usr.bin/sort/fields.c

   1 /*      $NetBSD: fields.c,v 1.31 2009/11/06 18:34:22 joerg Exp $        */
   2
   3 /*-
   4  * Copyright (c) 2000-2003 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Ben Harris and Jaromir Dolecek.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*-
  33  * Copyright (c) 1993
  34  *      The Regents of the University of California.  All rights reserved.
  35  *
  36  * This code is derived from software contributed to Berkeley by
  37  * Peter McIlroy.
  38  *
  39  * Redistribution and use in source and binary forms, with or without
  40  * modification, are permitted provided that the following conditions
  41  * are met:
  42  * 1. Redistributions of source code must retain the above copyright
  43  *    notice, this list of conditions and the following disclaimer.
  44  * 2. Redistributions in binary form must reproduce the above copyright
  45  *    notice, this list of conditions and the following disclaimer in the
  46  *    documentation and/or other materials provided with the distribution.
  47  * 3. Neither the name of the University nor the names of its contributors
  48  *    may be used to endorse or promote products derived from this software
  49  *    without specific prior written permission.
  50  *
  51  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  */
  63
  64 /* Subroutines to generate sort keys. */
  65
  66 #include "sort.h"
  67
  68 #define SKIP_BLANKS(ptr) {                                      \
  69         if (BLANK & d_mask[*(ptr)])                             \
  70                 while (BLANK & d_mask[*(++(ptr))]);             \
  71 }
  72
  73 #define NEXTCOL(pos) {                                          \
  74         if (!SEP_FLAG)                                          \
  75                 while (BLANK & l_d_mask[*(++pos)]);             \
  76         while ((*(pos+1) != '\0') && !((FLD_D | REC_D_F) & l_d_mask[*++pos]));\
  77 }
  78
  79 static u_char *enterfield(u_char *, const u_char *, struct field *, int);
  80 static u_char *number(u_char *, const u_char *, u_char *, u_char *, int);
  81 static u_char *length(u_char *, const u_char *, u_char *, u_char *, int);
  82
  83 #define DECIMAL_POINT '.'
  84
  85 /*
  86  * constructs sort key with leading recheader, followed by the key,
  87  * followed by the original line.
  88  */
  89 length_t
  90 enterkey(RECHEADER *keybuf, const u_char *keybuf_end, u_char *line_data,
  91     size_t line_size, struct field fieldtable[])
  92         /* keybuf:       pointer to start of key */
  93 {
  94         int i;
  95         u_char *l_d_mask;
  96         u_char *lineend, *pos;
  97         const u_char *endkey;
  98         u_char *keypos;
  99         struct coldesc *clpos;
 100         int col = 1;
 101         struct field *ftpos;
 102
 103         l_d_mask = d_mask;
 104         pos = line_data - 1;
 105         lineend = line_data + line_size-1;
 106                                 /* don't include rec_delimiter */
 107
 108         for (i = 0; i < ncols; i++) {
 109                 clpos = clist + i;
 110                 for (; (col < clpos->num) && (pos < lineend); col++) {
 111                         NEXTCOL(pos);
 112                 }
 113                 if (pos >= lineend)
 114                         break;
 115                 clpos->start = SEP_FLAG ? pos + 1 : pos;
 116                 NEXTCOL(pos);
 117                 clpos->end = pos;
 118                 col++;
 119                 if (pos >= lineend) {
 120                         clpos->end = lineend;
 121                         i++;
 122                         break;
 123                 }
 124         }
 125         for (; i <= ncols; i++)
 126                 clist[i].start = clist[i].end = lineend;
 127         if (clist[0].start < line_data)
 128                 clist[0].start++;
 129
 130         /*
 131          * We write the sort keys (concatenated) followed by the
 132          * original line data (for output) as the 'keybuf' data.
 133          * keybuf->length is the number of key bytes + data bytes.
 134          * keybuf->offset is the number of key bytes.
 135          * We add a record separator weight after the key in case
 136          * (as is usual) we need to preserve the order of equal lines,
 137          * and for 'sort -u'.
 138          * The key itself will have had the correct weight applied.
