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Diffstat (limited to 'libgo/go/runtime/print.go')
-rw-r--r-- | libgo/go/runtime/print.go | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/libgo/go/runtime/print.go b/libgo/go/runtime/print.go new file mode 100644 index 0000000..f789f89 --- /dev/null +++ b/libgo/go/runtime/print.go @@ -0,0 +1,221 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package runtime + +import "unsafe" + +// The compiler knows that a print of a value of this type +// should use printhex instead of printuint (decimal). +type hex uint64 + +func bytes(s string) (ret []byte) { + rp := (*slice)(unsafe.Pointer(&ret)) + sp := stringStructOf(&s) + rp.array = sp.str + rp.len = sp.len + rp.cap = sp.len + return +} + +var debuglock mutex + +// The compiler emits calls to printlock and printunlock around +// the multiple calls that implement a single Go print or println +// statement. Some of the print helpers (printsp, for example) +// call print recursively. There is also the problem of a crash +// happening during the print routines and needing to acquire +// the print lock to print information about the crash. +// For both these reasons, let a thread acquire the printlock 'recursively'. + +func printlock() { + mp := getg().m + mp.locks++ // do not reschedule between printlock++ and lock(&debuglock). + mp.printlock++ + if mp.printlock == 1 { + lock(&debuglock) + } + mp.locks-- // now we know debuglock is held and holding up mp.locks for us. +} + +func printunlock() { + mp := getg().m + mp.printlock-- + if mp.printlock == 0 { + unlock(&debuglock) + } +} + +// write to goroutine-local buffer if diverting output, +// or else standard error. +func gwrite(b []byte) { + if len(b) == 0 { + return + } + gp := getg() + if gp == nil || gp.writebuf == nil { + writeErr(b) + return + } + + n := copy(gp.writebuf[len(gp.writebuf):cap(gp.writebuf)], b) + gp.writebuf = gp.writebuf[:len(gp.writebuf)+n] +} + +func printsp() { + print(" ") +} + +func printnl() { + print("\n") +} + +func printbool(v bool) { + if v { + print("true") + } else { + print("false") + } +} + +func printfloat(v float64) { + switch { + case v != v: + print("NaN") + return + case v+v == v && v > 0: + print("+Inf") + return + case v+v == v && v < 0: + print("-Inf") + return + } + + const n = 7 // digits printed + var buf [n + 7]byte + buf[0] = '+' + e := 0 // exp + if v == 0 { + if 1/v < 0 { + buf[0] = '-' + } + } else { + if v < 0 { + v = -v + buf[0] = '-' + } + + // normalize + for v >= 10 { + e++ + v /= 10 + } + for v < 1 { + e-- + v *= 10 + } + + // round + h := 5.0 + for i := 0; i < n; i++ { + h /= 10 + } + v += h + if v >= 10 { + e++ + v /= 10 + } + } + + // format +d.dddd+edd + for i := 0; i < n; i++ { + s := int(v) + buf[i+2] = byte(s + '0') + v -= float64(s) + v *= 10 + } + buf[1] = buf[2] + buf[2] = '.' + + buf[n+2] = 'e' + buf[n+3] = '+' + if e < 0 { + e = -e + buf[n+3] = '-' + } + + buf[n+4] = byte(e/100) + '0' + buf[n+5] = byte(e/10)%10 + '0' + buf[n+6] = byte(e%10) + '0' + gwrite(buf[:]) +} + +func printcomplex(c complex128) { + print("(", real(c), imag(c), "i)") +} + +func printuint(v uint64) { + var buf [100]byte + i := len(buf) + for i--; i > 0; i-- { + buf[i] = byte(v%10 + '0') + if v < 10 { + break + } + v /= 10 + } + gwrite(buf[i:]) +} + +func printint(v int64) { + if v < 0 { + print("-") + v = -v + } + printuint(uint64(v)) +} + +func printhex(v uint64) { + const dig = "0123456789abcdef" + var buf [100]byte + i := len(buf) + for i--; i > 0; i-- { + buf[i] = dig[v%16] + if v < 16 { + break + } + v /= 16 + } + i-- + buf[i] = 'x' + i-- + buf[i] = '0' + gwrite(buf[i:]) +} + +func printpointer(p unsafe.Pointer) { + printhex(uint64(uintptr(p))) +} + +func printstring(s string) { + if uintptr(len(s)) > maxstring { + gwrite(bytes("[string too long]")) + return + } + gwrite(bytes(s)) +} + +func printslice(s []byte) { + sp := (*slice)(unsafe.Pointer(&s)) + print("[", len(s), "/", cap(s), "]") + printpointer(unsafe.Pointer(sp.array)) +} + +func printeface(e eface) { + print("(", e._type, ",", e.data, ")") +} + +func printiface(i iface) { + print("(", i.tab, ",", i.data, ")") +} |