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564 lines
12 KiB
564 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* -*- linux-c -*- ------------------------------------------------------- * |
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* |
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* Copyright (C) 1991, 1992 Linus Torvalds |
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* Copyright 2007 rPath, Inc. - All Rights Reserved |
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* |
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* ----------------------------------------------------------------------- */ |
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/* |
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* Oh, it's a waste of space, but oh-so-yummy for debugging. |
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*/ |
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#include <stdarg.h> |
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#include <linux/compiler.h> |
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#include <linux/ctype.h> |
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#include <linux/kernel.h> |
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#include <linux/limits.h> |
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#include <linux/string.h> |
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#include <linux/types.h> |
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static |
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int skip_atoi(const char **s) |
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{ |
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int i = 0; |
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while (isdigit(**s)) |
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i = i * 10 + *((*s)++) - '0'; |
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return i; |
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} |
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/* |
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* put_dec_full4 handles numbers in the range 0 <= r < 10000. |
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* The multiplier 0xccd is round(2^15/10), and the approximation |
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* r/10 == (r * 0xccd) >> 15 is exact for all r < 16389. |
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*/ |
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static |
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void put_dec_full4(char *end, unsigned int r) |
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{ |
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int i; |
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for (i = 0; i < 3; i++) { |
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unsigned int q = (r * 0xccd) >> 15; |
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*--end = '0' + (r - q * 10); |
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r = q; |
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} |
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*--end = '0' + r; |
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} |
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/* put_dec is copied from lib/vsprintf.c with small modifications */ |
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/* |
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* Call put_dec_full4 on x % 10000, return x / 10000. |
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* The approximation x/10000 == (x * 0x346DC5D7) >> 43 |
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* holds for all x < 1,128,869,999. The largest value this |
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* helper will ever be asked to convert is 1,125,520,955. |
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* (second call in the put_dec code, assuming n is all-ones). |
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*/ |
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static |
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unsigned int put_dec_helper4(char *end, unsigned int x) |
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{ |
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unsigned int q = (x * 0x346DC5D7ULL) >> 43; |
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put_dec_full4(end, x - q * 10000); |
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return q; |
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} |
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/* Based on code by Douglas W. Jones found at |
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* <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour> |
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* (with permission from the author). |
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* Performs no 64-bit division and hence should be fast on 32-bit machines. |
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*/ |
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static |
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char *put_dec(char *end, unsigned long long n) |
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{ |
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unsigned int d3, d2, d1, q, h; |
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char *p = end; |
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d1 = ((unsigned int)n >> 16); /* implicit "& 0xffff" */ |
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h = (n >> 32); |
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d2 = (h ) & 0xffff; |
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d3 = (h >> 16); /* implicit "& 0xffff" */ |
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/* n = 2^48 d3 + 2^32 d2 + 2^16 d1 + d0 |
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= 281_4749_7671_0656 d3 + 42_9496_7296 d2 + 6_5536 d1 + d0 */ |
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q = 656 * d3 + 7296 * d2 + 5536 * d1 + ((unsigned int)n & 0xffff); |
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q = put_dec_helper4(p, q); |
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p -= 4; |
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q += 7671 * d3 + 9496 * d2 + 6 * d1; |
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q = put_dec_helper4(p, q); |
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p -= 4; |
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q += 4749 * d3 + 42 * d2; |
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q = put_dec_helper4(p, q); |
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p -= 4; |
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q += 281 * d3; |
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q = put_dec_helper4(p, q); |
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p -= 4; |
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put_dec_full4(p, q); |
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p -= 4; |
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/* strip off the extra 0's we printed */ |
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while (p < end && *p == '0') |
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++p; |
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return p; |
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} |
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static |
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char *number(char *end, unsigned long long num, int base, char locase) |
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{ |
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/* |
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* locase = 0 or 0x20. ORing digits or letters with 'locase' |
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* produces same digits or (maybe lowercased) letters |
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*/ |
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/* we are called with base 8, 10 or 16, only, thus don't need "G..." */ |
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static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */ |
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switch (base) { |
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case 10: |
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if (num != 0) |
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end = put_dec(end, num); |
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break; |
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case 8: |
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for (; num != 0; num >>= 3) |
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*--end = '0' + (num & 07); |
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break; |
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case 16: |
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for (; num != 0; num >>= 4) |
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*--end = digits[num & 0xf] | locase; |
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break; |
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default: |
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unreachable(); |
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} |
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return end; |
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} |
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#define ZEROPAD 1 /* pad with zero */ |