 139          */
 140         keypos = keybuf->data;
 141         endkey = keybuf_end - line_size - 1;
 142         if (endkey <= keypos)
 143                 /* No room for any key bytes */
 144                 return 1;
 145
 146         for (ftpos = fieldtable + 1; ftpos->icol.num; ftpos++) {
 147                 if ((keypos = enterfield(keypos, endkey, ftpos,
 148                     fieldtable->flags)) == NULL)
 149                         return (1);
 150         }
 151
 152         keybuf->offset = keypos - keybuf->data;
 153         keybuf->length = keybuf->offset + line_size;
 154
 155         /*
 156          * Posix requires that equal keys be further sorted by the
 157          * entire original record.
 158          * NetBSD has (at least for some time) kept equal keys in
 159          * their original order.
 160          * For 'sort -u' posix_sort is unset.
 161          */
 162         keybuf->keylen = posix_sort ? keybuf->length : keybuf->offset;
 163
 164         memcpy(keypos, line_data, line_size);
 165         return (0);
 166 }
 167
 168 /*
 169  * constructs a field (as defined by -k) within a key
 170  */
 171 static u_char *
 172 enterfield(u_char *tablepos, const u_char *endkey, struct field *cur_fld,
 173     int __attribute__ ((unused)) gflags)
 174 {
 175         u_char *start, *end, *lineend, *mask, *lweight;
 176         struct column icol, tcol;
 177         u_int flags;
 178
 179         icol = cur_fld->icol;
 180         tcol = cur_fld->tcol;
 181         flags = cur_fld->flags;
 182         start = icol.p->start;
 183         lineend = clist[ncols].end;
 184         if (flags & BI)
 185                 SKIP_BLANKS(start);
 186         start += icol.indent;
 187         start = min(start, lineend);
 188
 189         if (!tcol.num)
 190                 end = lineend;
 191         else {
 192                 if (tcol.indent) {
 193                         end = tcol.p->start;
 194                         if (flags & BT)
 195                                 SKIP_BLANKS(end);
 196                         end += tcol.indent;
 197                         end = min(end, lineend);
 198                 } else
 199                         end = tcol.p->end;
 200         }
 201
 202         if (flags & L)
 203                 return length(tablepos, endkey, start, end, flags);
 204         if (flags & N)
 205                 return number(tablepos, endkey, start, end, flags);
 206
 207         /* Bound check space - assuming nothing is skipped */
 208         if (tablepos + (end - start) + 1 >= endkey)
 209                 return NULL;
 210
 211         mask = cur_fld->mask;
 212         lweight = cur_fld->weights;
 213         for (; start < end; start++) {
 214                 if (!mask || mask[*start]) {
 215                         *tablepos++ = lweight[*start];
 216                 }
 217         }
 218         /* Add extra byte (absent from lweight) to sort short keys correctly */
 219         *tablepos++ = lweight[REC_D];
 220         return tablepos;
 221 }
 222
 223 /*
 224  * Numbers are converted to a floating point format (exponent & mantissa)
 225  * so that they compare correctly as sequence of unsigned bytes.
 226  * Bytes 0x00 and 0xff are used to terminate positive and negative numbers
 227  * to ensure that 0.123 sorts after 0.12 and -0.123 sorts before -0.12.
 228  *
 229  * The first byte contain the overall sign, exponent sign and some of the
 230  * exponent. These have to be ordered (-ve value, decreasing exponent),
 231  * zero, (+ve value, increasing exponent).
 232  *
 233  * The first byte is 0x80 for zero, 0xc0 for +ve with exponent 0.
 234  * -ve values are the 1's compliments (so 0x7f isn't used!).
 235  *
 236  * This only leaves 63 byte values for +ve exponents - which isn't enough.
 237  * The largest 4 exponent values are used to hold a byte count of the
 238  * number of following bytes that contain 8 exponent bits per byte,
 239  * This lets us sort exponents from -2^31 to +2^31.
 240  *
 241  * The mantissa is stored 2 digits per byte offset by 0x40, for negative
 242  * numbers the order must be reversed (they are bit inverted).
 243  *
 244  * Reverse sorts are done by inverting the sign of the number.
