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Now it's a shared library.

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This commit is contained in:
overflowerror 2019-01-21 19:16:20 +01:00
parent b1dc633157
commit 0e511a94c3
5 changed files with 342 additions and 227 deletions
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3
.gitignore vendored
View file

@ -52,5 +52,4 @@ Mkfile.old
dkms.conf
# Executables
F6jigYck4v
benchmark
example

23
Makefile
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@ -1,11 +1,22 @@
all: F6jigYck4v
all: libsfuid.so example
benchmark: main.c
gcc -lm -DBENCHMARK -o $@ $<
libsfuid.so: lib/sfuid.o
@echo Linking shared object...
@gcc -shared -o $@ $^
F6jigYck4v: main.c
gcc -lm -o $@ $<
example: example.o libsfuid.so
@echo Linking example program...
@gcc -L. -lsfuid -lm -o $@ $<
example.o: lib/sfuid.h
lib/sfuid.o: lib/sfuid.h
%.o: %.c
@echo Compiling $<...
@gcc -Wall -fPIC -c $< -o $@
clean:
rm F6jigYck4v
@rm *.o
@rm lib/*.o
@rm *.so example

118
example.c Normal file
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@ -0,0 +1,118 @@
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>
#include <inttypes.h>
#include "lib/sfuid.h"
#define error(...) fprintf(stderr, __VA_ARGS__)
void help(const char* name) {
printf("SYNOPSIS: %s [OPTIONS] INPUT\n\n", name);
printf("options: \n");
printf(" -e encode INPUT (default)\n");
printf(" -d decode INPUT\n");
printf(" -l LENGTH set the length (default: 10)\n");
printf(" -c CHARSET set the charset (default: a-zA-Z0-9)\n");
printf(" -o OFFSET set the offset (default: 5)\n");
printf(" -h show this help message\n\n");
}
int main(int argc, char** argv) {
bool decodeMode = false;
int opt;
char* endptr;
sfuid_settings_t settings = sfuid_default_settings;
while((opt = getopt(argc, argv, "o:c:l:dehy")) != -1) {
switch(opt) {
case 'o':
settings.offset = strtol(optarg, &endptr, 10);
if (*endptr != 0) {
error("Argument for -o has to be a number.\nTry -h to get help.\n");
exit(2);
}
break;
case 'l':
settings.length = strtol(optarg, &endptr, 10);
if (*endptr != 0) {
error("Argument of -l has to be a number.\nTry -h to get help.\n");
exit(2);
}
break;
case 'c':
settings.charset = optarg;
break;
case 'e':
decodeMode = false;
break;
case 'd':
decodeMode = true;
break;
case 'h':
help(argv[0]);
exit(0);
case 'y':
settings.charset = "0-9A-Za-z-_";
break;
default:
error("Unknown option.\nTry -h to get help.\n");
exit(2);
}
}
if (optind >= argc) {
error("Expected data after options.\nTry -h to get help.\n");
exit(2);
}
int tmp;
tmp = sfuid_init(settings);
if (tmp != SFUID_ERROR_NONE) {
error("Error: %s\n", sfuid_error(tmp));
exit(4);
}
if (decodeMode) {
const char* string = argv[optind];
uint64_t value;
tmp = sfuid_decode(string, &value);
if (tmp != SFUID_ERROR_NONE) {
error("Error: %s\n", sfuid_error(tmp));
exit(4);
}
printf("%" PRIu64 "\n", value);
} else {
uint64_t value = strtoull(argv[optind], &endptr, 10);
if (*endptr != 0) {
error("Value has to be a number for encoding.\n");
exit(2);
}
if (value == ULLONG_MAX && errno == ERANGE) {
error("Value overflows the internal datatype.\n");
exit(2);
}
char* string = malloc(settings.length);
tmp = sfuid_encode(value, string);
if (tmp != SFUID_ERROR_NONE) {
error("Error: %s\n", sfuid_error(tmp));
exit(4);
}
printf("%s\n", string);
free(string);
}
}

