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-rw-r--r--ch8/8-02_fopen-and-fillbuf.c101
-rw-r--r--ch8/8-02_stdlib-fopen-and-fillbuf.c33
-rw-r--r--ch8/8-02_syscalls.h47
3 files changed, 181 insertions, 0 deletions
diff --git a/ch8/8-02_fopen-and-fillbuf.c b/ch8/8-02_fopen-and-fillbuf.c
new file mode 100644
index 0000000..e533da8
--- /dev/null
+++ b/ch8/8-02_fopen-and-fillbuf.c
@@ -0,0 +1,101 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "8-02_syscalls.h"
+
+/* The C Programming Language: 2nd Edition
+ *
+ * Exercise 8-2: Rewrite `fopen` and `_fillbuf` with fields instead of explicit
+ * bit operations. Compare code size and execution speed.
+ *
+ * Notes: Fields, in this case, are struct fields. I implemented them as 1-bit
+ * integers to simulate bit fields via struct.
+ *
+ * The resulting binary of this file (plus the custom header) runs through this
+ * source file in about 0.001s. However, the binary is 1KB larger.
+ */
+
+#define PERMS 0666
+
+int getc(FILE *);
+
+int my__fillbuf(my_FILE *fp) {
+ int bufsize;
+ if (fp->flags._READ == 0) {
+ return EOF;
+ }
+ bufsize = (fp->flags._UNBUF != 0) ? 1 : BUFSIZ;
+ if (fp->base == NULL) {
+ if ((fp->base = (char *) calloc(bufsize, sizeof (char))) == NULL) {
+ return EOF;
+ }
+ }
+ fp->ptr = fp->base;
+ fp->cnt = read(fp->fd, fp->ptr, bufsize);
+ if (--fp->cnt < 0) {
+ if (fp->cnt == -1) {
+ fp->flags._EOF = 1;
+ } else {
+ fp->flags._ERR = 1;
+ }
+ fp->cnt = 0;
+ return EOF;
+ }
+ return (unsigned char) *fp->ptr++;
+}
+
+my_FILE * my_fopen(char *name, char *mode) {
+ int fd;
+ my_FILE *fp;
+ if (*mode != 'r' && *mode != 'w' && *mode != 'a') {
+ return NULL;
+ }
+ for (fp = _iob; fp < _iob + FOPEN_MAX; fp++) {
+ if (fp->flags._READ == 0 && fp->flags._WRITE == 0) {
+ break;
+ }
+ }
+ if (fp >= _iob + FOPEN_MAX) {
+ return NULL;
+ }
+ if (*mode == 'w') {
+ fd = creat(name, PERMS);
+ } else if (*mode == 'a') {
+ if ((fd = open(name, O_WRONLY, 0)) == -1) {
+ fd = creat(name, PERMS);
+ }
+ lseek(fd, 0L, 2);
+ } else {
+ fd = open(name, O_RDONLY, 0);
+ }
+ if (fd == -1) {
+ return NULL;
+ }
+ fp->fd = fd;
+ fp->cnt = 0;
+ if (*mode == 'r') {
+ fp->flags._READ = 1;
+ } else {
+ fp->flags._WRITE = 1;
+ }
+ return fp;
+}
+
+int main() {
+ my_FILE *fp = my_fopen("8-02_fopen-and-fillbuf.c", "r");
+ if (fp != NULL) {
+ puts("We could read the file.\n");
+ /* pro tip: don't declare this as 'unsigned' or you'll create an
+ * endless loop thanks to EOF typically being negative. Don't waste
+ * half an hour on a newbie mistake like I did. :)
+ */
+ char c;
+ while ((c = my_getc(fp)) != EOF) {
+ putchar(c);
+ }
+ } else {
+ puts("Could not open file for reading.");
+ }
+ return 0;
+}
diff --git a/ch8/8-02_stdlib-fopen-and-fillbuf.c b/ch8/8-02_stdlib-fopen-and-fillbuf.c
new file mode 100644
index 0000000..2219757
--- /dev/null
+++ b/ch8/8-02_stdlib-fopen-and-fillbuf.c
@@ -0,0 +1,33 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+/* The C Programming Language: 2nd Edition
+ *
+ * Exercise 8-2: Rewrite `fopen` and `_fillbuf` with fields instead of explicit
+ * bit operations. Compare code size and execution speed.
+ *
+ * Notes: This file uses the standard library exclusively, in contrast to the
+ * partial replacement solution in the other 8-02 files.
+ *
+ * The resulting binary of this file executes in about 0.001s, just like the
+ * partial replacement solution. Its binary is 1KB smaller, however.
