APPEND: text put together from pieces (format 0.5)

docs/assembly.md

@@ -489,6 +489,7 @@ variable declared with `.var`; built-in variables are read-only.
 | 0x48 | `CLAMP` | `$d, lo, hi` | d = min(max(d, lo), hi) |
 | 0x49 | `TOGGLE` | `$d` | d = (d == 0) ? 1 : 0 |
 | 0x4A | `FORMAT` | `$d, str, n` | Format n into string variable d: `str` with one `%d` or `%x` - optionally with a width, padded with spaces or, after a `0`, with zeros (`%02d`, `%4x`) - and `%%` for `%` |
+| 0x4B | `APPEND` | `$d, str` | Append `str` (a literal or a string variable) to string variable d, as much of it as d's size takes - text put together from pieces (format 0.5) |
 
 `str` can be a string variable, so a format can be made by `FORMAT` itself -
 a clock from minutes:
@@ -502,6 +503,15 @@ a clock from minutes:
         FORMAT  $clock, $text, $n               ; 12:05
 ```
 
+Text from several pieces - a number and a unit, a name and a value - is
+`FORMAT` or `SET` followed by `APPEND`s:
+
+```
+        FORMAT  $speed, "%d", $kmh              ; "68"
+        APPEND  $speed, " "
+        APPEND  $speed, $unit                   ; "68 km/h"
+```
+
 A variable is "changed" only when its value differs from the previous one -
 `SET $v, 5` on a `$v` that already holds 5 invalidates nothing.
 

docs/binary-format.md

@@ -1,7 +1,7 @@
 # dmview Binary Format (`.dmv`)
 
-Status: **version 0.4** - follows the [assembly draft](assembly.md). Version
-0.2 added gradients, 0.3 the `OPACITY` instruction, 0.4 `ICON`.
+Status: **version 0.5** - follows the [assembly draft](assembly.md). Version
+0.2 added gradients, 0.3 the `OPACITY` instruction, 0.4 `ICON`, 0.5 `APPEND`.
 
 A `.dmv` file is what `libtodmv` produces from `.dmvs` assembly and what
 `libdmview` executes. Everything is **little-endian**; every table starts at a
@@ -57,7 +57,7 @@ start of the file. An empty table has count 0.
 
 A version 0.1 header ends at 80, without the gradient tables. `libtodmv`
 always writes the 96-byte header, but marks a view with the oldest version
-that has what it uses - 0.4 with `ICON`, 0.3 with `OPACITY`, 0.2 with gradients, else 0.1: a
+that has what it uses - 0.5 with `APPEND`, 0.4 with `ICON`, 0.3 with `OPACITY`, 0.2 with gradients, else 0.1: a
 reader that knows only 0.1 runs a 0.1 view, it finds every table through
 the header and never looks at bytes 80 ... 95.
 

include/dmview_format.h

@@ -25,10 +25,10 @@
 
 /** Format version this header describes. */
 #define DMV_VERSION_MAJOR        0
-#define DMV_VERSION_MINOR        4
+#define DMV_VERSION_MINOR        5
 
 /** Header size: version 0.2 added the gradient tables at its end (0.3:
- * OPACITY, 0.4: ICON - no change to the header). */
+ * OPACITY, 0.4: ICON, 0.5: APPEND - no change to the header). */
 #define DMV_HEADER_SIZE          96u
 #define DMV_HEADER_SIZE_0_1      80u
 
@@ -106,6 +106,7 @@ typedef enum
     DMV_OP_CLAMP     = 0x48,
     DMV_OP_TOGGLE    = 0x49,
     DMV_OP_FORMAT    = 0x4A,
+    DMV_OP_APPEND    = 0x4B,
 
     /* Input */
     DMV_OP_ON        = 0x60,
@@ -607,6 +608,7 @@ static const dmv_opcode_info_t dmv_opcode_table[DMV_OPCODE_TABLE_SIZE] = {
     OP(DMV_OP_CLAMP,    "CLAMP",    VARIA,  3, 0, F_NONE,  false, VAR, V32, V32),
     OP(DMV_OP_TOGGLE,   "TOGGLE",   VARIA,  1, 0, F_NONE,  false, VAR),
     OP(DMV_OP_FORMAT,   "FORMAT",   VARIA,  3, 0, F_NONE,  false, VAR, STR, V32),
+    OP(DMV_OP_APPEND,   "APPEND",   VARIA,  2, 0, F_NONE,  false, VAR, STR),
 
     OP(DMV_OP_ON,       "ON",       INPUT,  2, 0, F_NONE,  false, EVENT, LABEL),
 

src/exec.c

@@ -544,6 +544,13 @@ static void run(struct libdmview* v, uint32_t pc, bool box_region)
                 view_set_string(v, rd16(insn + OPOFF(FORMAT, 0)), text);
                 break;
             }
+            case DMV_OP_APPEND:
+            {
+                uint16_t d = rd16(insn + OPOFF(APPEND, 0));
+                record(v, d / 32U, 1U << (d % 32U));
+                view_append_string(v, d, vstr(v, insn, 1, OPOFF(APPEND, 1)));
+                break;
+            }
 
             /* ---- Input ---- */
             case DMV_OP_ON:

src/layout.h