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#define SIGN 2 /* unsigned/signed long */ |
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#define PLUS 4 /* show plus */ |
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#define SPACE 8 /* space if plus */ |
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#define LEFT 16 /* left justified */ |
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#define SMALL 32 /* Must be 32 == 0x20 */ |
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#define SPECIAL 64 /* 0x */ |
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#define WIDE 128 /* UTF-16 string */ |
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static |
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int get_flags(const char **fmt) |
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{ |
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int flags = 0; |
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do { |
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switch (**fmt) { |
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case '-': |
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flags |= LEFT; |
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break; |
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case '+': |
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flags |= PLUS; |
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break; |
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case ' ': |
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flags |= SPACE; |
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break; |
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case '#': |
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flags |= SPECIAL; |
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break; |
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case '0': |
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flags |= ZEROPAD; |
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break; |
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default: |
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return flags; |
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} |
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++(*fmt); |
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} while (1); |
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} |
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static |
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int get_int(const char **fmt, va_list *ap) |
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{ |
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if (isdigit(**fmt)) |
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return skip_atoi(fmt); |
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if (**fmt == '*') { |
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++(*fmt); |
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/* it's the next argument */ |
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return va_arg(*ap, int); |
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} |
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return 0; |
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} |
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static |
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unsigned long long get_number(int sign, int qualifier, va_list *ap) |
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{ |
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if (sign) { |
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switch (qualifier) { |
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case 'L': |
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return va_arg(*ap, long long); |
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case 'l': |
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return va_arg(*ap, long); |
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case 'h': |
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return (short)va_arg(*ap, int); |
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case 'H': |
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return (signed char)va_arg(*ap, int); |
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default: |
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return va_arg(*ap, int); |
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}; |
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} else { |
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switch (qualifier) { |
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case 'L': |
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return va_arg(*ap, unsigned long long); |
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case 'l': |
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return va_arg(*ap, unsigned long); |
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case 'h': |
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return (unsigned short)va_arg(*ap, int); |
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case 'H': |
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return (unsigned char)va_arg(*ap, int); |
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default: |
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return va_arg(*ap, unsigned int); |
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} |
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} |
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} |
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static |
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char get_sign(long long *num, int flags) |
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{ |
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if (!(flags & SIGN)) |
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return 0; |
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if (*num < 0) { |
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*num = -(*num); |
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return '-'; |
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} |
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if (flags & PLUS) |
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return '+'; |
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if (flags & SPACE) |
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return ' '; |
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return 0; |
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} |
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static |
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size_t utf16s_utf8nlen(const u16 *s16, size_t maxlen) |
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{ |
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size_t len, clen; |
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for (len = 0; len < maxlen && *s16; len += clen) { |
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u16 c0 = *s16++; |
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/* First, get the length for a BMP character */ |
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clen = 1 + (c0 >= 0x80) + (c0 >= 0x800); |
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if (len + clen > maxlen) |
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break; |
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/* |
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* If this is a high surrogate, and we're already at maxlen, we |
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* can't include the character if it's a valid surrogate pair. |
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* Avoid accessing one extra word just to check if it's valid |
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* or not. |
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*/ |
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if ((c0 & 0xfc00) == 0xd800) { |
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if (len + clen == maxlen) |
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break; |
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if ((*s16 & 0xfc00) == 0xdc00) { |
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++s16; |
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++clen; |
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} |
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} |
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} |
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return len; |
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} |
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static |
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u32 utf16_to_utf32(const u16 **s16) |
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{ |
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u16 c0, c1; |
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c0 = *(*s16)++; |
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/* not a surrogate */ |
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if ((c0 & 0xf800) != 0xd800) |
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return c0; |
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/* invalid: low surrogate instead of high */ |
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if (c0 & 0x0400) |
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return 0xfffd; |
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c1 = **s16; |
