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Diffstat (limited to 'nexgb/help.go')
-rw-r--r-- | nexgb/help.go | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/nexgb/help.go b/nexgb/help.go new file mode 100644 index 0000000..f692442 --- /dev/null +++ b/nexgb/help.go @@ -0,0 +1,105 @@ +package xgb + +/* +help.go is meant to contain a rough hodge podge of functions that are mainly +used in the auto generated code. Indeed, several functions here are simple +wrappers so that the sub-packages don't need to be smart about which stdlib +packages to import. + +Also, the 'Get..' and 'Put..' functions are used through the core xgb package +too. (xgbutil uses them too.) +*/ + +import ( + "fmt" + "strings" +) + +// StringsJoin is an alias to strings.Join. It allows us to avoid having to +// import 'strings' in each of the generated Go files. +func StringsJoin(ss []string, sep string) string { + return strings.Join(ss, sep) +} + +// Sprintf is so we don't need to import 'fmt' in the generated Go files. +func Sprintf(format string, v ...interface{}) string { + return fmt.Sprintf(format, v...) +} + +// Errorf is just a wrapper for fmt.Errorf. Exists for the same reason +// that 'stringsJoin' and 'sprintf' exists. +func Errorf(format string, v ...interface{}) error { + return fmt.Errorf(format, v...) +} + +// Pad a length to align on 4 bytes. +func Pad(n int) int { + return (n + 3) & ^3 +} + +// PopCount counts the number of bits set in a value list mask. +func PopCount(mask0 int) int { + mask := uint32(mask0) + n := 0 + for i := uint32(0); i < 32; i++ { + if mask&(1<<i) != 0 { + n++ + } + } + return n +} + +// Put16 takes a 16 bit integer and copies it into a byte slice. +func Put16(buf []byte, v uint16) { + buf[0] = byte(v) + buf[1] = byte(v >> 8) +} + +// Put32 takes a 32 bit integer and copies it into a byte slice. +func Put32(buf []byte, v uint32) { + buf[0] = byte(v) + buf[1] = byte(v >> 8) + buf[2] = byte(v >> 16) + buf[3] = byte(v >> 24) +} + +// Put64 takes a 64 bit integer and copies it into a byte slice. +func Put64(buf []byte, v uint64) { + buf[0] = byte(v) + buf[1] = byte(v >> 8) + buf[2] = byte(v >> 16) + buf[3] = byte(v >> 24) + buf[4] = byte(v >> 32) + buf[5] = byte(v >> 40) + buf[6] = byte(v >> 48) + buf[7] = byte(v >> 56) +} + +// Get16 constructs a 16 bit integer from the beginning of a byte slice. +func Get16(buf []byte) uint16 { + v := uint16(buf[0]) + v |= uint16(buf[1]) << 8 + return v +} + +// Get32 constructs a 32 bit integer from the beginning of a byte slice. +func Get32(buf []byte) uint32 { + v := uint32(buf[0]) + v |= uint32(buf[1]) << 8 + v |= uint32(buf[2]) << 16 + v |= uint32(buf[3]) << 24 + return v +} + +// Get64 constructs a 64 bit integer from the beginning of a byte slice. +func Get64(buf []byte) uint64 { + v := uint64(buf[0]) + v |= uint64(buf[1]) << 8 + v |= uint64(buf[2]) << 16 + v |= uint64(buf[3]) << 24 + v |= uint64(buf[4]) << 32 + v |= uint64(buf[5]) << 40 + v |= uint64(buf[6]) << 48 + v |= uint64(buf[7]) << 56 + return v +} |