sha1_file.c: cleanup "offset" usage

First there are too many offsets there and it is getting confusing.
So 'offset' is now 'curpos' to distinguish from other offsets like
'obj_offset'.

Then structures like x = foo(x, &y) are now done as y = foo(&x).
It looks more natural that the result y be returned directly and
x be passed as reference to be updated in place.  This has the effect
of reducing some line length and removing a few, needing a bit less
stack space, and it even reduces the compiled code size.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/sha1_file.c b/sha1_file.c
index 57a9b532cfbfb56d4812555fb0079bcfe73f42eb..8147a4f5054694a1d715128b7e9bd761ade930ca 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1043,12 +1043,11 @@ void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned l
 
 static unsigned long get_delta_base(struct packed_git *p,
                                    struct pack_window **w_curs,
-                                   unsigned long offset,
+                                   unsigned long *curpos,
                                    enum object_type kind,
-                                   unsigned long delta_obj_offset,
-                                   unsigned long *base_obj_offset)
+                                   unsigned long delta_obj_offset)
 {
-       unsigned char *base_info = use_pack(p, w_curs, offset, NULL);
+       unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
        unsigned long base_offset;
 
        /* use_pack() assured us we have [base_info, base_info + 20)
@@ -1071,18 +1070,17 @@ static unsigned long get_delta_base(struct packed_git *p,
                base_offset = delta_obj_offset - base_offset;
                if (base_offset >= delta_obj_offset)
                        die("delta base offset out of bound");
-               offset += used;
+               *curpos += used;
        } else if (kind == OBJ_REF_DELTA) {
                /* The base entry _must_ be in the same pack */
                base_offset = find_pack_entry_one(base_info, p);
                if (!base_offset)
                        die("failed to find delta-pack base object %s",
                                sha1_to_hex(base_info));
-               offset += 20;
+               *curpos += 20;
        } else
                die("I am totally screwed");
-       *base_obj_offset = base_offset;
-       return offset;
+       return base_offset;
 }
 
 /* forward declaration for a mutually recursive function */
@@ -1091,7 +1089,7 @@ static int packed_object_info(struct packed_git *p, unsigned long offset,
 
 static int packed_delta_info(struct packed_git *p,
                             struct pack_window **w_curs,
-                            unsigned long offset,
+                            unsigned long curpos,
                             enum object_type kind,
                             unsigned long obj_offset,
                             char *type,
@@ -1099,8 +1097,7 @@ static int packed_delta_info(struct packed_git *p,
 {
        unsigned long base_offset;
 
-       offset = get_delta_base(p, w_curs, offset, kind,
-               obj_offset, &base_offset);
+       base_offset = get_delta_base(p, w_curs, &curpos, kind, obj_offset);
 
        /* We choose to only get the type of the base object and
         * ignore potentially corrupt pack file that expects the delta
@@ -1113,7 +1110,6 @@ static int packed_delta_info(struct packed_git *p,
        if (sizep) {
                const unsigned char *data;
                unsigned char delta_head[20], *in;
-               unsigned long result_size;
                z_stream stream;
                int st;
 
@@ -1123,10 +1119,10 @@ static int packed_delta_info(struct packed_git *p,
 
                inflateInit(&stream);
                do {
-                       in = use_pack(p, w_curs, offset, &stream.avail_in);
+                       in = use_pack(p, w_curs, curpos, &stream.avail_in);
                        stream.next_in = in;
                        st = inflate(&stream, Z_FINISH);
-                       offset += stream.next_in - in;
+                       curpos += stream.next_in - in;
                } while ((st == Z_OK || st == Z_BUF_ERROR)
                        && stream.total_out < sizeof(delta_head));
                inflateEnd(&stream);
@@ -1143,21 +1139,20 @@ static int packed_delta_info(struct packed_git *p,
                get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 
                /* Read the result size */
-               result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
-               *sizep = result_size;
+               *sizep = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
        }
        return 0;
 }
 
