So I started with porting my pulleb program that pulls a EBCDIC Header from a SEG-Y file. I wrote a pulleb.py that looks like this:
with open("file", 'rb') as f:
for i in xrange(40):
print f.read(80).decode('cp500')
However in go, there is not straight cp500 (A.K.A. EBCDIC) decoder. So I copied the EBCDIC char table from python source package, called cp500.py.
And here is the go code:
pulleb.go
package main
import (
"fmt"
"os"
"flag"
"strconv"
)
func main() {
flag.Parse()
if flag.NArg() < 2 {
Usage()
os.Exit(1)
}
switch optnum, _ := strconv.Atoi(flag.Arg(0)); optnum {
case 1:
pull_1()
case 2:
pull_2()
default:
msg("option number unknown:", optnum)
}
}
func Usage() {
msg("usage: pulleb 1 filename")
}
func pull_1() {
fp, err := os.Open(flag.Arg(1))
if err != nil || fp == nil {
msg("Can't open file: ", flag.Arg(1), "\nError msg: ", err)
os.Exit(1)
}
defer func() {
fp.Close()
}()
ebcdic_header := make([]byte, 3200)
n, err := fp.Read(ebcdic_header)
if err != nil {
msg("Error when reading file: ", err)
}
if n != 3200 {
msg("File broken or not segy file, file size less than 3200")
os.Exit(1)
}
for i := 0; i < 40; i++ {
line := ebcdic_header[80*i : 80*i+80]
fmt.Fprintln(os.Stdout, string(ebc2asc(line)))
}
}
func pull_2() {
msg(os.Stderr, "func no implemented")
}
func msg(msgs ...interface{}) {
fmt.Fprintln(os.Stderr, msgs...)
}
ebcdic.go
package main
var decoding_table = [...]byte{
'\x00', // 0x00 -> NULL
'\x01', // 0x01 -> START OF HEADING
'\x02', // 0x02 -> START OF TEXT
'\x03', // 0x03 -> END OF TEXT
'\x9c', // 0x04 -> CONTROL
'\t', // 0x05 -> HORIZONTAL TABULATION
'\x86', // 0x06 -> CONTROL
'\x7f', // 0x07 -> DELETE
'\x97', // 0x08 -> CONTROL
'\x8d', // 0x09 -> CONTROL
'\x8e', // 0x0A -> CONTROL
'\x0b', // 0x0B -> VERTICAL TABULATION
'\x0c', // 0x0C -> FORM FEED
'\r', // 0x0D -> CARRIAGE RETURN
'\x0e', // 0x0E -> SHIFT OUT
'\x0f', // 0x0F -> SHIFT IN
'\x10', // 0x10 -> DATA LINK ESCAPE
'\x11', // 0x11 -> DEVICE CONTROL ONE
'\x12', // 0x12 -> DEVICE CONTROL TWO
'\x13', // 0x13 -> DEVICE CONTROL THREE
'\x9d', // 0x14 -> CONTROL
'\x85', // 0x15 -> CONTROL
'\x08', // 0x16 -> BACKSPACE
'\x87', // 0x17 -> CONTROL
'\x18', // 0x18 -> CANCEL
'\x19', // 0x19 -> END OF MEDIUM
'\x92', // 0x1A -> CONTROL
'\x8f', // 0x1B -> CONTROL