397
main.c → lib/sfuid.c
View file

@ -4,34 +4,50 @@
#include <math.h>
#include <stdbool.h>
#include <stdint.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#include <limits.h>
#include "sfuid.h"
const sfuid_settings_t sfuid_default_settings = {
.length = 10,
.charset = "a-zA-Z0-9",
.offset = 5
};
sfuid_settings_t settings;
bool settingsValid = false;
struct {
uint64_t max;
uint64_t prime;
char* charset;
int inverseCharset[(1 << 7)];
} properties = {
.charset = NULL,
.inverseCharset = {-1}
};
typedef __uint128_t uint128_t;
typedef __int128_t int128_t;
const char* charset = "a-zA-Z0-9";
int inverseCharset[(1 << 7)] = {-1};
unsigned int resultLength = 10;
unsigned int offset = 5;
bool verbose = false;
#define verbose(...) if (verbose) printf(__VA_ARGS__);
#define error(...) fprintf(stderr, __VA_ARGS__)
#ifdef DEBUG
#define verbose(...) printf(__VA_ARGS__);
#else
#define verbose(...)
#endif
int convertToString(char* string, uint64_t number) {
int charsetLength = strlen(charset);
int charsetLength = strlen(properties.charset);
int length = 0;
do {
string[length++] = charset[number % charsetLength];
string[length++] = properties.charset[number % charsetLength];
number /= charsetLength;
} while(number > 0);
for(; length < resultLength; length++) {
string[length] = charset[0];
for(; length < settings.length; length++) {
string[length] = properties.charset[0];
}
for(int i = 0; i < length / 2; i++) {
@ -42,27 +58,25 @@ int convertToString(char* string, uint64_t number) {
string[length] = '\0';
return length;
return SFUID_ERROR_NONE;
}
uint64_t convertFromString(const char* string) {
uint64_t result = 0;
int convertFromString(const char* string, uint64_t* result) {
int stringLength = strlen(string);
int charsetLength = strlen(charset);
int charsetLength = strlen(properties.charset);
*result = 0;
for (int i = 0; i < stringLength; i++) {
bool found = false;
int tmp = inverseCharset[string[i]];
int tmp = properties.inverseCharset[(int) string[i]];
if (tmp < 0) {
error("Parsing error.\nUnexpected character '%c'.\n", string[i]);
exit(3);
return SFUID_ERROR_PARSING;
}
uint64_t val = ((uint64_t) pow(charsetLength, stringLength - i - 1));
result += ((uint64_t) tmp) * val;
*result += ((uint64_t) tmp) * val;
}
return result;
return SFUID_ERROR_NONE;
}
uint64_t primelist[] = {
@ -137,7 +151,7 @@ uint64_t multiplicativeInverse(uint64_t prime, uint64_t maxValue) {
return x1;
}
uint64_t decode(uint64_t value, uint64_t prime, uint64_t maxValue) {
int decode(uint64_t* value, uint64_t prime, uint64_t maxValue) {
/*
* (x * p) mod m = v
* (x * p) == v (mod m)
@ -146,7 +160,7 @@ uint64_t decode(uint64_t value, uint64_t prime, uint64_t maxValue) {
* => p * i == i (mod m)
*/
uint128_t tmp = value;
uint128_t tmp = *value;
uint64_t inverse = multiplicativeInverse(prime, maxValue);
@ -154,96 +168,9 @@ uint64_t decode(uint64_t value, uint64_t prime, uint64_t maxValue) {
tmp *= inverse;
tmp &= (maxValue);
*value = tmp;
return (uint64_t) tmp;
}
typedef struct settings {
uint64_t max;
uint64_t prime;
} settings_t;
settings_t getSettings() {
verbose("charset length: %d\n", strlen(charset));
double maxValueDouble = pow(strlen(charset), resultLength);
uint64_t maxValue;
int maxBits;
if (maxValueDouble >= pow(2, 65)) {
verbose("Max value %.0lf > 2^64, caping to 64 bits.\n", maxValueDouble);
maxBits = 64;
} else {
maxValue = (uint64_t) maxValueDouble;
verbose("theoer max: %llu\n", maxValue);
maxBits = findMax(maxValue);
if (maxBits <= 0) {
error("Length or charset is too big. This should not have happend.\n");
exit(3);
}
}
if (maxBits == 64) {
/*
* we want to avoid undefined behaviour.
* so instead of using an underflow we'll
* make this one explicit.
*/
maxValue = UINT64_MAX;
} else {
maxValue = 1ll << maxBits;
maxValue--;
}
verbose("used bits: %d\n", maxBits);
verbose("max: %llu\n", maxValue);
verbose("usage: %.1f%\n", (100.0 * maxValue / maxValueDouble));
uint64_t prime = findPrime(maxBits);
