From f54e7e8c2aeb4fafebf0d5bd5570b060462c9ecf Mon Sep 17 00:00:00 2001
From: Jari Vetoniemi <mailroxas@gmail.com>
Date: Thu, 1 Feb 2018 08:31:01 +0200
Subject: Initial commit

---
 src/bin/starpbm.c | 153 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 153 insertions(+)
 create mode 100644 src/bin/starpbm.c

(limited to 'src/bin/starpbm.c')

diff --git a/src/bin/starpbm.c b/src/bin/starpbm.c
new file mode 100644
index 0000000..fd3f235
--- /dev/null
+++ b/src/bin/starpbm.c
@@ -0,0 +1,153 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+#include <err.h>
+
+#define MAX(x, y) (((x) > (y)) ? (x) : (y))
+
+enum cmd {
+   CMD_INIT,
+   CMD_PRINTABLE_WIDTH,
+   CMD_RASTER_MODE_START,
+   CMD_RASTER_PAGE_LENGTH,
+   CMD_START_PAGE,
+   CMD_END_PAGE,
+   CMD_END_JOB,
+};
+
+static void
+putcmd(FILE *f, const enum cmd cmd)
+{
+   assert(f);
+
+   const struct {
+      const uint8_t *bytes;
+      size_t len;
+   } map[] = {
+#define CMD(...) { .bytes = (uint8_t[]){__VA_ARGS__ }, .len = sizeof((uint8_t[]){__VA_ARGS__}) }
+      CMD(0x1b, '@'), // CMD_INIT
+      CMD(0x1b, 0x1e, 'A', 0x00), // CMD_PRINTABLE_WIDTH
+      CMD(0x1b, '*', 'r', 'R', 0x1b, '*', 'r', 'A'), // CMD_RASTER_MODE_START
+      CMD(0x1b, '*', 'r', 'P', '0', 0x00), // CMD_SET_RASTER_PAGE_LENGTH
+      CMD(0x00), // CMD_START_PAGE
+      CMD(0x1b, '*', 'r', 'Y', '1', 0x00, 0x1b, 0x0c), // CMD_END_PAGE
+      CMD(0x04, 0x1b, '*', 'r', 'B'), // CMD_END_JOB
+#undef CMD
+   };
+
+   if (fwrite(map[cmd].bytes, 1, map[cmd].len, f) != map[cmd].len)
+      err(EXIT_FAILURE, "fwrite");
+}
+
+static FILE*
+fopen_or_die(const char *path, const char *mode)
+{
+   assert(path && mode);
+
+   FILE *f;
+   if (!(f = fopen(path, mode)))
+      err(EXIT_FAILURE, "fopen(%s, %s)", path, mode);
+
+   return f;
+}
+
+static uint8_t*
+find_pixel_not_rev(const uint8_t *data, const size_t len, const uint8_t pixel)
+{
+   for (const uint8_t *p = data + MAX(len, 1) - 1; p != data; --p) {
+      if (*p != pixel)
+         return (uint8_t*)p;
+   }
+   return NULL;
+}
+
+uint8_t*
+pixels_from_pbm(FILE *f, size_t *out_w, size_t *out_h)
+{
+   // NOTE: This does not support comments or extra whitespaces
+   //       Assumes PBM is structured!
+
+   uint8_t magic[3];
+   if (fread(magic, 1, sizeof(magic), f) != sizeof(magic))
+      return NULL;
+
+   if (memcmp(magic, "P4", 2) || !isspace(magic[2]))
+      errx(EXIT_FAILURE, "not a valid pbm (P4) file");
+
+   uint32_t cfg[2];
+   for (uint8_t i = 0; i < sizeof(cfg) / sizeof(cfg[0]); ++i) {
+      char buf[32];
+      size_t x = 0;
+      do {
+         if (fread(buf + x, 1, 1, f) != 1)
+            err(EXIT_FAILURE, "fread");
+      } while (!isspace(buf[x]) && ++x < sizeof(buf));
+
+      if (!isspace(buf[x]))
+         errx(EXIT_FAILURE, "not a valid pbm (P4) file");
+
+      cfg[i] = strtol(buf, NULL, 10);
+   }
+
+   if (!cfg[0] || !cfg[2])
+      errx(EXIT_FAILURE, "invalid width / height");
+
+   uint8_t *bw;
+#define div_round_up(x, y) (1 + ((x - 1) / y))
+   const size_t bw_sz = div_round_up(cfg[0], 8) * cfg[1];
+   if (!(bw = calloc(bw_sz, 1)))
+      err(EXIT_FAILURE, "calloc");
+
+   for (size_t read = 0, r; read < bw_sz; read += r) {
+      if (!(r = fread(bw + read, 1, bw_sz - read, f)))
+         errx(EXIT_FAILURE, "fread");
+   }
+
+   *out_w = div_round_up(cfg[0], 8), *out_h = cfg[1];
+   return bw;
+}
+
+int
+main(int argc, char *argv[])
+{
+   FILE *input = (argc >= 2 ? fopen_or_die(argv[1], "rb") : stdin);
+   FILE *output = (argc >= 3 ? fopen_or_die(argv[2], "wb") : stdout);
+
+   putcmd(output, CMD_INIT);
+   putcmd(output, CMD_PRINTABLE_WIDTH);
+   putcmd(output, CMD_RASTER_MODE_START);
+   putcmd(output, CMD_RASTER_PAGE_LENGTH);
+
+   size_t w, h;
+   uint8_t *pixels;
+   while ((pixels = pixels_from_pbm(input, &w, &h))) {
+      putcmd(output, CMD_START_PAGE);
+
+      size_t blank = 0;
+      for (size_t y = 0; y < h; ++y) {
+         const uint8_t *last_black;
+         if (!(last_black = find_pixel_not_rev(&pixels[y * w], w, 0))) {
+            ++blank;
+            continue;
+         }
+
+         if (blank) {
+            fprintf(output, "\x01b*rY%zu%c", blank, 0);
+            blank = 0;
+         }
+
+         const size_t pos = (last_black - &pixels[y * w]) + 1;
+         fprintf(output, "b%c%c", (char)(pos % 256), (char)(pos / 256));
+         fwrite(&pixels[y * w], 1, pos, output);
+      }
+
+      putcmd(output, CMD_END_PAGE);
+      free(pixels);
+   }
+
+   putcmd(output, CMD_END_JOB);
+   return EXIT_SUCCESS;
+}
-- 
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