格式化函数源码，支持各种格式化

/* * linux/lib/vsprintf.c * * Copyright (C) 1991, 1992 Linus Torvalds */ /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */ /* * Wirzenius wrote this portably, Torvalds fucked it up :-) */ /* * Fri Jul 13 2001 Crutcher Dunnavant <crutcher+kernel@datastacks.com> * - changed to provide snprintf and vsnprintf functions * So Feb 1 16:51:32 CET 2004 Juergen Quade <quade@hsnr.de> * - scnprintf and vscnprintf */ //#include <stdarg.h> //#include <linux/module.h> #include "types.h" #include "kernel.h" #include "ctype.h" #include "string.h" #include "div64.h" #include "vsprintf.h" #include "bsp_uart.h" #define unlikely(x) __builtin_expect(!!(x), 0) #define ADDCH(str, ch) do { \ if ((str) < end) \ *(str) = (ch); \ ++str; \ } while (0) /** * simple_strtoul - convert a string to an unsigned long * @cp: The start of the string * @endp: A pointer to the end of the parsed string will be placed here * @base: The number base to use */ unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base) { unsigned long result = 0,value; if (!base) { base = 10; if (*cp == '0') { base = 8; cp++; if ((toupper(*cp) == 'X') && isxdigit(cp[1])) { cp++; base = 16; } } } else if (base == 16) { if (cp[0] == '0' && toupper(cp[1]) == 'X') cp += 2; } while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : toupper(*cp)-'A'+10) < base) { result = result*base + value; cp++; } if (endp) *endp = (char *)cp; return result; } //EXPORT_SYMBOL(simple_strtoul); /** * simple_strtol - convert a string to a signed long * @cp: The start of the string * @endp: A pointer to the end of the parsed string will be placed here * @base: The number base to use */ long simple_strtol(const char *cp,char **endp,unsigned int base) { if(*cp=='-') return -simple_strtoul(cp+1,endp,base); return simple_strtoul(cp,endp,base); } //EXPORT_SYMBOL(simple_strtol); /** * simple_strtoull - convert a string to an unsigned long long * @cp: The start of the string * @endp: A pointer to the end of the parsed string will be placed here * @base: The number base to use */ unsigned long long simple_strtoull(const char *cp,char **endp,unsigned int base) { unsigned long long result = 0,value; if (!base) { base = 10; if (*cp == '0') { base = 8; cp++; if ((toupper(*cp) == 'X') && isxdigit(cp[1])) { cp++; base = 16; } } } else if (base == 16) { if (cp[0] == '0' && toupper(cp[1]) == 'X') cp += 2; } while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : (islower(*cp) ? toupper(*cp) : *cp)-'A'+10) < base) { result = result*base + value; cp++; } if (endp) *endp = (char *)cp; return result; } //EXPORT_SYMBOL(simple_strtoull); /** * simple_strtoll - convert a string to a signed long long * @cp: The start of the string * @endp: A pointer to the end of the parsed string will be placed here * @base: The number base to use */ long long simple_strtoll(const char *cp,char **endp,unsigned int base) { if(*cp=='-') return -simple_strtoull(cp+1,endp,base); return simple_strtoull(cp,endp,base); } static int skip_atoi(const char **s) { int i=0; while (isdigit(**s)) i = i*10 + *((*s)++) - '0'; return i; } #define ZEROPAD 1 /* pad with zero */ #define SIGN 2 /* unsigned/signed long */ #define PLUS 4 /* show plus */ #define SPACE 8 /* space if plus */ #define LEFT 16 /* left justified */ #define SPECIAL 32 /* 0x */ #define LARGE 64 /* use 'ABCDEF' instead of 'abcdef' */ #define SMALL 32 /* Must be 32 == 0x20 */ //static char * number(char * buf, char * end, unsigned long long num, int base, int size, int precision, int type) static char *put_dec_trunc(char *buf, unsigned q) { unsigned d3, d2, d1, d0; d1 = (q>>4) & 0xf; d2 = (q>>8) & 0xf; d3 = (q>>12); d0 = 6*(d3 + d2 + d1) + (q & 0xf); q = (d0 * 0xcd) >> 11; d0 = d0 - 10*q; *buf++ = d0 + '0'; /* least