'\x1c', // 0x1C -> FILE SEPARATOR
'\x1d', // 0x1D -> GROUP SEPARATOR
'\x1e', // 0x1E -> RECORD SEPARATOR
'\x1f', // 0x1F -> UNIT SEPARATOR
'\x80', // 0x20 -> CONTROL
'\x81', // 0x21 -> CONTROL
'\x82', // 0x22 -> CONTROL
'\x83', // 0x23 -> CONTROL
'\x84', // 0x24 -> CONTROL
'\n', // 0x25 -> LINE FEED
'\x17', // 0x26 -> END OF TRANSMISSION BLOCK
'\x1b', // 0x27 -> ESCAPE
'\x88', // 0x28 -> CONTROL
'\x89', // 0x29 -> CONTROL
'\x8a', // 0x2A -> CONTROL
'\x8b', // 0x2B -> CONTROL
'\x8c', // 0x2C -> CONTROL
'\x05', // 0x2D -> ENQUIRY
'\x06', // 0x2E -> ACKNOWLEDGE
'\x07', // 0x2F -> BELL
'\x90', // 0x30 -> CONTROL
'\x91', // 0x31 -> CONTROL
'\x16', // 0x32 -> SYNCHRONOUS IDLE
'\x93', // 0x33 -> CONTROL
'\x94', // 0x34 -> CONTROL
'\x95', // 0x35 -> CONTROL
'\x96', // 0x36 -> CONTROL
'\x04', // 0x37 -> END OF TRANSMISSION
'\x98', // 0x38 -> CONTROL
'\x99', // 0x39 -> CONTROL
'\x9a', // 0x3A -> CONTROL
'\x9b', // 0x3B -> CONTROL
'\x14', // 0x3C -> DEVICE CONTROL FOUR
'\x15', // 0x3D -> NEGATIVE ACKNOWLEDGE
'\x9e', // 0x3E -> CONTROL
'\x1a', // 0x3F -> SUBSTITUTE
' ', // 0x40 -> SPACE
'\xa0', // 0x41 -> NO-BREAK SPACE
'\xe2', // 0x42 -> LATIN SMALL LETTER A WITH CIRCUMFLEX
'\xe4', // 0x43 -> LATIN SMALL LETTER A WITH DIAERESIS
'\xe0', // 0x44 -> LATIN SMALL LETTER A WITH GRAVE
'\xe1', // 0x45 -> LATIN SMALL LETTER A WITH ACUTE
'\xe3', // 0x46 -> LATIN SMALL LETTER A WITH TILDE
'\xe5', // 0x47 -> LATIN SMALL LETTER A WITH RING ABOVE
'\xe7', // 0x48 -> LATIN SMALL LETTER C WITH CEDILLA
'\xf1', // 0x49 -> LATIN SMALL LETTER N WITH TILDE
'[', // 0x4A -> LEFT SQUARE BRACKET
'.', // 0x4B -> FULL STOP
'<', // 0x4C -> LESS-THAN SIGN
'(', // 0x4D -> LEFT PARENTHESIS
'+', // 0x4E -> PLUS SIGN
'!', // 0x4F -> EXCLAMATION MARK
'&', // 0x50 -> AMPERSAND
'\xe9', // 0x51 -> LATIN SMALL LETTER E WITH ACUTE
'\xea', // 0x52 -> LATIN SMALL LETTER E WITH CIRCUMFLEX
'\xeb', // 0x53 -> LATIN SMALL LETTER E WITH DIAERESIS
'\xe8', // 0x54 -> LATIN SMALL LETTER E WITH GRAVE
'\xed', // 0x55 -> LATIN SMALL LETTER I WITH ACUTE
'\xee', // 0x56 -> LATIN SMALL LETTER I WITH CIRCUMFLEX
'\xef', // 0x57 -> LATIN SMALL LETTER I WITH DIAERESIS
'\xec', // 0x58 -> LATIN SMALL LETTER I WITH GRAVE
'\xdf', // 0x59 -> LATIN SMALL LETTER SHARP S (GERMAN)