verbose("prime: %llu\n", prime);
return (settings_t) {.max = maxValue, .prime = prime};
}
void toString(char* string, uint64_t value, settings_t settings) {
#ifdef BENCHMARK
struct timespec before, after;
clock_gettime(CLOCK_MONOTONIC, &before);
#endif
value = encode(value, settings.prime, settings.max);
verbose("encoded: %llu\n", value);
convertToString(string, value);
#ifdef BENCHMARK
clock_gettime(CLOCK_MONOTONIC, &after);
uint64_t diff = (int64_t)(after.tv_sec - before.tv_sec) * (int64_t) 1000000000UL + (int64_t)(after.tv_nsec - before.tv_nsec);
fprintf(stderr, "Time for conversion: %llu ns\n", diff);
#endif
}
uint64_t fromString(const char* string, settings_t settings) {
#ifdef BENCHMARK
struct timespec before, after;
clock_gettime(CLOCK_MONOTONIC, &before);
#endif
uint64_t result = convertFromString(string);
verbose("encoded: %llu\n", result);
result = decode(result, settings.prime, settings.max);
#ifdef BENCHMARK
clock_gettime(CLOCK_MONOTONIC, &after);
uint64_t diff = (int64_t)(after.tv_sec - before.tv_sec) * (int64_t) 1000000000UL + (int64_t)(after.tv_nsec - before.tv_nsec);
fprintf(stderr, "Time for conversion: %llu ns\n", diff);
#endif
return result;
return SFUID_ERROR_NONE;
}
struct {
@ -264,14 +191,15 @@ struct {
}
};
void prepareCharset() {
verbose("prepareing charset\n");
int size = strlen(charset);
int size = strlen(settings.charset);
const char* tmp;
for(int i = 0; i < ((sizeof shortcuts) / (sizeof shortcuts[0])); i++) {
tmp = charset;
tmp = settings.charset;
while((tmp = strstr(tmp, shortcuts[i].needle)) != NULL) {
tmp++;
size += strlen(shortcuts[i].replacement) - strlen(shortcuts[i].needle);
@ -279,7 +207,7 @@ void prepareCharset() {
}
char* inflatedCharset = malloc(size + 1);
strcpy(inflatedCharset, charset);
strcpy(inflatedCharset, settings.charset);
while(true) {
char* first = NULL;
@ -303,114 +231,145 @@ void prepareCharset() {
//verbose("full charset: %s\n", inflatedCharset);
charset = inflatedCharset;
if (properties.charset != NULL)
free(properties.charset);
properties.charset = inflatedCharset;
}
void prepareInverseCharset() {
for(int i = 0; i < strlen(charset); i++) {
inverseCharset[charset[i]] = i;
for(int i = 0; i < 127; i++) {
properties.inverseCharset[i] = -1;
}
for(int i = 0; i < strlen(properties.charset); i++) {
properties.inverseCharset[(int) properties.charset[i]] = i;
}
}
void help(const char* name) {
printf("SYNOPSIS: %s [OPTIONS] INPUT\n\n", name);
printf("options: \n");
printf(" -e encode INPUT (default)\n");
printf(" -d decode INPUT\n");
printf(" -l LENGTH set the length (default: 10)\n");
printf(" -c CHARSET set the charset (default: a-zA-Z0-9)\n");
printf(" -o OFFSET set the offset (default: 5)\n");
printf(" -v enable verbose mode\n");
printf(" -h show this help message\n\n");
}
int main(int argc, char** argv) {
bool decodeMode = false;
int opt;
char* endptr;
while((opt = getopt(argc, argv, "o:c:l:devhy")) != -1) {
switch(opt) {
case 'o':
offset = strtol(optarg, &endptr, 10);
if (*endptr != 0) {
error("Argument for -o has to be a number.\nTry -h to get help.\n");
exit(2);
}
break;
case 'l':
resultLength = strtol(optarg, &endptr, 10);
if (*endptr != 0) {
error("Argument of -l has to be a number.\nTry -h to get help.\n");
exit(2);
}
break;
case 'c':
charset = optarg;
break;
case 'e':
decodeMode = false;
break;
case 'd':
decodeMode = true;
break;
case 'v':
verbose = true;
break;
case 'h':
help(argv[0]);
exit(0);
case 'y':
charset = "0-9A-Za-z-_";
break;
default:
error("Unknown option.\nTry -h to get help.\n");
exit(2);
}
}
if (optind >= argc) {
error("Expected data after options.\nTry -h to get help.\n");
exit(2);
}
verbose("charset: %s\n", charset);
verbose("length: %d\n", resultLength);
verbose("offset: %d\n", offset);
int setProperties() {
prepareCharset();
prepareInverseCharset();
settings_t settings = getSettings();
verbose("charset length: %d\n", strlen(properties.charset));
double maxValueDouble = pow(strlen(properties.charset), settings.length);