significant digit */ d1 = q + 9*d3 + 5*d2 + d1; if (d1 != 0) { q = (d1 * 0xcd) >> 11; d1 = d1 - 10*q; *buf++ = d1 + '0'; /* next digit */ d2 = q + 2*d2; if ((d2 != 0) || (d3 != 0)) { q = (d2 * 0xd) >> 7; d2 = d2 - 10*q; *buf++ = d2 + '0'; /* next digit */ d3 = q + 4*d3; if (d3 != 0) { q = (d3 * 0xcd) >> 11; d3 = d3 - 10*q; *buf++ = d3 + '0'; /* next digit */ if (q != 0) *buf++ = q + '0'; /* most sign. digit */ } } } return buf; } /* Same with if's removed. Always emits five digits */ static char *put_dec_full(char *buf, unsigned q) { /* BTW, if q is in [0,9999], 8-bit ints will be enough, */ /* but anyway, gcc produces better code with full-sized ints */ unsigned d3, d2, d1, d0; d1 = (q>>4) & 0xf; d2 = (q>>8) & 0xf; d3 = (q>>12); /* * Possible ways to approx. divide by 10 * gcc -O2 replaces multiply with shifts and adds * (x * 0xcd) >> 11: 11001101 - shorter code than * 0x67 (on i386) * (x * 0x67) >> 10: 1100111 * (x * 0x34) >> 9: 110100 - same * (x * 0x1a) >> 8: 11010 - same * (x * 0x0d) >> 7: 1101 - same, shortest code (on i386) */ d0 = 6*(d3 + d2 + d1) + (q & 0xf); q = (d0 * 0xcd) >> 11; d0 = d0 - 10*q; *buf++ = d0 + '0'; d1 = q + 9*d3 + 5*d2 + d1; q = (d1 * 0xcd) >> 11; d1 = d1 - 10*q; *buf++ = d1 + '0'; d2 = q + 2*d2; q = (d2 * 0xd) >> 7; d2 = d2 - 10*q; *buf++ = d2 + '0'; d3 = q + 4*d3; q = (d3 * 0xcd) >> 11; /* - shorter code */ /* q = (d3 * 0x67) >> 10; - would also work */ d3 = d3 - 10*q; *buf++ = d3 + '0'; *buf++ = q + '0'; return buf; } /* No inlining helps gcc to use registers better */ static char *put_dec(char *buf, uint64_t num) { while (1) { unsigned rem; if (num < 100000) return put_dec_trunc(buf, num); rem = do_div(num, 100000); buf = put_dec_full(buf, rem); } } static char *number(char *buf, char *end, signed long long num, int base, int size, int precision, int type) { /* we are called with base 8, 10 or 16, only, thus don't need "G..." */ static const char digits[16] = "0123456789ABCDEF"; char tmp[100]; char sign; char locase; int need_pfx = ((type & SPECIAL) && base != 10); int i; /* locase = 0 or 0x20. ORing digits or letters with 'locase' * produces same digits or (maybe lowercased) letters */ locase = (type & SMALL); if (type & LEFT) type &= ~ZEROPAD; sign = 0; if (type & SIGN) { if (num < 0) { sign = '-'; num = - num; size--; } else if (type & PLUS) { sign = '+'; size--; } else if (type & SPACE) { sign = ' '; size--; } } if (need_pfx) { size--; if (base == 16) size--; } /* generate full string in tmp[], in reverse order */ i = 0; if (num == 0) tmp[i++] = '0'; /* Generic code, for any base: else do { tmp[i++] = (digits[do_div(num,base)] | locase); } while (num != 0); */ else if (base != 10) { /* 8 or 16 */ int mask = base - 1; int shift = 3; if (base == 16) shift = 4; do { tmp[i++] = (digits[((unsigned char)num) & mask] | locase); num >>= shift; } while (num); } else { /* base 10 */ i = put_dec(tmp, num) - tmp; } /* printing 100 using %2d gives "100", not "00" */ if (i > precision) precision = i; /* leading space padding */ size -= precision; if (!(type & (ZEROPAD + LEFT))) { while (--size >= 0) ADDCH(buf, ' '); } /* sign */ if (sign) ADDCH(buf, sign); /* "0x" / "0" prefix */ if (need_pfx) { ADDCH(buf, '0'); if (base == 16) ADDCH(buf, 'X' | locase); } /* zero or space padding */ if (!(type & LEFT)) { char c = (type & ZEROPAD) ? '0' : ' '; while (--size >= 0) ADDCH(buf, c); } /* hmm even more zero padding? */ while (i <= --precision) ADDCH(buf, '0'); /* actual digits of result */ while (--i >= 0) ADDCH(buf, tmp[i]); /* trailing space padding */ while (--size >= 0) ADDCH(buf, ' '); return buf; } #if 0 static char * number(char * buf, char * end, unsigned long long num, int base, int size, int precision, int type) { char c,sign,tmp[66]; const char *digits; st