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{
"metadata": {
"name": "",
"signature": "sha256:4a14f929c77abfd0a54b26e2baa48a2c7f478d22968a4f6231afc128a12dd480"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 20: Low-Level Programming"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example xor.c, Page 515"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"KEY='&'\n",
"orig=raw_input()\n",
"orig_char=list(orig)\n",
"new_char=[]\n",
"\n",
"def sxor(s1,s2): \n",
" return ''.join(chr(ord(a) ^ ord(b)) for a,b in zip(s1,s2))\n",
"for i in orig_char:\n",
" N=sxor(i,KEY)\n",
" new_char.append(N)\n",
"print ''.join(new_char)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Trust not him with your secrets, who, when left alone in your room, turns over your papers. Johann Kaspar Lavater \n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"rTSUR\u0006HIR\u0006NOK\u0006QORN\u0006_IST\u0006UCETCRU\n",
"\u0006QNI\n",
"\u0006QNCH\u0006JC@R\u0006GJIHC\u0006OH\u0006_IST\u0006TIIK\n",
"\u0006RSTHU\u0006IPCT\u0006_IST\u0006VGVCTU\b\u0006lINGHH\u0006mGUVGT\u0006jGPGRCT\u0006\n"
]
}
],
"prompt_number": 17
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example viewmemory.c, Page 521"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from itertools import product\n",
"def main():\n",
" \n",
" addr=\"\"\n",
" i=0\n",
" n=0\n",
" print \"Address of main function: %s\" % hex(id(main))\n",
" print \"Address of addr variable: %s\" % hex(id(addr))\n",
" addr=raw_input( \"Enter a (hex) address: \")\n",
" n=int(raw_input( \"Enter number of bytes to view: \"))\n",
" #printf(\"\\n\");\n",
" print \" Address Bytes Characters\\n\"\n",
" print \" - - - - - - - - - - - - - - - - - - - - - - \"\n",
" ptr = addr;\n",
" for nn in range(n,0,-10):\n",
" print \"%8s \"% hex(id(addr))\n",
" # for i,i in product(range(0//10), range(0//n)) :\n",
" #print \"%.2X \", *(ptr + i)); \n",
" #for (; i <10; i++)\n",
" # printf(\" \"); #pointer dereferencing not in python\n",
" #printf(\" \");\n",
" #for (i = 0; i < 10 && i < n; i++) {\n",
" # BYTE ch = *(ptr + i);\n",
" #if (!isprint(ch))\n",
" # ch = '.';\n",
" # printf(\"%c\", ch);\n",
" #}\n",
" #printf(\"\\n\");\n",
" #ptr += 10;\n",
" #} \n",
" #return 0;\n",
" #}\n",
"if __name__=='__main__':\n",
" main()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Address of main function: 0x4117eb8L\n",
"Address of addr variable: 0x1c3c148L\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter a (hex) address: 8048000\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter number of bytes to view: 40\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Address Bytes Characters\n",
"\n",
" - - - - - - - - - - - - - - - - - - - - - - \n",
"0x41884b8L \n",
"0x41884b8L \n",
"0x41884b8L \n",
"0x41884b8L \n"
]
}
],
"prompt_number": 11
}
],
"metadata": {}
}
]
}
|
