source: MondoRescue/branches/stable/mindi-busybox/editors/awk.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * awk implementation for busybox
 *
 * Copyright (C) 2002 by Dmitry Zakharov <dmit@crp.bank.gov.ua>
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

#include "libbb.h"
#include "xregex.h"
#include <math.h>
extern char **environ;

/* This is a NOEXEC applet. Be very careful! */


#define MAXVARFMT       240
#define MINNVBLOCK      64

/* variable flags */
#define VF_NUMBER       0x0001  /* 1 = primary type is number */
#define VF_ARRAY        0x0002  /* 1 = it's an array */

#define VF_CACHED       0x0100  /* 1 = num/str value has cached str/num eq */
#define VF_USER         0x0200  /* 1 = user input (may be numeric string) */
#define VF_SPECIAL      0x0400  /* 1 = requires extra handling when changed */
#define VF_WALK         0x0800  /* 1 = variable has alloc'd x.walker list */
#define VF_FSTR         0x1000  /* 1 = var::string points to fstring buffer */
#define VF_CHILD        0x2000  /* 1 = function arg; x.parent points to source */
#define VF_DIRTY        0x4000  /* 1 = variable was set explicitly */

/* these flags are static, don't change them when value is changed */
#define VF_DONTTOUCH    (VF_ARRAY | VF_SPECIAL | VF_WALK | VF_CHILD | VF_DIRTY)

/* Variable */
typedef struct var_s {
    unsigned type;            /* flags */
    double number;
    char *string;
    union {
        int aidx;               /* func arg idx (for compilation stage) */
        struct xhash_s *array;  /* array ptr */
        struct var_s *parent;   /* for func args, ptr to actual parameter */
        char **walker;          /* list of array elements (for..in) */
    } x;
} var;

/* Node chain (pattern-action chain, BEGIN, END, function bodies) */
typedef struct chain_s {
    struct node_s *first;
    struct node_s *last;
    const char *programname;
} chain;

/* Function */
typedef struct func_s {
    unsigned nargs;
    struct chain_s body;
} func;

/* I/O stream */
typedef struct rstream_s {
    FILE *F;
    char *buffer;
    int adv;
    int size;
    int pos;
    smallint is_pipe;
} rstream;

typedef struct hash_item_s {
    union {
        struct var_s v;         /* variable/array hash */
        struct rstream_s rs;    /* redirect streams hash */
        struct func_s f;        /* functions hash */
    } data;
    struct hash_item_s *next;       /* next in chain */
    char name[1];                   /* really it's longer */
} hash_item;

typedef struct xhash_s {
    unsigned nel;           /* num of elements */
    unsigned csize;         /* current hash size */
    unsigned nprime;        /* next hash size in PRIMES[] */
    unsigned glen;          /* summary length of item names */
    struct hash_item_s **items;
} xhash;

/* Tree node */
typedef struct node_s {
    uint32_t info;
    unsigned lineno;
    union {
        struct node_s *n;
        var *v;
        int i;
        char *s;
        regex_t *re;
    } l;
    union {
        struct node_s *n;
        regex_t *ire;
        func *f;
        int argno;
    } r;
    union {
        struct node_s *n;
    } a;
} node;

/* Block of temporary variables */
typedef struct nvblock_s {
    int size;
    var *pos;
    struct nvblock_s *prev;
    struct nvblock_s *next;
    var nv[0];
} nvblock;

typedef struct tsplitter_s {
    node n;
    regex_t re[2];
} tsplitter;

/* simple token classes */
/* Order and hex values are very important!!!  See next_token() */
#define TC_SEQSTART  1              /* ( */
#define TC_SEQTERM  (1 << 1)        /* ) */
#define TC_REGEXP   (1 << 2)        /* /.../ */
#define TC_OUTRDR   (1 << 3)        /* | > >> */
#define TC_UOPPOST  (1 << 4)        /* unary postfix operator */
#define TC_UOPPRE1  (1 << 5)        /* unary prefix operator */
#define TC_BINOPX   (1 << 6)        /* two-opnd operator */
#define TC_IN       (1 << 7)
#define TC_COMMA    (1 << 8)
#define TC_PIPE     (1 << 9)        /* input redirection pipe */
#define TC_UOPPRE2  (1 << 10)       /* unary prefix operator */
#define TC_ARRTERM  (1 << 11)       /* ] */
#define TC_GRPSTART (1 << 12)       /* { */
#define TC_GRPTERM  (1 << 13)       /* } */
#define TC_SEMICOL  (1 << 14)
#define TC_NEWLINE  (1 << 15)
#define TC_STATX    (1 << 16)       /* ctl statement (for, next...) */
#define TC_WHILE    (1 << 17)
#define TC_ELSE     (1 << 18)
#define TC_BUILTIN  (1 << 19)
#define TC_GETLINE  (1 << 20)
#define TC_FUNCDECL (1 << 21)       /* `function' `func' */
#define TC_BEGIN    (1 << 22)
#define TC_END      (1 << 23)
#define TC_EOF      (1 << 24)
#define TC_VARIABLE (1 << 25)
#define TC_ARRAY    (1 << 26)
#define TC_FUNCTION (1 << 27)
#define TC_STRING   (1 << 28)
#define TC_NUMBER   (1 << 29)

#define TC_UOPPRE  (TC_UOPPRE1 | TC_UOPPRE2)

/* combined token classes */
#define TC_BINOP   (TC_BINOPX | TC_COMMA | TC_PIPE | TC_IN)
#define TC_UNARYOP (TC_UOPPRE | TC_UOPPOST)
#define TC_OPERAND (TC_VARIABLE | TC_ARRAY | TC_FUNCTION \
                   | TC_BUILTIN | TC_GETLINE | TC_SEQSTART | TC_STRING | TC_NUMBER)

#define TC_STATEMNT (TC_STATX | TC_WHILE)
#define TC_OPTERM  (TC_SEMICOL | TC_NEWLINE)

/* word tokens, cannot mean something else if not expected */
#define TC_WORD    (TC_IN | TC_STATEMNT | TC_ELSE | TC_BUILTIN \
                   | TC_GETLINE | TC_FUNCDECL | TC_BEGIN | TC_END)

/* discard newlines after these */
#define TC_NOTERM  (TC_COMMA | TC_GRPSTART | TC_GRPTERM \
                   | TC_BINOP | TC_OPTERM)

/* what can expression begin with */
#define TC_OPSEQ   (TC_OPERAND | TC_UOPPRE | TC_REGEXP)
/* what can group begin with */
#define TC_GRPSEQ  (TC_OPSEQ | TC_OPTERM | TC_STATEMNT | TC_GRPSTART)

/* if previous token class is CONCAT1 and next is CONCAT2, concatenation */
/* operator is inserted between them */
#define TC_CONCAT1 (TC_VARIABLE | TC_ARRTERM | TC_SEQTERM \
                   | TC_STRING | TC_NUMBER | TC_UOPPOST)
#define TC_CONCAT2 (TC_OPERAND | TC_UOPPRE)

#define OF_RES1    0x010000
#define OF_RES2    0x020000
#define OF_STR1    0x040000
#define OF_STR2    0x080000
#define OF_NUM1    0x100000
#define OF_CHECKED 0x200000

/* combined operator flags */
#define xx  0
#define xV  OF_RES2
#define xS  (OF_RES2 | OF_STR2)
#define Vx  OF_RES1
#define VV  (OF_RES1 | OF_RES2)
#define Nx  (OF_RES1 | OF_NUM1)
#define NV  (OF_RES1 | OF_NUM1 | OF_RES2)
#define Sx  (OF_RES1 | OF_STR1)
#define SV  (OF_RES1 | OF_STR1 | OF_RES2)
#define SS  (OF_RES1 | OF_STR1 | OF_RES2 | OF_STR2)

#define OPCLSMASK 0xFF00
#define OPNMASK   0x007F

/* operator priority is a highest byte (even: r->l, odd: l->r grouping)
 * For builtins it has different meaning: n n s3 s2 s1 v3 v2 v1,
 * n - min. number of args, vN - resolve Nth arg to var, sN - resolve to string
 */
#define P(x)      (x << 24)
#define PRIMASK   0x7F000000
#define PRIMASK2  0x7E000000

/* Operation classes */

#define SHIFT_TIL_THIS  0x0600
#define RECUR_FROM_THIS 0x1000

enum {
    OC_DELETE = 0x0100,     OC_EXEC = 0x0200,       OC_NEWSOURCE = 0x0300,
    OC_PRINT = 0x0400,      OC_PRINTF = 0x0500,     OC_WALKINIT = 0x0600,

    OC_BR = 0x0700,         OC_BREAK = 0x0800,      OC_CONTINUE = 0x0900,
    OC_EXIT = 0x0a00,       OC_NEXT = 0x0b00,       OC_NEXTFILE = 0x0c00,
    OC_TEST = 0x0d00,       OC_WALKNEXT = 0x0e00,

    OC_BINARY = 0x1000,     OC_BUILTIN = 0x1100,    OC_COLON = 0x1200,
    OC_COMMA = 0x1300,      OC_COMPARE = 0x1400,    OC_CONCAT = 0x1500,
    OC_FBLTIN = 0x1600,     OC_FIELD = 0x1700,      OC_FNARG = 0x1800,
    OC_FUNC = 0x1900,       OC_GETLINE = 0x1a00,    OC_IN = 0x1b00,
    OC_LAND = 0x1c00,       OC_LOR = 0x1d00,        OC_MATCH = 0x1e00,
    OC_MOVE = 0x1f00,       OC_PGETLINE = 0x2000,   OC_REGEXP = 0x2100,
    OC_REPLACE = 0x2200,    OC_RETURN = 0x2300,     OC_SPRINTF = 0x2400,
    OC_TERNARY = 0x2500,    OC_UNARY = 0x2600,      OC_VAR = 0x2700,
    OC_DONE = 0x2800,

    ST_IF = 0x3000,         ST_DO = 0x3100,         ST_FOR = 0x3200,
    ST_WHILE = 0x3300
};

/* simple builtins */
enum {
    F_in,   F_rn,   F_co,   F_ex,   F_lg,   F_si,   F_sq,   F_sr,
    F_ti,   F_le,   F_sy,   F_ff,   F_cl
};

/* builtins */
enum {
    B_a2,   B_ix,   B_ma,   B_sp,   B_ss,   B_ti,   B_lo,   B_up,
    B_ge,   B_gs,   B_su,
    B_an,   B_co,   B_ls,   B_or,   B_rs,   B_xo,
};

/* tokens and their corresponding info values */

#define NTC     "\377"  /* switch to next token class (tc<<1) */
#define NTCC    '\377'

