# [PATCH] Fix git to be (more) ANSI C99 compliant.

15 messages from 2006-06-18 to 2006-06-21. Participants: Florian Forster, Timo Hirvonen, Thomas Glanzmann, Rene Scharfe, Junio C Hamano, Linus Torvalds.
Thread: https://gitlist.dev/t/4553

## Florian Forster, 2006-06-18 05:50

Subject: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <1150609831500-git-send-email-octo@verplant.org>
URL: https://gitlist.dev/e/1150609831500-git-send-email-octo%40verplant.org

```
Using this patch I was able to build git with
$ make CFLAGS="-Wall -Werror -ansi -pedantic -std=c99 -D_XOPEN_SOURCE=500 -D_BSD_SOURCE"

While most of this patch fixes void-pointer arithmetic and is therefore
trivial, I had to change the use of a struct with FAMs in `diff-lib.c'. Since
this is the first time I encountered FAMs it'd probably be a good idea if
someone who knows would take a look at that.

Signed-off-by: Florian Forster <octo@verplant.org>


---

 blame.c             |    4 ++--
 builtin-apply.c     |    6 +++---
 builtin-read-tree.c |    3 +--
 builtin-tar-tree.c  |    6 +++---
 convert-objects.c   |   22 +++++++++++-----------
 csum-file.c         |    4 ++--
 diff-delta.c        |    5 +++--
 diff-lib.c          |   41 ++++++++++++++++++++++-------------------
 diff.c              |    2 +-
 diffcore-order.c    |    2 +-
 http-fetch.c        |   15 ++++++++-------
 http-push.c         |   15 ++++++++-------
 http.c              |    4 ++--
 imap-send.c         |    2 +-
 pack-check.c        |    6 +++---
 pack-objects.c      |    4 ++--
 pack-redundant.c    |   16 ++++++++--------
 patch-delta.c       |    4 ++--
 pkt-line.c          |    4 ++--
 quote.c             |    9 ++++++++-
 read-cache.c        |   13 +++++++------
 sha1_file.c         |   27 ++++++++++++++-------------
 ssh-fetch.c         |    2 +-
 tag.c               |    4 ++--
 tree-walk.c         |   11 ++++++-----
 25 files changed, 123 insertions(+), 108 deletions(-)

714b7eca861ad3b6863209f0298d55c0c2292116
diff --git a/blame.c b/blame.c
index 25d3bcf..51eab2e 100644
--- a/blame.c
+++ b/blame.c
@@ -301,9 +301,9 @@ static void fill_line_map(struct commit 
 				if (DEBUG)
 					printf("map: i1: %d %d %p i2: %d %d %p\n",
 					       i1, map[i1],
-					       i1 != -1 ? blame_lines[map[i1]] : NULL,
+					       (void *) (i1 != -1 ? blame_lines[map[i1]] : NULL),
 					       i2, map2[i2],
-					       i2 != -1 ? blame_lines[map2[i2]] : NULL);
+					       (void *) (i2 != -1 ? blame_lines[map2[i2]] : NULL));
 				if (map2[i2] != -1 &&
 				    blame_lines[map[i1]] &&
 				    !blame_lines[map2[i2]])
diff --git a/builtin-apply.c b/builtin-apply.c
index e113c74..6dd0472 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -148,7 +148,7 @@ static void *read_patch_file(int fd, uns
 			buffer = xrealloc(buffer, alloc);
 			nr = alloc - size;
 		}
-		nr = xread(fd, buffer + size, nr);
+		nr = xread(fd, (char *) buffer + size, nr);
 		if (!nr)
 			break;
 		if (nr < 0)
@@ -164,7 +164,7 @@ static void *read_patch_file(int fd, uns
 	 */
 	if (alloc < size + SLOP)
 		buffer = xrealloc(buffer, size + SLOP);
-	memset(buffer + size, 0, SLOP);
+	memset((char *) buffer + size, 0, SLOP);
 	return buffer;
 }
 
@@ -1194,7 +1194,7 @@ static int read_old_data(struct stat *st
 			return error("unable to open %s", path);
 		got = 0;
 		for (;;) {
-			int ret = xread(fd, buf + got, size - got);
+			int ret = xread(fd, (char *) buf + got, size - got);
 			if (ret <= 0)
 				break;
 			got += ret;
diff --git a/builtin-read-tree.c b/builtin-read-tree.c
index bb50fbd..fdd6706 100644
--- a/builtin-read-tree.c
+++ b/builtin-read-tree.c
@@ -30,8 +30,7 @@ static int merge_size = 0;
 
 static struct object_list *trees = NULL;
 
-static struct cache_entry df_conflict_entry = {
-};
+static struct cache_entry df_conflict_entry;
 
 struct tree_entry_list {
 	struct tree_entry_list *next;
diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
index f6310b9..646322d 100644
--- a/builtin-tar-tree.c
+++ b/builtin-tar-tree.c
@@ -34,7 +34,7 @@ static void reliable_write(void *buf, un
 			die("git-tar-tree: disk full?");
 		}
 		size -= ret;
-		buf += ret;
+		buf   = (char *) buf + ret;
 	}
 }
 
@@ -87,13 +87,13 @@ static void write_blocked(void *buf, uns
 		memcpy(block + offset, buf, chunk);
 		size -= chunk;
 		offset += chunk;
-		buf += chunk;
+		buf     = (char *) buf + chunk;
 		write_if_needed();
 	}
 	while (size >= BLOCKSIZE) {
 		reliable_write(buf, BLOCKSIZE);
 		size -= BLOCKSIZE;
-		buf += BLOCKSIZE;
+		buf   = (char *) buf + BLOCKSIZE;
 	}
 	if (size) {
 		memcpy(block + offset, buf, size);
diff --git a/convert-objects.c b/convert-objects.c
index a67d6b4..0fabd89 100644
--- a/convert-objects.c
+++ b/convert-objects.c
@@ -103,12 +103,12 @@ static int write_subdirectory(void *buff
 		if (!slash) {
 			newlen += sprintf(new + newlen, "%o %s", mode, path);
 			new[newlen++] = '\0';
-			memcpy(new + newlen, buffer + len - 20, 20);
+			memcpy(new + newlen, (char *) buffer + len - 20, 20);
 			newlen += 20;
 
 			used += len;
 			size -= len;
-			buffer += len;
+			buffer = (char *) buffer + len;
 			continue;
 		}
 
@@ -121,7 +121,7 @@ static int write_subdirectory(void *buff
 
 		used += len;
 		size -= len;
-		buffer += len;
+		buffer = (char *) buffer + len;
 	}
 
 	write_sha1_file(new, newlen, tree_type, result_sha1);
@@ -137,13 +137,13 @@ static void convert_tree(void *buffer, u
 	while (size) {
 		int len = 1+strlen(buffer);
 
-		convert_binary_sha1(buffer + len);
+		convert_binary_sha1((char *) buffer + len);
 
 		len += 20;
 		if (len > size)
 			die("corrupt tree object");
 		size -= len;
-		buffer += len;
+		buffer = (char *) buffer + len;
 	}
 
 	write_subdirectory(orig_buffer, orig_size, "", 0, result_sha1);
@@ -244,14 +244,14 @@ static void convert_date(void *buffer, u
 	// "tree <sha1>\n"
 	memcpy(new + newlen, buffer, 46);
 	newlen += 46;
-	buffer += 46;
+	buffer = (char *) buffer + 46;
 	size -= 46;
 
 	// "parent <sha1>\n"
 	while (!memcmp(buffer, "parent ", 7)) {
 		memcpy(new + newlen, buffer, 48);
 		newlen += 48;
-		buffer += 48;
+		buffer = (char *) buffer + 48;
 		size -= 48;
 	}
 
@@ -275,11 +275,11 @@ static void convert_commit(void *buffer,
 
 	if (memcmp(buffer, "tree ", 5))
 		die("Bad commit '%s'", (char*) buffer);
-	convert_ascii_sha1(buffer+5);
-	buffer += 46;    /* "tree " + "hex sha1" + "\n" */
+	convert_ascii_sha1((char *) buffer + 5);
+	buffer = (char *) buffer + 46;    /* "tree " + "hex sha1" + "\n" */
 	while (!memcmp(buffer, "parent ", 7)) {
-		convert_ascii_sha1(buffer+7);
