Diff: vm/img.c

Revision:

0:65f1469d6bfb

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vm/img.c	Sat Mar 02 11:54:20 2013 +0000
@@ -0,0 +1,147 @@
+/*
+# This file is Copyright 2002 Dean Hall.
+# This file is part of the PyMite VM.
+# This file is licensed under the MIT License.
+# See the LICENSE file for details.
+*/
+
+
+#undef __FILE_ID__
+#define __FILE_ID__ 0x07
+
+
+/**
+ * \file
+ * \brief Image routines
+ *
+ * Created to eliminate a circular include
+ * among mem, string and obj.
+ */
+
+
+#include "pm.h"
+
+
+/*
+ * Searches for a module's name in a contiguous array of images
+ * in the given namespace starting at the given address.
+ * A module's name is stored in the last index of the names tuple of an image.
+ */
+static PmReturn_t
+img_findInPath(uint8_t *cname, uint16_t cnamelen, PmMemSpace_t memspace,
+               uint8_t const **paddr)
+{
+    uint8_t const *imgtop;
+    PmType_t type;
+    uint16_t len;
+    int16_t size = 0;
+    uint8_t i = 0;
+
+    /* Addr is top of img */
+    imgtop = *paddr;
+
+    /* Get img's type byte */
+    type = (PmType_t)mem_getByte(memspace, paddr);
+
+    /* Search all sequential images */
+    while (type == OBJ_TYPE_CIM)
+    {
+        /* Use size field to calc addr of next potential img */
+        size = mem_getWord(memspace, paddr);
+
+        /* Point to names tuple */
+        *paddr = imgtop + CI_NAMES_FIELD;
+
+        /* Ensure it's a tuple */
+        type = (PmType_t)mem_getByte(memspace, paddr);
+        C_ASSERT(type == OBJ_TYPE_TUP);
+
+        /* Scan to last name in tuple (it's the module's name) */
+        i = mem_getByte(memspace, paddr) - (uint8_t)1;
+        for (; i > 0; i--)
+        {
+            /* Ensure obj is a string */
+            type = (PmType_t)mem_getByte(memspace, paddr);
+            C_ASSERT(type == OBJ_TYPE_STR);
+
+            /* Skip the length of the string */
+            len = mem_getWord(memspace, paddr);
+            (*paddr) += len;
+        }
+
+        /* Ensure it's a string */
+        type = (PmType_t)mem_getByte(memspace, paddr);
+        C_ASSERT(type == OBJ_TYPE_STR);
+
+        /* If strings match, return the address of this image */
+        if ((cnamelen == mem_getWord(memspace, paddr))
+            && (PM_RET_OK == mem_cmpn(cname, cnamelen, memspace, paddr)))
+        {
+            *paddr = imgtop;
+            return PM_RET_OK;
+        }
+
+        /* Calc imgtop for next iteration */
+        imgtop += size;
+
+        /* Point to next potential img */
+        *paddr = imgtop;
+
+        /* Check if another img follows this one */
+        type = (PmType_t)mem_getByte(memspace, paddr);
+    }
+    return PM_RET_NO;
+}
+
+
+PmReturn_t
+img_findInPaths(pPmObj_t pname, PmMemSpace_t *r_memspace,
+                uint8_t const **r_imgaddr)
+{
+    uint8_t i;
+    PmReturn_t retval = PM_RET_NO;
+
+    /* Search in each path in the paths */
+    for (i = 0; i < gVmGlobal.imgPaths.pathcount; i++)
+    {
+        *r_imgaddr = gVmGlobal.imgPaths.pimg[i];
+        *r_memspace = gVmGlobal.imgPaths.memspace[i];
+        retval = img_findInPath(((pPmString_t)pname)->val,
+                                ((pPmString_t)pname)->length,
+                                *r_memspace, r_imgaddr);
+        if (retval == PM_RET_NO)
+        {
+            continue;
+        }
+        else if (retval == PM_RET_OK)
+        {
+            break;
+        }
+        else
+        {
+            return retval;
+        }
+    }
+
+    return retval;
+}
+
+
+PmReturn_t
+img_appendToPath(PmMemSpace_t memspace, uint8_t const * const paddr)
+{
+    uint8_t i;
+
+    if (gVmGlobal.imgPaths.pathcount >= PM_NUM_IMG_PATHS)
+    {
+        return PM_RET_NO;
+    }
+
+    i = gVmGlobal.imgPaths.pathcount;
+
+    gVmGlobal.imgPaths.memspace[i] = memspace;
+    gVmGlobal.imgPaths.pimg[i] = paddr;
+    gVmGlobal.imgPaths.pathcount++;
+
+    return PM_RET_OK;
+}