[Qemu-devel] [PATCH 07/11] acpi_table_add(): eliminate 'allen' variable

[Eduardo Habkost]

Instead of calculating 'allen - start' every time, just keep the
'newlen' variable up to date and use it instead.

The math in g_realloc() call is now more complex (using 'start + newlen'
instead of 'allen'), but it be simplified later, when the g_realloc()
calls get moved to a separate function.

Now behavior change, just calculation method changes.

Signed-off-by: Eduardo Habkost <address@hidden>
---
 hw/acpi.c |   18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/hw/acpi.c b/hw/acpi.c
index e69b37a..e116528 100644
--- a/hw/acpi.c
+++ b/hw/acpi.c
@@ -189,7 +189,7 @@ static int acpi_make_table_header(const char *t, bool 
has_header, char *f,
 int acpi_table_add(const char *t)
 {
     char buf[1024], *f;
-    size_t start, allen;
+    size_t start;
     size_t newlen; /* length of the new table */
     bool has_header;
     int r;
@@ -214,10 +214,9 @@ int acpi_table_add(const char *t)
 
     init_acpi_tables();
 
-    allen = acpi_tables_len;
-    start = allen;
+    start = acpi_tables_len;
     acpi_tables = g_realloc(acpi_tables, start + ACPI_TABLE_HDR_SIZE);
-    allen += has_header ? ACPI_TABLE_PFX_SIZE : ACPI_TABLE_HDR_SIZE;
+    newlen = has_header ? ACPI_TABLE_PFX_SIZE : ACPI_TABLE_HDR_SIZE;
 
     /* now read in the data files, reallocating buffer as needed */
 
@@ -235,9 +234,9 @@ int acpi_table_add(const char *t)
             if (r == 0) {
                 break;
             } else if (r > 0) {
-                acpi_tables = g_realloc(acpi_tables, allen + r);
-                memcpy(acpi_tables + allen, data, r);
-                allen += r;
+                acpi_tables = g_realloc(acpi_tables, start + newlen + r);
+                memcpy(acpi_tables + start + newlen, data, r);
+                newlen += r;
             } else if (errno != EINTR) {
                 fprintf(stderr, "can't read file %s: %s\n",
                         f, strerror(errno));
@@ -253,9 +252,6 @@ int acpi_table_add(const char *t)
 
     f = acpi_tables + start;   /* start of the table */
 
-    /* length of the whole table, including our prefix */
-    newlen = allen - start;
-
     if (acpi_make_table_header(t, has_header, f, newlen) < 0) {
         return -1;
     }
@@ -264,7 +260,7 @@ int acpi_table_add(const char *t)
     (*(uint16_t *)acpi_tables) =
         cpu_to_le32(le32_to_cpu(*(uint16_t *)acpi_tables) + 1);
 
-    acpi_tables_len = allen;
+    acpi_tables_len = start + newlen;
     return 0;
 
 }
-- 
1.7.10.4