-		buffer += 48;
+		convert_ascii_sha1((char *) buffer + 7);
+		buffer = (char *) buffer + 48;
 	}
 	convert_date(orig_buffer, orig_size, result_sha1);
 }
diff --git a/csum-file.c b/csum-file.c
index 5f9249a..ebaad03 100644
--- a/csum-file.c
+++ b/csum-file.c
@@ -17,7 +17,7 @@ static int sha1flush(struct sha1file *f,
 	for (;;) {
 		int ret = xwrite(f->fd, buf, count);
 		if (ret > 0) {
-			buf += ret;
+			buf = (char *) buf + ret;
 			count -= ret;
 			if (count)
 				continue;
@@ -57,7 +57,7 @@ int sha1write(struct sha1file *f, void *
 		memcpy(f->buffer + offset, buf, nr);
 		count -= nr;
 		offset += nr;
-		buf += nr;
+		buf = (char *) buf + nr;
 		left -= nr;
 		if (!left) {
 			SHA1_Update(&f->ctx, f->buffer, offset);
diff --git a/diff-delta.c b/diff-delta.c
index 25a798d..8b9172a 100644
--- a/diff-delta.c
+++ b/diff-delta.c
@@ -22,6 +22,7 @@ #include <stdlib.h>
 #include <string.h>
 #include "delta.h"
 
+#include "git-compat-util.h"
 
 /* maximum hash entry list for the same hash bucket */
 #define HASH_LIMIT 64
@@ -131,7 +132,7 @@ struct delta_index {
 	const void *src_buf;
 	unsigned long src_size;
 	unsigned int hash_mask;
-	struct index_entry *hash[0];
+	struct index_entry *hash[FLEX_ARRAY];
 };
 
 struct delta_index * create_delta_index(const void *buf, unsigned long bufsize)
@@ -283,7 +284,7 @@ create_delta(const struct delta_index *i
 	ref_data = index->src_buf;
 	ref_top = ref_data + index->src_size;
 	data = trg_buf;
-	top = trg_buf + trg_size;
+	top = (const unsigned char *) trg_buf + trg_size;
 
 	outpos++;
 	val = 0;
diff --git a/diff-lib.c b/diff-lib.c
index 2183b41..fdc1173 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -34,21 +34,23 @@ int run_diff_files(struct rev_info *revs
 			continue;
 
 		if (ce_stage(ce)) {
-			struct {
-				struct combine_diff_path p;
-				struct combine_diff_parent filler[5];
-			} combine;
+			struct combine_diff_path *dpath;
 			int num_compare_stages = 0;
+			size_t path_len;
 
-			combine.p.next = NULL;
-			combine.p.len = ce_namelen(ce);
-			combine.p.path = xmalloc(combine.p.len + 1);
-			memcpy(combine.p.path, ce->name, combine.p.len);
-			combine.p.path[combine.p.len] = 0;
-			combine.p.mode = 0;
-			memset(combine.p.sha1, 0, 20);
-			memset(&combine.p.parent[0], 0,
-			       sizeof(combine.filler));
+			path_len = ce_namelen(ce);
+
+			dpath = xmalloc (combine_diff_path_size (5, path_len));
+			dpath->path = (char *) &(dpath->parent[5]);
+
+			dpath->next = NULL;
+			dpath->len = path_len;
+			memcpy(dpath->path, ce->name, path_len);
+			dpath->path[path_len] = '\0';
+			dpath->mode = 0;
+			memset(dpath->sha1, 0, 20);
+			memset(&(dpath->parent[0]), 0,
+					sizeof(struct combine_diff_parent)*5);
 
 			while (i < entries) {
 				struct cache_entry *nce = active_cache[i];
@@ -64,11 +66,11 @@ int run_diff_files(struct rev_info *revs
 				if (2 <= stage) {
 					int mode = ntohl(nce->ce_mode);
 					num_compare_stages++;
-					memcpy(combine.p.parent[stage-2].sha1,
+					memcpy(dpath->parent[stage-2].sha1,
 					       nce->sha1, 20);
-					combine.p.parent[stage-2].mode =
+					dpath->parent[stage-2].mode =
 						canon_mode(mode);
-					combine.p.parent[stage-2].status =
+					dpath->parent[stage-2].status =
 						DIFF_STATUS_MODIFIED;
 				}
 
@@ -83,13 +85,14 @@ int run_diff_files(struct rev_info *revs
 			i--;
 
 			if (revs->combine_merges && num_compare_stages == 2) {
-				show_combined_diff(&combine.p, 2,
+				show_combined_diff(dpath, 2,
 						   revs->dense_combined_merges,
 						   revs);
-				free(combine.p.path);
+				free(dpath);
 				continue;
 			}
-			free(combine.p.path);
+			free(dpath);
+			dpath = NULL;
 
 			/*
 			 * Show the diff for the 'ce' if we found the one
diff --git a/diff.c b/diff.c
index 9e9cfc8..fb1411c 100644
--- a/diff.c
+++ b/diff.c
@@ -515,7 +515,7 @@ static void emit_binary_diff(mmfile_t *o
 		else
 			line[0] = bytes - 26 + 'a' - 1;
 		encode_85(line + 1, cp, bytes);
-		cp += bytes;
+		cp = (char *) cp + bytes;
 		puts(line);
 	}
 	printf("\n");
diff --git a/diffcore-order.c b/diffcore-order.c
index 0bc2b22..aef6da6 100644
--- a/diffcore-order.c
+++ b/diffcore-order.c
@@ -30,7 +30,7 @@ static void prepare_order(const char *or
 	close(fd);
 	if (map == MAP_FAILED)
 		return;
-	endp = map + st.st_size;
+	endp = (char *) map + st.st_size;
 	for (pass = 0; pass < 2; pass++) {
 		cnt = 0;
 		cp = map;
diff --git a/http-fetch.c b/http-fetch.c
index da1a7f5..2b63d89 100644
--- a/http-fetch.c
+++ b/http-fetch.c
@@ -123,7 +123,7 @@ static size_t fwrite_sha1_file(void *ptr
 	struct object_request *obj_req = (struct object_request *)data;
 	do {
 		ssize_t retval = write(obj_req->local,
-				       ptr + posn, size - posn);
+				       (char *) ptr + posn, size - posn);
 		if (retval < 0)
 			return posn;
 		posn += retval;
@@ -1136,13 +1136,14 @@ int fetch(unsigned char *sha1)
 
 static inline int needs_quote(int ch)
 {
-	switch (ch) {
-	case '/': case '-': case '.':
-	case 'A'...'Z':	case 'a'...'z':	case '0'...'9':
+	if (((ch >= 'A') && (ch <= 'Z'))
+			|| ((ch >= 'a') && (ch <= 'z'))
+			|| ((ch >= '0') && (ch <= '9'))
+			|| (ch == '/')
+			|| (ch == '-')
+			|| (ch == '.'))
 		return 0;
-	default:
-		return 1;
-	}
+	return 1;
 }
 
 static inline int hex(int v)
diff --git a/http-push.c b/http-push.c
index 2d9441e..0684e46 100644
--- a/http-push.c
+++ b/http-push.c
@@ -196,7 +196,7 @@ static size_t fwrite_sha1_file(void *ptr
 	struct transfer_request *request = (struct transfer_request *)data;
 	do {
 		ssize_t retval = write(request->local_fileno,
-				       ptr + posn, size - posn);
+				       (char *) ptr + posn, size - posn);
 		if (retval < 0)
 			return posn;
 		posn += retval;
@@ -1077,13 +1077,14 @@ static int fetch_indices(void)
 
 static inline int needs_quote(int ch)
 {
-	switch (ch) {
-	case '/': case '-': case '.':
-	case 'A'...'Z':	case 'a'...'z':	case '0'...'9':
+	if (((ch >= 'A') && (ch <= 'Z'))
+			|| ((ch >= 'a') && (ch <= 'z'))
+			|| ((ch >= '0') && (ch <= '9'))
+			|| (ch == '/')
+			|| (ch == '-')
+			|| (ch == '.'))
 		return 0;
-	default:
-		return 1;
-	}
+	return 1;
 }
 
 static inline int hex(int v)
diff --git a/http.c b/http.c
index 08769cc..6c1937b 100644
--- a/http.c
+++ b/http.c
@@ -34,7 +34,7 @@ size_t fread_buffer(void *ptr, size_t el
 	size_t size = eltsize * nmemb;
 	if (size > buffer->size - buffer->posn)
 		size = buffer->size - buffer->posn;
-	memcpy(ptr, buffer->buffer + buffer->posn, size);
+	memcpy(ptr, (char *) buffer->buffer + buffer->posn, size);
 	buffer->posn += size;
