flight/libraries/PyMite/vm/img.c

   1 /*
   2 # This file is Copyright 2003, 2006, 2007, 2009, 2010 Dean Hall.
   3 #
   4 # This file is part of the PyMite VM.
   5 # The PyMite VM is free software: you can redistribute it and/or modify
   6 # it under the terms of the GNU GENERAL PUBLIC LICENSE Version 2.
   7 #
   8 # The PyMite VM is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11 # A copy of the GNU GENERAL PUBLIC LICENSE Version 2
  12 # is seen in the file COPYING in this directory.
  13 */
  14
  15
  16 #undef __FILE_ID__
  17 #define __FILE_ID__ 0x07
  18
  19
  20 /**
  21  * \file
  22  * \brief Image routines
  23  *
  24  * Created to eliminate a circular include
  25  * among mem, string and obj.
  26  */
  27
  28
  29 #include "pm.h"
  30
  31
  32 /*
  33  * Searches for a module's name in a contiguous array of images
  34  * in the given namespace starting at the given address.
  35  * A module's name is stored in the last index of the names tuple of an image.
  36  */
  37 static PmReturn_t
  38 img_findInPath(uint8_t *cname, uint8_t cnamelen, PmMemSpace_t memspace,
  39                uint8_t const **paddr)
  40 {
  41     uint8_t const *imgtop;
  42     PmType_t type;
  43     uint16_t len;
  44     int16_t size = 0;
  45     uint8_t i = 0;
  46
  47     /* Addr is top of img */
  48     imgtop = *paddr;
  49
  50     /* Get img's type byte */
  51     type = (PmType_t)mem_getByte(memspace, paddr);
  52
  53     /* Search all sequential images */
  54     while (type == OBJ_TYPE_CIM)
  55     {
  56         /* Use size field to calc addr of next potential img */
  57         size = mem_getWord(memspace, paddr);
  58
  59         /* Point to names tuple */
  60         *paddr = imgtop + CI_NAMES_FIELD;
  61
  62         /* Ensure it's a tuple */
  63         type = (PmType_t)mem_getByte(memspace, paddr);
  64         C_ASSERT(type == OBJ_TYPE_TUP);
  65
  66         /* Scan to last name in tuple (it's the module's name) */
  67         i = mem_getByte(memspace, paddr) - (uint8_t)1;
  68         for (; i > 0; i--)
  69         {
  70             /* Ensure obj is a string */
  71             type = (PmType_t)mem_getByte(memspace, paddr);
  72             C_ASSERT(type == OBJ_TYPE_STR);
  73
  74             /* Skip the length of the string */
  75             len = mem_getWord(memspace, paddr);
  76             (*paddr) += len;
  77         }
  78
  79         /* Ensure it's a string */
  80         type = (PmType_t)mem_getByte(memspace, paddr);
  81         C_ASSERT(type == OBJ_TYPE_STR);
  82
  83         /* If strings match, return the address of this image */
  84         if ((cnamelen == mem_getWord(memspace, paddr))
  85             && (PM_RET_OK == mem_cmpn(cname, cnamelen, memspace, paddr)))
  86         {
  87             *paddr = imgtop;
  88             return PM_RET_OK;
  89         }
  90
  91         /* Calc imgtop for next iteration */
  92         imgtop += size;
  93
  94         /* Point to next potential img */
  95         *paddr = imgtop;
  96
  97         /* Check if another img follows this one */
  98         type = (PmType_t)mem_getByte(memspace, paddr);
  99     }
 100     return PM_RET_NO;
 101 }
 102
 103
 104 PmReturn_t
 105 img_findInPaths(pPmObj_t pname, PmMemSpace_t *r_memspace,
 106                 uint8_t const **r_imgaddr)
 107 {
 108     uint8_t i;
 109     PmReturn_t retval = PM_RET_NO;
 110
 111     /* Search in each path in the paths */
 112     for (i = 0; i < gVmGlobal.imgPaths.pathcount; i++)
 113     {
 114         *r_imgaddr = gVmGlobal.imgPaths.pimg[i];
 115         *r_memspace = gVmGlobal.imgPaths.memspace[i];
 116         retval = img_findInPath(((pPmString_t)pname)->val,
 117                                 ((pPmString_t)pname)->length,
 118                                 *r_memspace, r_imgaddr);
 119         if (retval == PM_RET_NO)
 120         {
 121             continue;
 122         }
 123         else if (retval == PM_RET_OK)
 124         {
 125             break;
 126         }
 127         else
 128         {
 129             return retval;
 130         }
 131     }
 132
 133     return retval;
 134 }
 135
 136
 137 PmReturn_t
 138 img_appendToPath(PmMemSpace_t memspace, uint8_t const * const paddr)
 139 {
 140     uint8_t i;
 141
 142     if (gVmGlobal.imgPaths.pathcount >= PM_NUM_IMG_PATHS)
 143     {
 144         return PM_RET_NO;
 145     }
 146
 147     i = gVmGlobal.imgPaths.pathcount;
 148
 149     gVmGlobal.imgPaths.memspace[i] = memspace;
 150     gVmGlobal.imgPaths.pimg[i] = paddr;
 151     gVmGlobal.imgPaths.pathcount++;
 152
 153     return PM_RET_OK;
 154 }