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clean up IO library (#1232)

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guberathome 2021-06-08 21:05:51 +02:00 committed by GitHub
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8 changed files with 102 additions and 33 deletions
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90
core/IO.carp
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@ -3,62 +3,64 @@
(register-type FILE)
(defmodule IO
(doc stdin "the standard input file (thin wrapper for the C standard library).")
(register stdin (Ptr FILE) "stdin")
(doc stdout "the standard output file (thin wrapper for the C standard library).")
(register stdout (Ptr FILE) "stdout")
(doc stderr "the standard error file (thin wrapper for the C standard library).")
(register stderr (Ptr FILE) "stderr")
(doc println "prints a string ref to stdout, appends a newline.")
(doc println "prints a string ref to stdout, appends a newline.")
(register println (Fn [(Ref String)] ()))
(doc print "prints a string ref to stdout, does not append a newline.")
(doc print "prints a string ref to stdout, does not append a newline.")
(register print (Fn [(Ref String)] ()))
(doc errorln "prints a string ref to stderr, appends a newline.")
(doc errorln "prints a string ref to stderr, appends a newline.")
(register errorln (Fn [(Ref String)] ()))
(doc error "prints a string ref to stderr, does not append a newline.")
(doc error "prints a string ref to stderr, does not append a newline.")
(register error (Fn [(Ref String)] ()))
(doc get-line "gets a line from stdin.")
(doc get-line "gets a line from stdin.")
(register get-line (Fn [] String))
(doc get-char "gets a character from stdin.")
(doc get-char "gets a character from stdin (thin wrapper for getchar() from C standard library).")
(register get-char (Fn [] Char) "getchar")
(doc read-file "returns the contents of a file passed as argument as a string.")
(register read-file (Fn [&String] String))
(doc exit "exit the current program with a return code.")
(doc exit "exit the current program with a return code (thin wrapper for the C standard library).")
(register exit (Fn [Int] ()) "exit")
(doc EOF "the End-Of-File character as a literal (thin wrapper for the C standard library)")
(register EOF Char)
(doc EOF "the End-Of-File character as a literal.")
(doc fopen "opens a file by name using a mode (one or multiple of [r]ead, [w]rite, and [a]ppend), returns a file pointer. Consider using the function open-file instead.")
(doc fopen "opens a file for input/output/appending (thin wrapper for fopen(pathname, mode) from C standard library). Consider using the function [`open-file`](#open-file) instead.")
(register fopen (Fn [&String &String] (Ptr FILE)))
(doc open-file "opens a file by name using a mode (one or multiple of [r]ead, [w]rite, and [a]ppend), returns a Result type that contains an error string or a file pointer.")
(doc open-file "opens a file by name using a mode (e.g. [r]ead, [w]rite, [a]ppend), [rb] read binary...). See fopen() in the C standard library for a detailed description of valid parameters.")
(defn open-file [filename mode]
(let [ptr (IO.fopen filename mode)]
(if (null? ptr)
(do
(Result.Error System.errno))
(Result.Success ptr))))
(doc fclose "closes a file pointer.")
(doc fclose "closes a file pointer (thin wrapper for the C standard library).")
(register fclose (Fn [(Ptr FILE)] ()))
(doc fgetc "gets a character from a file pointer.")
(doc fgetc "gets a character from a file pointer (thin wrapper for the C standard library).")
(register fgetc (Fn [(Ptr FILE)] Char))
(doc fwrite "writes to a file pointer.")
(register fwrite (Fn [a Int Int (Ptr FILE)] ()) "fwrite")
(doc fread "reads from a file pointer into a pointer.")
(doc fwrite "writes a C-string to a file and returns the number of written items (thin wrapper for fwrite(cstr, item-size, items-count, file) from C standard library). Consider using [`write-file`](#write-file) instead.")
(register fwrite (Fn [(Ptr CChar) Int Int (Ptr FILE)] Int) "fwrite") ; any reason to use 'a' instead of '(Ptr CChar)' here?
(doc fread "reads from a file into C-String (thin wrapper for fread(cstr, item-size, items-count, file) from C standard library). Consider using [`read-file`](#read-file) or [`unsafe-read-file`](#unsafe-read-file) instead.")