#define OC_B    OC_BUILTIN

static const char tokenlist[] ALIGN1 =
    "\1("       NTC
    "\1)"       NTC
    "\1/"       NTC                                 /* REGEXP */
    "\2>>"      "\1>"       "\1|"       NTC         /* OUTRDR */
    "\2++"      "\2--"      NTC                     /* UOPPOST */
    "\2++"      "\2--"      "\1$"       NTC         /* UOPPRE1 */
    "\2=="      "\1="       "\2+="      "\2-="      /* BINOPX */
    "\2*="      "\2/="      "\2%="      "\2^="
    "\1+"       "\1-"       "\3**="     "\2**"
    "\1/"       "\1%"       "\1^"       "\1*"
    "\2!="      "\2>="      "\2<="      "\1>"
    "\1<"       "\2!~"      "\1~"       "\2&&"
    "\2||"      "\1?"       "\1:"       NTC
    "\2in"      NTC
    "\1,"       NTC
    "\1|"       NTC
    "\1+"       "\1-"       "\1!"       NTC         /* UOPPRE2 */
    "\1]"       NTC
    "\1{"       NTC
    "\1}"       NTC
    "\1;"       NTC
    "\1\n"      NTC
    "\2if"      "\2do"      "\3for"     "\5break"   /* STATX */
    "\10continue"           "\6delete"  "\5print"
    "\6printf"  "\4next"    "\10nextfile"
    "\6return"  "\4exit"    NTC
    "\5while"   NTC
    "\4else"    NTC

    "\3and"     "\5compl"   "\6lshift"  "\2or"
    "\6rshift"  "\3xor"
    "\5close"   "\6system"  "\6fflush"  "\5atan2"   /* BUILTIN */
    "\3cos"     "\3exp"     "\3int"     "\3log"
    "\4rand"    "\3sin"     "\4sqrt"    "\5srand"
    "\6gensub"  "\4gsub"    "\5index"   "\6length"
    "\5match"   "\5split"   "\7sprintf" "\3sub"
    "\6substr"  "\7systime" "\10strftime"
    "\7tolower" "\7toupper" NTC
    "\7getline" NTC
    "\4func"    "\10function"   NTC
    "\5BEGIN"   NTC
    "\3END"     "\0"
    ;

static const uint32_t tokeninfo[] = {
    0,
    0,
    OC_REGEXP,
    xS|'a',     xS|'w',     xS|'|',
    OC_UNARY|xV|P(9)|'p',       OC_UNARY|xV|P(9)|'m',
    OC_UNARY|xV|P(9)|'P',       OC_UNARY|xV|P(9)|'M',
        OC_FIELD|xV|P(5),
    OC_COMPARE|VV|P(39)|5,      OC_MOVE|VV|P(74),
        OC_REPLACE|NV|P(74)|'+',    OC_REPLACE|NV|P(74)|'-',
    OC_REPLACE|NV|P(74)|'*',    OC_REPLACE|NV|P(74)|'/',
        OC_REPLACE|NV|P(74)|'%',    OC_REPLACE|NV|P(74)|'&',
    OC_BINARY|NV|P(29)|'+',     OC_BINARY|NV|P(29)|'-',
        OC_REPLACE|NV|P(74)|'&',    OC_BINARY|NV|P(15)|'&',
    OC_BINARY|NV|P(25)|'/',     OC_BINARY|NV|P(25)|'%',
        OC_BINARY|NV|P(15)|'&',     OC_BINARY|NV|P(25)|'*',
    OC_COMPARE|VV|P(39)|4,      OC_COMPARE|VV|P(39)|3,
        OC_COMPARE|VV|P(39)|0,      OC_COMPARE|VV|P(39)|1,
    OC_COMPARE|VV|P(39)|2,      OC_MATCH|Sx|P(45)|'!',
        OC_MATCH|Sx|P(45)|'~',      OC_LAND|Vx|P(55),
    OC_LOR|Vx|P(59),            OC_TERNARY|Vx|P(64)|'?',
        OC_COLON|xx|P(67)|':',
    OC_IN|SV|P(49),
    OC_COMMA|SS|P(80),
    OC_PGETLINE|SV|P(37),
    OC_UNARY|xV|P(19)|'+',      OC_UNARY|xV|P(19)|'-',
        OC_UNARY|xV|P(19)|'!',
    0,
    0,
    0,
    0,
    0,
    ST_IF,          ST_DO,          ST_FOR,         OC_BREAK,
    OC_CONTINUE,                    OC_DELETE|Vx,   OC_PRINT,
    OC_PRINTF,      OC_NEXT,        OC_NEXTFILE,
    OC_RETURN|Vx,   OC_EXIT|Nx,
    ST_WHILE,
    0,

    OC_B|B_an|P(0x83), OC_B|B_co|P(0x41), OC_B|B_ls|P(0x83), OC_B|B_or|P(0x83),
    OC_B|B_rs|P(0x83), OC_B|B_xo|P(0x83),
    OC_FBLTIN|Sx|F_cl, OC_FBLTIN|Sx|F_sy, OC_FBLTIN|Sx|F_ff, OC_B|B_a2|P(0x83),
    OC_FBLTIN|Nx|F_co, OC_FBLTIN|Nx|F_ex, OC_FBLTIN|Nx|F_in, OC_FBLTIN|Nx|F_lg,
    OC_FBLTIN|F_rn,    OC_FBLTIN|Nx|F_si, OC_FBLTIN|Nx|F_sq, OC_FBLTIN|Nx|F_sr,
    OC_B|B_ge|P(0xd6), OC_B|B_gs|P(0xb6), OC_B|B_ix|P(0x9b), OC_FBLTIN|Sx|F_le,
    OC_B|B_ma|P(0x89), OC_B|B_sp|P(0x8b), OC_SPRINTF,        OC_B|B_su|P(0xb6),
    OC_B|B_ss|P(0x8f), OC_FBLTIN|F_ti,    OC_B|B_ti|P(0x0b),
    OC_B|B_lo|P(0x49), OC_B|B_up|P(0x49),
    OC_GETLINE|SV|P(0),
    0,  0,
    0,
    0
};

/* internal variable names and their initial values       */
/* asterisk marks SPECIAL vars; $ is just no-named Field0 */
enum {
    CONVFMT,    OFMT,       FS,         OFS,
    ORS,        RS,         RT,         FILENAME,
    SUBSEP,     ARGIND,     ARGC,       ARGV,
    ERRNO,      FNR,
    NR,         NF,         IGNORECASE,
    ENVIRON,    F0,         NUM_INTERNAL_VARS
};

static const char vNames[] ALIGN1 =
    "CONVFMT\0" "OFMT\0"    "FS\0*"     "OFS\0"
    "ORS\0"     "RS\0*"     "RT\0"      "FILENAME\0"
    "SUBSEP\0"  "ARGIND\0"  "ARGC\0"    "ARGV\0"
    "ERRNO\0"   "FNR\0"
    "NR\0"      "NF\0*"     "IGNORECASE\0*"
    "ENVIRON\0" "$\0*"      "\0";

static const char vValues[] ALIGN1 =
    "%.6g\0"    "%.6g\0"    " \0"       " \0"
    "\n\0"      "\n\0"      "\0"        "\0"
    "\034\0"
    "\377";

/* hash size may grow to these values */
#define FIRST_PRIME 61
static const uint16_t PRIMES[] ALIGN2 = { 251, 1021, 4093, 16381, 65521 };


/* Globals. Split in two parts so that first one is addressed
 * with (mostly short) negative offsets */
struct globals {
    chain beginseq, mainseq, endseq, *seq;
    node *break_ptr, *continue_ptr;
    rstream *iF;
    xhash *vhash, *ahash, *fdhash, *fnhash;
    const char *g_progname;
    int g_lineno;
    int nfields;
    int maxfields; /* used in fsrealloc() only */
    var *Fields;
    nvblock *g_cb;
    char *g_pos;
    char *g_buf;
    smallint icase;
    smallint exiting;
    smallint nextrec;
    smallint nextfile;
    smallint is_f0_split;
};
struct globals2 {
    uint32_t t_info; /* often used */
    uint32_t t_tclass;
    char *t_string;
    int t_lineno;
    int t_rollback;

    var *intvar[NUM_INTERNAL_VARS]; /* often used */

    /* former statics from various functions */
    char *split_f0__fstrings;

    uint32_t next_token__save_tclass;
    uint32_t next_token__save_info;
    uint32_t next_token__ltclass;
    smallint next_token__concat_inserted;

    smallint next_input_file__files_happen;
    rstream next_input_file__rsm;

    var *evaluate__fnargs;
    unsigned evaluate__seed;
    regex_t evaluate__sreg;

    var ptest__v;

    tsplitter exec_builtin__tspl;

    /* biggest and least used members go last */
    double t_double;
    tsplitter fsplitter, rsplitter;
};
#define G1 (ptr_to_globals[-1])
#define G (*(struct globals2 *const)ptr_to_globals)
/* For debug. nm --size-sort awk.o | grep -vi ' [tr] ' */
/* char G1size[sizeof(G1)]; - 0x6c */
/* char Gsize[sizeof(G)]; - 0x1cc */
/* Trying to keep most of members accessible with short offsets: */
/* char Gofs_seed[offsetof(struct globals2, evaluate__seed)]; - 0x90 */
#define beginseq     (G1.beginseq    )
#define mainseq      (G1.mainseq     )
#define endseq       (G1.endseq      )
#define seq          (G1.seq         )
#define break_ptr    (G1.break_ptr   )
#define continue_ptr (G1.continue_ptr)
#define iF           (G1.iF          )
#define vhash        (G1.vhash       )
#define ahash        (G1.ahash       )
#define fdhash       (G1.fdhash      )
#define fnhash       (G1.fnhash      )
#define g_progname   (G1.g_progname  )
#define g_lineno     (G1.g_lineno    )
#define nfields      (G1.nfields     )
#define maxfields    (G1.maxfields   )
#define Fields       (G1.Fields      )
#define g_cb         (G1.g_cb        )
#define g_pos        (G1.g_pos       )
#define g_buf        (G1.g_buf       )
#define icase        (G1.icase       )
#define exiting      (G1.exiting     )
#define nextrec      (G1.nextrec     )
#define nextfile     (G1.nextfile    )
#define is_f0_split  (G1.is_f0_split )
#define t_info       (G.t_info      )
#define t_tclass     (G.t_tclass    )
#define t_string     (G.t_string    )
#define t_double     (G.t_double    )
#define t_lineno     (G.t_lineno    )
#define t_rollback   (G.t_rollback  )
#define intvar       (G.intvar      )
#define fsplitter    (G.fsplitter   )
#define rsplitter    (G.rsplitter   )
#define INIT_G() do { \
    PTR_TO_GLOBALS = xzalloc(sizeof(G1) + sizeof(G)) + sizeof(G1); \
    G.next_token__ltclass = TC_OPTERM; \
    G.evaluate__seed = 1; \
} while (0)


/* function prototypes */
static void handle_special(var *);
static node *parse_expr(uint32_t);
static void chain_group(void);
static var *evaluate(node *, var *);
static rstream *next_input_file(void);
static int fmt_num(char *, int, const char *, double, int);
static int awk_exit(int) ATTRIBUTE_NORETURN;