 	return size;
 }
@@ -49,7 +49,7 @@ size_t fwrite_buffer(const void *ptr, si
 			buffer->size = buffer->posn + size;
 		buffer->buffer = xrealloc(buffer->buffer, buffer->size);
 	}
-	memcpy(buffer->buffer + buffer->posn, ptr, size);
+	memcpy((char *) buffer->buffer + buffer->posn, ptr, size);
 	buffer->posn += size;
 	data_received++;
 	return size;
diff --git a/imap-send.c b/imap-send.c
index 285ad29..87db8e2 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -93,7 +93,7 @@ typedef struct {
 	char *data;
 	int len;
 	unsigned char flags;
-	unsigned char crlf:1;
+	unsigned int  crlf:1;
 } msg_data_t;
 
 #define DRV_OK          0
diff --git a/pack-check.c b/pack-check.c
index e575879..3a62e1b 100644
--- a/pack-check.c
+++ b/pack-check.c
@@ -29,10 +29,10 @@ static int verify_packfile(struct packed
 	pack_base = p->pack_base;
 	SHA1_Update(&ctx, pack_base, pack_size - 20);
 	SHA1_Final(sha1, &ctx);
-	if (memcmp(sha1, pack_base + pack_size - 20, 20))
+	if (memcmp(sha1, (char *) pack_base + pack_size - 20, 20))
 		return error("Packfile %s SHA1 mismatch with itself",
 			     p->pack_name);
-	if (memcmp(sha1, index_base + index_size - 40, 20))
+	if (memcmp(sha1, (char *) index_base + index_size - 40, 20))
 		return error("Packfile %s SHA1 mismatch with idx",
 			     p->pack_name);
 
@@ -135,7 +135,7 @@ int verify_pack(struct packed_git *p, in
 	SHA1_Init(&ctx);
 	SHA1_Update(&ctx, index_base, index_size - 20);
 	SHA1_Final(sha1, &ctx);
-	if (memcmp(sha1, index_base + index_size - 20, 20))
+	if (memcmp(sha1, (char *) index_base + index_size - 20, 20))
 		ret = error("Packfile index for %s SHA1 mismatch",
 			    p->pack_name);
 
diff --git a/pack-objects.c b/pack-objects.c
index 179560f..ba6525d 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -156,7 +156,7 @@ static void prepare_pack_revindex(struct
 
 	rix->revindex = xmalloc(sizeof(unsigned long) * (num_ent + 1));
 	for (i = 0; i < num_ent; i++) {
-		unsigned int hl = *((unsigned int *)(index + 24 * i));
+		unsigned int hl = *((unsigned int *)((char *) index + 24*i));
 		rix->revindex[i] = ntohl(hl);
 	}
 	/* This knows the pack format -- the 20-byte trailer
@@ -300,7 +300,7 @@ static unsigned long write_object(struct
 		use_packed_git(p);
 
 		datalen = find_packed_object_size(p, entry->in_pack_offset);
-		buf = p->pack_base + entry->in_pack_offset;
+		buf = (char *) p->pack_base + entry->in_pack_offset;
 		sha1write(f, buf, datalen);
 		unuse_packed_git(p);
 		hdrlen = 0; /* not really */
diff --git a/pack-redundant.c b/pack-redundant.c
index cd81f5a..4864a2b 100644
--- a/pack-redundant.c
+++ b/pack-redundant.c
@@ -246,12 +246,12 @@ static struct pack_list * pack_list_diff
 static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
 {
 	int p1_off, p2_off;
-	void *p1_base, *p2_base;
+	unsigned char *p1_base, *p2_base;
 	struct llist_item *p1_hint = NULL, *p2_hint = NULL;
 	
 	p1_off = p2_off = 256 * 4 + 4;
-	p1_base = (void *)p1->pack->index_base;
-	p2_base = (void *)p2->pack->index_base;
+	p1_base = (unsigned char *) p1->pack->index_base;
+	p2_base = (unsigned char *) p2->pack->index_base;
 
 	while (p1_off <= p1->pack->index_size - 3 * 20 &&
 	       p2_off <= p2->pack->index_size - 3 * 20)
@@ -351,11 +351,11 @@ static size_t sizeof_union(struct packed
 {
 	size_t ret = 0;
 	int p1_off, p2_off;
-	void *p1_base, *p2_base;
+	char *p1_base, *p2_base;
 
 	p1_off = p2_off = 256 * 4 + 4;
-	p1_base = (void *)p1->index_base;
-	p2_base = (void *)p2->index_base;
+	p1_base = (char *)p1->index_base;
+	p2_base = (char *)p2->index_base;
 
 	while (p1_off <= p1->index_size - 3 * 20 &&
 	       p2_off <= p2->index_size - 3 * 20)
@@ -534,7 +534,7 @@ static struct pack_list * add_pack(struc
 {
 	struct pack_list l;
 	size_t off;
-	void *base;
+	unsigned char *base;
 
 	if (!p->pack_local && !(alt_odb || verbose))
 		return NULL;
@@ -543,7 +543,7 @@ static struct pack_list * add_pack(struc
 	llist_init(&l.all_objects);
 
 	off = 256 * 4 + 4;
-	base = (void *)p->index_base;
+	base = (unsigned char *)p->index_base;
 	while (off <= p->index_size - 3 * 20) {
 		llist_insert_back(l.all_objects, base + off);
 		off += 24;
diff --git a/patch-delta.c b/patch-delta.c
index 8f318ed..e3a1d42 100644
--- a/patch-delta.c
+++ b/patch-delta.c
@@ -25,7 +25,7 @@ void *patch_delta(const void *src_buf, u
 		return NULL;
 
 	data = delta_buf;
-	top = delta_buf + delta_size;
+	top = (const unsigned char *) delta_buf + delta_size;
 
 	/* make sure the orig file size matches what we expect */
 	size = get_delta_hdr_size(&data, top);
@@ -56,7 +56,7 @@ void *patch_delta(const void *src_buf, u
 			    cp_off + cp_size > src_size ||
 			    cp_size > size)
 				goto bad;
-			memcpy(out, src_buf + cp_off, cp_size);
+			memcpy(out, (char *) src_buf + cp_off, cp_size);
 			out += cp_size;
 			size -= cp_size;
 		} else if (cmd) {
diff --git a/pkt-line.c b/pkt-line.c
index bb3bab0..44d4296 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -21,7 +21,7 @@ static void safe_write(int fd, const voi
 	while (n) {
 		int ret = xwrite(fd, buf, n);
 		if (ret > 0) {
-			buf += ret;
+			buf = (char *) buf + ret;
 			n -= ret;
 			continue;
 		}
@@ -66,7 +66,7 @@ static void safe_read(int fd, void *buff
 	int n = 0;
 
 	while (n < size) {
-		int ret = xread(fd, buffer + n, size - n);
+		int ret = xread(fd, (char *) buffer + n, size - n);
 		if (ret < 0)
 			die("read error (%s)", strerror(errno));
 		if (!ret)
diff --git a/quote.c b/quote.c
index 06792d4..dcc2326 100644
--- a/quote.c
+++ b/quote.c
@@ -206,7 +206,14 @@ #define EMIT(c) (outp ? (*outp++ = (c)) 
 				case '\\': case '"':
 					break; /* verbatim */
 
-				case '0'...'7':
+				case '0':
+				case '1':
+				case '2':
+				case '3':
+				case '4':
+				case '5':
+				case '6':
+				case '7':
 					/* octal */
 					ac = ((ch - '0') << 6);
 					if ((ch = *sp++) < '0' || '7' < ch)
diff --git a/read-cache.c b/read-cache.c
index c499c51..3c32aae 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -706,7 +706,7 @@ static int verify_hdr(struct cache_heade
 	SHA1_Init(&c);
 	SHA1_Update(&c, hdr, size - 20);
 	SHA1_Final(sha1, &c);
-	if (memcmp(sha1, (void *)hdr + size - 20, 20))
+	if (memcmp(sha1, (char *) hdr + size - 20, 20))
 		return error("bad index file sha1 signature");
 	return 0;
 }
@@ -770,7 +770,7 @@ int read_cache(void)
 
 	offset = sizeof(*hdr);
 	for (i = 0; i < active_nr; i++) {
-		struct cache_entry *ce = map + offset;
+		struct cache_entry *ce = (struct cache_entry *) ((char *) map + offset);
 		offset = offset + ce_size(ce);