uint64_t maxValue;
int maxBits;
if (decodeMode) {
prepareInverseCharset();
verbose("decode mode\n");
const char* string = argv[optind];
verbose("string: %s\n", string);
uint64_t value = fromString(string, settings);
value -= offset;
printf("%llu\n", value);
if (maxValueDouble >= pow(2, 65)) {
verbose("Max value %.0lf > 2^64, caping to 64 bits.\n", maxValueDouble);
maxBits = 64;
} else {
uint64_t value = strtoull(argv[optind], &endptr, 10);
if (*endptr != 0) {
error("Value has to be a number for encoding.\n");
exit(2);
}
if (value == ULLONG_MAX && errno == ERANGE) {
error("Value overflows the internal datatype.\n");
exit(2);
}
value += offset;
if (value > settings.max) {
error("value is too big!\nThe maximum value for the current settings is %llu.\n", settings.max - offset);
exit(1);
}
verbose("encode mode\n");
verbose("value: %llu\n", value)
char* string = malloc(resultLength);
toString(string, value, settings);
printf("%s\n", string);
free(string);
maxValue = (uint64_t) maxValueDouble;
verbose("theoer max: %llu\n", maxValue);
maxBits = findMax(maxValue);
}
if (maxBits == 64) {
/*
* we want to avoid undefined behaviour.
* so instead of using an underflow we'll
* make this one explicit.
*/
maxValue = UINT64_MAX;
} else {
maxValue = 1ll << maxBits;
maxValue--;
}
verbose("used bits: %d\n", maxBits);
verbose("max: %llu\n", maxValue);
verbose("usage: %.1f%\n", (100.0 * maxValue / maxValueDouble));
uint64_t prime = findPrime(maxBits);
verbose("prime: %llu\n", prime);
properties.max = maxValue;
properties.prime = prime;
return SFUID_ERROR_NONE;
}
int checkCharset() {
int tmp = strlen(properties.charset);
if (tmp <= 0)
return SFUID_ERROR_CHARSET;
for(int i = 0; i < tmp; i++) {
if (properties.charset[i] < 0 || properties.charset[i] > 127)
return SFUID_ERROR_CHARSET;
for(int j = i+1; j < tmp; j++) {
if (properties.charset[i] == properties.charset[j])
return SFUID_ERROR_CHARSET;
}
}
return SFUID_ERROR_NONE;
}
int sfuid_init(sfuid_settings_t _settings) {
settings = _settings;
settingsValid = false;
if (settings.length == 0) {
return SFUID_ERROR_LENGTH;
}
int tmp = setProperties();
if (tmp != SFUID_ERROR_NONE)
return tmp;
tmp = checkCharset();
if (tmp != SFUID_ERROR_NONE)
return tmp;
settingsValid = true;
return SFUID_ERROR_NONE;
}
int sfuid_encode(uint64_t value, char* string) {
if (!settingsValid)
return SFUID_ERROR_SETTINGS_INVALID;
value += settings.offset;
if (value > properties.max)
return SFUID_ERROR_VALUE;
value = encode(value, properties.prime, properties.max);
int tmp = convertToString(string, value);
if (tmp != SFUID_ERROR_NONE)
return tmp;
return SFUID_ERROR_NONE;
}
int sfuid_decode(const char* string, uint64_t* value) {
int tmp = convertFromString(string, value);
if (tmp != SFUID_ERROR_NONE)
return tmp;
tmp = decode(value, properties.prime, properties.max);
if (tmp != SFUID_ERROR_NONE)
return tmp;
*value -= settings.offset;
return SFUID_ERROR_NONE;
}
const char* errors[] = {
"No error.",
"Length parameter not valid.",
"Charset parameter not valid.",
"Error while parsing input.",
"Settings not valid.",
"Value not valid."
};
const char* sfuid_error(int error) {
if (error < 0 || error >= ((sizeof errors) / sizeof errors[0])) {
return "Unknown error.";
}
return errors[error];
}

28
lib/sfuid.h Normal file
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@ -0,0 +1,28 @@
#ifndef SFUID_H
#define SFUID_H
#include <stdint.h>
#define SFUID_ERROR_NONE 0
#define SFUID_ERROR_LENGTH 1
#define SFUID_ERROR_CHARSET 2
#define SFUID_ERROR_PARSING 3
#define SFUID_ERROR_SETTINGS_INVALID 4
#define SFUID_ERROR_VALUE 5
typedef struct {
unsigned int length;
const char* charset;
uint64_t offset;
} sfuid_settings_t;
extern const sfuid_settings_t sfuid_default_settings;
int sfuid_init(sfuid_settings_t settings);
int sfuid_encode(uint64_t value, char* string);
int sfuid_decode(const char* string, uint64_t* value);
const char* sfuid_error(int error);
#endif