/* ---- error handling ---- */

static const char EMSG_INTERNAL_ERROR[] ALIGN1 = "Internal error";
static const char EMSG_UNEXP_EOS[] ALIGN1 = "Unexpected end of string";
static const char EMSG_UNEXP_TOKEN[] ALIGN1 = "Unexpected token";
static const char EMSG_DIV_BY_ZERO[] ALIGN1 = "Division by zero";
static const char EMSG_INV_FMT[] ALIGN1 = "Invalid format specifier";
static const char EMSG_TOO_FEW_ARGS[] ALIGN1 = "Too few arguments for builtin";
static const char EMSG_NOT_ARRAY[] ALIGN1 = "Not an array";
static const char EMSG_POSSIBLE_ERROR[] ALIGN1 = "Possible syntax error";
static const char EMSG_UNDEF_FUNC[] ALIGN1 = "Call to undefined function";
#if !ENABLE_FEATURE_AWK_MATH
static const char EMSG_NO_MATH[] ALIGN1 = "Math support is not compiled in";
#endif

static void zero_out_var(var * vp)
{
    memset(vp, 0, sizeof(*vp));
}

static void syntax_error(const char *const message) ATTRIBUTE_NORETURN;
static void syntax_error(const char *const message)
{
    bb_error_msg_and_die("%s:%i: %s", g_progname, g_lineno, message);
}

/* ---- hash stuff ---- */

static unsigned hashidx(const char *name)
{
    unsigned idx = 0;

    while (*name) idx = *name++ + (idx << 6) - idx;
    return idx;
}

/* create new hash */
static xhash *hash_init(void)
{
    xhash *newhash;

    newhash = xzalloc(sizeof(xhash));
    newhash->csize = FIRST_PRIME;
    newhash->items = xzalloc(newhash->csize * sizeof(hash_item *));

    return newhash;
}

/* find item in hash, return ptr to data, NULL if not found */
static void *hash_search(xhash *hash, const char *name)
{
    hash_item *hi;

    hi = hash->items [ hashidx(name) % hash->csize ];
    while (hi) {
        if (strcmp(hi->name, name) == 0)
            return &(hi->data);
        hi = hi->next;
    }
    return NULL;
}

/* grow hash if it becomes too big */
static void hash_rebuild(xhash *hash)
{
    unsigned newsize, i, idx;
    hash_item **newitems, *hi, *thi;

    if (hash->nprime == ARRAY_SIZE(PRIMES))
        return;

    newsize = PRIMES[hash->nprime++];
    newitems = xzalloc(newsize * sizeof(hash_item *));

    for (i = 0; i < hash->csize; i++) {
        hi = hash->items[i];
        while (hi) {
            thi = hi;
            hi = thi->next;
            idx = hashidx(thi->name) % newsize;
            thi->next = newitems[idx];
            newitems[idx] = thi;
        }
    }

    free(hash->items);
    hash->csize = newsize;
    hash->items = newitems;
}

/* find item in hash, add it if necessary. Return ptr to data */
static void *hash_find(xhash *hash, const char *name)
{
    hash_item *hi;
    unsigned idx;
    int l;

    hi = hash_search(hash, name);
    if (!hi) {
        if (++hash->nel / hash->csize > 10)
            hash_rebuild(hash);

        l = strlen(name) + 1;
        hi = xzalloc(sizeof(hash_item) + l);
        memcpy(hi->name, name, l);

        idx = hashidx(name) % hash->csize;
        hi->next = hash->items[idx];
        hash->items[idx] = hi;
        hash->glen += l;
    }
    return &(hi->data);
}

#define findvar(hash, name) ((var*)    hash_find((hash), (name)))
#define newvar(name)        ((var*)    hash_find(vhash, (name)))
#define newfile(name)       ((rstream*)hash_find(fdhash, (name)))
#define newfunc(name)       ((func*)   hash_find(fnhash, (name)))

static void hash_remove(xhash *hash, const char *name)
{
    hash_item *hi, **phi;

    phi = &(hash->items[hashidx(name) % hash->csize]);
    while (*phi) {
        hi = *phi;
        if (strcmp(hi->name, name) == 0) {
            hash->glen -= (strlen(name) + 1);
            hash->nel--;
            *phi = hi->next;
            free(hi);
            break;
        }
        phi = &(hi->next);
    }
}

/* ------ some useful functions ------ */

static void skip_spaces(char **s)
{
    char *p = *s;

    while (1) {
        if (*p == '\\' && p[1] == '\n') {
            p++;
            t_lineno++;
        } else if (*p != ' ' && *p != '\t') {
            break;
        }
        p++;
    }
    *s = p;
}

static char *nextword(char **s)
{
    char *p = *s;

    while (*(*s)++) /* */;

    return p;
}

static char nextchar(char **s)
{
    char c, *pps;

    c = *((*s)++);
    pps = *s;
    if (c == '\\') c = bb_process_escape_sequence((const char**)s);
    if (c == '\\' && *s == pps) c = *((*s)++);
    return c;
}

static int ALWAYS_INLINE isalnum_(int c)
{
    return (isalnum(c) || c == '_');
}

static FILE *afopen(const char *path, const char *mode)
{
    return (*path == '-' && *(path+1) == '\0') ? stdin : xfopen(path, mode);
}

/* -------- working with variables (set/get/copy/etc) -------- */

static xhash *iamarray(var *v)
{
    var *a = v;

    while (a->type & VF_CHILD)
        a = a->x.parent;

    if (!(a->type & VF_ARRAY)) {
        a->type |= VF_ARRAY;
        a->x.array = hash_init();
    }
    return a->x.array;
}

static void clear_array(xhash *array)
{
    unsigned i;
    hash_item *hi, *thi;

    for (i = 0; i < array->csize; i++) {
        hi = array->items[i];
        while (hi) {
            thi = hi;
            hi = hi->next;
            free(thi->data.v.string);
            free(thi);
        }
        array->items[i] = NULL;
    }
    array->glen = array->nel = 0;
}

/* clear a variable */
static var *clrvar(var *v)
{
    if (!(v->type & VF_FSTR))
        free(v->string);

    v->type &= VF_DONTTOUCH;
    v->type |= VF_DIRTY;
    v->string = NULL;
    return v;
}

/* assign string value to variable */
static var *setvar_p(var *v, char *value)
{
    clrvar(v);
    v->string = value;
    handle_special(v);
    return v;
}

/* same as setvar_p but make a copy of string */
static var *setvar_s(var *v, const char *value)
{
    return setvar_p(v, (value && *value) ? xstrdup(value) : NULL);
}

/* same as setvar_s but set USER flag */
static var *setvar_u(var *v, const char *value)
{
    setvar_s(v, value);
    v->type |= VF_USER;
    return v;
}

/* set array element to user string */
static void setari_u(var *a, int idx, const char *s)
{
    char sidx[sizeof(int)*3 + 1];
    var *v;

    sprintf(sidx, "%d", idx);
    v = findvar(iamarray(a), sidx);
    setvar_u(v, s);
}

/* assign numeric value to variable */
static var *setvar_i(var *v, double value)
{
    clrvar(v);
    v->type |= VF_NUMBER;
    v->number = value;
    handle_special(v);
    return v;
}

static const char *getvar_s(var *v)
{
    /* if v is numeric and has no cached string, convert it to string */
    if ((v->type & (VF_NUMBER | VF_CACHED)) == VF_NUMBER) {
        fmt_num(g_buf, MAXVARFMT, getvar_s(intvar[CONVFMT]), v->number, TRUE);
        v->string = xstrdup(g_buf);
        v->type |= VF_CACHED;
    }
    return (v->string == NULL) ? "" : v->string;
}

static double getvar_i(var *v)
{
    char *s;

    if ((v->type & (VF_NUMBER | VF_CACHED)) == 0) {
        v->number = 0;
        s = v->string;
        if (s && *s) {
            v->number = strtod(s, &s);
            if (v->type & VF_USER) {
                skip_spaces(&s);
                if (*s != '\0')
                    v->type &= ~VF_USER;
            }
        } else {
            v->type &= ~VF_USER;
        }
        v->type |= VF_CACHED;
    }
    return v->number;
}

static var *copyvar(var *dest, const var *src)
{
    if (dest != src) {
        clrvar(dest);
        dest->type |= (src->type & ~(VF_DONTTOUCH | VF_FSTR));
        dest->number = src->number;
        if (src->string)
            dest->string = xstrdup(src->string);
    }
    handle_special(dest);
    return dest;
}

static var *incvar(var *v)
{
    return setvar_i(v, getvar_i(v) + 1.);
}

/* return true if v is number or numeric string */
static int is_numeric(var *v)
{
    getvar_i(v);
    return ((v->type ^ VF_DIRTY) & (VF_NUMBER | VF_USER | VF_DIRTY));
}

/* return 1 when value of v corresponds to true, 0 otherwise */
static int istrue(var *v)
{
    if (is_numeric(v))
        return (v->number == 0) ? 0 : 1;
    return (v->string && *(v->string)) ? 1 : 0;
}

/* temporary variables allocator. Last allocated should be first freed */
static var *nvalloc(int n)
{
    nvblock *pb = NULL;
    var *v, *r;
    int size;

    while (g_cb) {
        pb = g_cb;
        if ((g_cb->pos - g_cb->nv) + n <= g_cb->size) break;
        g_cb = g_cb->next;
    }

    if (!g_cb) {
        size = (n <= MINNVBLOCK) ? MINNVBLOCK : n;
        g_cb = xmalloc(sizeof(nvblock) + size * sizeof(var));
        g_cb->size = size;
        g_cb->pos = g_cb->nv;
        g_cb->prev = pb;
        g_cb->next = NULL;
        if (pb) pb->next = g_cb;
    }

    v = r = g_cb->pos;
    g_cb->pos += n;

    while (v < g_cb->pos) {
        v->type = 0;
        v->string = NULL;
        v++;
    }

    return r;
}

static void nvfree(var *v)
{
    var *p;

    if (v < g_cb->nv || v >= g_cb->pos)
        syntax_error(EMSG_INTERNAL_ERROR);

    for (p = v; p < g_cb->pos; p++) {
        if ((p->type & (VF_ARRAY | VF_CHILD)) == VF_ARRAY) {
            clear_array(iamarray(p));
            free(p->x.array->items);
            free(p->x.array);
        }
        if (p->type & VF_WALK)
            free(p->x.walker);

        clrvar(p);
    }

    g_cb->pos = v;
    while (g_cb->prev && g_cb->pos == g_cb->nv) {
        g_cb = g_cb->prev;
    }
}

/* ------- awk program text parsing ------- */

/* Parse next token pointed by global pos, place results into global ttt.
 * If token isn't expected, give away. Return token class
 */
static uint32_t next_token(uint32_t expected)
{
#define concat_inserted (G.next_token__concat_inserted)
#define save_tclass     (G.next_token__save_tclass)
#define save_info       (G.next_token__save_info)
/* Initialized to TC_OPTERM: */
#define ltclass         (G.next_token__ltclass)

    char *p, *pp, *s;
    const char *tl;
    uint32_t tc;
    const uint32_t *ti;
    int l;

    if (t_rollback) {
        t_rollback = FALSE;

    } else if (concat_inserted) {
        concat_inserted = FALSE;
        t_tclass = save_tclass;
        t_info = save_info;

