Addition of memstream for osx and bsd

include/libp2p/os/memstream.h

@@ -0,0 +1,11 @@
+#if defined(__linux__)
+# include <features.h>
+#endif
+
+#include <stdio.h>
+
+#if _POSIX_C_SOURCE < 200809L
+
+FILE *open_memstream(char **ptr, size_t *sizeloc);
+
+#endif /* _POSIX_C_SOURCE < 200809L */

os/Makefile

@@ -2,7 +2,7 @@ CC = gcc
 CFLAGS = -O0 -I../include -I../../c-protobuf -I../../c-multihash/include -I../../c-multiaddr/include -g3
 LFLAGS =
 DEPS = 
-OBJS = utils.o
+OBJS = utils.o memstream.o
 
 %.o: %.c $(DEPS)
 	$(CC) -c -o $@ $< $(CFLAGS)

os/memstream.c

@@ -0,0 +1,177 @@
+/* Compile this file and link the object with your program.  On a recent
+ * GNU/Linux machine the object file will be empty.  On anything derived from
+ * 4.4BSD (Darwin, the Three BSDs, etc.) it will contain an implementation of
+ * open_memstream() as described in the POSIX and Linux manual pages.  On
+ * anything else it will probably cause a compilation error.
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * OPEN_MEMSTREAM(3)      BSD and Linux Library Functions     OPEN_MEMSTREAM(3)
+ *
+ * SYNOPSIS
+ *     #include "memstream.h"
+ *
+ *     FILE *open_memstream(char **bufp, size_t *sizep);
+ *
+ * DESCRIPTION
+ *     The open_memstream()  function opens a  stream for writing to  a buffer.
+ *     The   buffer  is   dynamically  allocated   (as  with   malloc(3)),  and
+ *     automatically grows  as required.  After closing the  stream, the caller
+ *     should free(3) this buffer.
+ *
+ *     When  the  stream is  closed  (fclose(3))  or  flushed (fflush(3)),  the
+ *     locations  pointed  to  by  bufp  and  sizep  are  updated  to  contain,
+ *     respectively,  a pointer  to  the buffer  and  the current  size of  the
+ *     buffer.  These values  remain valid only as long  as the caller performs
+ *     no further output  on the stream.  If further  output is performed, then
+ *     the  stream  must  again  be  flushed  before  trying  to  access  these
+ *     variables.
+ *
+ *     A null byte  is maintained at the  end of the buffer.  This  byte is not
+ *     included in the size value stored at sizep.
+ *
+ *     The stream's  file position can  be changed with fseek(3)  or fseeko(3).
+ *     Moving the file position past the  end of the data already written fills
+ *     the intervening space with zeros.
+ *
+ * RETURN VALUE
+ *     Upon  successful  completion open_memstream()  returns  a FILE  pointer.
+ *     Otherwise, NULL is returned and errno is set to indicate the error.
+ *
+ * CONFORMING TO
+ *     POSIX.1-2008
+ *
+ * ----------------------------------------------------------------------------
+ */
+
+#include "libp2p/os/memstream.h"
+
+#if _POSIX_C_SOURCE < 200809L
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+
+#define min(X, Y) (((X) < (Y)) ? (X) : (Y))
+
+struct memstream
+{
+    int      position;
+    int      size;
+    int      capacity;
+    char    *contents;
+    char   **ptr;
+    size_t  *sizeloc;
+};
+
+#if MEMSTREAM_DEBUG
+  static void memstream_print(struct memstream *ms)
+  {
+      printf("memstream %p {", ms);
+      printf(" %i", ms->position);
+      printf(" %i", ms->size);
+      printf(" %i", ms->capacity);
+      printf(" %p", ms->contents);
+      printf(" }\n");
+  }
+# define memstream_info(ARGS) printf ARGS
+#else
+# define memstream_print(ms)
+# define memstream_info(ARGS)
+#endif
+
+#define memstream_check(MS) if (!(MS)->contents) { errno= ENOMEM;  return -1; }
