Add argument parsing

Added (IMHO) relatively simple argument parsing function (as well as helper
function for printing help information).

src/Args.c

@@ -0,0 +1,219 @@
+#include <BH/Args.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <memory.h>
+
+
+static int BH_ArgsExtractArg(int argc,
+                             char **argv,
+                             BH_ArgsOption *option,
+                             BH_ArgsCallback callback,
+                             void *data,
+                             int *i,
+                             int isLong,
+                             char *next)
+{
+    if (isLong && *next == '=')
+        return callback(option->key, next + 1, data);
+
+    if (!isLong && *next)
+        return callback(option->key, next, data);
+
+    if ((*i) + 1 < argc && !(argv[(*i) + 1][0] == '-' && argv[(*i) + 1][1]))
+        return callback(option->key, argv[++(*i)], data);
+
+    if (option->flags & BH_ARGS_OPTIONAL)
+        return callback(option->key, NULL, data);
+
+    return BH_ERROR;
+}
+
+
+static int BH_ArgsParseShort(int argc,
+                             char **argv,
+                             BH_ArgsOption *options,
+                             BH_ArgsCallback callback,
+                             void *data,
+                             int *i)
+{
+    char *symbol;
+    BH_ArgsOption *option;
+
+    for (symbol = argv[*i] + 1; *symbol; symbol++)
+    {
+        /* Find and process option */
+        for (option = options; option->key || option->name; option++)
+        {
+            if (option->key > 128 || *symbol != option->key)
+                continue;
+
+            if (option->flags & BH_ARGS_VALUE)
+                return BH_ArgsExtractArg(argc, argv, option, callback, data, i, 0, symbol + 1);
+
+            if (callback(option->key, NULL, data))
+                return BH_ERROR;
+
+            break;
+        }
+
+        /* Unknown option */
+        if (!option->key && !option->name)
+        {
+            callback(BH_ARGS_UNKNOWN, argv[*i], data);
+            return BH_ERROR;
+        }
+    }
+
+    return BH_OK;
+}
+
+
+static int BH_ArgsParseLong(int argc,
+                            char **argv,
+                            BH_ArgsOption *options,
+                            BH_ArgsCallback callback,
+                            void *data,
+                            int *i)
+{
+    char *start, *end;
+    BH_ArgsOption *option;
+
+    /* Extract option name from argv */
+    start = argv[*i] + 2;
+    end = argv[*i] + 2;
+    while (isgraph(*end) && *end != '=')
+        end++;
+
+    if (end == start)
+        return BH_ERROR;
+
+    /* Find and process option */
+    for (option = options; option->key || option->name; option++)
+    {
+        if (!option->name || strlen(option->name) != (size_t)(end - start))
+            continue;
+
+        if (memcmp(option->name, start, end - start))
+            continue;
+
+        if (option->flags & BH_ARGS_VALUE)
+            return BH_ArgsExtractArg(argc, argv, option, callback, data, i, 1, end);
+
+        return callback(option->key, NULL, data);
+    }
+
+    /* Unknown long option */
+    callback(BH_ARGS_UNKNOWN, argv[*i], data);
+    return BH_ERROR;
+}
+
+
+int BH_ArgsParse(int argc,
+                 char **argv,
+                 BH_ArgsOption *options,
+                 BH_ArgsCallback callback,
+                 void *data)
+{
+    int i, j, ignoreRest, size;
+    char *arg;
+
+    ignoreRest = 0; i = 1; size = argc;
+    while (i < argc)
+    {
+        arg = argv[i];
+
+        if (arg[0] == '-' && arg[1] && !ignoreRest)
+        {
+            /* Parse ingore, short or long option */
+            if (arg[1] == '-')
+            {
+                if (arg[2] && BH_ArgsParseLong(argc, argv, options, callback, data, &i))
+                    return BH_ERROR;
+                else if (!arg[2])
+                    ignoreRest = 1;
+
+            }
+            else if (arg[1] && BH_ArgsParseShort(argc, argv, options, callback, data, &i))
+                return BH_ERROR;
+
+            i++;
+        }
+        else
+        {
+            /* Shift arguments */
+            for (j = i; j < size - 1; j++)
+                argv[j] = argv[j + 1];
+            argv[size - 1] = arg;
+
+            if (callback(BH_ARGS_ARGUMENT, arg, data))
+                return BH_ERROR;
+
+            argc--;
+        }
+    }
+    return BH_OK;
+}
+
+
+void BH_ArgsHelp(BH_ArgsOption *options,
+                 int padding)
+{
+    int width = 0;
+    BH_ArgsOption *option;
+
+    if (padding == 0)
+    padding = 30;
+
+    /* Calculate option column width */
+    for (option = options; option->key || option->name; option++)
+    {
+        const char *symbol;
+        width = 5;
+
+        /* Print option column with padding */
+        if (isgraph(option->key))
+        {
+            fputs(" -", stdout);
+            fputc(option->key, stdout);
+        }
+        else
+            fputs("   ", stdout);
+
+        if (isgraph(option->key) && option->name)
+            fputs(", ", stdout);
+        else
+            fputs("  ", stdout);
+
+        if (option->name)
+        {
+            width += 3 + strlen(option->name);
+            fputs("--", stdout);
+            fputs(option->name, stdout);
+            fputc(' ', stdout);
+        }
+
+        if (option->flags & BH_ARGS_VALUE)
+        {
+            width += 8;
+            if (option->flags & BH_ARGS_OPTIONAL)
+            {
+                width += 2;
+                fputs("[<value>] ", stdout);
+            }
+            else
+                fputs("<value> ", stdout);
+        }
+        for (; width++ < padding; fputc(' ', stdout));
+
+        /* Print description */
+        for (symbol = option->description; symbol && *symbol; symbol++)
+        {
+            fputc(*symbol, stdout);
+
+            if (*symbol == '\n')
+                for (width = 0; width++ < padding; fputc(' ', stdout));
+        }
+        fputc('\n', stdout);
+    }
+}