 		active_cache[i] = ce;
 	}
@@ -783,10 +783,11 @@ int read_cache(void)
 		 * in 4-byte network byte order.
 		 */
 		unsigned long extsize;
-		memcpy(&extsize, map + offset + 4, 4);
+		memcpy(&extsize, (char *) map + offset + 4, 4);
 		extsize = ntohl(extsize);
-		if (read_index_extension(map + offset,
-					 map + offset + 8, extsize) < 0)
+		if (read_index_extension(((const char *) map) + offset,
+					 (char *) map + offset + 8,
+					 extsize) < 0)
 			goto unmap;
 		offset += 8;
 		offset += extsize;
@@ -820,7 +821,7 @@ static int ce_write(SHA_CTX *context, in
 		}
 		write_buffer_len = buffered;
 		len -= partial;
-		data += partial;
+		data = (char *) data + partial;
  	}
  	return 0;
 }
diff --git a/sha1_file.c b/sha1_file.c
index b4ff233..3c001d7 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -486,7 +486,8 @@ int use_packed_git(struct packed_git *p)
 		 * this is cheap.
 		 */
 		if (memcmp((char*)(p->index_base) + p->index_size - 40,
-			   p->pack_base + p->pack_size - 20, 20)) {
+			   (char *) p->pack_base + p->pack_size - 20,
+			   20)) {
 			      
 			die("packfile %s does not match index.", p->pack_name);
 		}
@@ -701,7 +702,7 @@ static void *unpack_sha1_rest(z_stream *
 	int bytes = strlen(buffer) + 1;
 	unsigned char *buf = xmalloc(1+size);
 
-	memcpy(buf, buffer + bytes, stream->total_out - bytes);
+	memcpy(buf, (char *) buffer + bytes, stream->total_out - bytes);
 	bytes = stream->total_out - bytes;
 	if (bytes < size) {
 		stream->next_out = buf + bytes;
@@ -853,7 +854,7 @@ static unsigned long unpack_object_heade
 	if (offset >= p->pack_size)
 		die("object offset outside of pack file");
 
-	pack =  p->pack_base + offset;
+	pack =  (unsigned char *) p->pack_base + offset;
 	c = *pack++;
 	offset++;
 	*type = (c >> 4) & 7;
@@ -883,7 +884,7 @@ int check_reuse_pack_delta(struct packed
 	ptr = unpack_object_header(p, ptr, kindp, sizep);
 	if (*kindp != OBJ_DELTA)
 		goto done;
-	memcpy(base, p->pack_base + ptr, 20);
+	memcpy(base, (char *) p->pack_base + ptr, 20);
 	status = 0;
  done:
 	unuse_packed_git(p);
@@ -903,7 +904,7 @@ void packed_object_info_detail(struct pa
 	enum object_type kind;
 
 	offset = unpack_object_header(p, e->offset, &kind, size);
-	pack = p->pack_base + offset;
+	pack = (unsigned char *) p->pack_base + offset;
 	if (kind != OBJ_DELTA)
 		*delta_chain_length = 0;
 	else {
@@ -919,7 +920,7 @@ void packed_object_info_detail(struct pa
 			find_pack_entry_one(pack, &base_ent, p);
 			offset = unpack_object_header(p, base_ent.offset,
 						      &kind, &junk);
-			pack = p->pack_base + offset;
+			pack = (unsigned char *) p->pack_base + offset;
 			chain_length++;
 		} while (kind == OBJ_DELTA);
 		*delta_chain_length = chain_length;
@@ -957,7 +958,7 @@ static int packed_object_info(struct pac
 		die("cannot map packed file");
 
 	offset = unpack_object_header(p, entry->offset, &kind, &size);
-	pack = p->pack_base + offset;
+	pack = (unsigned char *) p->pack_base + offset;
 	left = p->pack_size - offset;
 
 	switch (kind) {
@@ -1096,7 +1097,7 @@ void *unpack_entry_gently(struct pack_en
 	void *retval;
 
 	offset = unpack_object_header(p, entry->offset, &kind, &size);
-	pack = p->pack_base + offset;
+	pack = (unsigned char *) p->pack_base + offset;
 	left = p->pack_size - offset;
 	switch (kind) {
 	case OBJ_DELTA:
@@ -1134,7 +1135,7 @@ int nth_packed_object_sha1(const struct 
 	void *index = p->index_base + 256;
 	if (n < 0 || num_packed_objects(p) <= n)
 		return -1;
-	memcpy(sha1, (index + 24 * n + 4), 20);
+	memcpy(sha1, (char *) index + (24 * n) + 4, 20);
 	return 0;
 }
 
@@ -1148,9 +1149,9 @@ int find_pack_entry_one(const unsigned c
 
 	do {
 		int mi = (lo + hi) / 2;
-		int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
+		int cmp = memcmp((char *) index + (24 * mi) + 4, sha1, 20);
 		if (!cmp) {
-			e->offset = ntohl(*((unsigned int *)(index + 24 * mi)));
+			e->offset = ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
 			memcpy(e->sha1, sha1, 20);
 			e->p = p;
 			return 1;
@@ -1290,7 +1291,7 @@ void *read_object_with_reference(const u
 		ref_length = strlen(ref_type);
 
 		if (memcmp(buffer, ref_type, ref_length) ||
-		    get_sha1_hex(buffer + ref_length, actual_sha1)) {
+		    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
 			free(buffer);
 			return NULL;
 		}
@@ -1408,7 +1409,7 @@ static int write_buffer(int fd, const vo
 			return error("file write error (%s)", strerror(errno));
 		}
 		len -= size;
-		buf += size;
+		buf = (char *) buf + size;
 	}
 	return 0;
 }
diff --git a/ssh-fetch.c b/ssh-fetch.c
index e3067b8..1e59cd2 100644
--- a/ssh-fetch.c
+++ b/ssh-fetch.c
@@ -24,7 +24,7 @@ static ssize_t force_write(int fd, void 
 {
 	ssize_t ret = 0;
 	while (ret < length) {
-		ssize_t size = write(fd, buffer + ret, length - ret);
+		ssize_t size = write(fd, (char *) buffer + ret, length - ret);
 		if (size < 0) {
 			return size;
 		}
diff --git a/tag.c b/tag.c
index f390ee7..13c364d 100644
--- a/tag.c
+++ b/tag.c
@@ -47,10 +47,10 @@ int parse_tag_buffer(struct tag *item, v
 
 	if (size < 64)
 		return -1;
-	if (memcmp("object ", data, 7) || get_sha1_hex(data + 7, object))
+	if (memcmp("object ", data, 7) || get_sha1_hex((char *) data + 7, object))
 		return -1;
 
-	type_line = data + 48;
+	type_line = (char *) data + 48;
 	if (memcmp("\ntype ", type_line-1, 6))
 		return -1;
 
diff --git a/tree-walk.c b/tree-walk.c
index 297c697..3f83e98 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -43,7 +43,7 @@ void update_tree_entry(struct tree_desc 
 
 	if (size < len)
 		die("corrupt tree file");
-	desc->buf = buf + len;
+	desc->buf = (char *) buf + len;
 	desc->size = size - len;
 }
 
@@ -66,7 +66,7 @@ const unsigned char *tree_entry_extract(
 	const void *tree = desc->buf;
 	unsigned long size = desc->size;
 	int len = strlen(tree)+1;
-	const unsigned char *sha1 = tree + len;
+	const unsigned char *sha1 = (unsigned char *) tree + len;
 	const char *path;
 	unsigned int mode;
 
@@ -80,7 +80,8 @@ const unsigned char *tree_entry_extract(
 
 int tree_entry(struct tree_desc *desc, struct name_entry *entry)
 {
-	const void *tree = desc->buf, *path;
+	const void *tree = desc->buf;
+	const char *path;
 	unsigned long len, size = desc->size;
 
 	if (!size)
@@ -95,10 +96,10 @@ int tree_entry(struct tree_desc *desc, s
 	entry->pathlen = len;
 
 	path += len + 1;
-	entry->sha1 = path;
+	entry->sha1 = (const unsigned char *) path;
 
 	path += 20;
-	len = path - tree;
+	len = path - (char *) tree;
 	if (len > size)
 		die("corrupt tree file");
 
-- 
1.3.3

