Write the port's own text in the game's message font

docs/PC.md

@@ -774,6 +774,46 @@ retail's 0x136A7-byte image. `sce/sifdev.cpp` implements `sceOpen`,
 device prefix stripped (the debug dump `edit.cpp` writes to `host0:`), and
 `WriteFile` writes there too.
 
+## Game text
+
+`port/src/gametext.cpp` writes the port's own text in the game's message
+font, so menus the port adds can match the game's. A message is an s16 code
+per character ending in `MES_CODE_END` (-0xFF); a space is
+`MES_CODE_SPACE` (-0xFE) and a line break `MES_CODE_NEWLINE` (-0x100). The
+PAL font draws only the external characters from -0x300: -0x300 to -0x2E0
+are the pad buttons and icons; -0x2DF to -0x288 are the 88 cells of
+`gaiji.img`'s letter grid in order (`A`-`Z`, `a`-`z`,
+`'="!?#&+-*/%()@|<>{}[]:,.$` and `0`-`9`); -0x287 to -0x254 are `œ ¡ ¿ ß Œ
+Ç ç` and the letters `DrawGaijiFont` draws an accent over (`ÀÁÂÄÈÉÊËÌÍÎÏÑ
+ÒÓÔÖÙÚÛÜàáâäèéêëìíîïñòóôöùúûü`). -0x263 to -0x261, -0x253 and -0x252
+draw a bare `?`. There is no `;`, `_`, `~`, `^`, backquote or backslash.
+The table was read off the `gaiji.img` of every `meswin/mes_tex_N.pak` (all
+seven draw these characters in the same cells; only the pixels differ) and
+checked by decoding every `.mes` on the disc: each language uses only
+characters in it, and its own accents only.
+
+`GameTextEncode` turns UTF-8 into codes. Curly quotes and dashes become the
+font's own; any other character the font lacks, and any byte that is not
+UTF-8, becomes `?` and is counted. `{N}` writes code N as it is, for control
+codes and icons, and `{{` a `{`; `GameTextDecode` writes the same form, so
+any message reads back and encodes to the same codes. `GameTextFile` lays
+texts out as a message file for `ClsMes::SetBuff`. `GameText` is one piece of
+text drawn as the menus draw their help line (`InitMenuMesSet`'s
+`CommonMenuMes2`: the menu font, white with a black edge, shown whole): `Set`
+the text, `SetColour` a `FontColor`, then `Draw(x, y, alpha)` from a menu's
+draw function; `Width` gives its width for aligning a value.
+
+Both have retail's fixed sizes. A window lays out at most `MES_WIN_LINE_MAX`
+(720) characters, counting the end and what a `{N}` name, value or system
+message code expands to; retail's `SetMesWinTbl` writes on past the table, so
+the port's (`port/src/clsmes.cpp`) takes no more, and `GameText::Set` gives back
+-1, draws nothing and has a width of 0 for a text that did not fit. A line past
+the window's ten `line_pos` entries draws in the block layout, as a line
+without one does. A message file is s16 throughout: an id is -0x8000 to
+0x7FFF. Every message must start within 0x7FFF codes of `&buff[1 + count]`;
+the last message by id may extend beyond that range. `GameTextFile::Set`
+gives back -1 and leaves the file as it was where either would not hold.
+
 ## Arenas
 
 `CDataAlloc2<1>::Alloc/Alloc64/Align64` and the carving in

port/src/clsmes.cpp

@@ -3,6 +3,7 @@
 
 #include <array>
 #include <cmath>
+#include <iterator>
 #include <vector>
 
 #include "draw2d_port.hpp"
@@ -457,6 +458,56 @@ PC_OVERRIDE void ClsMes::MakeFukidashi(sceVif1Packet *packet) {
     services.set_alpha(nullptr);
 }
 
+// Retail's, but a full table takes no more: past MES_WIN_LINE_MAX laid-out characters retail writes
+// on over the fields that follow it. MakeMesWinTbl then lays out no MES_CODE_END, which tells a
+// caller the text did not fit.
+PC_OVERRIDE int ClsMes::SetMesWinTbl(int code, int mode, short x, short y) {
+    if (code >= -0x200 && code <= -0x101) {
+        if (this->win_line_num > 0) {
+            this->win_line[this->win_line_num - 1].space += code + 0x200;
+        }
+
+        return 0;
+    }
+
+    if (code >= -0x400 && code <= -0x301) {
+        if (code + 0x400 == 0) {
+            this->clut_now = this->clut_default;
+        } else if (code == -0x301) {
+            this->clut_now = 0xFF;
+        } else {
+            this->clut_now = code + 0x401;
+        }
+
+        return 0;
+    }
+
+    if (code >= -0xA00 && code <= -0x901) {
+        this->fukidashi_shape = code + 0xA00;
+        return 0;
+    }
+
+    if (this->win_line_num >= MES_WIN_LINE_MAX) {
+        return 0;
+    }
+
+    if (mode == 1) {
+        this->win_line[this->win_line_num].code = code + 0x1000;
+        this->win_line[this->win_line_num].x = x;
+        this->win_line[this->win_line_num].y = y;
+        this->win_line[this->win_line_num].clut = this->clut_now;
+        this->win_line_num++;
+    } else {
+        this->win_line[this->win_line_num].code = code;
+        this->win_line[this->win_line_num].x = x;
+        this->win_line[this->win_line_num].y = y;
+        this->win_line[this->win_line_num].clut = this->clut_now;
+        this->win_line_num++;
+    }
+
+    return 1;
+}
+
 PC_OVERRIDE void ClsMes::DrawMesWin() {
     CTexture *texture;
     int       offset_x;
@@ -599,7 +650,9 @@ PC_OVERRIDE void ClsMes::DrawMesWin() {
 
         int row = this->win_line[index].y / this->char_height;
 
-        if (this->line_pos[row].x < 0 || this->line_pos[row].y < 0) {
+        // A line past the last line_pos entry takes the block layout, as one with no entry does.
+        if (row >= static_cast<int>(std::size(this->line_pos)) || this->line_pos[row].x < 0 ||
+            this->line_pos[row].y < 0) {
             int      line_x = this->win_line[index].x + this->text_x;
             int      line_y = this->win_line[index].y + this->text_y;
             int      screen_x = offset_x + (line_x + dx);