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/* invalid: missing low surrogate */ |
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if ((c1 & 0xfc00) != 0xdc00) |
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return 0xfffd; |
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/* valid surrogate pair */ |
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++(*s16); |
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return (0x10000 - (0xd800 << 10) - 0xdc00) + (c0 << 10) + c1; |
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} |
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#define PUTC(c) \ |
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do { \ |
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if (pos < size) \ |
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buf[pos] = (c); \ |
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++pos; \ |
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} while (0); |
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int vsnprintf(char *buf, size_t size, const char *fmt, va_list ap) |
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{ |
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/* The maximum space required is to print a 64-bit number in octal */ |
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char tmp[(sizeof(unsigned long long) * 8 + 2) / 3]; |
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char *tmp_end = &tmp[ARRAY_SIZE(tmp)]; |
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long long num; |
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int base; |
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const char *s; |
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size_t len, pos; |
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char sign; |
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int flags; /* flags to number() */ |
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int field_width; /* width of output field */ |
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int precision; /* min. # of digits for integers; max |
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number of chars for from string */ |
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int qualifier; /* 'h', 'hh', 'l' or 'll' for integer fields */ |
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va_list args; |
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/* |
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* We want to pass our input va_list to helper functions by reference, |
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* but there's an annoying edge case. If va_list was originally passed |
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* to us by value, we could just pass &ap down to the helpers. This is |
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* the case on, for example, X86_32. |
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* However, on X86_64 (and possibly others), va_list is actually a |
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* size-1 array containing a structure. Our function parameter ap has |
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* decayed from T[1] to T*, and &ap has type T** rather than T(*)[1], |
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* which is what will be expected by a function taking a va_list * |
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* parameter. |
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* One standard way to solve this mess is by creating a copy in a local |
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* variable of type va_list and then passing a pointer to that local |
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* copy instead, which is what we do here. |
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*/ |
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va_copy(args, ap); |
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for (pos = 0; *fmt; ++fmt) { |
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if (*fmt != '%' || *++fmt == '%') { |
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PUTC(*fmt); |
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continue; |
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} |
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/* process flags */ |
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flags = get_flags(&fmt); |
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/* get field width */ |
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field_width = get_int(&fmt, &args); |
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if (field_width < 0) { |
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field_width = -field_width; |
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flags |= LEFT; |
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} |
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if (flags & LEFT) |
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flags &= ~ZEROPAD; |
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/* get the precision */ |
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precision = -1; |
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if (*fmt == '.') { |
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++fmt; |
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precision = get_int(&fmt, &args); |
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if (precision >= 0) |
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flags &= ~ZEROPAD; |
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} |
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/* get the conversion qualifier */ |
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qualifier = -1; |
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if (*fmt == 'h' || *fmt == 'l') { |
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qualifier = *fmt; |
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++fmt; |
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if (qualifier == *fmt) { |
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qualifier -= 'a'-'A'; |
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++fmt; |
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} |
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} |
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sign = 0; |
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switch (*fmt) { |
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case 'c': |
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flags &= LEFT; |
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s = tmp; |
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if (qualifier == 'l') { |
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((u16 *)tmp)[0] = (u16)va_arg(args, unsigned int); |
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((u16 *)tmp)[1] = L'\0'; |
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precision = INT_MAX; |
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goto wstring; |
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} else { |
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tmp[0] = (unsigned char)va_arg(args, int); |
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precision = len = 1; |
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} |
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goto output; |
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case 's': |
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flags &= LEFT; |
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if (precision < 0) |
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precision = INT_MAX; |
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s = va_arg(args, void *); |
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if (!s) |
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s = precision < 6 ? "" : "(null)"; |
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else if (qualifier == 'l') { |
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wstring: |
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flags |= WIDE; |
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precision = len = utf16s_utf8nlen((const u16 *)s, precision); |
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goto output; |
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} |
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precision = len = strnlen(s, precision); |
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goto output; |
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/* integer number formats - set up the flags and "break" */ |
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case 'o': |
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base = 8; |
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break; |
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case 'p': |
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if (precision < 0) |
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precision = 2 * sizeof(void *); |
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fallthrough; |
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case 'x': |
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flags |= SMALL; |
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fallthrough; |
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case 'X': |
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base = 16; |
