initial

7 files changed, 360 insertions, 0 deletions

diff --git a/src/command.h b/src/command.h
new file mode 100644
index 0000000..4f44ab0
--- /dev/null
+++ b/src/command.h
@@ -0,0 +1,13 @@
+#include "shared.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#define ARGUMENTS int argc, char** argv
+#define NEXT_ARGS argc - 1, &argv[1]
+#define COMMAND(name) int name (ARGUMENTS) 
+
+COMMAND(dd);
+COMMAND(cat);
+COMMAND(yes);
diff --git a/src/commands/cat.c b/src/commands/cat.c
new file mode 100644
index 0000000..e2c471b
--- /dev/null
+++ b/src/commands/cat.c
@@ -0,0 +1,152 @@
+#include "../command.h"
+
+#include <ctype.h>
+#include <string.h>
+
+struct Flags {
+    bool number_lines;
+    bool number_non_empty;
+    bool change_non_print;
+    bool change_tabs;
+    bool end_lines_dollar;
+};
+
+static bool printable(char c) {
+    switch (c) {
+        case '\n': return true;
+        case '\r': return true;
+        case '\b': return true;
+        case '\t': return true;
+        default: return isprint(c);
+    }
+}
+
+static void help() {
+    printf("Usage: cat [-nbvteA] [FILE]...\n\n");
+    printf("Print FILEs to stdout\n\n");
+	printf("-n	Number output lines\n");
+	printf("-b	Number nonempty lines\n");
+	printf("-v	Show nonprinting characters as ^x or M-x\n");
+	printf("-t	...and tabs as ^I\n");
+	printf("-e	...and end lines with $\n");
+	printf("-A	Same as -vte\n");
+    exit(EXIT_SUCCESS);
+}
+
+static void cat_file(FILE* file, struct Flags flags) {
+    char c;
+    size_t read;
+    
+    size_t line = 1;
+    bool empty = true;
+    bool newline = true;
+    
+    while ((read = fread(&c, 1, 1, file)) != 0) {
+        if (c == '\n') {
+            if (empty && flags.number_lines) {
+                printf("\t%ld ", line);
+            }
+            if (flags.end_lines_dollar) {
+                printf("$");
+            }
+            line++;
+            newline = true;
+            empty = true;
+            goto print;
+        } else {
+            empty = false;
+        }
+
+        if (!newline) {
+            goto print;
+        }
+
+        if (!empty && (flags.number_non_empty || flags.number_lines)) {
+            printf("\t%ld ", line);
+            newline = false;
+        }
+    print:
+        if (!flags.change_non_print || printable(c)) {
+            if (flags.change_tabs && c == '\t') {
+                fwrite("^I", 1, 2, stdout);
+            } else {
+                fwrite(&c, 1, 1, stdout);
+            }
+        } else {
+            c |= '@';
+            fwrite(&c, 1, 1, stdout);
+        }
+    }
+}
+
+COMMAND(cat) {
+
+    struct Flags flags;
+    flags.number_lines = false;
+    flags.number_non_empty = false;
+    flags.change_non_print = false;
+    flags.change_tabs = false;
+    flags.end_lines_dollar = false;
+
+    for (int i = 0; i < argc; i++) {
+        if (!prefix("-", argv[i])) {
+            continue;
+        }
+
+        if (streql("--help", argv[i])) {
+            help();
+        }
+
+        size_t len = strlen(argv[i] + 1);
+        for (size_t j = 0; j < len; j++) {
+            char c = argv[i][j + 1];
+            switch (c) {
+                case 'n':
+                    flags.number_lines = true;
+                    break;
+                case 'b':
+                    flags.number_non_empty = true;
+                    break;
+                case 'v':
+                    flags.change_non_print = true;
+                    break;
+                case 't':
+                    flags.change_non_print = true;
+                    flags.change_tabs = true;
+                    break;
+                case 'e':
+                    flags.change_non_print = true;
+                    flags.end_lines_dollar = true;
+                    break;
+                case 'A':
+                    flags.change_non_print = true;
+                    flags.change_tabs = true;
+                    flags.end_lines_dollar = true;
+                    break;
+                default:
+                    error("error: unkown flag -%c", c);
+            }
+        } 
+    }
+
+    bool files = false;
+    for (int i = 0; i < argc; i++) {
+        if (streql("-", argv[i])) {
+            files = true;
+            cat_file(stdin, flags);
+        } else if (prefix("-", argv[i])) {
+            continue;
+        } else {
+            files = true;
+            FILE* in = get_file(argv[i], "r");
+            cat_file(in, flags);
+            fclose(in);
+        }
+    }
+
+    if (!files) {
+        cat_file(stdin, flags);
+    }
+    
+    return EXIT_SUCCESS;
+}
diff --git a/src/commands/dd.c b/src/commands/dd.c
new file mode 100644
index 0000000..278dee3
--- /dev/null
+++ b/src/commands/dd.c
@@ -0,0 +1,59 @@
+#include "../command.h"
+#include <stdio.h>
+
+static void help() {
+    printf("Usage: dd [if=FILE] [of=FILE] [bs=N] [count=N]\n\n");
+    printf("Copy a file with converting and formatting\n\n");
+    printf("if=FILE\t\tRead from FILE instead of stdin\n");