    } else {
        p = g_pos;
 readnext:
        skip_spaces(&p);
        g_lineno = t_lineno;
        if (*p == '#')
            while (*p != '\n' && *p != '\0')
                p++;

        if (*p == '\n')
            t_lineno++;

        if (*p == '\0') {
            tc = TC_EOF;

        } else if (*p == '\"') {
            /* it's a string */
            t_string = s = ++p;
            while (*p != '\"') {
                if (*p == '\0' || *p == '\n')
                    syntax_error(EMSG_UNEXP_EOS);
                *(s++) = nextchar(&p);
            }
            p++;
            *s = '\0';
            tc = TC_STRING;

        } else if ((expected & TC_REGEXP) && *p == '/') {
            /* it's regexp */
            t_string = s = ++p;
            while (*p != '/') {
                if (*p == '\0' || *p == '\n')
                    syntax_error(EMSG_UNEXP_EOS);
                *s = *p++;
                if (*s++ == '\\') {
                    pp = p;
                    *(s-1) = bb_process_escape_sequence((const char **)&p);
                    if (*pp == '\\')
                        *s++ = '\\';
                    if (p == pp)
                        *s++ = *p++;
                }
            }
            p++;
            *s = '\0';
            tc = TC_REGEXP;

        } else if (*p == '.' || isdigit(*p)) {
            /* it's a number */
            t_double = strtod(p, &p);
            if (*p == '.')
                syntax_error(EMSG_UNEXP_TOKEN);
            tc = TC_NUMBER;

        } else {
            /* search for something known */
            tl = tokenlist;
            tc = 0x00000001;
            ti = tokeninfo;
            while (*tl) {
                l = *(tl++);
                if (l == NTCC) {
                    tc <<= 1;
                    continue;
                }
                /* if token class is expected, token
                 * matches and it's not a longer word,
                 * then this is what we are looking for
                 */
                if ((tc & (expected | TC_WORD | TC_NEWLINE))
                 && *tl == *p && strncmp(p, tl, l) == 0
                 && !((tc & TC_WORD) && isalnum_(p[l]))
                ) {
                    t_info = *ti;
                    p += l;
                    break;
                }
                ti++;
                tl += l;
            }

            if (!*tl) {
                /* it's a name (var/array/function),
                 * otherwise it's something wrong
                 */
                if (!isalnum_(*p))
                    syntax_error(EMSG_UNEXP_TOKEN);

                t_string = --p;
                while (isalnum_(*(++p))) {
                    *(p-1) = *p;
                }
                *(p-1) = '\0';
                tc = TC_VARIABLE;
                /* also consume whitespace between functionname and bracket */
                if (!(expected & TC_VARIABLE))
                    skip_spaces(&p);
                if (*p == '(') {
                    tc = TC_FUNCTION;
                } else {
                    if (*p == '[') {
                        p++;
                        tc = TC_ARRAY;
                    }
                }
            }
        }
        g_pos = p;

        /* skipping newlines in some cases */
        if ((ltclass & TC_NOTERM) && (tc & TC_NEWLINE))
            goto readnext;

        /* insert concatenation operator when needed */
        if ((ltclass & TC_CONCAT1) && (tc & TC_CONCAT2) && (expected & TC_BINOP)) {
            concat_inserted = TRUE;
            save_tclass = tc;
            save_info = t_info;
            tc = TC_BINOP;
            t_info = OC_CONCAT | SS | P(35);
        }

        t_tclass = tc;
    }
    ltclass = t_tclass;

    /* Are we ready for this? */
    if (!(ltclass & expected))
        syntax_error((ltclass & (TC_NEWLINE | TC_EOF)) ?
                EMSG_UNEXP_EOS : EMSG_UNEXP_TOKEN);

    return ltclass;
#undef concat_inserted
#undef save_tclass
#undef save_info
#undef ltclass
}

static void rollback_token(void)
{
    t_rollback = TRUE;
}

static node *new_node(uint32_t info)
{
    node *n;

    n = xzalloc(sizeof(node));
    n->info = info;
    n->lineno = g_lineno;
    return n;
}

static node *mk_re_node(const char *s, node *n, regex_t *re)
{
    n->info = OC_REGEXP;
    n->l.re = re;
    n->r.ire = re + 1;
    xregcomp(re, s, REG_EXTENDED);
    xregcomp(re + 1, s, REG_EXTENDED | REG_ICASE);

    return n;
}

static node *condition(void)
{
    next_token(TC_SEQSTART);
    return parse_expr(TC_SEQTERM);
}

/* parse expression terminated by given argument, return ptr
 * to built subtree. Terminator is eaten by parse_expr */
static node *parse_expr(uint32_t iexp)
{
    node sn;
    node *cn = &sn;
    node *vn, *glptr;
    uint32_t tc, xtc;
    var *v;

    sn.info = PRIMASK;
    sn.r.n = glptr = NULL;
    xtc = TC_OPERAND | TC_UOPPRE | TC_REGEXP | iexp;

    while (!((tc = next_token(xtc)) & iexp)) {
        if (glptr && (t_info == (OC_COMPARE | VV | P(39) | 2))) {
            /* input redirection (<) attached to glptr node */
            cn = glptr->l.n = new_node(OC_CONCAT | SS | P(37));
            cn->a.n = glptr;
            xtc = TC_OPERAND | TC_UOPPRE;
            glptr = NULL;

        } else if (tc & (TC_BINOP | TC_UOPPOST)) {
            /* for binary and postfix-unary operators, jump back over
             * previous operators with higher priority */
            vn = cn;
            while ( ((t_info & PRIMASK) > (vn->a.n->info & PRIMASK2))
             || ((t_info == vn->info) && ((t_info & OPCLSMASK) == OC_COLON)) )
                vn = vn->a.n;
            if ((t_info & OPCLSMASK) == OC_TERNARY)
                t_info += P(6);
            cn = vn->a.n->r.n = new_node(t_info);
            cn->a.n = vn->a.n;
            if (tc & TC_BINOP) {
                cn->l.n = vn;
                xtc = TC_OPERAND | TC_UOPPRE | TC_REGEXP;
                if ((t_info & OPCLSMASK) == OC_PGETLINE) {
                    /* it's a pipe */
                    next_token(TC_GETLINE);
                    /* give maximum priority to this pipe */
                    cn->info &= ~PRIMASK;
                    xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | iexp;
                }
            } else {
                cn->r.n = vn;
                xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | iexp;
            }
            vn->a.n = cn;

        } else {
            /* for operands and prefix-unary operators, attach them
             * to last node */
            vn = cn;
            cn = vn->r.n = new_node(t_info);
            cn->a.n = vn;
            xtc = TC_OPERAND | TC_UOPPRE | TC_REGEXP;
            if (tc & (TC_OPERAND | TC_REGEXP)) {
                xtc = TC_UOPPRE | TC_UOPPOST | TC_BINOP | TC_OPERAND | iexp;
                /* one should be very careful with switch on tclass -
                 * only simple tclasses should be used! */
                switch (tc) {
                case TC_VARIABLE:
                case TC_ARRAY:
                    cn->info = OC_VAR;
                    v = hash_search(ahash, t_string);
                    if (v != NULL) {
                        cn->info = OC_FNARG;
                        cn->l.i = v->x.aidx;
                    } else {
                        cn->l.v = newvar(t_string);
                    }
                    if (tc & TC_ARRAY) {
                        cn->info |= xS;
                        cn->r.n = parse_expr(TC_ARRTERM);
                    }
                    break;

                case TC_NUMBER:
                case TC_STRING:
                    cn->info = OC_VAR;
                    v = cn->l.v = xzalloc(sizeof(var));
                    if (tc & TC_NUMBER)
                        setvar_i(v, t_double);
                    else
                        setvar_s(v, t_string);
                    break;

                case TC_REGEXP:
                    mk_re_node(t_string, cn, xzalloc(sizeof(regex_t)*2));
                    break;

                case TC_FUNCTION:
                    cn->info = OC_FUNC;
                    cn->r.f = newfunc(t_string);
                    cn->l.n = condition();
                    break;

                case TC_SEQSTART:
                    cn = vn->r.n = parse_expr(TC_SEQTERM);
                    cn->a.n = vn;
                    break;

                case TC_GETLINE:
                    glptr = cn;
                    xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | iexp;
                    break;

                case TC_BUILTIN:
                    cn->l.n = condition();
                    break;
                }
            }
        }
    }
    return sn.r.n;
}

/* add node to chain. Return ptr to alloc'd node */
static node *chain_node(uint32_t info)
{
    node *n;

    if (!seq->first)
        seq->first = seq->last = new_node(0);

    if (seq->programname != g_progname) {
        seq->programname = g_progname;
        n = chain_node(OC_NEWSOURCE);
        n->l.s = xstrdup(g_progname);
    }

    n = seq->last;
    n->info = info;
    seq->last = n->a.n = new_node(OC_DONE);

    return n;
}

static void chain_expr(uint32_t info)
{
    node *n;

    n = chain_node(info);
    n->l.n = parse_expr(TC_OPTERM | TC_GRPTERM);
    if (t_tclass & TC_GRPTERM)
        rollback_token();
}

static node *chain_loop(node *nn)
{
    node *n, *n2, *save_brk, *save_cont;

    save_brk = break_ptr;
    save_cont = continue_ptr;

    n = chain_node(OC_BR | Vx);
    continue_ptr = new_node(OC_EXEC);
    break_ptr = new_node(OC_EXEC);
    chain_group();
    n2 = chain_node(OC_EXEC | Vx);
    n2->l.n = nn;
    n2->a.n = n;
    continue_ptr->a.n = n2;
    break_ptr->a.n = n->r.n = seq->last;

    continue_ptr = save_cont;
    break_ptr = save_brk;

    return n;
}

/* parse group and attach it to chain */
static void chain_group(void)
{
    uint32_t c;
    node *n, *n2, *n3;

    do {
        c = next_token(TC_GRPSEQ);
    } while (c & TC_NEWLINE);

    if (c & TC_GRPSTART) {
        while (next_token(TC_GRPSEQ | TC_GRPTERM) != TC_GRPTERM) {
            if (t_tclass & TC_NEWLINE) continue;
            rollback_token();
            chain_group();
        }
    } else if (c & (TC_OPSEQ | TC_OPTERM)) {
        rollback_token();
        chain_expr(OC_EXEC | Vx);
    } else {                        /* TC_STATEMNT */
        switch (t_info & OPCLSMASK) {
        case ST_IF:
            n = chain_node(OC_BR | Vx);
            n->l.n = condition();
            chain_group();
            n2 = chain_node(OC_EXEC);
            n->r.n = seq->last;
            if (next_token(TC_GRPSEQ | TC_GRPTERM | TC_ELSE) == TC_ELSE) {
                chain_group();
                n2->a.n = seq->last;
            } else {
                rollback_token();
            }
            break;

        case ST_WHILE:
            n2 = condition();
            n = chain_loop(NULL);
            n->l.n = n2;
            break;

        case ST_DO:
            n2 = chain_node(OC_EXEC);
            n = chain_loop(NULL);
            n2->a.n = n->a.n;
            next_token(TC_WHILE);
            n->l.n = condition();
            break;