+
+static int memstream_grow(struct memstream *ms, int minsize)
+{
+    int newcap= ms->capacity * 2;					memstream_check(ms);
+    while (newcap <= minsize) newcap *= 2;				memstream_info(("grow %p to %i\n", ms, newcap));
+    ms->contents= realloc(ms->contents, newcap);
+    if (!ms->contents) return -1;	/* errno == ENOMEM */
+    memset(ms->contents + ms->capacity, 0, newcap - ms->capacity);
+    ms->capacity= newcap;
+    *ms->ptr= ms->contents;		/* size has not changed */
+    return 0;
+}
+
+static int memstream_read(void *cookie, char *buf, int count)
+{
+    struct memstream *ms= (struct memstream *)cookie;			memstream_check(ms);
+    int n= min(ms->size - ms->position, count);				memstream_info(("memstream_read %p %i\n", ms, count));
+    if (n < 1) return 0;
+    memcpy(buf, ms->contents, n);
+    ms->position += n;							memstream_print(ms);
+    return n;
+}
+
+static int memstream_write(void *cookie, const char *buf, int count)
+{
+    struct memstream *ms= (struct memstream *)cookie;			memstream_check(ms);
+    if (ms->capacity <= ms->position + count)
+	if (memstream_grow(ms, ms->position + count) < 0)		/* errno == ENOMEM */
+	    return -1;
+    memcpy(ms->contents + ms->position, buf, count);			memstream_info(("memstream_write %p %i\n", ms, count));
+    ms->position += count;
+    if (ms->size < ms->position) *ms->sizeloc= ms->size= ms->position;	memstream_print(ms);
+									assert(ms->size < ms->capacity);
+									assert(ms->contents[ms->size] == 0);
+    return count;
+}
+
+static fpos_t memstream_seek(void *cookie, fpos_t offset, int whence)
+{
+    struct memstream *ms= (struct memstream *)cookie;
+    fpos_t pos= 0;							memstream_check(ms);
+									memstream_info(("memstream_seek %p %i %i\n", ms, (int)offset, whence));
+    switch (whence) {
+	case SEEK_SET:	pos= offset;			break;
+	case SEEK_CUR:	pos= ms->position + offset;	break;
+	case SEEK_END:	pos= ms->size + offset;		break;
+	default:	errno= EINVAL;			return -1;
+    }
+    if (pos >= ms->capacity) memstream_grow(ms, pos);
+    ms->position= pos;
+    if (ms->size < ms->position) *ms->sizeloc= ms->size= ms->position;	memstream_print(ms);  memstream_info(("=> %i\n", (int)pos));
+									assert(ms->size < ms->capacity && ms->contents[ms->size] == 0);
+    return pos;
+}
+
+static int memstream_close(void *cookie)
+{
+    struct memstream *ms= (struct memstream *)cookie;			if (!ms->contents) { free(ms);  errno= ENOMEM;  return -1; }
+    ms->size= min(ms->size, ms->position);
+    *ms->ptr= ms->contents;
+    *ms->sizeloc= ms->size;						assert(ms->size < ms->capacity);
+    ms->contents[ms->size]= 0;
+    free(ms);
+    return 0;
+}
+
+FILE *open_memstream(char **ptr, size_t *sizeloc)
+{
+    if (ptr && sizeloc) {
+	struct memstream *ms= calloc(1, sizeof(struct memstream));
+	FILE *fp= 0;							if (!ms) return 0;	/* errno == ENOMEM */
+	ms->position= ms->size= 0;
+	ms->capacity= 4096;
+	ms->contents= calloc(ms->capacity, 1);				if (!ms->contents) { free(ms);  return 0; } /* errno == ENOMEM */
+	ms->ptr= ptr;
+	ms->sizeloc= sizeloc;
+	memstream_print(ms);
+	fp= funopen(ms, memstream_read, memstream_write, memstream_seek, memstream_close);
+	if (!fp) {
+	    free(ms->contents);
+	    free(ms);
+	    return 0;	/* errno set by funopen */
+	}
+	*ptr= ms->contents;
+	*sizeloc= ms->size;
+	return fp;
+    }
+    errno= EINVAL;
+    return 0;
+}
+
+#endif /* _POSIX_C_SOURCE < 200809L */