| 1 | /* The pwb version this is based on */ |
| 2 | static char *printf_id = "@(#) printf.c:2.2 6/5/79"; |
| 3 | /* The local sccs version within ex */ |
| 4 | static char *sccsid = "@(#)printf.c 4.3 %G%"; |
| 5 | #include "varargs.h" |
| 6 | /* |
| 7 | * This version of printf is compatible with the Version 7 C |
| 8 | * printf. The differences are only minor except that this |
| 9 | * printf assumes it is to print through putchar. Version 7 |
| 10 | * printf is more general (and is much larger) and includes |
| 11 | * provisions for floating point. |
| 12 | */ |
| 13 | |
| 14 | |
| 15 | #define MAXOCT 11 /* Maximum octal digits in a long */ |
| 16 | #define MAXINT 32767 /* largest normal length positive integer */ |
| 17 | #define BIG 1000000000 /* largest power of 10 less than an unsigned long */ |
| 18 | #define MAXDIGS 10 /* number of digits in BIG */ |
| 19 | |
| 20 | static int width, sign, fill; |
| 21 | |
| 22 | char *_p_dconv(); |
| 23 | |
| 24 | printf(va_alist) |
| 25 | va_dcl |
| 26 | { |
| 27 | va_list ap; |
| 28 | register char *fmt; |
| 29 | char fcode; |
| 30 | int prec; |
| 31 | int length,mask1,nbits,n; |
| 32 | long int mask2, num; |
| 33 | register char *bptr; |
| 34 | char *ptr; |
| 35 | char buf[134]; |
| 36 | |
| 37 | va_start(ap); |
| 38 | fmt = va_arg(ap,char *); |
| 39 | for (;;) { |
| 40 | /* process format string first */ |
| 41 | while ((fcode = *fmt++)!='%') { |
| 42 | /* ordinary (non-%) character */ |
| 43 | if (fcode=='\0') |
| 44 | return; |
| 45 | putchar(fcode); |
| 46 | } |
| 47 | /* length modifier: -1 for h, 1 for l, 0 for none */ |
| 48 | length = 0; |
| 49 | /* check for a leading - sign */ |
| 50 | sign = 0; |
| 51 | if (*fmt == '-') { |
| 52 | sign++; |
| 53 | fmt++; |
| 54 | } |
| 55 | /* a '0' may follow the - sign */ |
| 56 | /* this is the requested fill character */ |
| 57 | fill = 1; |
| 58 | if (*fmt == '0') { |
| 59 | fill--; |
| 60 | fmt++; |
| 61 | } |
| 62 | |
| 63 | /* Now comes a digit string which may be a '*' */ |
| 64 | if (*fmt == '*') { |
| 65 | width = va_arg(ap, int); |
| 66 | if (width < 0) { |
| 67 | width = -width; |
| 68 | sign = !sign; |
| 69 | } |
| 70 | fmt++; |
| 71 | } |
| 72 | else { |
| 73 | width = 0; |
| 74 | while (*fmt>='0' && *fmt<='9') |
| 75 | width = width * 10 + (*fmt++ - '0'); |
| 76 | } |
| 77 | |
| 78 | /* maybe a decimal point followed by more digits (or '*') */ |
| 79 | if (*fmt=='.') { |
| 80 | if (*++fmt == '*') { |
| 81 | prec = va_arg(ap, int); |
| 82 | fmt++; |
| 83 | } |
| 84 | else { |
| 85 | prec = 0; |
| 86 | while (*fmt>='0' && *fmt<='9') |
| 87 | prec = prec * 10 + (*fmt++ - '0'); |
| 88 | } |
| 89 | } |
| 90 | else |
| 91 | prec = -1; |
| 92 | |
| 93 | /* |
| 94 | * At this point, "sign" is nonzero if there was |
| 95 | * a sign, "fill" is 0 if there was a leading |
| 96 | * zero and 1 otherwise, "width" and "prec" |
| 97 | * contain numbers corresponding to the digit |
| 98 | * strings before and after the decimal point, |
| 99 | * respectively, and "fmt" addresses the next |
| 100 | * character after the whole mess. If there was |
| 101 | * no decimal point, "prec" will be -1. |
| 102 | */ |
| 103 | switch (*fmt) { |
| 104 | case 'L': |
| 105 | case 'l': |
| 106 | length = 2; |
| 107 | /* no break!! */ |
| 108 | case 'h': |
| 109 | case 'H': |
| 110 | length--; |
| 111 | fmt++; |
| 112 | break; |
