ref: f208e59263d823ebdd8f4160825be3de63556a10
dir: /libc/fmt.c/
#include <u.h> #include <libc.h> #include "fmtdef.h" enum { Maxfmt = 64 }; typedef struct Convfmt Convfmt; struct Convfmt { int c; volatile Fmts fmt; /* for spin lock in fmtfmt; avoids race due to write order */ }; struct { /* lock by calling __fmtlock, __fmtunlock */ int nfmt; Convfmt fmt[Maxfmt]; } fmtalloc; static Convfmt knownfmt[] = { ' ', __flagfmt, '#', __flagfmt, '%', __percentfmt, '+', __flagfmt, ',', __flagfmt, '-', __flagfmt, 'C', __runefmt, /* Plan 9 addition */ 'E', __efgfmt, #ifndef PLAN9PORT 'F', __efgfmt, /* ANSI only */ #endif 'G', __efgfmt, #ifndef PLAN9PORT 'L', __flagfmt, /* ANSI only */ #endif 'S', __runesfmt, /* Plan 9 addition */ 'X', __ifmt, 'b', __ifmt, /* Plan 9 addition */ 'c', __charfmt, 'd', __ifmt, 'e', __efgfmt, 'f', __efgfmt, 'g', __efgfmt, 'h', __flagfmt, #ifndef PLAN9PORT 'i', __ifmt, /* ANSI only */ #endif 'l', __flagfmt, 'n', __countfmt, 'o', __ifmt, 'p', __ifmt, // 'r', __errfmt, 's', __strfmt, #ifdef PLAN9PORT 'u', __flagfmt, #else 'u', __ifmt, #endif 'x', __ifmt, 0, 0, }; int (*fmtdoquote)(int); /* * __fmtlock() must be set */ static int __fmtinstall(int c, Fmts f) { Convfmt *p, *ep; if(c<=0 || c>=65536) return -1; if(!f) f = __badfmt; ep = &fmtalloc.fmt[fmtalloc.nfmt]; for(p=fmtalloc.fmt; p<ep; p++) if(p->c == c) break; if(p == &fmtalloc.fmt[Maxfmt]) return -1; p->fmt = f; if(p == ep){ /* installing a new format character */ fmtalloc.nfmt++; p->c = c; } return 0; } int fmtinstall(int c, int (*f)(Fmt*)) { int ret; __fmtlock(); ret = __fmtinstall(c, f); __fmtunlock(); return ret; } static Fmts fmtfmt(int c) { Convfmt *p, *ep; ep = &fmtalloc.fmt[fmtalloc.nfmt]; for(p=fmtalloc.fmt; p<ep; p++) if(p->c == c){ while(p->fmt == 0) /* loop until value is updated */ ; return p->fmt; } /* is this a predefined format char? */ __fmtlock(); for(p=knownfmt; p->c; p++) if(p->c == c){ __fmtinstall(p->c, p->fmt); __fmtunlock(); return p->fmt; } __fmtunlock(); return __badfmt; } void* __fmtdispatch(Fmt *f, void *fmt, int isrunes) { Rune rune, r; int i, n; f->flags = 0; f->width = f->prec = 0; for(;;){ if(isrunes){ r = *(Rune*)fmt; fmt = (Rune*)fmt + 1; }else{ fmt = (char*)fmt + chartorune(&rune, (char*)fmt); r = rune; } f->r = r; switch(r){ case '\0': return nil; case '.': f->flags |= FmtWidth|FmtPrec; continue; case '0': if(!(f->flags & FmtWidth)){ f->flags |= FmtZero; continue; } /* fall through */ case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': i = 0; while(r >= '0' && r <= '9'){ i = i * 10 + r - '0'; if(isrunes){ r = *(Rune*)fmt; fmt = (Rune*)fmt + 1; }else{ r = *(char*)fmt; fmt = (char*)fmt + 1; } } if(isrunes) fmt = (Rune*)fmt - 1; else fmt = (char*)fmt - 1; numflag: if(f->flags & FmtWidth){ f->flags |= FmtPrec; f->prec = i; }else{ f->flags |= FmtWidth; f->width = i; } continue; case '*': i = va_arg(f->args, int); if(i < 0){ /* * negative precision => * ignore the precision. */ if(f->flags & FmtPrec){ f->flags &= ~FmtPrec; f->prec = 0; continue; } i = -i; f->flags |= FmtLeft; } goto numflag; } n = (*fmtfmt(r))(f); if(n < 0) return nil; if(n == 0) return fmt; } }