        case ST_FOR:
            next_token(TC_SEQSTART);
            n2 = parse_expr(TC_SEMICOL | TC_SEQTERM);
            if (t_tclass & TC_SEQTERM) {    /* for-in */
                if ((n2->info & OPCLSMASK) != OC_IN)
                    syntax_error(EMSG_UNEXP_TOKEN);
                n = chain_node(OC_WALKINIT | VV);
                n->l.n = n2->l.n;
                n->r.n = n2->r.n;
                n = chain_loop(NULL);
                n->info = OC_WALKNEXT | Vx;
                n->l.n = n2->l.n;
            } else {            /* for (;;) */
                n = chain_node(OC_EXEC | Vx);
                n->l.n = n2;
                n2 = parse_expr(TC_SEMICOL);
                n3 = parse_expr(TC_SEQTERM);
                n = chain_loop(n3);
                n->l.n = n2;
                if (!n2)
                    n->info = OC_EXEC;
            }
            break;

        case OC_PRINT:
        case OC_PRINTF:
            n = chain_node(t_info);
            n->l.n = parse_expr(TC_OPTERM | TC_OUTRDR | TC_GRPTERM);
            if (t_tclass & TC_OUTRDR) {
                n->info |= t_info;
                n->r.n = parse_expr(TC_OPTERM | TC_GRPTERM);
            }
            if (t_tclass & TC_GRPTERM)
                rollback_token();
            break;

        case OC_BREAK:
            n = chain_node(OC_EXEC);
            n->a.n = break_ptr;
            break;

        case OC_CONTINUE:
            n = chain_node(OC_EXEC);
            n->a.n = continue_ptr;
            break;

        /* delete, next, nextfile, return, exit */
        default:
            chain_expr(t_info);
        }
    }
}

static void parse_program(char *p)
{
    uint32_t tclass;
    node *cn;
    func *f;
    var *v;

    g_pos = p;
    t_lineno = 1;
    while ((tclass = next_token(TC_EOF | TC_OPSEQ | TC_GRPSTART |
            TC_OPTERM | TC_BEGIN | TC_END | TC_FUNCDECL)) != TC_EOF) {

        if (tclass & TC_OPTERM)
            continue;

        seq = &mainseq;
        if (tclass & TC_BEGIN) {
            seq = &beginseq;
            chain_group();

        } else if (tclass & TC_END) {
            seq = &endseq;
            chain_group();

        } else if (tclass & TC_FUNCDECL) {
            next_token(TC_FUNCTION);
            g_pos++;
            f = newfunc(t_string);
            f->body.first = NULL;
            f->nargs = 0;
            while (next_token(TC_VARIABLE | TC_SEQTERM) & TC_VARIABLE) {
                v = findvar(ahash, t_string);
                v->x.aidx = (f->nargs)++;

                if (next_token(TC_COMMA | TC_SEQTERM) & TC_SEQTERM)
                    break;
            }
            seq = &(f->body);
            chain_group();
            clear_array(ahash);

        } else if (tclass & TC_OPSEQ) {
            rollback_token();
            cn = chain_node(OC_TEST);
            cn->l.n = parse_expr(TC_OPTERM | TC_EOF | TC_GRPSTART);
            if (t_tclass & TC_GRPSTART) {
                rollback_token();
                chain_group();
            } else {
                chain_node(OC_PRINT);
            }
            cn->r.n = mainseq.last;

        } else /* if (tclass & TC_GRPSTART) */ {
            rollback_token();
            chain_group();
        }
    }
}


/* -------- program execution part -------- */

static node *mk_splitter(const char *s, tsplitter *spl)
{
    regex_t *re, *ire;
    node *n;

    re = &spl->re[0];
    ire = &spl->re[1];
    n = &spl->n;
    if ((n->info & OPCLSMASK) == OC_REGEXP) {
        regfree(re);
        regfree(ire); // TODO: nuke ire, use re+1?
    }
    if (strlen(s) > 1) {
        mk_re_node(s, n, re);
    } else {
        n->info = (uint32_t) *s;
    }

    return n;
}

/* use node as a regular expression. Supplied with node ptr and regex_t
 * storage space. Return ptr to regex (if result points to preg, it should
 * be later regfree'd manually
 */
static regex_t *as_regex(node *op, regex_t *preg)
{
    var *v;
    const char *s;

    if ((op->info & OPCLSMASK) == OC_REGEXP) {
        return icase ? op->r.ire : op->l.re;
    }
    v = nvalloc(1);
    s = getvar_s(evaluate(op, v));
    xregcomp(preg, s, icase ? REG_EXTENDED | REG_ICASE : REG_EXTENDED);
    nvfree(v);
    return preg;
}

/* gradually increasing buffer */
static void qrealloc(char **b, int n, int *size)
{
    if (!*b || n >= *size)
        *b = xrealloc(*b, *size = n + (n>>1) + 80);
}

/* resize field storage space */
static void fsrealloc(int size)
{
    int i;

    if (size >= maxfields) {
        i = maxfields;
        maxfields = size + 16;
        Fields = xrealloc(Fields, maxfields * sizeof(var));
        for (; i < maxfields; i++) {
            Fields[i].type = VF_SPECIAL;
            Fields[i].string = NULL;
        }
    }

    if (size < nfields) {
        for (i = size; i < nfields; i++) {
            clrvar(Fields + i);
        }
    }
    nfields = size;
}

static int awk_split(const char *s, node *spl, char **slist)
{
    int l, n = 0;
    char c[4];
    char *s1;
    regmatch_t pmatch[2]; // TODO: why [2]? [1] is enough...

    /* in worst case, each char would be a separate field */
    *slist = s1 = xzalloc(strlen(s) * 2 + 3);
    strcpy(s1, s);

    c[0] = c[1] = (char)spl->info;
    c[2] = c[3] = '\0';
    if (*getvar_s(intvar[RS]) == '\0')
        c[2] = '\n';

    if ((spl->info & OPCLSMASK) == OC_REGEXP) {  /* regex split */
        if (!*s)
            return n; /* "": zero fields */
        n++; /* at least one field will be there */
        do {
            l = strcspn(s, c+2); /* len till next NUL or \n */
            if (regexec(icase ? spl->r.ire : spl->l.re, s, 1, pmatch, 0) == 0
             && pmatch[0].rm_so <= l
            ) {
                l = pmatch[0].rm_so;
                if (pmatch[0].rm_eo == 0) {
                    l++;
                    pmatch[0].rm_eo++;
                }
                n++; /* we saw yet another delimiter */
            } else {
                pmatch[0].rm_eo = l;
                if (s[l]) pmatch[0].rm_eo++;
            }
            memcpy(s1, s, l);
            s1[l] = '\0';
            nextword(&s1);
            s += pmatch[0].rm_eo;
        } while (*s);
        return n;
    }
    if (c[0] == '\0') {  /* null split */
        while (*s) {
            *s1++ = *s++;
            *s1++ = '\0';
            n++;
        }
        return n;
    }
    if (c[0] != ' ') {  /* single-character split */
        if (icase) {
            c[0] = toupper(c[0]);
            c[1] = tolower(c[1]);
        }
        if (*s1) n++;
        while ((s1 = strpbrk(s1, c))) {
            *s1++ = '\0';
            n++;
        }
        return n;
    }
    /* space split */
    while (*s) {
        s = skip_whitespace(s);
        if (!*s) break;
        n++;
        while (*s && !isspace(*s))
            *s1++ = *s++;
        *s1++ = '\0';
    }
    return n;
}

static void split_f0(void)
{
/* static char *fstrings; */
#define fstrings (G.split_f0__fstrings)

    int i, n;
    char *s;

    if (is_f0_split)
        return;

    is_f0_split = TRUE;
    free(fstrings);
    fsrealloc(0);
    n = awk_split(getvar_s(intvar[F0]), &fsplitter.n, &fstrings);
    fsrealloc(n);
    s = fstrings;
    for (i = 0; i < n; i++) {
        Fields[i].string = nextword(&s);
        Fields[i].type |= (VF_FSTR | VF_USER | VF_DIRTY);
    }

    /* set NF manually to avoid side effects */
    clrvar(intvar[NF]);
    intvar[NF]->type = VF_NUMBER | VF_SPECIAL;
    intvar[NF]->number = nfields;
#undef fstrings
}

/* perform additional actions when some internal variables changed */
static void handle_special(var *v)
{
    int n;
    char *b;
    const char *sep, *s;
    int sl, l, len, i, bsize;

    if (!(v->type & VF_SPECIAL))
        return;

    if (v == intvar[NF]) {
        n = (int)getvar_i(v);
        fsrealloc(n);

        /* recalculate $0 */
        sep = getvar_s(intvar[OFS]);
        sl = strlen(sep);
        b = NULL;
        len = 0;
        for (i = 0; i < n; i++) {
            s = getvar_s(&Fields[i]);
            l = strlen(s);
            if (b) {
                memcpy(b+len, sep, sl);
                len += sl;
            }
            qrealloc(&b, len+l+sl, &bsize);
            memcpy(b+len, s, l);
            len += l;
        }
        if (b)
            b[len] = '\0';
        setvar_p(intvar[F0], b);
        is_f0_split = TRUE;

    } else if (v == intvar[F0]) {
        is_f0_split = FALSE;

    } else if (v == intvar[FS]) {
        mk_splitter(getvar_s(v), &fsplitter);

    } else if (v == intvar[RS]) {
        mk_splitter(getvar_s(v), &rsplitter);

    } else if (v == intvar[IGNORECASE]) {
        icase = istrue(v);

    } else {                /* $n */
        n = getvar_i(intvar[NF]);
        setvar_i(intvar[NF], n > v-Fields ? n : v-Fields+1);
        /* right here v is invalid. Just to note... */
    }
}

/* step through func/builtin/etc arguments */
static node *nextarg(node **pn)
{
    node *n;

    n = *pn;
    if (n && (n->info & OPCLSMASK) == OC_COMMA) {
        *pn = n->r.n;
        n = n->l.n;
    } else {
        *pn = NULL;
    }
    return n;
}

static void hashwalk_init(var *v, xhash *array)
{
    char **w;
    hash_item *hi;
    int i;

    if (v->type & VF_WALK)
        free(v->x.walker);

    v->type |= VF_WALK;
    w = v->x.walker = xzalloc(2 + 2*sizeof(char *) + array->glen);
    w[0] = w[1] = (char *)(w + 2);
    for (i = 0; i < array->csize; i++) {
        hi = array->items[i];
        while (hi) {
            strcpy(*w, hi->name);
            nextword(w);
            hi = hi->next;
        }
    }
}

static int hashwalk_next(var *v)
{
    char **w;

    w = v->x.walker;
    if (w[1] == w[0])
        return FALSE;

    setvar_s(v, nextword(w+1));
    return TRUE;
}

/* evaluate node, return 1 when result is true, 0 otherwise */
static int ptest(node *pattern)
{
    /* ptest__v is "static": to save stack space? */
    return istrue(evaluate(pattern, &G.ptest__v));
}