```

## Timo Hirvonen, 2006-06-18 08:07

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <20060618110749.e6fb9030.tihirvon@gmail.com>
URL: https://gitlist.dev/e/20060618110749.e6fb9030.tihirvon%40gmail.com
In-Reply-To: <1150609831500-git-send-email-octo@verplant.org>

```
Florian Forster <octo@verplant.org> wrote:

> Using this patch I was able to build git with
> $ make CFLAGS="-Wall -Werror -ansi -pedantic -std=c99 -D_XOPEN_SOURCE=500 -D_BSD_SOURCE"
> 
> While most of this patch fixes void-pointer arithmetic and is therefore
> trivial, I had to change the use of a struct with FAMs in `diff-lib.c'. Since
> this is the first time I encountered FAMs it'd probably be a good idea if
> someone who knows would take a look at that.

Many of the void-pointer arithmetic warnings could be fixed by changing
the variable types to char * instead of casting them in many places.

> --- a/diff-lib.c
> +++ b/diff-lib.c
> @@ -34,21 +34,23 @@ int run_diff_files(struct rev_info *revs
>  			continue;
>  
>  		if (ce_stage(ce)) {
> -			struct {
> -				struct combine_diff_path p;
> -				struct combine_diff_parent filler[5];
> -			} combine;

Yes this is somewhat ugly but avoids a malloc.  You could use alloca but
the man-page says:

    "The alloca() function is machine and compiler dependent. On many systems
     its implementation is buggy. Its use is discouraged."

Leave the code as it is now unless it causes real problems.

>  static inline int needs_quote(int ch)
>  {
> -	switch (ch) {
> -	case '/': case '-': case '.':
> -	case 'A'...'Z':	case 'a'...'z':	case '0'...'9':
> +	if (((ch >= 'A') && (ch <= 'Z'))
> +			|| ((ch >= 'a') && (ch <= 'z'))
> +			|| ((ch >= '0') && (ch <= '9'))
> +			|| (ch == '/')
> +			|| (ch == '-')
> +			|| (ch == '.'))

'A'...'Z' is more readable.  Does some compiler fail to compile it?

> +++ b/http-push.c

>  static inline int needs_quote(int ch)

Hmm.. same function in http-fetch.c.  Lots of common code could be moved
to http.h.

-- 
http://onion.dynserv.net/~timo/