 245  */
 246 #define MAX_EXP_ENC  ((int)sizeof(int))
 247
 248 static u_char *
 249 number(u_char *pos, const u_char *bufend, u_char *line, u_char *lineend,
 250     int reverse)
 251 {
 252         int exponent = -1;
 253         int had_dp = 0;
 254         u_char *tline;
 255         char ch;
 256         unsigned int val;
 257         u_char *last_nz_pos;
 258         u_char negate;
 259
 260         if (reverse & R)
 261                 negate = 0xff;
 262         else
 263                 negate = 0;
 264
 265         /* Give ourselves space for the key terminator */
 266         bufend--;
 267
 268         /* Ensure we have enough space for the exponent */
 269         if (pos + 1 + MAX_EXP_ENC > bufend)
 270                 return (NULL);
 271
 272         SKIP_BLANKS(line);
 273         if (*line == '-') {     /* set the sign */
 274                 negate ^= 0xff;
 275                 line++;
 276         }
 277         /* eat initial zeroes */
 278         for (; *line == '0' && line < lineend; line++)
 279                 continue;
 280
 281         /* calculate exponents */
 282         if (*line == DECIMAL_POINT) {
 283                 /* Decimal fraction */
 284                 had_dp = 1;
 285                 while (*++line == '0' && line < lineend)
 286                         exponent--;
 287         } else {
 288                 /* Large (absolute) value, count digits */
 289                 for (tline = line; *tline >= '0' &&
 290                     *tline <= '9' && tline < lineend; tline++)
 291                         exponent++;
 292         }
 293
 294         /* If the first/next character isn't a digit, value is zero */
 295         if (*line < '1' || *line > '9' || line >= lineend) {
 296                 /* This may be "0", "0.00", "000" or "fubar" but sorts as 0 */
 297                 /* XXX what about NaN, NAN, inf and INF */
 298                 *pos++ = 0x80;
 299                 return pos;
 300         }
 301
 302         /* Maybe here we should allow for e+12 (etc) */
 303
 304         if (exponent < 0x40 - MAX_EXP_ENC && -exponent < 0x40 - MAX_EXP_ENC) {
 305                 /* Value ok for simple encoding */
 306                 /* exponent 0 is 0xc0 for +ve numbers and 0x40 for -ve ones */
 307                 exponent += 0xc0;
 308                 *pos++ = negate ^ exponent;
 309         } else {
 310                 /* Out or range for a single byte */
 311                 int c, t;
 312                 t = exponent > 0 ? exponent : -exponent;
 313                 /* Count how many 8-bit bytes are needed */
 314                 for (c = 0; ; c++) {
 315                         t >>= 8;
 316                         if (t == 0)
 317                                 break;
 318                 }
 319                 /* 'c' better be 0..3 here - but probably 0..1 */
 320                 /* Offset just outside valid range */
 321                 t = c + 0x40 - MAX_EXP_ENC;
 322                 if (exponent < 0)
 323                         t = -t;
 324                 *pos++ = negate ^ (t + 0xc0);
 325                 /* now add each byte, most significant first */
 326                 for (; c >= 0; c--)
 327                         *pos++ = negate ^ (exponent >> (c * 8));
 328         }
 329
 330         /* Finally add mantissa, 2 digits per byte */
 331         for (last_nz_pos = pos; line < lineend; ) {
 332                 if (pos >= bufend)
 333                         return NULL;
 334                 ch = *line++;
 335                 val = (ch - '0') * 10;
 336                 if (val > 90) {
 337                         if (ch == DECIMAL_POINT && !had_dp) {
 338                                 had_dp = 1;
 339                                 continue;
 340                         }
 341                         break;
 342                 }
 343                 while (line < lineend) {
 344                         ch = *line++;
 345                         if (ch == DECIMAL_POINT && !had_dp) {
 346                                 had_dp = 1;
 347                                 continue;
 348                         }
 349                         if (ch < '0' || ch > '9')
 350                                 line = lineend;
 351                         else
 352                                 val += ch - '0';
 353                         break;
 354                 }
 355                 *pos++ = negate ^ (val + 0x40);
 356                 if (val != 0)
 357                         last_nz_pos = pos;
 358         }
 359
 360         /* Add key terminator, deleting any trailing "00" */
 361         *last_nz_pos++ = negate;
 362
 363         return (last_nz_pos);
 364 }
 365
 366 static u_char *
 367 length(u_char *pos, const u_char *bufend, u_char *line, u_char *lineend,
 368     int flag)
 369 {
 370         u_char buf[32];
 371         int l;
 372         SKIP_BLANKS(line);
 373         l = snprintf((char *)buf, sizeof(buf), "%td", lineend - line);
 374         return number(pos, bufend, buf, buf + l, flag);
 375 }