/* read next record from stream rsm into a variable v */
static int awk_getline(rstream *rsm, var *v)
{
    char *b;
    regmatch_t pmatch[2];
    int a, p, pp=0, size;
    int fd, so, eo, r, rp;
    char c, *m, *s;

    /* we're using our own buffer since we need access to accumulating
     * characters
     */
    fd = fileno(rsm->F);
    m = rsm->buffer;
    a = rsm->adv;
    p = rsm->pos;
    size = rsm->size;
    c = (char) rsplitter.n.info;
    rp = 0;

    if (!m) qrealloc(&m, 256, &size);
    do {
        b = m + a;
        so = eo = p;
        r = 1;
        if (p > 0) {
            if ((rsplitter.n.info & OPCLSMASK) == OC_REGEXP) {
                if (regexec(icase ? rsplitter.n.r.ire : rsplitter.n.l.re,
                            b, 1, pmatch, 0) == 0) {
                    so = pmatch[0].rm_so;
                    eo = pmatch[0].rm_eo;
                    if (b[eo] != '\0')
                        break;
                }
            } else if (c != '\0') {
                s = strchr(b+pp, c);
                if (!s) s = memchr(b+pp, '\0', p - pp);
                if (s) {
                    so = eo = s-b;
                    eo++;
                    break;
                }
            } else {
                while (b[rp] == '\n')
                    rp++;
                s = strstr(b+rp, "\n\n");
                if (s) {
                    so = eo = s-b;
                    while (b[eo] == '\n') eo++;
                    if (b[eo] != '\0')
                        break;
                }
            }
        }

        if (a > 0) {
            memmove(m, (const void *)(m+a), p+1);
            b = m;
            a = 0;
        }

        qrealloc(&m, a+p+128, &size);
        b = m + a;
        pp = p;
        p += safe_read(fd, b+p, size-p-1);
        if (p < pp) {
            p = 0;
            r = 0;
            setvar_i(intvar[ERRNO], errno);
        }
        b[p] = '\0';

    } while (p > pp);

    if (p == 0) {
        r--;
    } else {
        c = b[so]; b[so] = '\0';
        setvar_s(v, b+rp);
        v->type |= VF_USER;
        b[so] = c;
        c = b[eo]; b[eo] = '\0';
        setvar_s(intvar[RT], b+so);
        b[eo] = c;
    }

    rsm->buffer = m;
    rsm->adv = a + eo;
    rsm->pos = p - eo;
    rsm->size = size;

    return r;
}

static int fmt_num(char *b, int size, const char *format, double n, int int_as_int)
{
    int r = 0;
    char c;
    const char *s = format;

    if (int_as_int && n == (int)n) {
        r = snprintf(b, size, "%d", (int)n);
    } else {
        do { c = *s; } while (c && *++s);
        if (strchr("diouxX", c)) {
            r = snprintf(b, size, format, (int)n);
        } else if (strchr("eEfgG", c)) {
            r = snprintf(b, size, format, n);
        } else {
            syntax_error(EMSG_INV_FMT);
        }
    }
    return r;
}


/* formatted output into an allocated buffer, return ptr to buffer */
static char *awk_printf(node *n)
{
    char *b = NULL;
    char *fmt, *s, *f;
    const char *s1;
    int i, j, incr, bsize;
    char c, c1;
    var *v, *arg;

    v = nvalloc(1);
    fmt = f = xstrdup(getvar_s(evaluate(nextarg(&n), v)));

    i = 0;
    while (*f) {
        s = f;
        while (*f && (*f != '%' || *(++f) == '%'))
            f++;
        while (*f && !isalpha(*f)) {
            if (*f == '*')
                syntax_error("%*x formats are not supported");
            f++;
        }

        incr = (f - s) + MAXVARFMT;
        qrealloc(&b, incr + i, &bsize);
        c = *f;
        if (c != '\0') f++;
        c1 = *f;
        *f = '\0';
        arg = evaluate(nextarg(&n), v);

        j = i;
        if (c == 'c' || !c) {
            i += sprintf(b+i, s, is_numeric(arg) ?
                    (char)getvar_i(arg) : *getvar_s(arg));
        } else if (c == 's') {
            s1 = getvar_s(arg);
            qrealloc(&b, incr+i+strlen(s1), &bsize);
            i += sprintf(b+i, s, s1);
        } else {
            i += fmt_num(b+i, incr, s, getvar_i(arg), FALSE);
        }
        *f = c1;

        /* if there was an error while sprintf, return value is negative */
        if (i < j) i = j;
    }

    b = xrealloc(b, i + 1);
    free(fmt);
    nvfree(v);
    b[i] = '\0';
    return b;
}

/* common substitution routine
 * replace (nm) substring of (src) that match (n) with (repl), store
 * result into (dest), return number of substitutions. If nm=0, replace
 * all matches. If src or dst is NULL, use $0. If ex=TRUE, enable
 * subexpression matching (\1-\9)
 */
static int awk_sub(node *rn, const char *repl, int nm, var *src, var *dest, int ex)
{
    char *ds = NULL;
    const char *s;
    const char *sp;
    int c, i, j, di, rl, so, eo, nbs, n, dssize;
    regmatch_t pmatch[10];
    regex_t sreg, *re;

    re = as_regex(rn, &sreg);
    if (!src) src = intvar[F0];
    if (!dest) dest = intvar[F0];

    i = di = 0;
    sp = getvar_s(src);
    rl = strlen(repl);
    while (regexec(re, sp, 10, pmatch, sp==getvar_s(src) ? 0 : REG_NOTBOL) == 0) {
        so = pmatch[0].rm_so;
        eo = pmatch[0].rm_eo;

        qrealloc(&ds, di + eo + rl, &dssize);
        memcpy(ds + di, sp, eo);
        di += eo;
        if (++i >= nm) {
            /* replace */
            di -= (eo - so);
            nbs = 0;
            for (s = repl; *s; s++) {
                ds[di++] = c = *s;
                if (c == '\\') {
                    nbs++;
                    continue;
                }
                if (c == '&' || (ex && c >= '0' && c <= '9')) {
                    di -= ((nbs + 3) >> 1);
                    j = 0;
                    if (c != '&') {
                        j = c - '0';
                        nbs++;
                    }
                    if (nbs % 2) {
                        ds[di++] = c;
                    } else {
                        n = pmatch[j].rm_eo - pmatch[j].rm_so;
                        qrealloc(&ds, di + rl + n, &dssize);
                        memcpy(ds + di, sp + pmatch[j].rm_so, n);
                        di += n;
                    }
                }
                nbs = 0;
            }
        }

        sp += eo;
        if (i == nm) break;
        if (eo == so) {
            ds[di] = *sp++;
            if (!ds[di++]) break;
        }
    }

    qrealloc(&ds, di + strlen(sp), &dssize);
    strcpy(ds + di, sp);
    setvar_p(dest, ds);
    if (re == &sreg) regfree(re);
    return i;
}

static var *exec_builtin(node *op, var *res)
{
#define tspl (G.exec_builtin__tspl)

    int (*to_xxx)(int);
    var *tv;
    node *an[4];
    var *av[4];
    const char *as[4];
    regmatch_t pmatch[2];
    regex_t sreg, *re;
    node *spl;
    uint32_t isr, info;
    int nargs;
    time_t tt;
    char *s, *s1;
    int i, l, ll, n;

    tv = nvalloc(4);
    isr = info = op->info;
    op = op->l.n;

    av[2] = av[3] = NULL;
    for (i = 0; i < 4 && op; i++) {
        an[i] = nextarg(&op);
        if (isr & 0x09000000) av[i] = evaluate(an[i], &tv[i]);
        if (isr & 0x08000000) as[i] = getvar_s(av[i]);
        isr >>= 1;
    }

    nargs = i;
    if (nargs < (info >> 30))
        syntax_error(EMSG_TOO_FEW_ARGS);

    switch (info & OPNMASK) {

    case B_a2:
#if ENABLE_FEATURE_AWK_MATH
        setvar_i(res, atan2(getvar_i(av[i]), getvar_i(av[1])));
#else
        syntax_error(EMSG_NO_MATH);
#endif
        break;

    case B_sp:
        if (nargs > 2) {
            spl = (an[2]->info & OPCLSMASK) == OC_REGEXP ?
                an[2] : mk_splitter(getvar_s(evaluate(an[2], &tv[2])), &tspl);
        } else {
            spl = &fsplitter.n;
        }

        n = awk_split(as[0], spl, &s);
        s1 = s;
        clear_array(iamarray(av[1]));
        for (i=1; i<=n; i++)
            setari_u(av[1], i, nextword(&s1));
        free(s);
        setvar_i(res, n);
        break;

    case B_ss:
        l = strlen(as[0]);
        i = getvar_i(av[1]) - 1;
        if (i > l) i = l;
        if (i < 0) i = 0;
        n = (nargs > 2) ? getvar_i(av[2]) : l-i;
        if (n < 0) n = 0;
        s = xmalloc(n+1);
        strncpy(s, as[0]+i, n);
        s[n] = '\0';
        setvar_p(res, s);
        break;

    case B_an:
        setvar_i(res, (long)getvar_i(av[0]) & (long)getvar_i(av[1]));
        break;

    case B_co:
        setvar_i(res, ~(long)getvar_i(av[0]));
        break;

    case B_ls:
        setvar_i(res, (long)getvar_i(av[0]) << (long)getvar_i(av[1]));
        break;

    case B_or:
        setvar_i(res, (long)getvar_i(av[0]) | (long)getvar_i(av[1]));
        break;

    case B_rs:
        setvar_i(res, (long)((unsigned long)getvar_i(av[0]) >> (unsigned long)getvar_i(av[1])));
        break;

    case B_xo:
        setvar_i(res, (long)getvar_i(av[0]) ^ (long)getvar_i(av[1]));
        break;

    case B_lo:
        to_xxx = tolower;
        goto lo_cont;

    case B_up:
        to_xxx = toupper;
 lo_cont:
        s1 = s = xstrdup(as[0]);
        while (*s1) {
            *s1 = (*to_xxx)(*s1);
            s1++;
        }
        setvar_p(res, s);
        break;

    case B_ix:
        n = 0;
        ll = strlen(as[1]);
        l = strlen(as[0]) - ll;
        if (ll > 0 && l >= 0) {
            if (!icase) {
                s = strstr(as[0], as[1]);
                if (s) n = (s - as[0]) + 1;
            } else {
                /* this piece of code is terribly slow and
                 * really should be rewritten
                 */
                for (i=0; i<=l; i++) {
                    if (strncasecmp(as[0]+i, as[1], ll) == 0) {
                        n = i+1;
                        break;
                    }
                }
            }
        }
        setvar_i(res, n);
        break;

    case B_ti:
        if (nargs > 1)
            tt = getvar_i(av[1]);
        else
            time(&tt);
        //s = (nargs > 0) ? as[0] : "%a %b %d %H:%M:%S %Z %Y";
        i = strftime(g_buf, MAXVARFMT,
            ((nargs > 0) ? as[0] : "%a %b %d %H:%M:%S %Z %Y"),
            localtime(&tt));
        g_buf[i] = '\0';
        setvar_s(res, g_buf);
        break;