| 113 | } |
| 114 | |
| 115 | /* |
| 116 | * At exit from the following switch, we will |
| 117 | * emit the characters starting at "bptr" and |
| 118 | * ending at "ptr"-1, unless fcode is '\0'. |
| 119 | */ |
| 120 | switch (fcode = *fmt++) { |
| 121 | /* process characters and strings first */ |
| 122 | case 'c': |
| 123 | buf[0] = va_arg(ap, int); |
| 124 | ptr = bptr = &buf[0]; |
| 125 | if (buf[0] != '\0') |
| 126 | ptr++; |
| 127 | break; |
| 128 | case 's': |
| 129 | bptr = va_arg(ap,char *); |
| 130 | if (bptr==0) |
| 131 | bptr = "(null pointer)"; |
| 132 | if (prec < 0) |
| 133 | prec = MAXINT; |
| 134 | for (n=0; *bptr++ && n < prec; n++) ; |
| 135 | ptr = --bptr; |
| 136 | bptr -= n; |
| 137 | break; |
| 138 | case 'O': |
| 139 | length = 1; |
| 140 | fcode = 'o'; |
| 141 | /* no break */ |
| 142 | case 'o': |
| 143 | case 'X': |
| 144 | case 'x': |
| 145 | if (length > 0) |
| 146 | num = va_arg(ap,long); |
| 147 | else |
| 148 | num = (unsigned)va_arg(ap,int); |
| 149 | if (fcode=='o') { |
| 150 | mask1 = 0x7; |
| 151 | mask2 = 0x1fffffffL; |
| 152 | nbits = 3; |
| 153 | } |
| 154 | else { |
| 155 | mask1 = 0xf; |
| 156 | mask2 = 0x0fffffffL; |
| 157 | nbits = 4; |
| 158 | } |
| 159 | n = (num!=0); |
| 160 | bptr = buf + MAXOCT + 3; |
| 161 | /* shift and mask for speed */ |
| 162 | do |
| 163 | if (((int) num & mask1) < 10) |
| 164 | *--bptr = ((int) num & mask1) + 060; |
| 165 | else |
| 166 | *--bptr = ((int) num & mask1) + 0127; |
| 167 | while (num = (num >> nbits) & mask2); |
| 168 | |
| 169 | if (fcode=='o') { |
| 170 | if (n) |
| 171 | *--bptr = '0'; |
| 172 | } |
| 173 | else |
| 174 | if (!sign && fill <= 0) { |
| 175 | putchar('0'); |
| 176 | putchar(fcode); |
| 177 | width -= 2; |
| 178 | } |
| 179 | else { |
| 180 | *--bptr = fcode; |
| 181 | *--bptr = '0'; |
| 182 | } |
| 183 | ptr = buf + MAXOCT + 3; |
| 184 | break; |
| 185 | case 'D': |
| 186 | case 'U': |
| 187 | case 'I': |
| 188 | length = 1; |
| 189 | fcode = fcode + 'a' - 'A'; |
| 190 | /* no break */ |
| 191 | case 'd': |
| 192 | case 'i': |
| 193 | case 'u': |
| 194 | if (length > 0) |
| 195 | num = va_arg(ap,long); |
| 196 | else { |
| 197 | n = va_arg(ap,int); |
| 198 | if (fcode=='u') |
| 199 | num = (unsigned) n; |
| 200 | else |
| 201 | num = (long) n; |
| 202 | } |
| 203 | if (n = (fcode != 'u' && num < 0)) |
| 204 | num = -num; |
| 205 | /* now convert to digits */ |
| 206 | bptr = _p_dconv(num, buf); |
| 207 | if (n) |
| 208 | *--bptr = '-'; |
| 209 | if (fill == 0) |
| 210 | fill = -1; |
| 211 | ptr = buf + MAXDIGS + 1; |
| 212 | break; |
| 213 | default: |
| 214 | /* not a control character, |
| 215 | * print it. |
| 216 | */ |
| 217 | ptr = bptr = &fcode; |
| 218 | ptr++; |
| 219 | break; |
| 220 | } |
| 221 | if (fcode != '\0') |
| 222 | _p_emit(bptr,ptr); |
| 223 | } |
| 224 | va_end(ap); |
| 225 | } |
| 226 | |
| 227 | /* _p_dconv converts the unsigned long integer "value" to |
| 228 | * printable decimal and places it in "buffer", right-justified. |
| 229 | * The value returned is the address of the first non-zero character, |
| 230 | * or the address of the last character if all are zero. |
| 231 | * The result is NOT null terminated, and is MAXDIGS characters long, |
| 232 | * starting at buffer[1] (to allow for insertion of a sign). |
| 233 | * |
| 234 | * This program assumes it is running on 2's complement machine |