(register fread (Fn [a Int Int (Ptr FILE)] Int) "fread")
(doc fflush "flushes a file pointer (i.e. commits every write).")
(doc fflush "flushes a file pointer, i.e. commits every write (thin wrapper for the C standard library).")
(register fflush (Fn [(Ptr FILE)] ()) "fflush")
(doc rewind "rewinds a file pointer (i.e. puts input and output stream to beginning).")
(doc rewind "rewinds a file pointer, i.e. puts input and output stream to beginning (thin wrapper for the C standard library).")
(register rewind (Fn [(Ptr FILE)] ()) "rewind")
(doc unlink "unlinks a file (i.e. deletes it).")
(doc unlink "unlinks a file, i.e. deletes it (thin wrapper for POSIX api in <unistd.h>).")
(register unlink (Fn [String] ()) "unlink")
(doc fseek "sets the position indicator of a file.")
(doc fseek "sets the position indicator of a file (thin wrapper for fseek(file, offset, whence) from C standard library).")
(register fseek (Fn [(Ptr FILE) Int Int] ()) "fseek")
(doc ftell "gets the position indicator of a file.")
(doc ftell "gets the position indicator of a file (thin wrapper for the C standard library).")
(register ftell (Fn [(Ptr FILE)] Int) "ftell")
(doc SEEK-SET "to be used with fseek (thin wrapper for the C standard library).")
(register SEEK-SET Int "SEEK_SET")
(doc SEEK-CUR "to be used with fseek (thin wrapper for the C standard library).")
(register SEEK-CUR Int "SEEK_CUR")
(doc SEEK-END "to be used with fseek (thin wrapper for the C standard library).")
(register SEEK-END Int "SEEK_END")
(doc read->EOF "reads a file given by name until the End-Of-File character is reached.")
(doc read->EOF "reads a file given by name until the End-Of-File character is reached.")
(defn read->EOF [filename]
(let [maybe (IO.open-file filename "rb")]
(match maybe
@ -72,9 +74,47 @@
(IO.fclose f)
(Result.Success (String.from-chars &r)))))))
(doc unsafe-read-file "returns the contents of a file passed as argument as a string. Note: there is no way to distinguish the output for an empty file and a missing file!")
(register unsafe-read-file (Fn [&String] String))
(doc read-file "Reads the content of a file into a (Result String String).\nIt is intended for text files, since the way to determine the length of a String is to use strlen() which probably will be inaccurate for binaries.")
(defn read-file [filename]
(let [ finp? (open-file filename "rb") ]
(if (Result.error? &finp?)
(Result.Error (fmt "Failed to open file='%s', error-number=%d" filename (Result.unsafe-from-error finp?) ))
(let [ finput (Result.unsafe-from-success finp?)
length (do
(fseek finput 0 SEEK-END)
(let-do [ flength (ftell finput) ]
(rewind finput) ; aka (fseek ofile 0 SEEK-SET)
flength ))
buffer (String.allocate length \0 ) ]
(if (not (String.allocated? &buffer))
(do
(fclose finput)
(Result.Error (fmt "Failed to open buffer with size=%d from file='%s'" length filename)) )
(let [ bytes-read (fread (String.cstr &buffer) 1 length finput)
nop1 (fclose finput) ]
(if (not (Int.= bytes-read length))
(Result.Error (fmt "Error: file='%s' has length=%d but bytes-read=%d" filename length bytes-read))
(Result.Success buffer) )))))))
(doc write-file "Writes a string into a (text) file, overwriting it if it already exists.")
(defn write-file [content file-name]
(let [ fOut? (open-file file-name "wb") ; open as binary so line breaks don't multiply on Windows
bytes2write (String.length content) ]
(if (Result.error? &fOut?)
(Result.Error (fmt "error=%d opening file='%s'" (Result.unsafe-from-error fOut?) file-name))
(let-do [ fOut (Result.unsafe-from-success fOut?)
bytes-written (fwrite (String.cstr content) 1 bytes2write fOut) ]
(fclose fOut)
(if (Int.= bytes-written bytes2write)
(Result.Success true)
(Result.Error (fmt "only %d of %d bytes were written" bytes-written bytes2write)) )))))
(private getenv-)
(hidden getenv-)
(doc getenv- "gets the value of an environment variable (thin wrapper for the C standard library)")
(register getenv- (Fn [String] (Ptr CChar)) "getenv")
(doc getenv "gets the value of an environment variable (Carp-style wrapper for the C standard library)")
(defn getenv [s]
(let [e (getenv- s)]
(if (null? e)