-static unsigned long unpack_object_header(struct packed_git *p,
-               struct pack_window **w_curs,
-               unsigned long offset,
-               enum object_type *type,
-               unsigned long *sizep)
+static int unpack_object_header(struct packed_git *p,
+                               struct pack_window **w_curs,
+                               unsigned long *curpos,
+                               unsigned long *sizep)
 {
        unsigned char *base;
        unsigned int left;
        unsigned long used;
+       enum object_type type;
 
        /* use_pack() assures us we have [base, base + 20) available
         * as a range that we can look at at.  (Its actually the hash
@@ -1165,16 +1160,17 @@ static unsigned long unpack_object_header(struct packed_git *p,
         * the maximum deflated object size is 2^137, which is just
         * insane, so we know won't exceed what we have been given.
         */
-       base = use_pack(p, w_curs, offset, &left);
-       used = unpack_object_header_gently(base, left, type, sizep);
+       base = use_pack(p, w_curs, *curpos, &left);
+       used = unpack_object_header_gently(base, left, &type, sizep);
        if (!used)
                die("object offset outside of pack file");
+       *curpos += used;
 
-       return offset + used;
+       return type;
 }
 
 void packed_object_info_detail(struct packed_git *p,
-                              unsigned long offset,
+                              unsigned long obj_offset,
                               char *type,
                               unsigned long *size,
                               unsigned long *store_size,
@@ -1182,13 +1178,13 @@ void packed_object_info_detail(struct packed_git *p,
                               unsigned char *base_sha1)
 {
        struct pack_window *w_curs = NULL;
-       unsigned long obj_offset, val;
+       unsigned long curpos, dummy;
        unsigned char *next_sha1;
        enum object_type kind;
 
        *delta_chain_length = 0;
-       obj_offset = offset;
-       offset = unpack_object_header(p, &w_curs, offset, &kind, size);
+       curpos = obj_offset;
+       kind = unpack_object_header(p, &w_curs, &curpos, size);
 
        for (;;) {
                switch (kind) {
@@ -1204,61 +1200,58 @@ void packed_object_info_detail(struct packed_git *p,
                        unuse_pack(&w_curs);
                        return;
                case OBJ_OFS_DELTA:
-                       get_delta_base(p, &w_curs, offset, kind,
-                               obj_offset, &offset);
+                       obj_offset = get_delta_base(p, &w_curs, &curpos, kind, obj_offset);
                        if (*delta_chain_length == 0) {
-                               /* TODO: find base_sha1 as pointed by offset */
+                               /* TODO: find base_sha1 as pointed by curpos */
                        }
                        break;
                case OBJ_REF_DELTA:
-                       next_sha1 = use_pack(p, &w_curs, offset, NULL);
+                       next_sha1 = use_pack(p, &w_curs, curpos, NULL);
                        if (*delta_chain_length == 0)
                                hashcpy(base_sha1, next_sha1);
-                       offset = find_pack_entry_one(next_sha1, p);
+                       obj_offset = find_pack_entry_one(next_sha1, p);
                        break;
                }
-               obj_offset = offset;
-               offset = unpack_object_header(p, &w_curs, offset, &kind, &val);
                (*delta_chain_length)++;
+               curpos = obj_offset;
+               kind = unpack_object_header(p, &w_curs, &curpos, &dummy);
        }
 }
 
-static int packed_object_info(struct packed_git *p, unsigned long offset,
+static int packed_object_info(struct packed_git *p, unsigned long obj_offset,
                              char *type, unsigned long *sizep)
 {
        struct pack_window *w_curs = NULL;
-       unsigned long size, obj_offset = offset;
+       unsigned long size, curpos = obj_offset;
        enum object_type kind;
-       int r;
 