```

## Thomas Glanzmann, 2006-06-18 08:14

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <20060618081440.GD22641@cip.informatik.uni-erlangen.de>
URL: https://gitlist.dev/e/20060618081440.GD22641%40cip.informatik.uni-erlangen.de
In-Reply-To: <20060618110749.e6fb9030.tihirvon@gmail.com>

```
Hello,

> 'A'...'Z' is more readable.  Does some compiler fail to compile it?

yes, it is GCC (GNU) specific IIRC. So for example the Sun Compiler will
choke on this one.

        Thomas

```

## Florian Forster, 2006-06-18 08:21

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <20060618082103.GA1331@verplant.org>
URL: https://gitlist.dev/e/20060618082103.GA1331%40verplant.org
In-Reply-To: <20060618110749.e6fb9030.tihirvon@gmail.com>

```
Hi,

On Sun, Jun 18, 2006 at 11:07:49AM +0300, Timo Hirvonen wrote:
> Many of the void-pointer arithmetic warnings could be fixed by
> changing the variable types to char * instead of casting them in many
> places.

true. Casting to a void-pointer can be done implicitely (even according
to the standard), so changing a function's argument from `void *' to
`char *' might break code somewhere else.

> > -			struct {
> > -				struct combine_diff_path p;
> > -				struct combine_diff_parent filler[5];
> > -			} combine;
> 
> Yes this is somewhat ugly but avoids a malloc.

No, malloc is still needed to allocate `combine.p.path'. My change does
allocate all memory in one pass, so the number of calls to malloc
doesn't differ.

> Leave the code as it is now unless it causes real problems.

`struct combine_diff_path' has a flexible array member (FAM) and is
therefore an incomplete type. This means you may not instanciate it.

GCC ignores the FAM in this case and allocates `sizeof (struct
combine_diff_path)' bytes. However, this is not correct according to
ANSI and prevents building using other compilers (e.g. Sun cc).

To be honest, I don't get the point of FAMs anyways. Why don't we just
use a pointer to `struct combine_diff_parent' there in the first place?

> 'A'...'Z' is more readable.  Does some compiler fail to compile it?

It's not in ANSI, therefore GCC with `-ansi' failes, so does the Sun cc.

> >  static inline int needs_quote(int ch)
> 
> Hmm.. same function in http-fetch.c.  Lots of common code could be
> moved to http.h.

Right, I wanted to keep the changes as minimal as possible, though.

As you can probably tell my goal is building a Solaris version of git
using the Sun cc. I'm not quite there yet and don't have time to look
into the remaining issue(s) today nor tomorrow, but I might have some
time at the end of the week.

Regards,
-octo
-- 
Florian octo Forster
Hacker in training
GnuPG: 0x91523C3D
http://verplant.org/

```

## Rene Scharfe, 2006-06-18 08:26

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <44950E32.10904@lsrfire.ath.cx>
URL: https://gitlist.dev/e/44950E32.10904%40lsrfire.ath.cx
In-Reply-To: <1150609831500-git-send-email-octo@verplant.org>

```
Florian Forster schrieb:
> Using this patch I was able to build git with
> $ make CFLAGS="-Wall -Werror -ansi -pedantic -std=c99 -D_XOPEN_SOURCE=500 -D_BSD_SOURCE"
> 
> While most of this patch fixes void-pointer arithmetic and is therefore
> trivial, I had to change the use of a struct with FAMs in `diff-lib.c'. Since
> this is the first time I encountered FAMs it'd probably be a good idea if
> someone who knows would take a look at that.

Nice work!  However, could you split it up a bit?  I.e. please send one
patch per error class/topic.  A comment on why the changes are needed
would be nice too, e.g. "void pointer arithmetic is a GNU extension, get
rid of it".

Thanks,
René

```

## Junio C Hamano, 2006-06-18 08:29

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <7vac8a50ji.fsf@assigned-by-dhcp.cox.net>
URL: https://gitlist.dev/e/7vac8a50ji.fsf%40assigned-by-dhcp.cox.net
In-Reply-To: <1150609831500-git-send-email-octo@verplant.org>

```
Florian Forster <octo@verplant.org> writes:

> While most of this patch fixes void-pointer arithmetic and is therefore
> trivial, I had to change the use of a struct with FAMs in `diff-lib.c'. Since
> this is the first time I encountered FAMs it'd probably be a good idea if
> someone who knows would take a look at that.

Thanks.  I am very tempted to apply it, but I started to wonder
that in some places it might make sense to convert void* to
char* instead of casting.  Undecided.

> diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
> index f6310b9..646322d 100644
> --- a/builtin-tar-tree.c
> +++ b/builtin-tar-tree.c
> @@ -34,7 +34,7 @@ static void reliable_write(void *buf, un
>  			die("git-tar-tree: disk full?");
>  		}
>  		size -= ret;
> -		buf += ret;
> +		buf   = (char *) buf + ret;

Please do not add the extra whitespace to align "=".

> @@ -244,14 +244,14 @@ static void convert_date(void *buffer, u
>  	// "tree <sha1>\n"
>  	memcpy(new + newlen, buffer, 46);
>  	newlen += 46;
> -	buffer += 46;
> +	buffer = (char *) buffer + 46;
>  	size -= 46;
>  
>  	// "parent <sha1>\n"
>  	while (!memcmp(buffer, "parent ", 7)) {
>  		memcpy(new + newlen, buffer, 48);
>  		newlen += 48;
> -		buffer += 48;
> +		buffer = (char *) buffer + 48;
>  		size -= 48;
>  	}
>  
> @@ -275,11 +275,11 @@ static void convert_commit(void *buffer,
>  
>  	if (memcmp(buffer, "tree ", 5))
>  		die("Bad commit '%s'", (char*) buffer);
> -	convert_ascii_sha1(buffer+5);
> -	buffer += 46;    /* "tree " + "hex sha1" + "\n" */
> +	convert_ascii_sha1((char *) buffer + 5);
> +	buffer = (char *) buffer + 46;    /* "tree " + "hex sha1" + "\n" */
>  	while (!memcmp(buffer, "parent ", 7)) {
> -		convert_ascii_sha1(buffer+7);
> -		buffer += 48;
> +		convert_ascii_sha1((char *) buffer + 7);
> +		buffer = (char *) buffer + 48;
>  	}
>  	convert_date(orig_buffer, orig_size, result_sha1);
>  }

Hmmmmmmm.  Now I start to wonder if changing the type of "void *buffer"
to "char *buffer" is cleaner.

> diff --git a/diff-delta.c b/diff-delta.c
> index 25a798d..8b9172a 100644
> --- a/diff-delta.c
> +++ b/diff-delta.c
> @@ -22,6 +22,7 @@ #include <stdlib.h>
>  #include <string.h>
>  #include "delta.h"
>  
> +#include "git-compat-util.h"
>  
>  /* maximum hash entry list for the same hash bucket */
>  #define HASH_LIMIT 64
> @@ -131,7 +132,7 @@ struct delta_index {
>  	const void *src_buf;
>  	unsigned long src_size;
>  	unsigned int hash_mask;
> -	struct index_entry *hash[0];
> +	struct index_entry *hash[FLEX_ARRAY];
>  };

Good -- I missed this when we did FLEX_ARRAY.  Thanks.

> diff --git a/diff-lib.c b/diff-lib.c
> index 2183b41..fdc1173 100644
> --- a/diff-lib.c
> +++ b/diff-lib.c
> @@ -34,21 +34,23 @@ int run_diff_files(struct rev_info *revs
>  			continue;
>  
>  		if (ce_stage(ce)) {
> -			struct {
> -				struct combine_diff_path p;
> -				struct combine_diff_parent filler[5];
> -			} combine;

I admit this part was ugly.  The new code does not do any extra
allocations and matches the other use of "struct combine_diff_path"
more closely.  Good change.

> @@ -1136,13 +1136,14 @@ int fetch(unsigned char *sha1)
>  
>  static inline int needs_quote(int ch)
>  {
> -	switch (ch) {
> -	case '/': case '-': case '.':
> -	case 'A'...'Z':	case 'a'...'z':	case '0'...'9':
> +	if (((ch >= 'A') && (ch <= 'Z'))
> +			|| ((ch >= 'a') && (ch <= 'z'))
> +			|| ((ch >= '0') && (ch <= '9'))
> +			|| (ch == '/')
> +			|| (ch == '-')
> +			|| (ch == '.'))
>  		return 0;
> -	default:
> -		return 1;
> -	}
> +	return 1;
>  }

Ugh.  Delight of standard compliance X-<.

> diff --git a/http-push.c b/http-push.c
> index 2d9441e..0684e46 100644
> --- a/http-push.c
> +++ b/http-push.c
> @@ -1077,13 +1077,14 @@ static int fetch_indices(void)
>  
>  static inline int needs_quote(int ch)

Hmph.  Thanks for noticing the duplicated code; maybe move it to
cache.h perhaps?

