From ce5ba841d996449810bcff72dc167e20a73481fe Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Wed, 6 Mar 1991 13:06:18 +0000 Subject: [PATCH] Fixed read() and readline() to do arbitrarily long reads. And readline() now reads null bytes correctly. Added tell(), seek() and flush(). --- Objects/fileobject.c | 215 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 178 insertions(+), 37 deletions(-) diff --git a/Objects/fileobject.c b/Objects/fileobject.c index 09f19e51ade..f0383275115 100644 --- a/Objects/fileobject.c +++ b/Objects/fileobject.c @@ -32,6 +32,8 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. #include "allobjects.h" +#define BUF(v) GETSTRINGVALUE((stringobject *)v) + #include "errno.h" #ifndef errno extern int errno; @@ -161,35 +163,132 @@ file_close(f, args) } static object * -file_read(f, args) +file_seek(f, args) fileobject *f; object *args; { - int n; - object *v; + long offset; + long whence; + if (f->f_fp == NULL) { err_badarg(); return NULL; } - if (args == NULL || !is_intobject(args)) { + if (args != NULL && is_intobject(args)) { + offset = getintvalue(args); + whence = 0; /* SEEK_SET */ + } + else { + if (!getlonglongargs(args, &offset, &whence)) + return NULL; + } + errno = 0; + if (fseek(f->f_fp, offset, (int)whence) != 0) { + if (errno == 0) + errno = EIO; + return err_errno(RuntimeError); + } + INCREF(None); + return None; +} + +static object * +file_tell(f, args) + fileobject *f; + object *args; +{ + long offset; + if (args != NULL || f->f_fp == NULL) { err_badarg(); return NULL; } - n = getintvalue(args); - if (n < 0) { + errno = 0; + offset = ftell(f->f_fp); + if (offset == -1L) { + if (errno == 0) + errno = EIO; + return err_errno(RuntimeError); + } + return newintobject(offset); +} + +static object * +file_flush(f, args) + fileobject *f; + object *args; +{ + if (args != NULL || f->f_fp == NULL) { err_badarg(); return NULL; } - v = newsizedstringobject((char *)NULL, n); + errno = 0; + if (fflush(f->f_fp) != 0) { + if (errno == 0) + errno = EIO; + return err_errno(RuntimeError); + } + INCREF(None); + return None; +} + +static object * +file_read(f, args) + fileobject *f; + object *args; +{ + int n, n1, n2, n3; + object *v; + + if (f->f_fp == NULL) { + err_badarg(); + return NULL; + } + if (args == 0) + n = 0; + else { + if (!getintarg(args, &n)) + return NULL; + if (n < 0) { + err_badarg(); + return NULL; + } + } + + n2 = n != 0 ? n : BUFSIZ; + v = newsizedstringobject((char *)NULL, n2); if (v == NULL) return NULL; - n = fread(getstringvalue(v), 1, n, f->f_fp); - /* EOF is reported as an empty string */ - /* XXX should detect real I/O errors? */ - resizestring(&v, n); + n1 = 0; + for (;;) { + n3 = fread(BUF(v)+n1, 1, n2-n1, f->f_fp); + /* XXX Error check? */ + if (n3 == 0) + break; + n1 += n3; + if (n1 == n) + break; + if (n == 0) { + n2 = n1 + BUFSIZ; + if (resizestring(&v, n2) < 0) + return NULL; + } + } + if (n1 != n2) + resizestring(&v, n1); return v; } +/* Read a line. + Without argument, or with a zero argument, read until end of line + or EOF, whichever comes first. + With a positive argument n, read at most n bytes until end of line + or EOF, whichever comes first. + Negative and non-integer arguments are illegal. + When EOF is hit immediately, return an empty string. + A newline character is returned as the last character of the buffer + if it is read. +*/ + /* XXX Should this be unified with raw_input()? */ static object * @@ -197,45 +296,83 @@ file_readline(f, args) fileobject *f; object *args; { - int n; + register FILE *fp; + register int c; + register char *buf, *end; + int n, n1, n2; object *v; - if (f->f_fp == NULL) { + + if ((fp = f->f_fp) == NULL) { err_badarg(); return NULL; } - if (args == NULL) { - n = 10000; /* XXX should really be unlimited */ - } - else if (is_intobject(args)) { - n = getintvalue(args); + + if (args == NULL) + n = 0; /* Unlimited */ + else { + if (!getintarg(args, &n)) + return NULL; if (n < 0) { err_badarg(); return NULL; } } - else { - err_badarg(); - return NULL; - } - v = newsizedstringobject((char *)NULL, n); + + n2 = n != 0 ? n : 100; + v = newsizedstringobject((char *)NULL, n2); if (v == NULL) return NULL; -#ifndef THINK_C_3_0 - /* XXX Think C 3.0 wrongly reads up to n characters... */ - n = n+1; -#endif - if (fgets(getstringvalue(v), n, f->f_fp) == NULL) { - /* EOF is reported as an empty string */ - /* XXX should detect real I/O errors? */ - n = 0; + buf = BUF(v); + end = buf + n2; + + for (;;) { + if ((c = getc(fp)) == EOF || (*buf++ = c) == '\n') + break; + /* XXX Error check? */ + if (buf == end) { + if (n != 0) + break; + n1 = n2; + n2 += 1000; + if (resizestring(&v, n2) < 0) + return NULL; + buf = BUF(v) + n1; + end = BUF(v) + n2; + } } - else { - n = strlen(getstringvalue(v)); - } - resizestring(&v, n); + + n1 = buf - BUF(v); + if (n1 != n2) + resizestring(&v, n1); return v; } +static object * +file_readlines(f, args) + fileobject *f; + object *args; +{ + object *list; + object *line; + + if ((list = newlistobject(0)) == NULL) + return NULL; + for (;;) { + line = file_readline(f, args); + if (line != NULL && getstringsize(line) == 0) { + DECREF(line); + break; + } + if (line == NULL || addlistitem(list, line) != 0) { + DECREF(list); + XDECREF(line); + return NULL; + } + DECREF(line); + } + return list; +} + static object * file_write(f, args) fileobject *f; @@ -263,10 +400,14 @@ file_write(f, args) } static struct methodlist file_methods[] = { - {"write", file_write}, + {"close", file_close}, + {"flush", file_flush}, {"read", file_read}, {"readline", file_readline}, - {"close", file_close}, + {"readlines", file_readlines}, + {"seek", file_seek}, + {"tell", file_tell}, + {"write", file_write}, {NULL, NULL} /* sentinel */ };