@@ -47,6 +47,7 @@ static inline uint8_t layout_offset(uint8_t op, unsigned i)
         case DMV_OP_CLAMP:    { static const uint8_t o[] = { 4, 8, 12 };                 return o[i]; }
         case DMV_OP_TOGGLE:   { static const uint8_t o[] = { 4 };                        return o[i]; }
         case DMV_OP_FORMAT:   { static const uint8_t o[] = { 4, 6, 8 };                  return o[i]; }
+        case DMV_OP_APPEND:   { static const uint8_t o[] = { 4, 6 };                     return o[i]; }
         case DMV_OP_ON:       { static const uint8_t o[] = { 4, 6 };                     return o[i]; }
         case DMV_OP_REDRAW:
         case DMV_OP_EXEC:

src/private.h

@@ -321,6 +321,7 @@ void            draw_icon(const libdmview_surface_t* s, const rect_t* clip, int3
 const char* view_string(const struct libdmview* v, uint32_t index);
 void        view_set_int(struct libdmview* v, uint32_t index, int32_t value);
 void        view_set_string(struct libdmview* v, uint32_t index, const char* value);
+void        view_append_string(struct libdmview* v, uint32_t index, const char* tail);
 void        view_invalidate_deps(struct libdmview* v, uint32_t word, uint32_t bit);
 void        view_mark_dirty(struct libdmview* v, int32_t box);
 

src/validate.c

@@ -274,6 +274,7 @@ static int dest_type(uint8_t opcode)
     {
         case DMV_OP_SET:    return -1;              /* Either */
         case DMV_OP_FORMAT: return DMV_VAR_STR;
+        case DMV_OP_APPEND: return DMV_VAR_STR;
         default:            return DMV_VAR_INT;
     }
 }

src/view.c

@@ -162,6 +162,30 @@ void view_set_string(struct libdmview* v, uint32_t index, const char* value)
         (void)Dmod_SetEnv(view_string(v, v->vars[index].env), dst, 1);
 }
 
+/* The string after what the variable holds - as much of it as its size takes */
+void view_append_string(struct libdmview* v, uint32_t index, const char* tail)
+{
+    char* dst = v->strs[index];
+    size_t n = strlen(dst), room = v->vars[index].capacity;
+    size_t m = strlen(tail);
+    if (n >= room || m == 0)
+        return;
+    if (m > room - n)
+        m = room - n;
+    if (tail >= dst && tail <= dst + room)
+    {
+        /* Appended to itself: copy it from before it grows */
+        memmove(dst + n, tail, m);
+    }
+    else
+        memcpy(dst + n, tail, m);
+    dst[n + m] = '\0';
+    if (!v->drawing)
+        view_invalidate_deps(v, index / 32U, 1U << (index % 32U));
+    if ((v->vars[index].flags & DMV_VARF_ENV) != 0)
+        (void)Dmod_SetEnv(view_string(v, v->vars[index].env), dst, 1);
+}
+
 /* ---- Loading ---- */
 
 static void free_view(struct libdmview* v)

tests/fixtures/append.dmvs

@@ -0,0 +1,27 @@
+; APPEND: text put together from pieces - every line is drawn above the same
+; text as a literal, in the built-in font, on a 64x32 surface
+.view   append
+.size   64, 32
+.entry  draw
+
+.font   fixed, "builtin-8"
+
+.var    $a,     str[12], ""
+.var    $b,     str[4],  ""
+.var    $t,     str[8],  "km"
+.var    $n,     str[8],  ""
+
+draw:
+        FILL    #000000
+        FORMAT  $n, "%d", 68
+        SET     $a, $n
+        APPEND  $a, " "
+        APPEND  $a, $t
+        APPEND  $a, "/h"
+        TEXT    0, 0, 64, 8, $a, fixed, #FFFFFF, LEFT     ; "68 km/h"
+        TEXT    0, 8, 64, 8, "68 km/h", fixed, #FFFFFF, LEFT
+        SET     $b, "ab"
+        APPEND  $b, "cdef"
+        TEXT    0, 16, 64, 8, $b, fixed, #FFFFFF, LEFT    ; "abcd": its size
+        TEXT    0, 24, 64, 8, "abcd", fixed, #FFFFFF, LEFT
+        RET

tests/libdmview_test.c

@@ -389,6 +389,16 @@ DMOD_TEST_STEP(libdmview_formats_with_padding)
     DMOD_TEST_EXPECT_EQ(libdmview_get_size(NULL, &w, &h), -EINVAL);
 }
 
+DMOD_TEST_STEP(libdmview_appends_strings)
+{
+    DMOD_TEST_EXPECT_TRUE(open_fixture(FIXTURE("append.dmv")));
+    if (g_view == NULL)
+        return;
+    DMOD_TEST_EXPECT_EQ(libdmview_render(g_view, &g_s32, NULL), 1);
+    DMOD_TEST_EXPECT_TRUE(same_as_below(0, 64, 0));     /* "68" " " "km" "/h": "68 km/h" */
+    DMOD_TEST_EXPECT_TRUE(same_as_below(0, 64, 16));    /* "ab" + "cdef" into str[4]: "abcd" */
+}
+
 /* ---- Antialiasing ---- */