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break; |
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case 'd': |
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case 'i': |
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flags |= SIGN; |
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fallthrough; |
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case 'u': |
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flags &= ~SPECIAL; |
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base = 10; |
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break; |
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default: |
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/* |
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* Bail out if the conversion specifier is invalid. |
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* There's probably a typo in the format string and the |
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* remaining specifiers are unlikely to match up with |
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* the arguments. |
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*/ |
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goto fail; |
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} |
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if (*fmt == 'p') { |
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num = (unsigned long)va_arg(args, void *); |
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} else { |
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num = get_number(flags & SIGN, qualifier, &args); |
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} |
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sign = get_sign(&num, flags); |
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if (sign) |
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--field_width; |
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s = number(tmp_end, num, base, flags & SMALL); |
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len = tmp_end - s; |
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/* default precision is 1 */ |
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if (precision < 0) |
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precision = 1; |
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/* precision is minimum number of digits to print */ |
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if (precision < len) |
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precision = len; |
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if (flags & SPECIAL) { |
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/* |
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* For octal, a leading 0 is printed only if necessary, |
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* i.e. if it's not already there because of the |
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* precision. |
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*/ |
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if (base == 8 && precision == len) |
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++precision; |
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/* |
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* For hexadecimal, the leading 0x is skipped if the |
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* output is empty, i.e. both the number and the |
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* precision are 0. |
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*/ |
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if (base == 16 && precision > 0) |
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field_width -= 2; |
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else |
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flags &= ~SPECIAL; |
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} |
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/* |
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* For zero padding, increase the precision to fill the field |
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* width. |
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*/ |
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if ((flags & ZEROPAD) && field_width > precision) |
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precision = field_width; |
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output: |
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/* Calculate the padding necessary */ |
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field_width -= precision; |
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/* Leading padding with ' ' */ |
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if (!(flags & LEFT)) |
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while (field_width-- > 0) |
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PUTC(' '); |
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/* sign */ |
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if (sign) |
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PUTC(sign); |
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/* 0x/0X for hexadecimal */ |
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if (flags & SPECIAL) { |
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PUTC('0'); |
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PUTC( 'X' | (flags & SMALL)); |
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} |
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/* Zero padding and excess precision */ |
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while (precision-- > len) |
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PUTC('0'); |
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/* Actual output */ |
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if (flags & WIDE) { |
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const u16 *ws = (const u16 *)s; |
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while (len-- > 0) { |
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u32 c32 = utf16_to_utf32(&ws); |
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u8 *s8; |
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size_t clen; |
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if (c32 < 0x80) { |
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PUTC(c32); |
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continue; |
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} |
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/* Number of trailing octets */ |
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clen = 1 + (c32 >= 0x800) + (c32 >= 0x10000); |
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len -= clen; |
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s8 = (u8 *)&buf[pos]; |
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/* Avoid writing partial character */ |
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PUTC('\0'); |
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pos += clen; |
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if (pos >= size) |
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continue; |
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/* Set high bits of leading octet */ |
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*s8 = (0xf00 >> 1) >> clen; |
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/* Write trailing octets in reverse order */ |
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for (s8 += clen; clen; --clen, c32 >>= 6) |
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*s8-- = 0x80 | (c32 & 0x3f); |
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/* Set low bits of leading octet */ |
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*s8 |= c32; |
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} |
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} else { |
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while (len-- > 0) |
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PUTC(*s++); |
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} |
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/* Trailing padding with ' ' */ |
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while (field_width-- > 0) |
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PUTC(' '); |
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} |
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fail: |
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va_end(args); |
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if (size) |
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buf[min(pos, size-1)] = '\0'; |
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return pos; |
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} |
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int snprintf(char *buf, size_t size, const char *fmt, ...) |
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{ |
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va_list args; |
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int i; |
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va_start(args, fmt); |
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i = vsnprintf(buf, size, fmt, args); |
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va_end(args); |
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return i; |
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}
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