    case B_ma:
        re = as_regex(an[1], &sreg);
        n = regexec(re, as[0], 1, pmatch, 0);
        if (n == 0) {
            pmatch[0].rm_so++;
            pmatch[0].rm_eo++;
        } else {
            pmatch[0].rm_so = 0;
            pmatch[0].rm_eo = -1;
        }
        setvar_i(newvar("RSTART"), pmatch[0].rm_so);
        setvar_i(newvar("RLENGTH"), pmatch[0].rm_eo - pmatch[0].rm_so);
        setvar_i(res, pmatch[0].rm_so);
        if (re == &sreg) regfree(re);
        break;

    case B_ge:
        awk_sub(an[0], as[1], getvar_i(av[2]), av[3], res, TRUE);
        break;

    case B_gs:
        setvar_i(res, awk_sub(an[0], as[1], 0, av[2], av[2], FALSE));
        break;

    case B_su:
        setvar_i(res, awk_sub(an[0], as[1], 1, av[2], av[2], FALSE));
        break;
    }

    nvfree(tv);
    return res;
#undef tspl
}

/*
 * Evaluate node - the heart of the program. Supplied with subtree
 * and place where to store result. returns ptr to result.
 */
#define XC(n) ((n) >> 8)

static var *evaluate(node *op, var *res)
{
/* This procedure is recursive so we should count every byte */
#define fnargs (G.evaluate__fnargs)
/* seed is initialized to 1 */
#define seed   (G.evaluate__seed)
#define sreg   (G.evaluate__sreg)

    node *op1;
    var *v1;
    union {
        var *v;
        const char *s;
        double d;
        int i;
    } L, R;
    uint32_t opinfo;
    int opn;
    union {
        char *s;
        rstream *rsm;
        FILE *F;
        var *v;
        regex_t *re;
        uint32_t info;
    } X;

    if (!op)
        return setvar_s(res, NULL);

    v1 = nvalloc(2);

    while (op) {
        opinfo = op->info;
        opn = (opinfo & OPNMASK);
        g_lineno = op->lineno;

        /* execute inevitable things */
        op1 = op->l.n;
        if (opinfo & OF_RES1) X.v = L.v = evaluate(op1, v1);
        if (opinfo & OF_RES2) R.v = evaluate(op->r.n, v1+1);
        if (opinfo & OF_STR1) L.s = getvar_s(L.v);
        if (opinfo & OF_STR2) R.s = getvar_s(R.v);
        if (opinfo & OF_NUM1) L.d = getvar_i(L.v);

        switch (XC(opinfo & OPCLSMASK)) {

        /* -- iterative node type -- */

        /* test pattern */
        case XC( OC_TEST ):
            if ((op1->info & OPCLSMASK) == OC_COMMA) {
                /* it's range pattern */
                if ((opinfo & OF_CHECKED) || ptest(op1->l.n)) {
                    op->info |= OF_CHECKED;
                    if (ptest(op1->r.n))
                        op->info &= ~OF_CHECKED;

                    op = op->a.n;
                } else {
                    op = op->r.n;
                }
            } else {
                op = (ptest(op1)) ? op->a.n : op->r.n;
            }
            break;

        /* just evaluate an expression, also used as unconditional jump */
        case XC( OC_EXEC ):
            break;

        /* branch, used in if-else and various loops */
        case XC( OC_BR ):
            op = istrue(L.v) ? op->a.n : op->r.n;
            break;

        /* initialize for-in loop */
        case XC( OC_WALKINIT ):
            hashwalk_init(L.v, iamarray(R.v));
            break;

        /* get next array item */
        case XC( OC_WALKNEXT ):
            op = hashwalk_next(L.v) ? op->a.n : op->r.n;
            break;

        case XC( OC_PRINT ):
        case XC( OC_PRINTF ):
            X.F = stdout;
            if (op->r.n) {
                X.rsm = newfile(R.s);
                if (!X.rsm->F) {
                    if (opn == '|') {
                        X.rsm->F = popen(R.s, "w");
                        if (X.rsm->F == NULL)
                            bb_perror_msg_and_die("popen");
                        X.rsm->is_pipe = 1;
                    } else {
                        X.rsm->F = xfopen(R.s, opn=='w' ? "w" : "a");
                    }
                }
                X.F = X.rsm->F;
            }

            if ((opinfo & OPCLSMASK) == OC_PRINT) {
                if (!op1) {
                    fputs(getvar_s(intvar[F0]), X.F);
                } else {
                    while (op1) {
                        L.v = evaluate(nextarg(&op1), v1);
                        if (L.v->type & VF_NUMBER) {
                            fmt_num(g_buf, MAXVARFMT, getvar_s(intvar[OFMT]),
                                    getvar_i(L.v), TRUE);
                            fputs(g_buf, X.F);
                        } else {
                            fputs(getvar_s(L.v), X.F);
                        }

                        if (op1) fputs(getvar_s(intvar[OFS]), X.F);
                    }
                }
                fputs(getvar_s(intvar[ORS]), X.F);

            } else {    /* OC_PRINTF */
                L.s = awk_printf(op1);
                fputs(L.s, X.F);
                free((char*)L.s);
            }
            fflush(X.F);
            break;

        case XC( OC_DELETE ):
            X.info = op1->info & OPCLSMASK;
            if (X.info == OC_VAR) {
                R.v = op1->l.v;
            } else if (X.info == OC_FNARG) {
                R.v = &fnargs[op1->l.i];
            } else {
                syntax_error(EMSG_NOT_ARRAY);
            }

            if (op1->r.n) {
                clrvar(L.v);
                L.s = getvar_s(evaluate(op1->r.n, v1));
                hash_remove(iamarray(R.v), L.s);
            } else {
                clear_array(iamarray(R.v));
            }
            break;

        case XC( OC_NEWSOURCE ):
            g_progname = op->l.s;
            break;

        case XC( OC_RETURN ):
            copyvar(res, L.v);
            break;

        case XC( OC_NEXTFILE ):
            nextfile = TRUE;
        case XC( OC_NEXT ):
            nextrec = TRUE;
        case XC( OC_DONE ):
            clrvar(res);
            break;

        case XC( OC_EXIT ):
            awk_exit(L.d);

        /* -- recursive node type -- */

        case XC( OC_VAR ):
            L.v = op->l.v;
            if (L.v == intvar[NF])
                split_f0();
            goto v_cont;

        case XC( OC_FNARG ):
            L.v = &fnargs[op->l.i];
 v_cont:
            res = op->r.n ? findvar(iamarray(L.v), R.s) : L.v;
            break;

        case XC( OC_IN ):
            setvar_i(res, hash_search(iamarray(R.v), L.s) ? 1 : 0);
            break;

        case XC( OC_REGEXP ):
            op1 = op;
            L.s = getvar_s(intvar[F0]);
            goto re_cont;

        case XC( OC_MATCH ):
            op1 = op->r.n;
 re_cont:
            X.re = as_regex(op1, &sreg);
            R.i = regexec(X.re, L.s, 0, NULL, 0);
            if (X.re == &sreg) regfree(X.re);
            setvar_i(res, (R.i == 0 ? 1 : 0) ^ (opn == '!' ? 1 : 0));
            break;

        case XC( OC_MOVE ):
            /* if source is a temporary string, jusk relink it to dest */
            if (R.v == v1+1 && R.v->string) {
                res = setvar_p(L.v, R.v->string);
                R.v->string = NULL;
            } else {
                res = copyvar(L.v, R.v);
            }
            break;

        case XC( OC_TERNARY ):
            if ((op->r.n->info & OPCLSMASK) != OC_COLON)
                syntax_error(EMSG_POSSIBLE_ERROR);
            res = evaluate(istrue(L.v) ? op->r.n->l.n : op->r.n->r.n, res);
            break;

        case XC( OC_FUNC ):
            if (!op->r.f->body.first)
                syntax_error(EMSG_UNDEF_FUNC);

            X.v = R.v = nvalloc(op->r.f->nargs+1);
            while (op1) {
                L.v = evaluate(nextarg(&op1), v1);
                copyvar(R.v, L.v);
                R.v->type |= VF_CHILD;
                R.v->x.parent = L.v;
                if (++R.v - X.v >= op->r.f->nargs)
                    break;
            }

            R.v = fnargs;
            fnargs = X.v;

            L.s = g_progname;
            res = evaluate(op->r.f->body.first, res);
            g_progname = L.s;

            nvfree(fnargs);
            fnargs = R.v;
            break;

        case XC( OC_GETLINE ):
        case XC( OC_PGETLINE ):
            if (op1) {
                X.rsm = newfile(L.s);
                if (!X.rsm->F) {
                    if ((opinfo & OPCLSMASK) == OC_PGETLINE) {
                        X.rsm->F = popen(L.s, "r");
                        X.rsm->is_pipe = TRUE;
                    } else {
                        X.rsm->F = fopen(L.s, "r");     /* not xfopen! */
                    }
                }
            } else {
                if (!iF) iF = next_input_file();
                X.rsm = iF;
            }

            if (!X.rsm->F) {
                setvar_i(intvar[ERRNO], errno);
                setvar_i(res, -1);
                break;
            }

            if (!op->r.n)
                R.v = intvar[F0];

            L.i = awk_getline(X.rsm, R.v);
            if (L.i > 0) {
                if (!op1) {
                    incvar(intvar[FNR]);
                    incvar(intvar[NR]);
                }
            }
            setvar_i(res, L.i);
            break;

