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Copy pathcommon.go
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212 lines (202 loc) · 5.11 KB
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Copy pathcommon.go
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212 lines (202 loc) · 5.11 KB
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package minify // import "github.com/tdewolff/minify"
import (
"bytes"
"encoding/base64"
"net/url"
"github.com/tdewolff/parse"
"github.com/tdewolff/strconv"
)
// Epsilon is the closest number to zero that is not considered to be zero.
var Epsilon = 0.00001
// ContentType minifies a given mediatype by removing all whitespace.
func ContentType(b []byte) []byte {
j := 0
start := 0
inString := false
for i, c := range b {
if !inString && parse.IsWhitespace(c) {
if start != 0 {
j += copy(b[j:], b[start:i])
} else {
j += i
}
start = i + 1
} else if c == '"' {
inString = !inString
}
}
if start != 0 {
j += copy(b[j:], b[start:])
return parse.ToLower(b[:j])
}
return parse.ToLower(b)
}
// DataURI minifies a data URI and calls a minifier by the specified mediatype. Specifications: https://www.ietf.org/rfc/rfc2397.txt.
func DataURI(m *M, dataURI []byte) []byte {
if mediatype, data, err := parse.DataURI(dataURI); err == nil {
dataURI, _ = m.Bytes(string(mediatype), data)
base64Len := len(";base64") + base64.StdEncoding.EncodedLen(len(dataURI))
asciiLen := len(dataURI)
for _, c := range dataURI {
if 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' || '0' <= c && c <= '9' || c == '-' || c == '_' || c == '.' || c == '~' || c == ' ' {
asciiLen++
} else {
asciiLen += 2
}
if asciiLen > base64Len {
break
}
}
if asciiLen > base64Len {
encoded := make([]byte, base64Len-len(";base64"))
base64.StdEncoding.Encode(encoded, dataURI)
dataURI = encoded
mediatype = append(mediatype, []byte(";base64")...)
} else {
dataURI = []byte(url.QueryEscape(string(dataURI)))
dataURI = bytes.Replace(dataURI, []byte("\""), []byte("\\\""), -1)
}
if len("text/plain") <= len(mediatype) && parse.EqualFold(mediatype[:len("text/plain")], []byte("text/plain")) {
mediatype = mediatype[len("text/plain"):]
}
for i := 0; i+len(";charset=us-ascii") <= len(mediatype); i++ {
// must start with semicolon and be followed by end of mediatype or semicolon
if mediatype[i] == ';' && parse.EqualFold(mediatype[i+1:i+len(";charset=us-ascii")], []byte("charset=us-ascii")) && (i+len(";charset=us-ascii") >= len(mediatype) || mediatype[i+len(";charset=us-ascii")] == ';') {
mediatype = append(mediatype[:i], mediatype[i+len(";charset=us-ascii"):]...)
break
}
}
dataURI = append(append(append([]byte("data:"), mediatype...), ','), dataURI...)
}
return dataURI
}
// Number minifies a given byte slice containing a number (see parse.Number) and removes superfluous characters.
func Number(num []byte) []byte {
// omit first + and register mantissa start and end, whether it's negative and the exponent
neg := false
start := 0
dot := -1
end := len(num)
exp := int64(0)
if 0 < len(num) && (num[0] == '+' || num[0] == '-') {
if num[0] == '-' {
neg = true
start++
} else {
num = num[1:]
end--
}
}
for i := 0; i < len(num); i++ {
c := num[i]
if c == '.' {
dot = i
} else if c == 'e' || c == 'E' {
end = i
i++
if i < len(num) && num[i] == '+' {
i++
}
var n int
if exp, n = strconv.ParseInt(num[i:]); n == 0 {
return num
}
break
}
}
if dot == -1 {
dot = end
}
// trim leading zeros but leave at least one digit
for start < end-1 && num[start] == '0' {
start++
}
// trim trailing zeros
i := end - 1
for ; i > dot; i-- {
if num[i] != '0' {
end = i + 1
break
}
}
if i == dot {
end = dot
if start == end {
num[start] = '0'
return num[start : start+1]
}
} else if start == end-1 && num[start] == '0' {
return num[start:end]
}
// shorten mantissa by increasing/decreasing the exponent
if end == dot {
for i = end - 1; i >= start; i-- {
if num[i] != '0' {
exp += int64(end - i - 1)
end = i + 1
break
}
}
} else {
exp -= int64(end - dot - 1)
if start == dot {
for i = dot + 1; i < end; i++ {
if num[i] != '0' {
copy(num[dot:], num[i:end])
end -= i - dot
break
}
}
} else {
copy(num[dot:], num[dot+1:end])
end--
}
}
// append the exponent or change the mantissa to incorporate the exponent
relExp := exp + int64(end-start) // exp when the first non-zero digit is directly after the dot
n := strconv.LenInt(exp) // number of exp digits
if exp == 0 {
if neg {
start--
num[start] = '-'
}
return num[start:end]
} else if int(relExp)+n+1 < 0 || 2 < exp { // add exponent for exp 3 and higher and where a lower exp really makes it shorter
num[end] = 'e'
end++
if exp < 0 {
num[end] = '-'
end++
exp = -exp
}
for i := end + n - 1; i >= end; i-- {
num[i] = byte(exp%10) + '0'
exp /= 10
}
end += n
} else if exp < 0 { // omit exponent
if relExp > 0 {
copy(num[start+int(relExp)+1:], num[start+int(relExp):end])
num[start+int(relExp)] = '.'
end++
} else {
copy(num[start-int(relExp)+1:], num[start:end])
num[start] = '.'
for i := 1; i < -int(relExp)+1; i++ {
num[start+i] = '0'
}
end -= int(relExp) - 1
}
} else { // for exponent 1 and 2
num[end] = '0'
if exp == 2 {
num[end+1] = '0'
}
end += int(exp)
}
if neg {
start--
num[start] = '-'
}
return num[start:end]
}