']', // 0x5A -> RIGHT SQUARE BRACKET
'$', // 0x5B -> DOLLAR SIGN
'*', // 0x5C -> ASTERISK
')', // 0x5D -> RIGHT PARENTHESIS
';', // 0x5E -> SEMICOLON
'^', // 0x5F -> CIRCUMFLEX ACCENT
'-', // 0x60 -> HYPHEN-MINUS
'/', // 0x61 -> SOLIDUS
'\xc2', // 0x62 -> LATIN CAPITAL LETTER A WITH CIRCUMFLEX
'\xc4', // 0x63 -> LATIN CAPITAL LETTER A WITH DIAERESIS
'\xc0', // 0x64 -> LATIN CAPITAL LETTER A WITH GRAVE
'\xc1', // 0x65 -> LATIN CAPITAL LETTER A WITH ACUTE
'\xc3', // 0x66 -> LATIN CAPITAL LETTER A WITH TILDE
'\xc5', // 0x67 -> LATIN CAPITAL LETTER A WITH RING ABOVE
'\xc7', // 0x68 -> LATIN CAPITAL LETTER C WITH CEDILLA
'\xd1', // 0x69 -> LATIN CAPITAL LETTER N WITH TILDE
'\xa6', // 0x6A -> BROKEN BAR
',', // 0x6B -> COMMA
'%', // 0x6C -> PERCENT SIGN
'_', // 0x6D -> LOW LINE
'>', // 0x6E -> GREATER-THAN SIGN
'?', // 0x6F -> QUESTION MARK
'\xf8', // 0x70 -> LATIN SMALL LETTER O WITH STROKE
'\xc9', // 0x71 -> LATIN CAPITAL LETTER E WITH ACUTE
'\xca', // 0x72 -> LATIN CAPITAL LETTER E WITH CIRCUMFLEX
'\xcb', // 0x73 -> LATIN CAPITAL LETTER E WITH DIAERESIS
'\xc8', // 0x74 -> LATIN CAPITAL LETTER E WITH GRAVE
'\xcd', // 0x75 -> LATIN CAPITAL LETTER I WITH ACUTE
'\xce', // 0x76 -> LATIN CAPITAL LETTER I WITH CIRCUMFLEX
'\xcf', // 0x77 -> LATIN CAPITAL LETTER I WITH DIAERESIS
'\xcc', // 0x78 -> LATIN CAPITAL LETTER I WITH GRAVE
'`', // 0x79 -> GRAVE ACCENT
':', // 0x7A -> COLON
'#', // 0x7B -> NUMBER SIGN
'@', // 0x7C -> COMMERCIAL AT
'\'', // 0x7D -> APOSTROPHE
'=', // 0x7E -> EQUALS SIGN
'"', // 0x7F -> QUOTATION MARK
'\xd8', // 0x80 -> LATIN CAPITAL LETTER O WITH STROKE
'a', // 0x81 -> LATIN SMALL LETTER A
'b', // 0x82 -> LATIN SMALL LETTER B
'c', // 0x83 -> LATIN SMALL LETTER C
'd', // 0x84 -> LATIN SMALL LETTER D
'e', // 0x85 -> LATIN SMALL LETTER E
'f', // 0x86 -> LATIN SMALL LETTER F
'g', // 0x87 -> LATIN SMALL LETTER G
'h', // 0x88 -> LATIN SMALL LETTER H
'i', // 0x89 -> LATIN SMALL LETTER I
'\xab', // 0x8A -> LEFT-POINTING DOUBLE ANGLE QUOTATION MARK
'\xbb', // 0x8B -> RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK
'\xf0', // 0x8C -> LATIN SMALL LETTER ETH (ICELANDIC)
'\xfd', // 0x8D -> LATIN SMALL LETTER Y WITH ACUTE
'\xfe', // 0x8E -> LATIN SMALL LETTER THORN (ICELANDIC)
'\xb1', // 0x8F -> PLUS-MINUS SIGN
