Fix build on OS X

OS X has no open_memstream and its linker has no --gc-sections.

Signed-off-by: Thiago Macieira <thiago.macieira@intel.com>

.gitignore

@@ -74,3 +74,4 @@ bin
 lib
 src/cjson
 !Makefile
+.config

Makefile

@@ -7,7 +7,8 @@ includedir = $(prefix)/include
 pkgconfigdir = $(libdir)/pkgconfig
 
 CFLAGS = -Wall -Wextra
-LDFLAGS = -Wl,--gc-sections
+LDFLAGS_GCSECTIONS = -Wl,--gc-sections
+LDFLAGS = $(if $(gc_sections-pass),$(LDFLAGS_GCSECTIONS))
 
 GIT_ARCHIVE = git archive --prefix="$(PACKAGE)/" -9
 INSTALL = install
@@ -27,6 +28,7 @@ TINYCBOR_SOURCES = \
 	src/cborparser.c \
 	src/cborpretty.c \
 	src/cbortojson.c \
+	$(if $(open_memstream-pass),,src/open_memstream.c) \
 #
 CBORDUMP_SOURCES = tools/cbordump/cbordump.c
 
@@ -67,12 +69,17 @@ ifeq ($(origin QMAKE),file)
   endif
 endif
 
+-include .config
+
 # Rules
-all: lib/libtinycbor.a bin/cbordump tinycbor.pc
+all: .config lib/libtinycbor.a bin/cbordump tinycbor.pc
 check: tests/Makefile | lib/libtinycbor.a
 	$(MAKE) -C tests check
 silentcheck: | lib/libtinycbor.a
 	TESTARGS=-silent $(MAKE) -f $(MAKEFILE) -s check
+configure: .config
+.config: Makefile.configure
+	$(MAKE) -f $(SRCDIR)Makefile.configure OUT='>&10' configure 10> $@
 
 lib bin:
 	$(MKDIR) $@
@@ -145,7 +152,7 @@ release: .git
 	v=v`cat $(SRCDIR)VERSION` && git -C $(SRCDIR) tag -a -m "TinyCBOR release $$v" $(GITTAGFLAGS) $$v
 	$(MAKE) -f $(MAKEFILE) dist
 
-.PHONY: all check silentcheck install uninstall
+.PHONY: all check silentcheck configure install uninstall
 .PHONY: mostlyclean clean distclean
 .PHONY: dist distcheck release
 .SECONDARY:
@@ -156,3 +163,4 @@ cflags += -std=c99 $(CFLAGS)
 %.o: %.c
 	@test -d $(@D) || $(MKDIR) $(@D)
 	$(CC) $(cflags) -c -o $@ $<
+

Makefile.configure

@@ -0,0 +1,21 @@
+ALLTESTS = open_memstream funopen gc_sections
+MAKEFILE := $(lastword $(MAKEFILE_LIST))
+OUT :=
+
+PROGRAM-open_memstream = extern int open_memstream(); int main() { return open_memstream(); }
+PROGRAM-funopen = extern int funopen(); int main() { return funopen(); }
+PROGRAM-gc_sections = int main() {}
+CCFLAGS-gc_sections = -Wl,--gc-sections
+
+sink:
+	@echo >&2 Please run from the top-level Makefile.
+
+configure: $(foreach it,$(ALLTESTS),check-$(it))
+
+check-%:
+	@echo $(subst check-,,$@)-tested := 1 $(OUT)
+	$(if $(V),,@)if echo "$($(subst check-,PROGRAM-,$@))" | \
+	    $(CC) -xc $($(subst check-,CCFLAGS-,$@)) -o /dev/null - $(if $(V),,>/dev/null 2>&1); \
+	then \
+	    echo $(subst check-,,$@)-pass := 1 $(OUT); \
+	fi

src/cbortojson.c

@@ -36,6 +36,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+extern FILE *open_memstream(char **bufptr, size_t *sizeptr);
+
 enum ConversionStatusFlags {
     TypeWasNotNative            = 0x100,    // anything but strings, boolean, null, arrays and maps
     TypeWasTagged               = 0x200,

src/compilersupport_p.h

@@ -33,6 +33,10 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#ifndef __cplusplus
+#  include <stdbool.h>
+#endif
+
 #if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L || __cpp_static_assert >= 200410
 #  define cbor_static_assert(x)         static_assert(x, #x)
 #elif !defined(__cplusplus) && defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 406)

src/open_memstream.c

@@ -0,0 +1,111 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Intel Corporation
+**
+** Permission is hereby granted, free of charge, to any person obtaining a copy
+** of this software and associated documentation files (the "Software"), to deal
+** in the Software without restriction, including without limitation the rights
+** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+** copies of the Software, and to permit persons to whom the Software is
+** furnished to do so, subject to the following conditions:
+**
+** The above copyright notice and this permission notice shall be included in
+** all copies or substantial portions of the Software.
+**
+** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+** THE SOFTWARE.
+**
+****************************************************************************/
+
+#define _BSD_SOURCE 1
+#define _GNU_SOURCE 1
+
+#include <sys/types.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined(__unix__) || defined(__APPLE__)
+#  include <unistd.h>
+#endif
+#ifdef __APPLE__
+typedef int RetType;
+typedef int LenType;
+#elif __GLIBC__
+typedef ssize_t RetType;
+typedef size_t LenType;
+#else
+#  error "Cannot implement open_memstream!"
+#endif
+
+#include "compilersupport_p.h"
+
+struct Buffer
+{
+    char **ptr;
+    size_t *len;
+    size_t alloc;
+};
+
+static RetType write_to_buffer(void *cookie, const char *data, LenType len)
+{
+    struct Buffer *b = (struct Buffer *)cookie;
+    char *ptr = *b->ptr;
+    size_t newsize;
+
+    errno = EFBIG;
+    if (unlikely(add_check_overflow(*b->len, len, &newsize)))
+        return -1;
+
+    if (newsize > b->alloc) {
+        // make room
+        size_t newalloc = newsize + newsize / 2 + 1;    // give 50% more room
+        ptr = realloc(ptr, newalloc);
+        if (ptr == NULL)
+            return -1;
+        b->alloc = newalloc;
+        *b->ptr = ptr;
+    }
+
+    memcpy(ptr + *b->len, data, len);
+    *b->len = newsize;
+    return len;
+}
+
+static int close_buffer(void *cookie)
+{
+    struct Buffer *b = (struct Buffer *)cookie;
+    (*b->ptr)[*b->len] = '\0';
+    free(b);
+    return 0;
+}
+
+FILE *open_memstream(char **bufptr, size_t *lenptr)
+{
+    struct Buffer *b = (struct Buffer *)malloc(sizeof(struct Buffer));
+    if (b == NULL)
+        return NULL;
+    b->alloc = 0;
+    b->len = lenptr;
+    b->ptr = bufptr;
+    *bufptr = NULL;
+    *lenptr = 0;
+
+#ifdef __APPLE__
+    return funopen(b, NULL, write_to_buffer, NULL, close_buffer);
+#elif __GLIBC__
+    static const cookie_io_functions_t vtable = {
+        NULL,
+        write_to_buffer,
+        NULL,
+        close_buffer
+    };
+#endif
+}
+