-       offset = unpack_object_header(p, &w_curs, offset, &kind, &size);
+       kind = unpack_object_header(p, &w_curs, &curpos, &size);
 
        switch (kind) {
        case OBJ_OFS_DELTA:
        case OBJ_REF_DELTA:
-               r = packed_delta_info(p, &w_curs, offset, kind,
-                       obj_offset, type, sizep);
-               unuse_pack(&w_curs);
-               return r;
+               packed_delta_info(p, &w_curs, curpos, kind,
+                                 obj_offset, type, sizep);
+               break;
        case OBJ_COMMIT:
        case OBJ_TREE:
        case OBJ_BLOB:
        case OBJ_TAG:
                strcpy(type, type_names[kind]);
-               unuse_pack(&w_curs);
+               if (sizep)
+                       *sizep = size;
                break;
        default:
                die("pack %s contains unknown object type %d",
                    p->pack_name, kind);
        }
-       if (sizep)
-               *sizep = size;
+       unuse_pack(&w_curs);
        return 0;
 }
 
 static void *unpack_compressed_entry(struct packed_git *p,
                                    struct pack_window **w_curs,
-                                   unsigned long offset,
+                                   unsigned long curpos,
                                    unsigned long size)
 {
        int st;
@@ -1273,10 +1266,10 @@ static void *unpack_compressed_entry(struct packed_git *p,
 
        inflateInit(&stream);
        do {
-               in = use_pack(p, w_curs, offset, &stream.avail_in);
+               in = use_pack(p, w_curs, curpos, &stream.avail_in);
                stream.next_in = in;
                st = inflate(&stream, Z_FINISH);
-               offset += stream.next_in - in;
+               curpos += stream.next_in - in;
        } while (st == Z_OK || st == Z_BUF_ERROR);
        inflateEnd(&stream);
        if ((st != Z_STREAM_END) || stream.total_out != size) {
@@ -1289,7 +1282,7 @@ static void *unpack_compressed_entry(struct packed_git *p,
 
 static void *unpack_delta_entry(struct packed_git *p,
                                struct pack_window **w_curs,
-                               unsigned long offset,
+                               unsigned long curpos,
                                unsigned long delta_size,
                                enum object_type kind,
                                unsigned long obj_offset,
@@ -1299,14 +1292,13 @@ static void *unpack_delta_entry(struct packed_git *p,
        void *delta_data, *result, *base;
        unsigned long result_size, base_size, base_offset;
 
-       offset = get_delta_base(p, w_curs, offset, kind,
-               obj_offset, &base_offset);
+       base_offset = get_delta_base(p, w_curs, &curpos, kind, obj_offset);
        base = unpack_entry(p, base_offset, type, &base_size);
        if (!base)
                die("failed to read delta base object at %lu from %s",
                    base_offset, p->pack_name);
 
-       delta_data = unpack_compressed_entry(p, w_curs, offset, delta_size);
+       delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
        result = patch_delta(base, base_size,
                             delta_data, delta_size,
                             &result_size);
@@ -1318,19 +1310,19 @@ static void *unpack_delta_entry(struct packed_git *p,
        return result;
 }
 
-void *unpack_entry(struct packed_git *p, unsigned long offset,
-                         char *type, unsigned long *sizep)
+void *unpack_entry(struct packed_git *p, unsigned long obj_offset,
+                  char *type, unsigned long *sizep)
 {
        struct pack_window *w_curs = NULL;
-       unsigned long size, obj_offset = offset;
+       unsigned long size, curpos = obj_offset;
        enum object_type kind;
        void *retval;
 
-       offset = unpack_object_header(p, &w_curs, offset, &kind, &size);
+       kind = unpack_object_header(p, &w_curs, &curpos, &size);
        switch (kind) {
        case OBJ_OFS_DELTA:
        case OBJ_REF_DELTA:
-               retval = unpack_delta_entry(p, &w_curs, offset, size,
+               retval = unpack_delta_entry(p, &w_curs, curpos, size,
                        kind, obj_offset, type, sizep);
                break;
        case OBJ_COMMIT:
@@ -1339,7 +1331,7 @@ void *unpack_entry(struct packed_git *p, unsigned long offset,
        case OBJ_TAG:
                strcpy(type, type_names[kind]);
                *sizep = size;
-               retval = unpack_compressed_entry(p, &w_curs, offset, size);
+               retval = unpack_compressed_entry(p, &w_curs, curpos, size);
                break;
        default:
                die("unknown object type %i in %s", kind, p->pack_name);