...') */
\' {
    cpStr = caStr;
    BEGIN(SS_SQ);
}
<SS_SQ>\' {
    *cpStr = '\0';
    yylval->cpString = strdup(caStr);
    BEGIN(INITIAL);
    return T_STRING;
}
<SS_SQ>\\\n[ \t]* {
    /* no-op */
}
<SS_SQ>\\[\\\'] {
    *cpStr++ = yytext[1];
}
<SS_SQ>\\[^\\\'] {
    *cpStr++ = yytext[0];
    *cpStr++ = yytext[1];
}
<SS_SQ>[^\\\']+ {
    char *cp = yytext;
    while (*cp != '\0')
        *cpStr++ = *cp++;
}
<SS_SQ>(.|\n) {
    *cpStr++ = yytext[1];
}
<SS_SQ><<EOF>> {
    cfg_syn_error(CTX, CFG_ERR_SYN, yylloc, "unterminated single-quoted string");
    return 0;
}

    /* flexible-quoted word (q(.)[^\1]\1) */
"q"{FQDEL} {
    cpStr = caStr;
    nQuoteOpen = 1;
    cQuoteOpen = yytext[1];
    cQuoteClose = closing_brace(yytext[1]);
    BEGIN(SS_FQ);
}
<SS_FQ>\\{FQDEL} {
    if (yytext[1] == cQuoteOpen || yytext[1] == cQuoteClose) {
        *cpStr++ = yytext[1];
    }
    else {
        *cpStr++ = yytext[0];
        *cpStr++ = yytext[1];
    }
}
<SS_FQ>\\\n[ \t]* {
    /* no-op */
}
<SS_FQ>{FQDELN} {
    char *cp = yytext;
    while (*cp != '\0')
        *cpStr++ = *cp++;
}
<SS_FQ>(.|\n) {
    if (yytext[0] == cQuoteOpen || yytext[0] == cQuoteClose) {
        if (cQuoteOpen != cQuoteClose)
            nQuoteOpen += (yytext[0] == cQuoteOpen ? 1 : -1);
        else
            nQuoteOpen = ((nQuoteOpen + 1) % 2);
    }
    if (yytext[0] == cQuoteClose && nQuoteOpen == 0) {
        *cpStr = '\0';
        yylval->cpString = strdup(caStr);
        BEGIN(INITIAL);
        return T_STRING;
    }
    else
        *cpStr++ = yytext[0];
}
<SS_FQ><<EOF>> {
    cfg_syn_error(CTX, CFG_ERR_SYN, yylloc, "unterminated flexible-quoted string");
    return 0;
}

   /* special tokens */
";" { return T_SEP;   }
"{" { return T_OPEN;  }
"}" { return T_CLOSE; }

    /* plain text word */
\\\n[ \t]* {
    /* no-op */
}
(.|\n) {
    cpStr = caStr;
    *cpStr++ = yytext[0];
    BEGIN(SS_PT);
}
<SS_PT>\\\n[ \t]* {
    /* no-op */
}
<SS_PT>[^ \t\n;{}\\"']+ {
    char *cp = yytext;
    while (*cp != '\0')
        *cpStr++ = *cp++;
}
<SS_PT>(.|\n) {
    *cpStr = '\0';
    yylval->cpString = strdup(caStr);
    yyless(0);
    BEGIN(INITIAL);
    return T_STRING;
}

%%

/* external scanner state transitions */
void cfg_syn_scan_push(cfg_syn_ctx_t *ctx, const char *state);
void cfg_syn_scan_push(cfg_syn_ctx_t *ctx, const char *state)
{
    if (strcmp(state, "SS_SQ") == 0)
        yy_push_state(SS_SQ, ctx->yyscan);
}
void cfg_syn_scan_pop(cfg_syn_ctx_t *ctx);
void cfg_syn_scan_pop(cfg_syn_ctx_t *ctx)
{
    yy_pop_state(ctx->yyscan);
}

/* buffer-based input routine */
static int yyinput(cfg_syn_ctx_t *ctx, char *buf, int max_size)
{
    int n;

    n = (ctx->inputbuf + ctx->inputlen - ctx->inputptr);
    if (n > max_size)
        n = max_size;
    if (n <= 0)
        return YY_NULL;
    memcpy(buf, ctx->inputptr, n);
    ctx->inputptr += n;
    return n;
}

/* closing brace */
static char closing_brace(char open)
{
    static struct {
        char open;
        char close;
    } openclose[] = {
        { '(', ')' },
        { '{', '}' },
        { '{', ']' },
        { '<', '>' },
    };
    int i;

    for (i = 0; i < sizeof(openclose)/sizeof(openclose[0]); i++) {
        if (openclose[i].open == open)
            return (char)openclose[i].close;
    }
    return open;
}

/* convert a hex digit into a nibble */
static int hex_nibble(const char hex)
{
    unsigned char nibble;

    if (hex >= '0' && hex <= '9')
        nibble = (unsigned char)(hex - '0');
    else if (hex >= 'a' && hex <= 'f')
        nibble = (unsigned char)(hex - 'a' + 10);
    else if (hex >= 'A' && hex <= 'F')
        nibble = (unsigned char)(hex - 'A' + 10);
    else
        nibble = -1;
    return nibble;
}

/* convert a hex digit sequence into an octet stream */
static int hex_sequence(char *out_ptr, size_t out_len, const char *in_ptr, size_t in_len)
{
    int i;
    size_t out_max;

    out_max = out_len;
    if (in_len % 2 != 0) {
        *out_ptr++ = hex_nibble(in_ptr[0]);
        out_len--;
        in_ptr++;
        in_len--;
    }
    for (i = 0; in_len > 0 && out_len > 0; i++) {
        *out_ptr++ = ((hex_nibble(in_ptr[0]) << 4) | (hex_nibble(in_ptr[1])));
        out_len--;
        in_ptr += 2;
        in_len -= 2;
    }
    return (out_max - out_len);
}