partially-written draft of fmemopen, still in #if 0

diff --git a/src/stdio/fmemopen.c b/src/stdio/fmemopen.c
index 77a6074..cc72a42 100644 (file)
--- a/src/stdio/fmemopen.c
+++ b/src/stdio/fmemopen.c
@@ -3,14 +3,59 @@
 
 static ssize_t mread(FILE *f, unsigned char *buf, size_t len)
 {
-       memcpy(buf, 
+       size_t rem = f->memsize - f->mempos;
+       if (len > rem) len = rem;
+       memcpy(buf, f->membuf+f->mempos, len);
+       f->mempos += len;
+       return len;
+}
+
+static ssize_t mwrite(FILE *f, const unsigned char *buf, size_t len)
+{
+       size_t rem;
+       if (f->memmode == 'a') f->mempos = f->memsize;
+       rem = f->memlim - f->mempos;
+       if (len > rem) len = rem;
+       memcpy(f->membuf+f->mempos, buf, len);
+       f->mempos += len;
+       if (f->mempos >= f->memsize) {
+               f->memsize = f->mempos;
+       }
+       return len;
 }
 
 FILE *fmemopen(void *buf, size_t size, const char *mode)
 {
-       FILE *f = calloc(sizeof(FILE), 1);
+       FILE *f;
+       int plus = !!strchr(mode, '+');
+       
+       if (!size || !strchr("rwa", *mode)) {
+               errno = EINVAL;
+               return 0;
+       }
+
+       if (!buf && size > SIZE_MAX-sizeof(FILE)-BUFSIZ-UNGET) {
+               errno = ENOMEM;
+               return 0;
+       }
+
+       f = calloc(sizeof(FILE) + UNGET + BUFSIZ + (buf?0:size), 1);
        if (!f) return 0;
+       f->fd = -1;
+       f->lbf = EOF;
+       f->buf = (unsigned char *)(f+1) + UNGET;
+       f->buf_size = BUFSIZ;
+       if (!buf) buf = f->buf + BUFSIZ;
        
-       //
+       if (!plus) f->flags = (*mode == 'r') ? F_NOWR : F_NORD;
+       if (*mode == 'a') f->mempos = strchr(buf, 0)-buf;
+
+       f->read = mread;
+       f->write = mwrite;
+       f->seek = mseek;
+       f->flush = mflush;
+       f->close = mclose;
+
+       return f;
 }
 #endif