        /* simple builtins */
        case XC( OC_FBLTIN ):
            switch (opn) {

            case F_in:
                R.d = (int)L.d;
                break;

            case F_rn:
                R.d = (double)rand() / (double)RAND_MAX;
                break;
#if ENABLE_FEATURE_AWK_MATH
            case F_co:
                R.d = cos(L.d);
                break;

            case F_ex:
                R.d = exp(L.d);
                break;

            case F_lg:
                R.d = log(L.d);
                break;

            case F_si:
                R.d = sin(L.d);
                break;

            case F_sq:
                R.d = sqrt(L.d);
                break;
#else
            case F_co:
            case F_ex:
            case F_lg:
            case F_si:
            case F_sq:
                syntax_error(EMSG_NO_MATH);
                break;
#endif
            case F_sr:
                R.d = (double)seed;
                seed = op1 ? (unsigned)L.d : (unsigned)time(NULL);
                srand(seed);
                break;

            case F_ti:
                R.d = time(NULL);
                break;

            case F_le:
                if (!op1)
                    L.s = getvar_s(intvar[F0]);
                R.d = strlen(L.s);
                break;

            case F_sy:
                fflush(NULL);
                R.d = (ENABLE_FEATURE_ALLOW_EXEC && L.s && *L.s)
                        ? (system(L.s) >> 8) : 0;
                break;

            case F_ff:
                if (!op1)
                    fflush(stdout);
                else {
                    if (L.s && *L.s) {
                        X.rsm = newfile(L.s);
                        fflush(X.rsm->F);
                    } else {
                        fflush(NULL);
                    }
                }
                break;

            case F_cl:
                X.rsm = (rstream *)hash_search(fdhash, L.s);
                if (X.rsm) {
                    R.i = X.rsm->is_pipe ? pclose(X.rsm->F) : fclose(X.rsm->F);
                    free(X.rsm->buffer);
                    hash_remove(fdhash, L.s);
                }
                if (R.i != 0)
                    setvar_i(intvar[ERRNO], errno);
                R.d = (double)R.i;
                break;
            }
            setvar_i(res, R.d);
            break;

        case XC( OC_BUILTIN ):
            res = exec_builtin(op, res);
            break;

        case XC( OC_SPRINTF ):
            setvar_p(res, awk_printf(op1));
            break;

        case XC( OC_UNARY ):
            X.v = R.v;
            L.d = R.d = getvar_i(R.v);
            switch (opn) {
            case 'P':
                L.d = ++R.d;
                goto r_op_change;
            case 'p':
                R.d++;
                goto r_op_change;
            case 'M':
                L.d = --R.d;
                goto r_op_change;
            case 'm':
                R.d--;
                goto r_op_change;
            case '!':
                L.d = istrue(X.v) ? 0 : 1;
                break;
            case '-':
                L.d = -R.d;
                break;
 r_op_change:
                setvar_i(X.v, R.d);
            }
            setvar_i(res, L.d);
            break;

        case XC( OC_FIELD ):
            R.i = (int)getvar_i(R.v);
            if (R.i == 0) {
                res = intvar[F0];
            } else {
                split_f0();
                if (R.i > nfields)
                    fsrealloc(R.i);
                res = &Fields[R.i - 1];
            }
            break;

        /* concatenation (" ") and index joining (",") */
        case XC( OC_CONCAT ):
        case XC( OC_COMMA ):
            opn = strlen(L.s) + strlen(R.s) + 2;
            X.s = xmalloc(opn);
            strcpy(X.s, L.s);
            if ((opinfo & OPCLSMASK) == OC_COMMA) {
                L.s = getvar_s(intvar[SUBSEP]);
                X.s = xrealloc(X.s, opn + strlen(L.s));
                strcat(X.s, L.s);
            }
            strcat(X.s, R.s);
            setvar_p(res, X.s);
            break;

        case XC( OC_LAND ):
            setvar_i(res, istrue(L.v) ? ptest(op->r.n) : 0);
            break;

        case XC( OC_LOR ):
            setvar_i(res, istrue(L.v) ? 1 : ptest(op->r.n));
            break;

        case XC( OC_BINARY ):
        case XC( OC_REPLACE ):
            R.d = getvar_i(R.v);
            switch (opn) {
            case '+':
                L.d += R.d;
                break;
            case '-':
                L.d -= R.d;
                break;
            case '*':
                L.d *= R.d;
                break;
            case '/':
                if (R.d == 0) syntax_error(EMSG_DIV_BY_ZERO);
                L.d /= R.d;
                break;
            case '&':
#if ENABLE_FEATURE_AWK_MATH
                L.d = pow(L.d, R.d);
#else
                syntax_error(EMSG_NO_MATH);
#endif
                break;
            case '%':
                if (R.d == 0) syntax_error(EMSG_DIV_BY_ZERO);
                L.d -= (int)(L.d / R.d) * R.d;
                break;
            }
            res = setvar_i(((opinfo & OPCLSMASK) == OC_BINARY) ? res : X.v, L.d);
            break;

        case XC( OC_COMPARE ):
            if (is_numeric(L.v) && is_numeric(R.v)) {
                L.d = getvar_i(L.v) - getvar_i(R.v);
            } else {
                L.s = getvar_s(L.v);
                R.s = getvar_s(R.v);
                L.d = icase ? strcasecmp(L.s, R.s) : strcmp(L.s, R.s);
            }
            switch (opn & 0xfe) {
            case 0:
                R.i = (L.d > 0);
                break;
            case 2:
                R.i = (L.d >= 0);
                break;
            case 4:
                R.i = (L.d == 0);
                break;
            }
            setvar_i(res, (opn & 0x1 ? R.i : !R.i) ? 1 : 0);
            break;

        default:
            syntax_error(EMSG_POSSIBLE_ERROR);
        }
        if ((opinfo & OPCLSMASK) <= SHIFT_TIL_THIS)
            op = op->a.n;
        if ((opinfo & OPCLSMASK) >= RECUR_FROM_THIS)
            break;
        if (nextrec)
            break;
    }
    nvfree(v1);
    return res;
#undef fnargs
#undef seed
#undef sreg
}


/* -------- main & co. -------- */

static int awk_exit(int r)
{
    var tv;
    unsigned i;
    hash_item *hi;

    zero_out_var(&tv);

    if (!exiting) {
        exiting = TRUE;
        nextrec = FALSE;
        evaluate(endseq.first, &tv);
    }

    /* waiting for children */
    for (i = 0; i < fdhash->csize; i++) {
        hi = fdhash->items[i];
        while (hi) {
            if (hi->data.rs.F && hi->data.rs.is_pipe)
                pclose(hi->data.rs.F);
            hi = hi->next;
        }
    }

    exit(r);
}

/* if expr looks like "var=value", perform assignment and return 1,
 * otherwise return 0 */
static int is_assignment(const char *expr)
{
    char *exprc, *s, *s0, *s1;

    exprc = xstrdup(expr);
    if (!isalnum_(*exprc) || (s = strchr(exprc, '=')) == NULL) {
        free(exprc);
        return FALSE;
    }

    *(s++) = '\0';
    s0 = s1 = s;
    while (*s)
        *(s1++) = nextchar(&s);

    *s1 = '\0';
    setvar_u(newvar(exprc), s0);
    free(exprc);
    return TRUE;
}

/* switch to next input file */
static rstream *next_input_file(void)
{
#define rsm          (G.next_input_file__rsm)
#define files_happen (G.next_input_file__files_happen)

    FILE *F = NULL;
    const char *fname, *ind;

    if (rsm.F) fclose(rsm.F);
    rsm.F = NULL;
    rsm.pos = rsm.adv = 0;

    do {
        if (getvar_i(intvar[ARGIND])+1 >= getvar_i(intvar[ARGC])) {
            if (files_happen)
                return NULL;
            fname = "-";
            F = stdin;
        } else {
            ind = getvar_s(incvar(intvar[ARGIND]));
            fname = getvar_s(findvar(iamarray(intvar[ARGV]), ind));
            if (fname && *fname && !is_assignment(fname))
                F = afopen(fname, "r");
        }
    } while (!F);

    files_happen = TRUE;
    setvar_s(intvar[FILENAME], fname);
    rsm.F = F;
    return &rsm;
#undef rsm
#undef files_happen
}

int awk_main(int argc, char **argv);
int awk_main(int argc, char **argv)
{
    unsigned opt;
    char *opt_F, *opt_W;
    llist_t *opt_v = NULL;
    int i, j, flen;
    var *v;
    var tv;
    char **envp;
    char *vnames = (char *)vNames; /* cheat */
    char *vvalues = (char *)vValues;

    INIT_G();

    /* Undo busybox.c, or else strtod may eat ','! This breaks parsing:
     * $1,$2 == '$1,' '$2', NOT '$1' ',' '$2' */
    if (ENABLE_LOCALE_SUPPORT)
        setlocale(LC_NUMERIC, "C");

    zero_out_var(&tv);

    /* allocate global buffer */
    g_buf = xmalloc(MAXVARFMT + 1);

    vhash = hash_init();
    ahash = hash_init();
    fdhash = hash_init();
    fnhash = hash_init();

    /* initialize variables */
    for (i = 0; *vnames; i++) {
        intvar[i] = v = newvar(nextword(&vnames));
        if (*vvalues != '\377')
            setvar_s(v, nextword(&vvalues));
        else
            setvar_i(v, 0);

        if (*vnames == '*') {
            v->type |= VF_SPECIAL;
            vnames++;
        }
    }

    handle_special(intvar[FS]);
    handle_special(intvar[RS]);

    newfile("/dev/stdin")->F = stdin;
    newfile("/dev/stdout")->F = stdout;
    newfile("/dev/stderr")->F = stderr;

    /* Huh, people report that sometimes environ is NULL. Oh well. */
    if (environ) for (envp = environ; *envp; envp++) {
        /* environ is writable, thus we don't strdup it needlessly */
        char *s = *envp;
        char *s1 = strchr(s, '=');
        if (s1) {
            *s1 = '\0';
            /* Both findvar and setvar_u take const char*
             * as 2nd arg -> environment is not trashed */
            setvar_u(findvar(iamarray(intvar[ENVIRON]), s), s1 + 1);
            *s1 = '=';
        }
    }
    opt_complementary = "v::";
    opt = getopt32(argv, "F:v:f:W:", &opt_F, &opt_v, &g_progname, &opt_W);
    argv += optind;
    argc -= optind;
    if (opt & 0x1)
        setvar_s(intvar[FS], opt_F); // -F
    while (opt_v) { /* -v */
        if (!is_assignment(llist_pop(&opt_v)))
            bb_show_usage();
    }
    if (opt & 0x4) { // -f
        char *s = s; /* die, gcc, die */
        FILE *from_file = afopen(g_progname, "r");
        /* one byte is reserved for some trick in next_token */
        if (fseek(from_file, 0, SEEK_END) == 0) {
            flen = ftell(from_file);
            s = xmalloc(flen + 4);
            fseek(from_file, 0, SEEK_SET);
            i = 1 + fread(s + 1, 1, flen, from_file);
        } else {
            for (i = j = 1; j > 0; i += j) {
                s = xrealloc(s, i + 4096);
                j = fread(s + i, 1, 4094, from_file);
            }
        }
        s[i] = '\0';
        fclose(from_file);
        parse_program(s + 1);
        free(s);
    } else { // no -f: take program from 1st parameter
        if (!argc)
            bb_show_usage();
        g_progname = "cmd. line";
        parse_program(*argv++);
        argc--;
    }
    if (opt & 0x8) // -W
        bb_error_msg("warning: unrecognized option '-W %s' ignored", opt_W);

    /* fill in ARGV array */
    setvar_i(intvar[ARGC], argc + 1);
    setari_u(intvar[ARGV], 0, "awk");
    i = 0;
    while (*argv)
        setari_u(intvar[ARGV], ++i, *argv++);

    evaluate(beginseq.first, &tv);
    if (!mainseq.first && !endseq.first)
        awk_exit(EXIT_SUCCESS);

    /* input file could already be opened in BEGIN block */
    if (!iF) iF = next_input_file();

    /* passing through input files */
    while (iF) {
        nextfile = FALSE;
        setvar_i(intvar[FNR], 0);

        while ((i = awk_getline(iF, intvar[F0])) > 0) {
            nextrec = FALSE;
            incvar(intvar[NR]);
            incvar(intvar[FNR]);
            evaluate(mainseq.first, &tv);

            if (nextfile)
                break;
        }

        if (i < 0)
            syntax_error(strerror(errno));

        iF = next_input_file();
    }

    awk_exit(EXIT_SUCCESS);
    /*return 0;*/
}