zxdump/src/hexdump.c

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/stat.h>

#include <zx/charset.h>
#include <zx/hexdump.h>

static ssize_t hexdump_line(off_t offset, void *buf, size_t len, int tty, FILE *stream) {
    size_t i;

    if (printf("%08zx: ", offset) < 0) {
        goto error_io;
    }

    for (i=0; i<len; i++) {
        if (i > 0 && (i % ZX81_HEXDUMP_STRIDE_GROUP) == 0) {
            if (fputc(' ', stream) < 0) {
                goto error_io;
            }
        }

        if (fprintf(stream, "%02x", ((uint8_t *)buf)[offset+i]) < 0) {
            goto error_io;
        }
    }

    if (fputs("  ", stream) < 0) {
        goto error_io;
    }

    for (i=0; i<len; i++) {
        uint8_t c = ((uint8_t *)buf)[offset+i];

        if (c <= 0x3f) {
            if (zx81_fputc(c, 0, stream) < 0) {
                goto error_io;
            }
        } else if (c >= 0xa0 && c <= 0xbf) {
            if (zx81_fputc(c - 0xa0, tty, stream) < 0) {
                goto error_io;
            }
        } else {
            if (fputc('.', stream) < 0) {
                goto error_io;
            }
        }
    }

    if (fputc('\n', stream) < 0) {
        goto error_io;
    }

    return fflush(stream);

error_io:
    return -1;
}

ssize_t zx81_hexdump(int fd, FILE *stream) {
    void *buf;
    ssize_t total = 0;
    int tty = isatty(fileno(stdout));
    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;
        off_t offset = 0;

        if ((len = read(fd, buf, st.st_blksize)) < 0) {
            goto error_read;
        } else if (len == 0) {
            break;
        }

        for (i=0; i<len; i+=ZX81_HEXDUMP_STRIDE_LINE) {
            size_t left   = len - i,
                   linesz = left < ZX81_HEXDUMP_STRIDE_LINE?  left: ZX81_HEXDUMP_STRIDE_LINE;

            if (hexdump_line(offset, buf, linesz, tty, stream) < 0) {
                goto error_hexdump_line;
            }

            offset += linesz;
            total  += linesz;
        }
    }

    free(buf);

    return total;

error_hexdump_line:
error_read:
    free(buf);

error_malloc:
error_fstat:
    return -1;
}