From 788e4546debb65839484112dae05a5e13c1070c6 Mon Sep 17 00:00:00 2001
From: XANTRONIX Development
Date: Sun, 10 Sep 2023 22:31:41 -0400
Subject: Initial commit

---
 main.c | 189 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 189 insertions(+)
 create mode 100644 main.c

diff --git a/main.c b/main.c
new file mode 100644
index 0000000..9d762b5
--- /dev/null
+++ b/main.c
@@ -0,0 +1,189 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <inttypes.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <errno.h>
+
+#define ZXDUMP_STRIDE_LINE 16
+#define ZXDUMP_STRIDE_GROUP 2
+#define ZXDUMP_CHARSET_LEN 64
+
+static uint16_t charset[ZXDUMP_CHARSET_LEN] = {
+    0x0020, 0x2598, 0x259d, 0x2580, 0x2596, 0x258c, 0x259e, 0x259b,
+    0x2592, '.',    '.',    '"',    0x00a3, '$',    ':',    '?',
+    '(',    ')',    '>',    '<',    '=',    '+',    '-',    '*',
+    '/',    ';',    ',',    '.',    '0',    '1',    '2',    '3',
+    '4',    '5',    '6',    '7',    '8',    '9',    'A',    'B',
+    'C',    'D',    'E',    'F',    'G',    'H',    'I',    'J',
+    'K',    'L',    'M',    'N',    'O',    'P',    'Q',    'R',
+    'S',    'T',    'U',    'V',    'W',    'X',    'Y',    'Z',
+};
+
+static void usage(int argc, char **argv, char *message, ...) {
+    if (message != NULL) {
+        va_list args;
+
+        va_start(args, message);
+        vfprintf(stderr, message, args);
+        fputc('\n', stderr);
+        va_end(args);
+    }
+
+    fprintf(stderr, "usage: %s file\n", argv[0]);
+    exit(1);
+}
+
+static ssize_t dump_line(off_t offset, void *buf, size_t len) {
+    size_t i;
+
+    if (printf("%08zx: ", offset) < 0) {
+        goto error_io;
+    }
+
+    for (i=0; i<ZXDUMP_STRIDE_LINE; i++) {
+        if (i > 0 && (i % ZXDUMP_STRIDE_GROUP) == 0) {
+            if (putchar(' ') < 0) {
+                goto error_io;
+            }
+        }
+
+        if (i < len) {
+            if (printf("%02x", ((uint8_t *)buf)[offset+i]) < 0) {
+                goto error_io;
+            }
+        } else {
+            if (printf("  ") < 0) {
+                goto error_io;
+            }
+        }
+    }
+
+    if (printf("  ") < 0) {
+        goto error_io;
+    }
+
+    for (i=0; i<ZXDUMP_STRIDE_LINE; i++) {
+        uint8_t c = ((uint8_t *)buf)[offset+i];
+
+        if (c <= ZXDUMP_CHARSET_LEN) {
+            uint16_t printable = charset[c];
+
+            /* XXX: Implement support for inverse colours */
+            if (printable & 0xf800) {
+                uint8_t sequence[2] = {
+                    0xc0 | ((printable & 0x1f00) >> 8),
+                    0x80 |  (printable & 0x003f)
+                };
+
+                if (fwrite(sequence, 2, 1, stdout) < 1) {
+                    goto error_io;
+                }
+            } else {
+                if (putchar((uint8_t)(printable & 0x00ff)) < 0) {
+                    goto error_io;
+                }
+            }
+        } else {
+            if (putchar('.') < 0) {
+                goto error_io;
+            }
+        }
+    }
+
+    if (putchar('\n') < 0) {
+        goto error_io;
+    }
+
+    return fflush(stdout);
+
+error_io:
+    return -1;
+}
+
+static ssize_t dump_fd(int fd) {
+    void *buf;
+    ssize_t offset = 0;
+    struct stat st;
+
+    if (fstat(fd, &st) < 0) {
+        goto error_fstat;
+    }
+
+    if ((buf = malloc(st.st_blksize)) == NULL) {
+        goto error_malloc;
+    }
+
+    while (1) {
+        ssize_t len, i;
+
+        if ((len = read(fd, buf, st.st_blksize)) < 0) {
+            goto error_read;
+        } else if (len == 0) {
+            break;
+        }
+
+        for (i=0; i<len; i+=ZXDUMP_STRIDE_LINE) {
+            size_t left   = len - i,
+                   linesz = left < ZXDUMP_STRIDE_LINE? left: ZXDUMP_STRIDE_LINE;
+
+            if (dump_line(offset, buf, linesz) < 0) {
+                goto error_dump_line;
+            }
+
+            offset += linesz;
+        }
+    }
+
+    free(buf);
+
+    return offset;
+
+error_dump_line:
+error_read:
+    free(buf);
+
+error_malloc:
+error_fstat:
+    return -1;
+}
+
+int main(int argc, char **argv) {
+    int fd;
+
+    if (argc == 1) {
+        fd = fileno(stdin);
+    } else if (argc == 2) {
+        if ((fd = open(argv[1], O_RDONLY)) < 0) {
+            goto error_open;
+        }
+    } else {
+        usage(argc, argv, "Too many arguments provided");
+    }
+
+    if (dump_fd(fd) < 0) {
+        fprintf(stderr, "%s: %s: %s\n",
+                argv[0],
+                (argc == 2)? argv[1]: "(stdin)",
+                strerror(errno));
+
+        goto error_dump_fd;
+    }
+
+    if (argc == 2) {
+        close(fd);
+    }
+
+    return 0;
+
+error_dump_fd:
+    if (argc == 2) {
+        close(fd);
+    }
+
+error_open:
+    return 1;
+}
-- 
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