```

## Florian Forster, 2006-06-18 08:35

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <20060618083502.GB1331@verplant.org>
URL: https://gitlist.dev/e/20060618083502.GB1331%40verplant.org
In-Reply-To: <44950E32.10904@lsrfire.ath.cx>

```
Hi Rene,

On Sun, Jun 18, 2006 at 10:26:26AM +0200, Rene Scharfe wrote:
> However, could you split it up a bit?

Sure, I'll follow up on this in a short while..

-octo
-- 
Florian octo Forster
Hacker in training
GnuPG: 0x91523C3D
http://verplant.org/

```

## Timo Hirvonen, 2006-06-18 08:43

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <20060618114352.15191199.tihirvon@gmail.com>
URL: https://gitlist.dev/e/20060618114352.15191199.tihirvon%40gmail.com
In-Reply-To: <20060618082103.GA1331@verplant.org>

```
Florian Forster <octo@verplant.org> wrote:

> GCC ignores the FAM in this case and allocates `sizeof (struct
> combine_diff_path)' bytes. However, this is not correct according to
> ANSI and prevents building using other compilers (e.g. Sun cc).

Fair enough.

> To be honest, I don't get the point of FAMs anyways. Why don't we just
> use a pointer to `struct combine_diff_parent' there in the first place?

In general FAMs are used to replace two mallocs with one.

    x = malloc(sizeof(struct foo) + 100)

instead of 

    x = malloc(sizeof(struct foo));
    x->y = malloc(100);

-- 
http://onion.dynserv.net/~timo/

```

## Florian Forster, 2006-06-18 15:18

Subject: [PATCH 0/7] Improve ANSI C99 compliance
Message-ID: <11506438892865-git-send-email-octo@verplant.org>
URL: https://gitlist.dev/e/11506438892865-git-send-email-octo%40verplant.org
In-Reply-To: <20060618083502.GB1331@verplant.org>

```
Hi,

as promised I've split up the changes into several smaller patches. The changes
are grouped by type of problem they fix, as requested. The patches should not
depend on each other, but I didn't actually test that.

Regards,
-octo

```

## Linus Torvalds, 2006-06-18 16:50

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <Pine.LNX.4.64.0606180946090.5498@g5.osdl.org>
URL: https://gitlist.dev/e/Pine.LNX.4.64.0606180946090.5498%40g5.osdl.org
In-Reply-To: <1150609831500-git-send-email-octo@verplant.org>

```


On Sun, 18 Jun 2006, Florian Forster wrote:
>
> Using this patch I was able to build git with
> $ make CFLAGS="-Wall -Werror -ansi -pedantic -std=c99 -D_XOPEN_SOURCE=500 -D_BSD_SOURCE"

"-ansi -pedantic" is really not useful.

> While most of this patch fixes void-pointer arithmetic

This one I disagree with. Doing arithmetic on "void *" is _really_ useful, 
and I think most compilers end up supporting it either to be compatible 
with gcc, or just because it's hard to not do it.

It makes code a _lot_ cleaner.

In general, explicit casts are a sign of bad programming, and "void *" is 
there exactly to avoid it. And doing arithmetic on pointers is useful and 
fairly common, and if you accept void-pointer arithmetic, it avoids a lot 
of ugly and useless casts.

> @@ -301,9 +301,9 @@ static void fill_line_map(struct commit 
>  				if (DEBUG)
>  					printf("map: i1: %d %d %p i2: %d %d %p\n",
>  					       i1, map[i1],
> -					       i1 != -1 ? blame_lines[map[i1]] : NULL,
> +					       (void *) (i1 != -1 ? blame_lines[map[i1]] : NULL),
>  					       i2, map2[i2],
> -					       i2 != -1 ? blame_lines[map2[i2]] : NULL);
> +					       (void *) (i2 != -1 ? blame_lines[map2[i2]] : NULL));

Gaah. This is another case of casting that I'm sure is technically 
correct, but that I wonder whether there is any machine that actually 
cares..

But at least in that case I suspect the cast _may_ be required due to 
different pointer representations.

		Linus

```

## Florian Forster, 2006-06-19 21:21

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <20060619212116.GL1331@verplant.org>
URL: https://gitlist.dev/e/20060619212116.GL1331%40verplant.org
In-Reply-To: <Pine.LNX.4.64.0606180946090.5498@g5.osdl.org>

```
On Sun, Jun 18, 2006 at 09:50:37AM -0700, Linus Torvalds wrote:
> > While most of this patch fixes void-pointer arithmetic
> 
> This one I disagree with. Doing arithmetic on "void *" is _really_ useful, 

Agreed: If you want to walk over the memory pointed to by a void-pointer
you want to do that byte-wise in the great majority of all cases.

> and I think most compilers end up supporting it either to be
> compatible with gcc, or just because it's hard to not do it.

Now this statement I don't agree with. (And by that I don't mean I
assume it to be false.)

I didn't start writing the patch because I like C99 so much. In fact, in
my opinion it introduces some possibilities I'd rather not have in C
because people might actually use them. But by default the Sun cc
complains about void-pointer arithmetic and I feel awkward to force the
compiler to accept broken code.

Maybe Rene Scharfe's method (as used in the patch to git-tar-tree) is a
good way around it? There are no explicit casts involved and standard-
compliant compilers like it, too. The downside is that you have two
variables for the same thing/memory.

Regards,
-octo
-- 
Florian octo Forster
Hacker in training
GnuPG: 0x91523C3D
http://verplant.org/