2
core/Result.carp
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@ -87,7 +87,7 @@ It is the inverse of [`error?`](#error?).")
(Error _) false
(Success _) true))
(doc success? "checks whether the given value `a` is an `Error`.
(doc error? "checks whether the given value `a` is an `Error`.
It is the inverse of [`success?`](#success?).")
(defn error? [a]

3
core/String.carp
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@ -24,6 +24,9 @@
(register string-set! (Fn [&String Int Char] ()))
(register string-set-at! (Fn [&String Int &String] ()))
(register allocate (Fn [Int Char] String))
(doc not-allocated? "checks if a String returned by String.allocate (e.g. when created under out-of-memory conditions) is NULL.")
(defn allocated? [s]
(not (null? (cstr s))) )
(register from-bytes (Fn [&(Array Byte)] String))
(register to-bytes (Fn [&String] (Array Byte)))

4
core/System.carp
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@ -1,5 +1,4 @@
(system-include "carp_system.h")
(system-include "errno.h")
(defmodule System
(doc carp-init-globals "Initializes all global variables (in correct order, based on interdependencies). Called automatically by `main` if the project is compiled as an executable. Client code needs to call this function manually when using a library written in Carp.")
@ -29,6 +28,9 @@
(register abort (Fn [] ()) "abort")
(register errno Int "errno")
(doc error-text "returns a description for the last function from the C standard library to set System.errno. Please note that System.errno may change if strerror() does not know it (and thus sets it to EINVAL), so consider copying it before, if you should need it. Calling error-text after a successful call will return 'SUCCESS' and leave System.errno unchanged.")
(register error-text (Fn [] String) "System_error_text")
(register EACCES Int "EACCES")
(register EEXIST Int "EEXIST")
(register EINVAL Int "EINVAL")

6
core/carp_io.h
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@ -29,7 +29,7 @@ String IO_get_MINUS_line() {
return b;
}
String IO_read_MINUS_file(const String *filename) {
String IO_unsafe_MINUS_read_MINUS_file(const String *filename) {
String buffer = 0;
Long length;
FILE *f = fopen(*filename, "rb");
@ -44,12 +44,12 @@ String IO_read_MINUS_file(const String *filename) {
assert(sz == length);
buffer[sz] = '\0';
} else {
printf("Failed to open buffer from file: %s\n", *filename);
fprintf(stderr, "Failed to open buffer from file: %s\n", *filename);
buffer = String_empty();
}
fclose(f);
} else {
printf("Failed to open file: %s\n", *filename);
fprintf(stderr, "Failed to open file: %s\n", *filename);
buffer = String_empty();
}

7
core/carp_string.h
View File

@ -8,8 +8,11 @@ String String_allocate(int len, char byte) {
* String_alloc(10, "a") == "aaaaaaaaaa"
*/
String ptr = CARP_MALLOC(len + 1);
memset(ptr, byte, len);
ptr[len] = '\0';
if( ptr!=NULL) {
// calling memset(NULL,...) would exercise undefined behaviour...
memset(ptr, byte, len);
ptr[len] = '\0';
}
return ptr;
}

8
core/carp_system.h
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@ -1,4 +1,3 @@
void System_free(void *p) {
CARP_FREE(p);
}
@ -40,3 +39,10 @@ int System_system(const String *command) {
}
Array System_args;
#include <errno.h>
#include <string.h>
String System_error_text() {
return String_from_MINUS_cstr( strerror(errno) );
}

15
test/io.carp
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@ -1,6 +1,16 @@
(load "Test.carp")
(use-all IO Test)
(defn write-then-read [content file-name]
(let [ written? (IO.write-file content file-name) ]
(if (Result.error? &written?)
(Result.unsafe-from-error written?)
(let-do [ read? (IO.read-file file-name) ]
(IO.unlink @file-name)
(if (Result.error? &read?)
(Result.unsafe-from-error read?)
(Result.unsafe-from-success read?) )))))
(deftest test
(assert-nothing test
&(IO.getenv @"thisdoesnotexist")
@ -10,4 +20,9 @@
&(IO.getenv @"PATH")
"getenv works on existant variable"
)
(let [ data "Icke\n\tdette\n\tkieke mal,\nOochen, Flesch und Beene." ] ; include \n in test data!
(assert-equal test
data
&(write-then-read data "io_carp_testdata.txt")
"write-file then read-file" ))
)