'\xb0', // 0x90 -> DEGREE SIGN
'j', // 0x91 -> LATIN SMALL LETTER J
'k', // 0x92 -> LATIN SMALL LETTER K
'l', // 0x93 -> LATIN SMALL LETTER L
'm', // 0x94 -> LATIN SMALL LETTER M
'n', // 0x95 -> LATIN SMALL LETTER N
'o', // 0x96 -> LATIN SMALL LETTER O
'p', // 0x97 -> LATIN SMALL LETTER P
'q', // 0x98 -> LATIN SMALL LETTER Q
'r', // 0x99 -> LATIN SMALL LETTER R
'\xaa', // 0x9A -> FEMININE ORDINAL INDICATOR
'\xba', // 0x9B -> MASCULINE ORDINAL INDICATOR
'\xe6', // 0x9C -> LATIN SMALL LIGATURE AE
'\xb8', // 0x9D -> CEDILLA
'\xc6', // 0x9E -> LATIN CAPITAL LIGATURE AE
'\xa4', // 0x9F -> CURRENCY SIGN
'\xb5', // 0xA0 -> MICRO SIGN
'~', // 0xA1 -> TILDE
's', // 0xA2 -> LATIN SMALL LETTER S
't', // 0xA3 -> LATIN SMALL LETTER T
'u', // 0xA4 -> LATIN SMALL LETTER U
'v', // 0xA5 -> LATIN SMALL LETTER V
'w', // 0xA6 -> LATIN SMALL LETTER W
'x', // 0xA7 -> LATIN SMALL LETTER X
'y', // 0xA8 -> LATIN SMALL LETTER Y
'z', // 0xA9 -> LATIN SMALL LETTER Z
'\xa1', // 0xAA -> INVERTED EXCLAMATION MARK
'\xbf', // 0xAB -> INVERTED QUESTION MARK
'\xd0', // 0xAC -> LATIN CAPITAL LETTER ETH (ICELANDIC)
'\xdd', // 0xAD -> LATIN CAPITAL LETTER Y WITH ACUTE
'\xde', // 0xAE -> LATIN CAPITAL LETTER THORN (ICELANDIC)
'\xae', // 0xAF -> REGISTERED SIGN
'\xa2', // 0xB0 -> CENT SIGN
'\xa3', // 0xB1 -> POUND SIGN
'\xa5', // 0xB2 -> YEN SIGN
'\xb7', // 0xB3 -> MIDDLE DOT
'\xa9', // 0xB4 -> COPYRIGHT SIGN
'\xa7', // 0xB5 -> SECTION SIGN
'\xb6', // 0xB6 -> PILCROW SIGN
'\xbc', // 0xB7 -> VULGAR FRACTION ONE QUARTER
'\xbd', // 0xB8 -> VULGAR FRACTION ONE HALF
'\xbe', // 0xB9 -> VULGAR FRACTION THREE QUARTERS
'\xac', // 0xBA -> NOT SIGN
'|', // 0xBB -> VERTICAL LINE
'\xaf', // 0xBC -> MACRON
'\xa8', // 0xBD -> DIAERESIS
'\xb4', // 0xBE -> ACUTE ACCENT
'\xd7', // 0xBF -> MULTIPLICATION SIGN
'{', // 0xC0 -> LEFT CURLY BRACKET
'A', // 0xC1 -> LATIN CAPITAL LETTER A
'B', // 0xC2 -> LATIN CAPITAL LETTER B
'C', // 0xC3 -> LATIN CAPITAL LETTER C
'D', // 0xC4 -> LATIN CAPITAL LETTER D
'E', // 0xC5 -> LATIN CAPITAL LETTER E
'F', // 0xC6 -> LATIN CAPITAL LETTER F
'G', // 0xC7 -> LATIN CAPITAL LETTER G
'H', // 0xC8 -> LATIN CAPITAL LETTER H
'I', // 0xC9 -> LATIN CAPITAL LETTER I
'\xad', // 0xCA -> SOFT HYPHEN
'\xf4', // 0xCB -> LATIN SMALL LETTER O WITH CIRCUMFLEX