```

## Junio C Hamano, 2006-06-20 01:59

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <7vac8860z9.fsf@assigned-by-dhcp.cox.net>
URL: https://gitlist.dev/e/7vac8860z9.fsf%40assigned-by-dhcp.cox.net
In-Reply-To: <20060619212116.GL1331@verplant.org>

```
Florian Forster <octo@verplant.org> writes:

> I didn't start writing the patch because I like C99 so much. In fact, in
> my opinion it introduces some possibilities I'd rather not have in C
> because people might actually use them. But by default the Sun cc
> complains about void-pointer arithmetic...

I am reasonably sympathetic to that, and judging from the number
of lines the patch touches, I am not as strongly opposed to it
as Linus seems to be.

> Maybe Rene Scharfe's method (as used in the patch to git-tar-tree) is a
> good way around it? There are no explicit casts involved and standard-
> compliant compilers like it, too. The downside is that you have two
> variables for the same thing/memory.

I think Rene's patch makes sense primarily because the functions
affected are small and we can easily see that the aliased input
variable ("data") is not used -- IOW, there is no confusion.

If it were a big function and the code used one variable for
some purpose and the other one for another purpose, it would be
far worse than having to cast the same variable occasionally.

BTW, I think we would probably want to have this patch on top of
Rene's patch.  In all instances, the variable "buf" is of type
"const char *" and the existing casts do not make sense to me.


diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
index 5c8a5f0..39a61b6 100644
--- a/builtin-tar-tree.c
+++ b/builtin-tar-tree.c
@@ -36,7 +36,7 @@ static void reliable_write(const void *d
 			die("git-tar-tree: disk full?");
 		}
 		size -= ret;
-		buf = (char *) buf + ret;
+		buf += ret;
 	}
 }
 
@@ -65,13 +65,13 @@ static void write_blocked(const void *da
 		memcpy(block + offset, buf, chunk);
 		size -= chunk;
 		offset += chunk;
-		buf = (char *) buf + chunk;
+		buf += chunk;
 		write_if_needed();
 	}
 	while (size >= BLOCKSIZE) {
 		reliable_write(buf, BLOCKSIZE);
 		size -= BLOCKSIZE;
-		buf = (char *) buf + BLOCKSIZE;
+		buf += BLOCKSIZE;
 	}
 	if (size) {
 		memcpy(block + offset, buf, size);

```

## Rene Scharfe, 2006-06-20 08:16

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <4497AED4.5060505@lsrfire.ath.cx>
URL: https://gitlist.dev/e/4497AED4.5060505%40lsrfire.ath.cx
In-Reply-To: <7vac8860z9.fsf@assigned-by-dhcp.cox.net>

```
Junio C Hamano schrieb:
> BTW, I think we would probably want to have this patch on top of
> Rene's patch.  In all instances, the variable "buf" is of type
> "const char *" and the existing casts do not make sense to me.
> 
> 
> diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
> index 5c8a5f0..39a61b6 100644

Your patch reverts builtin-tar-tree.c to the version which is
currently both in master and next, which I think is a good
change.  However, could it be avoided at merge time?

OT: I found the blobs 5c8a5f0 and 39a61b6 by guessing (they are
builtin-tar-tree.c in pu and master, respectively).  OK, that
was easy.  But is there a way to reversely look up an object
without guessing, i.e. find out which commit(s) introduced a
certain blob?

Thanks,
René

```

## Junio C Hamano, 2006-06-20 08:58

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <7vr71kcien.fsf@assigned-by-dhcp.cox.net>
URL: https://gitlist.dev/e/7vr71kcien.fsf%40assigned-by-dhcp.cox.net
In-Reply-To: <4497AED4.5060505@lsrfire.ath.cx>

```
Rene Scharfe <rene.scharfe@lsrfire.ath.cx> writes:

> Junio C Hamano schrieb:
>> BTW, I think we would probably want to have this patch on top of
>> Rene's patch.  In all instances, the variable "buf" is of type
>> "const char *" and the existing casts do not make sense to me.
>> 
>> diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
>> index 5c8a5f0..39a61b6 100644
>
> Your patch reverts builtin-tar-tree.c to the version which is
> currently both in master and next, which I think is a good
> change.  However, could it be avoided at merge time?

Sorry for attributing those "casts [that] do not make sense to
me" to you -- it is not your code but part of Florian's patch.

I think applying the patch in question on top of Florian's 11172e
would be the most sensible, since that is currently the tip of ff/c99
topic branch whose early parts have been merged to "next" and
the tip to "pu".  When Linus feels as sympathetic as I do, we
can pull the rest of ff/c99 branch to "next" and then eventually
to "master" and the patch will be merged together without
introducing the nonsense casts.

Another possibility is to amend the tip of ff/c99 topic branch,
since it is not merged to "next" yet.  I promised not to rewind
"master" nor "next", but never made promises not to rewind "pu",
so it is a fair game.  I think it is simpler and cleaner, so
that will be what I will do.

> OT: I found the blobs 5c8a5f0 and 39a61b6 by guessing (they are
> builtin-tar-tree.c in pu and master, respectively).  OK, that
> was easy.  But is there a way to reversely look up an object
> without guessing, i.e. find out which commit(s) introduced a
> certain blob?

You could do something like this (totally untested).

Going from the above "diff --git" index line you have object
name abbreviations and pathnames as clues.  To take advantage of
it, you could use "git rev-list pu -- builtin-tar-tree.c"
instead of unlimited list.

$ git rev-list pu |
  git diff-tree -r --stdin --pretty |
  perl -e '
	my @lines = ();
        sub flush_em {
        	my @found = ();
                my @comment = ();
		for my $l (@lines) {
                	if ($l !~ /^:/) {
				push @comment, $l;
				next;
			}
                        for (@ARGV) {
                        	if ($l =~ / $_/) {
                                	push @found, $l;
					last;
				}
                        }
                }
		if (@found) {
			print join("", @comment, @found);
                }
                @lines = ();
	}
        while (<STDIN>) {
        	if (/^commit [0-9a-f]{40}$/) { flush_em(); }
                push @lines, $_;
	}
        flush_em();
  ' 39a61b6 5c8a5f0

```

## Junio C Hamano, 2006-06-21 11:15

Subject: Re: [PATCH] Fix git to be (more) ANSI C99 compliant.
Message-ID: <7vodwmzrn5.fsf@assigned-by-dhcp.cox.net>
URL: https://gitlist.dev/e/7vodwmzrn5.fsf%40assigned-by-dhcp.cox.net
In-Reply-To: <7vr71kcien.fsf@assigned-by-dhcp.cox.net>

```
Junio C Hamano <junkio@cox.net> writes:

> I think applying the patch in question on top of Florian's 11172e
> would be the most sensible, since that is currently the tip of ff/c99
> topic branch whose early parts have been merged to "next" and
> the tip to "pu".  When Linus feels as sympathetic as I do, we
> can pull the rest of ff/c99 branch to "next" and then eventually
> to "master" and the patch will be merged together without
> introducing the nonsense casts.

Now, without asking Linus about this further, I felt sympathetic
enough to decide that void-pointer arithmetic avoidance is not
so bad (touches only 70 lines or so in 19 files); tonight's
"next" should be compilable with the default Solaris compiler.

```