+	printf("of=FILE\t\tWrite to FILE instead of stdout\n");
+	printf("bs=N\t\tRead and write N bytes at a time\n");
+	printf("count=N\t\tCopy only N input blocks\n");
+    exit(EXIT_SUCCESS);
+}
+
+COMMAND(dd) {
+
+    FILE* in_file = stdin;
+    FILE* out_file = stdout;
+    int bs = 1024;
+    int count = -1;
+
+    for (int i = 0; i < argc; i++) {
+        if (prefix("if=", argv[i])) {
+            char* path = argv[i] + 3;
+            in_file = get_file(path, "rb");
+        } else if (prefix("of=", argv[i])) {
+            char* path = argv[i] + 3;
+            out_file = get_file(path, "wb");
+        } else if (prefix("bs=", argv[i])) {
+            char* str = argv[i] + 3;
+            bs = get_number(str);
+            if (bs < 1) {
+                error("error: block size must be greater than 0");
+            }
+        } else if (prefix("count=", argv[i])) {
+            char* str = argv[i] + 6;
+            count = get_number(str);
+            if (count < 1) {
+                error("error: count must be greather than 0");
+            }
+        } else if (streql("--help", argv[i])) {
+            help();
+        } else {
+            error("error: unkown option %s", argv[i]);
+        }
+    }
+ 
+    char* buffer = malloc(bs);
+    size_t read;
+    while ((read = fread(buffer, 1, bs, in_file)) != 0) {
+        fwrite(buffer, 1, read, out_file);
+        if (--count, count == 0) break;
+    }
+
+    free(buffer);
+    fclose(in_file);
+    fclose(out_file);
+
+    return EXIT_SUCCESS;
+}
diff --git a/src/commands/yes.c b/src/commands/yes.c
new file mode 100644
index 0000000..c954810
--- /dev/null
+++ b/src/commands/yes.c
@@ -0,0 +1,26 @@
+#include "../command.h"
+
+static void help() {
+    printf("Usage: yes [STRING]\n\n");
+    printf("Repeatedly output a line with all specified STRING(s), or 'y'.\n");
+    exit(EXIT_SUCCESS);
+}
+
+COMMAND(yes) {
+    const char* repeat;
+    if (argc == 0) {
+        repeat = "y";
+    } else {
+        if (streql("--help", argv[0])) {
+            help();
+        }
+        repeat = argv[0];
+        for (int i = 1; i < argc; i++) {
+            *(argv[i]-1) = ' ';
+        }
+    }
+
+    while (true) {
+        printf("%s\n", repeat);
+    }
+}
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..a2582c2
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,49 @@
+#include "shared.h"
+#include "command.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+int main (ARGUMENTS) {
+    if (argc < 1) {
+        error("error: argument 0 missing");
+    }
+
+    struct stat buf;
+    lstat(argv[0], &buf);
+
+    if (!S_ISLNK(buf.st_mode)) {
+        if (argc < 2) {
+            printf("usage: lazysphere [function [arguments]...]\n\n");
+            printf("currently defined functions:\n");
+            printf("\tdd, cat, yes\n");
+            return EXIT_SUCCESS;
+        }
+        argc--;
+        argv = &argv[1];
+    }
+
+    const char* cmd;
+    if (strncmp("./", argv[0], 2) == 0) {
+        cmd = argv[0] + 2;
+    } else {
+        cmd = argv[0];
+    }
+
+    if (streql(cmd, "dd")) {
+        return dd(NEXT_ARGS);
+    } else if (streql(cmd, "cat")) {
+        return cat(NEXT_ARGS);
+    } else if (streql(cmd, "yes")) {
+        return yes(NEXT_ARGS);
+    } else {
+        error("error: invalid command %s", cmd);
+    }
+
+    return EXIT_SUCCESS;
+}
+
diff --git a/src/shared.c b/src/shared.c
new file mode 100644
index 0000000..ee3c2f1
--- /dev/null
+++ b/src/shared.c
@@ -0,0 +1,46 @@
+#include "shared.h"
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+
+void error(const char* format, ...) {
+    va_list list;
+    va_start(list, format);
+
+    vfprintf(stderr, format, list);
+    fprintf(stderr, "\n");
+    exit(EXIT_FAILURE);
+}
+
+FILE* get_file(const char* path, const char* type) {
+    FILE* file = fopen(path, type);
+    if (file == NULL) {
+        error("error: failed to open file %s: %s", path, strerror(errno));
+    }
+    return file;
+}
+
+long int get_number(const char* text) {
+    char* end;
+    long int n = strtol(text, &end, 10);
+    if (text == end) {
+        error("error: %s is not a valid number", text);
+    }
+    return n;
+}
+
+bool streql(const char* a, const char* b) {
+    if (*a != *b) return false;
+    int n = 0;
+    while (true) {
+        if (*(a+n) != *(b+n)) return false;
+        if (*(a+n) == '\0') return true;
+        ++n;
+    }
+}
+
+bool prefix(const char* pre, const char* str) {
+    return strncmp(pre, str, strlen(pre)) == 0;
+}
diff --git a/src/shared.h b/src/shared.h
new file mode 100644
index 0000000..430af4b
--- /dev/null
+++ b/src/shared.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <stdio.h>
+#include <stdbool.h>
+
+__attribute__ ((__format__(printf, 1, 2)))
+void error(const char* format, ...);
+
+FILE* get_file(const char* path, const char* type);
+
+long int get_number(const char* text);
+
+bool streql(const char* a, const char* b);
+
+bool prefix(const char* pre, const char* str);