'\xf6', // 0xCC -> LATIN SMALL LETTER O WITH DIAERESIS
'\xf2', // 0xCD -> LATIN SMALL LETTER O WITH GRAVE
'\xf3', // 0xCE -> LATIN SMALL LETTER O WITH ACUTE
'\xf5', // 0xCF -> LATIN SMALL LETTER O WITH TILDE
'}', // 0xD0 -> RIGHT CURLY BRACKET
'J', // 0xD1 -> LATIN CAPITAL LETTER J
'K', // 0xD2 -> LATIN CAPITAL LETTER K
'L', // 0xD3 -> LATIN CAPITAL LETTER L
'M', // 0xD4 -> LATIN CAPITAL LETTER M
'N', // 0xD5 -> LATIN CAPITAL LETTER N
'O', // 0xD6 -> LATIN CAPITAL LETTER O
'P', // 0xD7 -> LATIN CAPITAL LETTER P
'Q', // 0xD8 -> LATIN CAPITAL LETTER Q
'R', // 0xD9 -> LATIN CAPITAL LETTER R
'\xb9', // 0xDA -> SUPERSCRIPT ONE
'\xfb', // 0xDB -> LATIN SMALL LETTER U WITH CIRCUMFLEX
'\xfc', // 0xDC -> LATIN SMALL LETTER U WITH DIAERESIS
'\xf9', // 0xDD -> LATIN SMALL LETTER U WITH GRAVE
'\xfa', // 0xDE -> LATIN SMALL LETTER U WITH ACUTE
'\xff', // 0xDF -> LATIN SMALL LETTER Y WITH DIAERESIS
'\\', // 0xE0 -> REVERSE SOLIDUS
'\xf7', // 0xE1 -> DIVISION SIGN
'S', // 0xE2 -> LATIN CAPITAL LETTER S
'T', // 0xE3 -> LATIN CAPITAL LETTER T
'U', // 0xE4 -> LATIN CAPITAL LETTER U
'V', // 0xE5 -> LATIN CAPITAL LETTER V
'W', // 0xE6 -> LATIN CAPITAL LETTER W
'X', // 0xE7 -> LATIN CAPITAL LETTER X
'Y', // 0xE8 -> LATIN CAPITAL LETTER Y
'Z', // 0xE9 -> LATIN CAPITAL LETTER Z
'\xb2', // 0xEA -> SUPERSCRIPT TWO
'\xd4', // 0xEB -> LATIN CAPITAL LETTER O WITH CIRCUMFLEX
'\xd6', // 0xEC -> LATIN CAPITAL LETTER O WITH DIAERESIS
'\xd2', // 0xED -> LATIN CAPITAL LETTER O WITH GRAVE
'\xd3', // 0xEE -> LATIN CAPITAL LETTER O WITH ACUTE
'\xd5', // 0xEF -> LATIN CAPITAL LETTER O WITH TILDE
'0', // 0xF0 -> DIGIT ZERO
'1', // 0xF1 -> DIGIT ONE
'2', // 0xF2 -> DIGIT TWO
'3', // 0xF3 -> DIGIT THREE
'4', // 0xF4 -> DIGIT FOUR
'5', // 0xF5 -> DIGIT FIVE
'6', // 0xF6 -> DIGIT SIX
'7', // 0xF7 -> DIGIT SEVEN
'8', // 0xF8 -> DIGIT EIGHT
'9', // 0xF9 -> DIGIT NINE
'\xb3', // 0xFA -> SUPERSCRIPT THREE
'\xdb', // 0xFB -> LATIN CAPITAL LETTER U WITH CIRCUMFLEX
'\xdc', // 0xFC -> LATIN CAPITAL LETTER U WITH DIAERESIS
'\xd9', // 0xFD -> LATIN CAPITAL LETTER U WITH GRAVE
'\xda', // 0xFE -> LATIN CAPITAL LETTER U WITH ACUTE
'\x9f', // 0xFF -> CONTROL
}
func ebc2asc(ebc []byte) []byte {
asc := make([]byte, len(ebc))
for i, v := range ebc {
asc[i] = decoding_table[v]
}
return asc
}