+ */
+int main() {
+ FILE *fp = fopen("8-02_fopen-and-fillbuf.c", "r");
+ if (fp != NULL) {
+ puts("We could read the file.\n");
+ /* pro tip: don't declare this as 'unsigned' or you'll create an
+ * endless loop thanks to EOF typically being negative. Don't waste
+ * half an hour on a newbie mistake like I did. :)
+ */
+ char c;
+ while ((c = getc(fp)) != EOF) {
+ putchar(c);
+ }
+ } else {
+ puts("Could not open file for reading.");
+ }
+ return 0;
+}
diff --git a/ch8/8-02_syscalls.h b/ch8/8-02_syscalls.h
new file mode 100644
index 0000000..728c5af
--- /dev/null
+++ b/ch8/8-02_syscalls.h
@@ -0,0 +1,47 @@
+/* 8-02_syscalls.h
+ *
+ * A simpler stdio.h to aid in exercises 8-2
+ */
+
+long lseek(int fd, long offset, int origin);
+
+struct _flags {
+ unsigned int _READ : 1;
+ unsigned int _WRITE : 1;
+ unsigned int _UNBUF : 1;
+ unsigned int _EOF : 1;
+ unsigned int _ERR : 1;
+} flags;
+
+typedef struct _iobuf {
+ int cnt;
+ char *ptr;
+ char *base;
+ struct _flags flags;
+ int fd;
+} my_FILE;
+
+my_FILE _iob[FOPEN_MAX] = {
+ /* stdin is read-only */
+ { 0, (char *) 0, (char *) 0, {1, 0, 0, 0, 0}, 0 },
+ /* stdout is write only */
+ { 0, (char *) 0, (char *) 0, {0, 1, 0, 0, 0}, 1 },
+ /* stderr is written AND not buffered */
+ { 0, (char *) 0, (char *) 0, {0, 1, 1, 0, 0}, 2 }
+};
+
+#define feof(p) (((p)->flags._EOF) != 0)
+#define ferror(p) (((p)->flags._ERR) != 0)
+#define fileno(p) ((p)->fd)
+#define my_getc(p) (--(p)->cnt >= 0 ? (unsigned char) *(p)->ptr++ : my__fillbuf(p))
+#define getchar() getc(stdin)
+
+int my_fempty(struct _flags flags) {
+ if (!flags._READ && !flags._WRITE && !flags._UNBUF && !flags._EOF && !flags._ERR) {
+ return 1;
+ } else {
+ return 0;
+ }
+}
+
+int my_fclose(my_FILE*);

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ions'>-2/+2 2018-10-09cli: add 'update' commandzlg3-20/+92 Two helper functions were also added to the vgstash package to ease client workflows. This commit marks the final core function necessary to manipulate a vgstash DB on the command line. 2018-10-06cli: Add "delete" commandzlg2-0/+19 Unlike the old version of vgstash, the new one does not accept row IDs as arguments for removal. Instead, it accepts two mandatory arguments: the title of the game, and the system it's on. This is in line with the database itself, using the title and system as primary keys. 2018-10-06Remove ID field from DBzlg3-38/+46 The sqlite database already uses a game's title and system as the primary keys. Row IDs are redundant. 2018-10-06cli: change "Status" heading to "Progress"zlg2-36/+40 2018-09-29Bump to 0.3alpha5 for PyPIzlg1-1/+1 2018-09-29cli: Add pretty printing to 'list' commandzlg3-17/+107 Also add the "--width" option to specify the maximum width of the table. 2018-09-08setup.py: Bump to alpha4 for PyPIzlg1-1/+1 2018-09-08cli: add '--raw' option to list commandzlg2-9/+45 Add '--raw' option to the list command, in addition to proper note expansion. Newline characters in notes are escaped to be friendly to scripting. This option may be shortened to '-r' at the user's convenience. In raw output mode, the information is formatted in plain pipe-delimited strings, one line per row: title|system|ownership|progress|notes ownership and progress are printed in their numeric form, consistent with the OWNERSHIP and PROGRESS dictionaries in the vgstash package. An empty notes field will result in a line ending with a pipe and no whitespace following it. 2018-09-08Add remaining filters to vgstash packagezlg1-2/+11 2018-09-04Update LICENSE to match setup.pyzlg1-80/+67 Whoops. 2018-09-03Branch off from master with pytest, tox, clickzlg16-778/+779 This commit is huge, but contains everything needed for a "proper" build system built on pytest + tox and a CLI built with click. For now, this branch will contain all new vgstash development activity until it reaches feature parity with master. The CLI is installed to pip's PATH. Only the 'init', 'add', and 'list' commands work, with only two filters. This is pre-alpha software, and is therefore not stable yet. 2018-03-18Flesh out filter types and ownership statuszlg3-82/+144 It's time for a refactor to a module; the functionality and interface are clashing. 2018-03-18README.mdown: break line correctlyzlg1-1/+1 2018-03-18add 'playlog' list filterzlg2-2/+9 This filter is used to get an idea of which games you're currently playing through, so you can prioritize games to play when you're bored and detect it when you've beaten a game but haven't marked it as such. 2018-03-13Update helpers a bitzlg1-2/+9 At present, user modification is needed to make these seamless. vgup() may need to be axed in favor of telling the user to make an alias. 2018-03-13Make VGSTASH_DB_LOCATION point to a filezlg2-21/+20 It used to point to a directory, which would then look for .vgstash.db. This behavior was kind of backwards and I don't remember why I did it that way. This change gives users more control over where they put their DB. Be sure to update your environment variable if you have it set! 2016-11-18Remove settings from helpers.shZe Libertine Gamer1-5/+0 Sourcing them in .bash_profile screws up login if they're set. 2016-11-15Correct phrasing in README.Ze Libertine Gamer1-4/+4 2016-11-13DerpZe Libertine Gamer1-0/+1 2016-11-03Improve error handling in shell scriptsZe Libertine Gamer4-3/+23 2016-10-24Correct run_again, add recursionZe Libertine Gamer1-0/+4 Loops and functions -- oh my, what a useful combination. :) 2016-10-21Add quotes to correct behavior for arglistZe Libertine Gamer1-1/+1 2016-10-14updater.sh: add recursion, error handlingZe Libertine Gamer1-43/+101 2016-10-14Correct pipe-handling behaviorZe Libertine Gamer1-1/+9 2016-10-12Clarify a method to move between platformsZe Libertine Gamer1-2/+5 Also correct a typo.