| 235 | * with reasonable overflow treatment. |
| 236 | */ |
| 237 | char * |
| 238 | _p_dconv(value, buffer) |
| 239 | long value; |
| 240 | char *buffer; |
| 241 | { |
| 242 | register char *bp; |
| 243 | register int svalue; |
| 244 | int n; |
| 245 | long lval; |
| 246 | |
| 247 | bp = buffer; |
| 248 | |
| 249 | /* zero is a special case */ |
| 250 | if (value == 0) { |
| 251 | bp += MAXDIGS; |
| 252 | *bp = '0'; |
| 253 | return(bp); |
| 254 | } |
| 255 | |
| 256 | /* develop the leading digit of the value in "n" */ |
| 257 | n = 0; |
| 258 | while (value < 0) { |
| 259 | value -= BIG; /* will eventually underflow */ |
| 260 | n++; |
| 261 | } |
| 262 | while ((lval = value - BIG) >= 0) { |
| 263 | value = lval; |
| 264 | n++; |
| 265 | } |
| 266 | |
| 267 | /* stash it in buffer[1] to allow for a sign */ |
| 268 | bp[1] = n + '0'; |
| 269 | /* |
| 270 | * Now develop the rest of the digits. Since speed counts here, |
| 271 | * we do it in two loops. The first gets "value" down until it |
| 272 | * is no larger than MAXINT. The second one uses integer divides |
| 273 | * rather than long divides to speed it up. |
| 274 | */ |
| 275 | bp += MAXDIGS + 1; |
| 276 | while (value > MAXINT) { |
| 277 | *--bp = (int)(value % 10) + '0'; |
| 278 | value /= 10; |
| 279 | } |
| 280 | |
| 281 | /* cannot lose precision */ |
| 282 | svalue = value; |
| 283 | while (svalue > 0) { |
| 284 | *--bp = (svalue % 10) + '0'; |
| 285 | svalue /= 10; |
| 286 | } |
| 287 | |
| 288 | /* fill in intermediate zeroes if needed */ |
| 289 | if (buffer[1] != '0') { |
| 290 | while (bp > buffer + 2) |
| 291 | *--bp = '0'; |
| 292 | --bp; |
| 293 | } |
| 294 | return(bp); |
| 295 | } |
| 296 | |
| 297 | /* |
| 298 | * This program sends string "s" to putchar. The character after |
| 299 | * the end of "s" is given by "send". This allows the size of the |
| 300 | * field to be computed; it is stored in "alen". "width" contains the |
| 301 | * user specified length. If width<alen, the width will be taken to |
| 302 | * be alen. "sign" is zero if the string is to be right-justified |
| 303 | * in the field, nonzero if it is to be left-justified. "fill" is |
| 304 | * 0 if the string is to be padded with '0', positive if it is to be |
| 305 | * padded with ' ', and negative if an initial '-' should appear before |
| 306 | * any padding in right-justification (to avoid printing "-3" as |
| 307 | * "000-3" where "-0003" was intended). |
| 308 | */ |
| 309 | _p_emit(s, send) |
| 310 | register char *s; |
| 311 | char *send; |
| 312 | { |
| 313 | char cfill; |
| 314 | register int alen; |
| 315 | int npad; |
| 316 | |
| 317 | alen = send - s; |
| 318 | if (alen > width) |
| 319 | width = alen; |
| 320 | cfill = fill>0? ' ': '0'; |
| 321 | |
| 322 | /* we may want to print a leading '-' before anything */ |
| 323 | if (*s == '-' && fill < 0) { |
| 324 | putchar(*s++); |
| 325 | alen--; |
| 326 | width--; |
| 327 | } |
| 328 | npad = width - alen; |
| 329 | |
| 330 | /* emit any leading pad characters */ |
| 331 | if (!sign) |
| 332 | while (--npad >= 0) |
| 333 | putchar(cfill); |
| 334 | |
| 335 | /* emit the string itself */ |
| 336 | while (--alen >= 0) |
| 337 | putchar(*s++); |
| 338 | |
| 339 | /* emit trailing pad characters */ |
| 340 | if (sign) |
| 341 | while (--npad >= 0) |
| 342 | putchar(cfill); |
| 343 | } |